title: From active stresses and forces to self propulsion of droplets

abstract:
  We study the self-propulsion of spherical droplets as simplified hydrodynamic
models of swimming microorganisms or artificial microswimmers. In contrast to
approaches, which start from active velocity fields produced by the system, we
consider active surface force or body force densities or active stresses as the
origin of autonomous swimming. For negligible Reynolds number and given
activity we first calculate the external and the internal ow fields as well as
the center of mass velocity and an angular velocity of the droplet at fixed
time. To construct trajectories from single time snapshots, the evolution of
active forces or stresses must be determined in the laboratory frame. Here, we
consider the case of active matter, which is carried by a continuously
distributed, rigid but sparse (cyto)-sceleton that is immersed in the droplet's
interior. We calculate examples of trajectories of a droplet and its sceleton
from force densities or stresses, which may be explicitely time dependent in a
frame fixed within the sceleton


title: Hyperbolic surfaces with long systoles that form a pants decomposition

abstract:
  We present a construction of sequences of closed hyperbolic surfaces that
have long systoles which form pants decompositions of these surfaces. The
length of the systoles of these surfaces grows logarithmically as a function of
their genus.


title: On the existence of Lagrangian shadows of ample algebraic divisors

abstract:
  In previous papers we define certain Lagrangian shadows of ample divisors in
algebraic varieties. In the present brief note an existence condition is
discussed for these Lagrangian shadows.


title:
Strategies for Finding Prompt Radio Counterparts to Gravitational Wave
  Transients with the Murchison Widefield Array

abstract:
  We present and evaluate several strategies to search for prompt,
low-frequency radio emission associated with gravitational wave transients
using the Murchison Widefield Array (MWA). As we are able to repoint the MWA on
timescales of tens of seconds, we can search for the dispersed radio signal
that has been predicted to originate along with or shortly after a neutron
star-neutron star merger. We find that given the large, 600 deg^2 instantaneous
field-of-view of the MWA we can cover a significant fraction of the predicted
gravitational wave error region, although due to the complicated geometry of
the latter we only cover >50% of the error region for approximately 5% of
events, and roughly 15% of events will be located <10 deg from the MWA pointing
center such that they will be covered in the radio images. For optimal
conditions our limiting flux density for a 10-s long transient would be 0.1 Jy,
increasing to about 1 Jy for a wider range of events. This corresponds to
luminosity limits of 1e38-1e39 erg/s based on expectations for the distances of
the gravitational wave transients, which should be sufficient to detect or
significantly constrain a range of models for prompt emission.


title: Composable Models for Online Bayesian Analysis of Streaming Data

abstract:
  Data is rapidly increasing in volume and velocity and the Internet of Things
(IoT) is one important source of this data. The IoT is a collection of
connected devices (things) which are constantly recording data from their
surroundings using on-board sensors. These devices can record and stream data
to the cloud at a very high rate, leading to high storage and analysis costs.
In order to ameliorate these costs, we can analyse the data as it arrives in a
stream to learn about the underlying process, perform interpolation and
smoothing and make forecasts and predictions.
  Conventional tools of state space modelling assume data on a fixed regular
time grid. However, many sensors change their sampling frequency, sometimes
adaptively, or get interrupted and re-started out of sync with the previous
sampling grid, or just generate event data at irregular times. It is therefore
desirable to model the system as a partially and irregularly observed Markov
process which evolves in continuous time. Both the process and the observation
model are potentially non-linear. Particle filters therefore represent the
simplest approach to online analysis. A functional Scala library of composable
continuous time Markov process models has been developed in order to model the
wide variety of data captured in the IoT.


title: Phase-Transition Theory of Kerr Black Holes in Electromagnetic Field

abstract:
  For a Kerr black hole (KBH) with spin $J$ and mass $M$ in a steady
electromagnetic field, a special Wald vacuum solution (WVS) has been found in
the case of no-source uniform field. For WVS, the Meissner effect (ME) occurs
only in the the extreme KBH where $M^2/J=1$, in this case, the magnetic field
is totally excluded from the event horizon (EH) of KBH. However, WVS does not
consider the Hawking radiation (HR) but treats KBH as an absolutely black body.
If HR is added , researchers believe that the condition is not so restricted
and it is possible for ME to occur in less extreme case. How less is the "less
extreme case"? This paper tries to answer this question. Since the Hawking
temperature $T_H$ of KBH defined by HR is proportional to the surface gravity
$\kappa$ at the EH, this question is actually about the so-called
existence/non-existence of ME (ME/NME) or superconducting phase transition. In
this paper, we study the connection between the superconductivity of KBH-EH and
the existence of Weyl Fermion (WF). Using thermodynamic formulas and the KBH
state equation, we prove that the inherent-parameter condition for ME to occur
is $M^2/J\leq \epsilon_c=1.5$ in force-free fields whether it be in the simple
axisymmetric vacuum zero source case or in the non-zero source case which can
be described by the nonlinear Grad-Shafranov (G-S) equation. We suggest that
this is a second-order phase transition and we calculate the critical exponents
$\delta=1$ and $\eta=1/2$ for the specific heat diverging at constant $J$, and
the critical point $(M_c, \Omega_c)$, which equals $(1.22\sqrt{ J}, 0.16/\sqrt{
J})$ where $\Omega$ is the angular velocity of KBH. Furthermore we draw the
phase diagrams in both $(M, J)$ and $(M,\Omega)$ coordinates.


title: Robustness of Majorana bound states in the short junction limit

abstract:
  We study the effects of strong coupling between a superconductor and a
semiconductor nanowire on the creation of the Majorana bound states, when the
quasiparticle dwell time in the normal part of the nanowire is much shorter
than the inverse superconducting gap. This "short junction" limit is relevant
for the recent experiments using the epitaxially grown aluminum characterized
by a transparent interface with the semiconductor and a small superconducting
gap. We find that the small superconducting gap does not have a strong
detrimental effect on the Majorana properties. Specifically, both the critical
magnetic field required for creating a topological phase and the size of the
Majorana bound states are independent of the superconducting gap. The critical
magnetic field scales with the wire cross section, while the relative
importance of the orbital and Zeeman effects of the magnetic field is
controlled by the material parameters only: $g$-factor, effective electron
mass, and the semiconductor-superconductor interface transparency.


title: Miuz: measuring the impact of disconnecting a node

abstract:
  In this article we present Miuz, a robustness index for complex networks.
Miuz measures the impact of disconnecting a node from the network while
comparing the sizes of the remaining connected components. Strictly speaking,
Miuz for a node is defined as the inverse of the size of the largest connected
component divided by the sum of the sizes of the remaining ones. We tested our
index in attack strategies where the nodes are disconnected in decreasing order
of a specified metric. We considered Miuz and other well-known centrality
measures such as betweenness, degree , and harmonic centrality. All of these
metrics were compared regarding the behavior of the robust-ness (R-index)
during the attacks. In an attempt to simulate the internet backbone, the
attacks were performed in complex networks with power-law degree distributions
(scale-free networks). Preliminary results show that attacks based on
disconnecting a few number of nodes Miuz are more dangerous (decreasing the
robustness) than the same attacks based on other centrality measures. We
believe that Miuz, as well as other measures based on the size of the largest
connected component, provides a good addition to other robustness metrics for
complex networks.


title: Fast Online Deconvolution of Calcium Imaging Data

abstract:
  Fluorescent calcium indicators are a popular means for observing the spiking
activity of large neuronal populations, but extracting the activity of each
neuron from raw fluorescence calcium imaging data is a nontrivial problem. We
present a fast online active set method to solve this sparse non-negative
deconvolution problem. Importantly, the algorithm progresses through each time
series sequentially from beginning to end, thus enabling real-time online
estimation of neural activity during the imaging session. Our algorithm is a
generalization of the pool adjacent violators algorithm (PAVA) for isotonic
regression and inherits its linear-time computational complexity. We gain
remarkable increases in processing speed: more than one order of magnitude
compared to currently employed state of the art convex solvers relying on
interior point methods. Unlike these approaches, our method can exploit warm
starts; therefore optimizing model hyperparameters only requires a handful of
passes through the data. A minor modification can further improve the quality
of activity inference by imposing a constraint on the minimum spike size. The
algorithm enables real-time simultaneous deconvolution of $O(10^5)$ traces of
whole-brain larval zebrafish imaging data on a laptop.


title:
RoboPol: The optical polarization of gamma-ray--loud and
  gamma-ray--quiet blazars

abstract:
  We present average R-band optopolarimetric data, as well as variability
parameters, from the first and second RoboPol observing season. We investigate
whether gamma- ray--loud and gamma-ray--quiet blazars exhibit systematic
differences in their optical polarization properties. We find that
gamma-ray--loud blazars have a systematically higher polarization fraction
(0.092) than gamma-ray--quiet blazars (0.031), with the hypothesis of the two
samples being drawn from the same distribution of polarization fractions being
rejected at the 3{\sigma} level. We have not found any evidence that this
discrepancy is related to differences in the redshift distribution, rest-frame
R-band lu- minosity density, or the source classification. The median
polarization fraction versus synchrotron-peak-frequency plot shows an envelope
implying that high synchrotron- peaked sources have a smaller range of median
polarization fractions concentrated around lower values. Our gamma-ray--quiet
sources show similar median polarization fractions although they are all low
synchrotron-peaked. We also find that the random- ness of the polarization
angle depends on the synchrotron peak frequency. For high synchrotron-peaked
sources it tends to concentrate around preferred directions while for low
synchrotron-peaked sources it is more variable and less likely to have a pre-
ferred direction. We propose a scenario which mediates efficient particle
acceleration in shocks and increases the helical B-field component immediately
downstream of the shock.


title:
Discontinuous transitions in globally coupled potential systems with
  additive noise

abstract:
  An infinite array of globally coupled overdamped constituents moving in a
double-well potential with $n$-th order saturation term under the influence of
additive Gaussian white noise is investigated. The system exhibits a continuous
phase transition from a symmetric phase to a symmetry-broken phase. The
qualitative behavior is independent on $n$. The critical point is calculated
for strong and for weak noise, these limits are also bounds for the critical
point. Introducing an additional nonlinearity, such that the potential can have
up to three minima, leads to richer behavior. There the parameter space divides
in three regions, a region with a symmetric phase, a region with a phase of
broken symmetry and a region where both phases coexist. The region of
coexistence collapses into one of the others via a discontinuous phase
transition whereas the transition between the symmetric phase and the phase of
broken symmetry is continuous. The tricritical point where the three regions
intersect, can be calculated for strong and for weak noise. These limiting
values form optimal bounds on the tricritical point. In the region of
coexistence simulations of finite systems are performed. One finds that the
stationary distribution of finite but large systems differs qualitatively from
the one of the infinite system. Hence the limits of stationarity and large
system size do not commute.


title:
On total mean curvatures of foliated half-lightlike submanifolds in
  semi-Riemannian manifolds

abstract:
  We derive total mean curvature integration formulae of a three co-dimensional
foliation $\mathcal{F}^{n}$ on a screen integrable half-lightlike submanifold,
$M^{n+1}$ in a semi-Riemannian manifold $\overline{M}^{n+3}$. We give
generalized differential equations relating to mean curvatures of a totally
umbilical half-lightlike submanifold admitting a totally umbilical screen
distribution, and show that they are generalizations of those given by [4].


title:
Homodyne-like detection for state-discrimination in the presence of
  phase noise

abstract:
  We propose an innovative strategy to discriminate between two coherent states
affected by either uniform or gaussian phase noise. The strategy is based on a
homodyne-like detection scheme with photon-number-resolving detectors in the
regime of low-intensity local oscillator. The experimental implementation of
the detection scheme involves two hybrid photodetectors, whose outputs are used
in post processing to calculate the shot-by-shot photon-number difference. The
performance of this strategy is quantified in terms of the error probability in
discriminating the noisy coherent signals as a function of the characteristic
noise parameters.


title:
An analysis of nonadiabatic ring-polymer molecular dynamics and its
  application to vibronic spectra

abstract:
  Nonadiabatic ring-polymer molecular dynamics employs the mapping approach to
describe nonadiabatic effects within the ring-polymer ansatz. In this paper, it
is generalized to allow for the nuclear and electronic degrees of freedom to be
described by different numbers of ring-polymer beads. Analysis of the resulting
method shows that as the number of electronic mapping variables increases,
certain problems associated with the approach are removed, such as the
non-unique choice of the mapping Hamiltonian and negative populations leading
to inverted potential-energy surfaces. Explicit integration over cyclic
variables reduces the sign problem for the initial distribution in the general
case. A new application for the simulation of vibronic spectra is described and
promising results are presented for a model system.


title:
Exact Non-Markovian master equation for the Spin-Boson and
  Jaynes-Cummings models

abstract:
  We provide the exact non-Markovian master equation for a two-level system
interacting with a thermal bosonic bath, and we write the solution of such a
master equation in terms of the Bloch vector. We show that previous
approximated results are particular limits of our exact master equation. We
generalize these results to more complex systems involving an arbitrary number
of two-level systems coupled to different thermal baths, providing the exact
master equations also for these systems. As an example of this general case we
derive the master equation for the Jaynes-Cummings model.


title: Lectures on Higgs moduli and abelianisation

abstract:
  These are largely expanded notes from lectures on Higgs moduli and
abelianisation given in Angers, France (2014) and Guaruja, Brazil (2015).
Dedicated to Ugo Bruzzo on his 60-th birthday. Version 2: minor corrections.


title: Polytopes and large counterexamples

abstract:
  In this short note, we give large counterexamples to natural questions about
certain order polytopes, in particular, Gelfand--Tsetlin polytopes. Several of
the counterexamples are too large to be discovered via a brute-force computer
search.
  We also show that the multiset of hooks in a Young diagram is not enough
information to determine the Ehrhart polynomial for an associated order
polytope. This is somewhat counter-intuitive to the fact that the multiset of
hooks always determine the leading coefficient of the Ehrhart polynomial.


title:
Electron-phonon interaction during optically induced ultrafast
  magnetization dynamics of Au/GdFeCo bilayers

abstract:
  The temperature evolution of GdFeCo electrons following optical heating plays
a key role in all optical switching of GdFeCo and is primarily governed by the
strength of coupling between electrons and phonons. Typically, the strength of
electron-phonon coupling in a metal is deduced by monitoring changes in
reflectance following optical heating and then analyzing the transient
reflectance with a simple two-temperature thermal model. In a magnetic metal,
the change in reflectance cannot be assumed to depend only the electron and
phonon temperatures because a metal's reflectance also depends on the
magnetization. To deduce the electron-phonon coupling constant in GdFeCo, we
analyze thermal transport in Au and GdFeCo bilayers following optical heating
of the GdFeCo electrons. We use the reflectance of the Au layer to monitor the
temperature evolution of the Au phonons. By interpreting the response of the
bilayer to heating with a thermal model, we determine the electron-phonon
coupling constant in GdFeCo to be 6 x 10^17 W/(m^3-K) corresponding to an
electron-phonon relaxation time in GdFeCo of ~150 fs.


title:
Nuclear matter properties from local chiral interactions with $\Delta$
  isobar intermediate states

abstract:
  Using two-nucleon and three-nucleon interactions derived in the framework of
chiral perturbation theory (ChPT) with and without the explicit $\Delta$ isobar
contributions, we calculate the energy per particle of symmetric nuclear matter
and pure neutron matter in the framework of the microscopic
Brueckner-Hartree-Fock approach. In particular, we present for the first time
nuclear matter calculations using the new fully local in coordinate-space
two-nucleon interaction at the next-to-next-to-next-to-leading-order (N3LO) of
ChPT with $\Delta$ isobar intermediate states (N3LO$\Delta$) recently developed
by Piarulli et al. [arXiv:1606:06335]. We find that using this N3LO$\Delta$
potential, supplemented with a local N2LO three-nucleon interaction with
explicit $\Delta$ isobar degrees of freedom, it is possible to obtain a
satisfactory saturation point of symmetric nuclear matter. For this combination
of two- and three-nucleon interactions we also calculate the nuclear symmetry
energy and we compare our results with the empirical constraints on this
quantity obtained using the excitation energies to isobaric analog states in
nuclei and using experimental data on the neutron skin thickness of heavy
nuclei, finding a very good agreement with these empirical constraints in all
the considered nucleonic density range. In addition, we find that the explicit
inclusion of $\Delta$ isobars diminishes the strength of the three-nucleon
interactions needed the get a good saturation point of symmetric nuclear
matter. We also compare the results of our calculations with those obtained by
other research groups using chiral nuclear interactions with different
many-body methods, finding in many cases a very satisfactory agreement.


title: Complexes of triggered star formation in supergiant shell of Holmberg II

abstract:
  We report a detailed analysis of all regions of current star formation in the
walls of the supergiant HI shell (SGS) in the galaxy Holmberg II based on
observations with a scanning Fabry-Perot interferometer at the 6-m SAO RAS
telescope. We compare the structure and kinematics of ionized gas with that of
atomic hydrogen and with the stellar population of the SGS. Our deep H$\alpha$
images and archival images taken by the HST demonstrate that current star
formation episodes are larger and more complicated than previously thought:
they represent unified star-forming complexes with sizes of several hundred pc
rather than 'chains' of separate bright nebulae in the walls of the SGS. The
fact that we are dealing with unified complexes is evidenced by identified
faint shell-like structures of ionized and neutral gas which connect several
distinct bright HII regions. Formation of such complexes is due to the feedback
of stars with very inhomogeneous ambient gas in the walls of the SGS. The
arguments supporting an idea about the triggering of star formation in SGS by
the HI supershells collision are presented. We also found a faint ionized
supershell inside the HI SGS expanding with a velocity of no greater than 10-15
km/s. Five OB stars located inside the inner supershell are sufficient to
account for its radiation, although a possibility of leakage of ionizing
photons from bright HII regions is not ruled out as well.


title: Safety Barrier Certificates for Heterogeneous Multi-Robot Systems

abstract:
  This paper presents a formal framework for collision avoidance in multi-robot
systems, wherein an existing controller is modified in a minimally invasive
fashion to ensure safety. We build this framework through the use of control
barrier functions (CBFs) which guarantee forward invariance of a safe set;
these yield safety barrier certificates in the context of heterogeneous robot
dynamics subject to acceleration bounds. Moreover, safety barrier certificates
are extended to a distributed control framework, wherein neighboring agent
dynamics are unknown, through local parameter identification. The end result is
an optimization-based controller that formally guarantees collision free
behavior in heterogeneous multi-agent systems by minimally modifying the
desired controller via safety barrier constraints. This formal result is
verified in simulation on a multi-robot system consisting of both cumbersome
and agile robots, is demonstrated experimentally on a system with a Magellan
Pro robot and three Khepera III robots.


title: Regularity of CR-mappings into Levi-degenerate hypersurfaces

abstract:
  We provide regularity results for CR-maps between real hypersurfaces in
complex spaces of different dimension with a Levi-degenerate target. We address
both the real-analytic and the smooth case. Our results allow immediate
applications to the study of proper holomorphic maps between Bounded Symmetric
Domains.


title:
A Benchmark for the Performance of Time-varying Closed-loop Flow Control
  with Application to TCP

abstract:
  Closed-loop flow control protocols, such as the prominent implementation TCP,
are prevalent in the Internet, today. TCP has continuously been improved for
greedy traffic sources to achieve high throughput over networks with large
bandwidth delay products. Recently, the increasing use for streaming and
interactive applications, such as voice and video, has shifted the focus
towards its delay performance. Given the need for real-time communication of
non-greedy sources via TCP, we present an estimation method for performance
evaluation of closed-loop flow control protocols. We characterize an end-to-end
connection by a transfer function that provides statistical service guarantees
for arbitrary traffic. The estimation is based on end-to-end measurements at
the application level that include all effects induced by the network and by
the protocol stacks of the end systems. From our measurements, we identify
different causes for delays. We show that significant delays are due to
queueing in protocol stacks. Notably, this occurs even if the utilization is
moderate. Using our estimation method, we compare the impact of fundamental
mechanisms of TCP on delays at the application level: In detail, we analyze
parameters relevant for network dimensioning, including buffer provisioning and
active queue management, and parameters for server configuration, such as the
congestion control algorithm. By applying our method as a benchmark, we find
that a good selection can largely improve the delay performance of TCP.


title:
Wannier functions using a discrete variable representation for optical
  lattices

abstract:
  We propose a numerical method using the discrete variable representation
(DVR) for constructing real-valued Wannier functions localized in a unit cell
for both symmetric and asymmetric periodic potentials. We apply these results
to finding Wannier functions for ultracold atoms trapped in laser-generated
optical lattices. Following Kivelson \cite{kivelson_wannier_1982}, for a
symmetric lattice with inversion symmetry, we construct Wannier functions as
eigen states of the position operators $\hat x$, $\hat y$ and $\hat z$
restricted to single-particle Bloch functions belonging to one or more bands.
To ensure that the Wannier functions are real-valued, we numerically obtain the
band structure and real-valued eigen states using a uniform Fourier grid DVR.
We then show by a comparison of tunneling energies, that the Wannier functions
are accurate for both inversion symmetric and asymmetric potentials to better
than ten significant digits when using double-precision arithmetic. The
calculations are performed for an optical lattice with double-wells per unit
cell with tunable asymmetry along the $x$ axis and a single sinusoidal
potential along the perpendicular directions. Localized functions at the two
potential minima within each unit cell are similarly constructed, but using a
superposition of single-particle solutions from the two lowest bands. We
finally use these localized basis functions to determine the two-body
interaction energies in the Bose-Hubbard (BH) model, and show the dependence of
these energies on lattice asymmetry.


title:
Structured Optimal Feedback in Multi-Agent Systems: A Static Output
  Feedback Perspective

abstract:
  In this paper we demonstrate how certain structured feedback gains
necessarily emerge as the optimal controller gains in two linear optimal
control formulations for multi-agent systems. We consider the cases of linear
optimal synchronization and linear optimal centroid stabilization. In the
former problem, the considered cost functional integrates squared
synchronization error and input, and in the latter, the considered cost
functional integrates squared sum of the states and input. Our approach is to
view the structures in the feedback gains in terms of a static output feedback
with suitable output matrices and to relate this fact with the optimal control
formulations. We show that the two considered problems are special cases of a
more general case in which the optimal feedback to a linear quadratic regulator
problem with cost functionals integrating squared outputs and inputs is a
static output feedback. A treatment in this light leads to a very simple and
general solution which significantly generalizes a recent result for the linear
optimal synchronization problem. We illustrate the general problem in a
geometric light.


title:
Itemwise conditionally independent nonresponse modeling for incomplete
  multivariate data

abstract:
  We introduce a nonresponse mechanism for multivariate missing data in which
each study variable and its nonresponse indicator are conditionally independent
given the remaining variables and their nonresponse indicators. This is a
nonignorable missingness mechanism, in that nonresponse for any item can depend
on values of other items that are themselves missing. We show that, under this
itemwise conditionally independent nonresponse assumption, one can define and
identify nonparametric saturated classes of joint multivariate models for the
study variables and their missingness indicators. We also show how to perform
sensitivity analysis to violations of the conditional independence assumptions
encoded by this missingness mechanism. Throughout, we illustrate the use of
this modeling approach with data analyses.


title:
Gap solitons for the repulsive Gross-Pitaevskii equation with periodic
  potential: coding and method for computation

abstract:
  The paper is devoted to nonlinear localized modes ("gap solitons") for the
spatially one-dimensional Gross-Pitaevskii equation (1D GPE) with a periodic
potential and repulsive interparticle interactions. It has been recently shown
(G. L. Alfimov, A. I. Avramenko, Physica D, 254, 29 (2013)) that under certain
conditions all the stationary modes for the 1D GPE can be coded by bi-infinite
sequences of symbols of some finite alphabet (called "codes" of the solutions).
We present and justify a numerical method which allows to reconstruct the
profile of a localized mode by its code. As an example, the method is applied
to compute the profiles of gap solitons for 1D GPE with a cosine potential.

categories: nlin.PS cond-mat.quant-gas math-ph math.MP nlin.CD


title: On the quantum principles of cognitive learning

abstract:
  Pothos & Busemeyer's (P&B's) query about whether quantum probability can
provide a foundation for the cognitive modeling embodies so many underlying
implications that the subject is far from exhausted. In this brief commentary,
however, I suggest that the conceptual thresholds of the meaningful learning
give rise to a typical Boltzmann's weighting measure, which indicates a
statistical verisimilitude of quantum behavior in the human cognitive ensemble.


title: Rotation sensing with trapped ions

abstract:
  We present a protocol for using trapped ions to measure rotations via
matter-wave Sagnac interferometry. The trap allows the interferometer to
enclose a large area in a compact apparatus through repeated round-trips in a
Sagnac geometry. We show how a uniform magnetic field can be used to close the
interferometer over a large dynamic range in rotation speed and measurement
bandwidth without losing contrast. Since this technique does not require the
ions to be confined in the Lamb-Dicke regime, thermal states with many phonons
should be sufficient for operation.


title: Gibbs states defined by biorthogonal sequences

abstract:
  Motivated by the growing interest on PT-quantum mechanics, in this paper we
discuss some facts on generalized Gibbs states and on their related KMS-like
conditions. To achieve this, we first consider some useful connections between
similar (Hamiltonian) operators and we propose some extended version of the
Heisenberg algebraic dynamics, deducing some of their properties, useful for
our purposes.


title:
Localization by Fusing a Group of Fingerprints via Multiple Antennas in
  Indoor Environment

abstract:
  Most existing fingerprints-based indoor localization approaches are based on
some single fingerprints, such as received signal strength (RSS), channel
impulse response (CIR), and signal subspace. However, the localization accuracy
obtained by the single fingerprint approach is rather susceptible to the
changing environment, multi-path, and non-line-of-sight (NLOS) propagation.
Furthermore, building the fingerprints is a very time consuming process. In
this paper, we propose a novel localization framework by Fusing A Group Of
fingerprinTs (FAGOT) via multiple antennas for the indoor environment. We first
build a GrOup Of Fingerprints (GOOF), which includes five different
fingerprints, namely, RSS, covariance matrix, signal subspace, fractional low
order moment, and fourth-order cumulant, which are obtained by different
transformations of the received signals from multiple antennas in the offline
stage. Then, we design a parallel GOOF multiple classifiers based on AdaBoost
(GOOF-AdaBoost) to train each of these fingerprints in parallel as five strong
multiple classifiers. In the online stage, we input the corresponding
transformations of the real measurements into these strong classifiers to
obtain independent decisions. Finally, we propose an efficient combination
fusion algorithm, namely, MUltiple Classifiers mUltiple Samples (MUCUS) fusion
algorithm to improve the accuracy of localization by combining the predictions
of multiple classifiers with different samples. As compared with the single
fingerprint approaches, the prediction probability of our proposed approach is
improved significantly. The process for building fingerprints can also be
reduced drastically. We demonstrate the feasibility and performance of the
proposed algorithm through extensive simulations as well as via real
experimental data using a Universal Software Radio Peripheral (USRP) platform
with four antennas.


title: Escape rate and diffusion of a random walker

abstract:
  We determine the rate of escape from a potential well, and the diffusion
coefficient in a periodic potential, of a random walker that moves under the
influence of the potential in between successive collisions with the heat bath.
In the overdamped limit, both the escape rate and the diffusion coefficient
coincide with those of a Langevin particle. Conversely, in the underdamped
limit the two dynamics have a different temperature dependence. In particular,
at low temperature the random walk has a smaller escape rate, but a larger
diffusion coefficient.


title:
Semiclassical theory of anisotropic transport at LaAlO3/SrTiO3
  interfaces under in-plane magnetic field

abstract:
  The unconventional magnetotransport at the interface between transition-metal
oxides $LaAlO_3$ (LAO) and $SrTiO_3$ (STO) is frequently related to mobile
electrons interacting with localized magnetic moments. However nature and
properties of magnetism at this interface are not well understood so far. In
this paper, we focus on transport effects driven by spin-orbit coupling and
intentionally neglect possible strong correlations. The electrical resistivity
tensor is calculated as a function of the magnitude and orientation of an
external magnetic field parallel to the interface. The semiclassical Boltzmann
equation is solved numerically for the two-dimensional system of spin-orbit
coupled electrons accelerated by an electric field and scattered by
spatially-correlated impurities. At temperatures of a few Kelvin and densities
such that the chemical potential crosses the second pair of spin-orbit split
bands, we find a strongly anisotropic modulation of the (negative)
magnetoresistance above 10 T, characterized by multiple maxima and minima away
from the crystalline axes. Along with the drop of the magnetoresistance, an
abrupt enhancement of the transverse resistivity occurs. The angular modulation
of the latter considerably deviates from a (low-field) sinusoidal dependence to
a (high-field) step-like behaviour. These peculiar features are the
consequences of the anisotropy of both (intra-band and inter-band )
scattering-amplitudes in the Brillouin zone when the relevant energy scales in
the system - chemical potential, spin-orbit interaction and Zeeman energy - are
all comparable to each other. The theory provides good qualitative agreement
with experimental data in the literature.


title: Transparent Clouds: An Enhancement to Abstraction

abstract:
  With the introduction of various hardware/software technologies such as Cloud
Technologies or Virtualization technologies, there has been a great potential
to reuse ICT artifacts thanks to Abstraction and also Exchangeability features
achieved via these technologies. These technologies also provide various
advantages with respect to sustainability including resource consumption
reduction (in the use phase only or in the whole life cycle). However, there is
an additional but untapped potential associated with the anonymization of
resources introduced by both abstraction and exchangeability features. By
realizing on this potential, we can improve cloud solutions and reduce their
by-product opacity, which usually prevents leveraging on the specialized but
tweakable (i.e., nonessential modifications without changing the main function)
features of components that are captured in the component models. This is
especially a challenge in the case heterogeneous/disaggregated infrastructure
where developing models to cover everything is practically impossible. In this
work, by leveraging on the concept of pathways, we develop a few mechanisms
that enable transparency and therefore tweakability of features even in the
presence of abstraction and heterogeneity. In particular, the layered-stack
approach to system decomposition is considered because of its role in both
software defined networking (SDN) and Network Function Virtualization (NFV)
system decompositions. For a concrete example, the case of dynamic frequency
scaling of processors is considered and it is shown that the associated
consumption could be considerably reduced without requiring additional changes
to the middle components.


title: $PT$-symmetric graphene under a magnetic field

abstract:
  We propose a $PT$-symmetrically deformed version of the graphene
tight-binding model under a magnetic field. We analyze the structure of the
spectra and the eigenvectors of the Hamiltonians around the $K$ and $K'$
points, both in the $PT$-symmetric and $PT$-broken regions. In particular we
show that the presence of the deformation parameter $V$ produces several
interesting consequences, including the asymmetry of the zero-energy states of
the Hamiltonians and the breakdown of the completeness of the eigenvector sets.
We also discuss the biorthogonality of the eigenvectors, which {turns out to
be} different in the $PT$-symmetric and $PT$-broken regions.


title:
A Note on Moments of Limit Log Infinitely Divisible Stochastic Measures
  of Bacry and Muzy

abstract:
  A multiple integral representation of single and joint moments of the total
mass of the limit log-infinitely divisible stochastic measure of Bacry and Muzy
[$\textit{Comm. Math. Phys.}$ ${\bf 236}$: 449-475, 2003] is derived. The
covariance structure of the total mass of the measure is shown to be
logarithmic. A generalization of the Selberg integral corresponding to single
moments of the limit measure is proposed and shown to satisfy a recurrence
relation. The joint moments of the limit lognormal measure, classical Selberg
integral with $\lambda_1=\lambda_2=0,$ and Morris integral are represented in
the form of multiple binomial sums. For application, low moments of the limit
log-Poisson measure are computed exactly and low joint moments of the limit
lognormal measure are considered in detail.


title:
(Almost) Closing the $\nu$MSM Sterile Neutrino Dark Matter Window with
  NuSTAR

abstract:
  We use NuSTAR observations of the Galactic Center to search for X-ray lines
from the radiative decay of sterile neutrino dark matter. Finding no evidence
of unknown lines, we set limits on the sterile neutrino mass and mixing angle.
In most of the mass range 10-50 keV, these are now the strongest limits, at
some masses improving upon previous limits by a factor of ~10. In the neutrino
minimal standard model framework, where additional constraints from dark matter
production and structure formation apply, the allowed parameter space is
reduced by more than half. Future NuSTAR observations may be able to cover much
of the remaining parameter space.


title:
Structural Simplicity as a Restraint on the Structure of Amorphous
  Silicon

abstract:
  Understanding the structural origins of the properties of amorphous materials
remains one of the most important challenges in structural science. In this
study we demonstrate that local 'structural simplicity', embodied by the degree
to which atomic environments within a material are similar to each other, is
powerful concept for rationalising the structure of canonical amorphous
material amorphous silicon (a-Si). We show, by restraining a reverse Monte
Carlo refinement against pair distribution function (PDF) data to be simpler,
that the simplest model consistent with the PDF is a continuous random network
(CRN). A further effect of producing a simple model of a-Si is the generation
of a (pseudo)gap in the electronic density of states, suggesting that
structural homogeneity drives electronic homogeneity. That this method produces
models of a-Si that approach the state-of-the-art without the need for
chemically specific restraints (beyond the assumption of homogeneity) suggests
that simplicity-based refinement approaches may allow experiment-driven
structural modelling techniques to be developed for the wide variety of
amorphous semiconductors with strong local order.


title: Bootstrapping a Five-Loop Amplitude Using Steinmann Relations

abstract:
  The analytic structure of scattering amplitudes is restricted by Steinmann
relations, which enforce the vanishing of certain discontinuities of
discontinuities. We show that these relations dramatically simplify the
function space for the hexagon function bootstrap in planar maximally
supersymmetric Yang-Mills theory. Armed with this simplification, along with
the constraints of dual conformal symmetry and Regge exponentiation, we obtain
the complete five-loop six-particle amplitude.


title: An EM based Iterative Method for Solving Large Sparse Linear Systems

abstract:
  We propose a novel iterative algorithm for solving a large sparse linear
system. The method is based on the EM algorithm. If the system has a unique
solution, the algorithm guarantees convergence with a geometric rate.
Otherwise, convergence to a minimal Kullback--Leibler divergence point is
guaranteed. The algorithm is easy to code and competitive with other iterative
algorithms.


title:
Structural Convergence Results for Approximation of Dominant Subspaces
  from Block Krylov Spaces

abstract:
  This paper is concerned with approximating the dominant left singular vector
space of a real matrix $A$ of arbitrary dimension, from block Krylov spaces
generated by the matrix $AA^T$ and the block vector $AX$. Two classes of
results are presented. First are bounds on the distance, in the two and
Frobenius norms, between the Krylov space and the target space. The distance is
expressed in terms of principal angles. Second are quality of approximation
bounds, relative to the best approximation in the Frobenius norm. For starting
guesses $X$ of full column-rank, the bounds depend on the tangent of the
principal angles between $X$ and the dominant right singular vector space of
$A$. The results presented here form the structural foundation for the analysis
of randomized Krylov space methods. The innovative feature is a combination of
traditional Lanczos convergence analysis with optimal approximations via least
squares problems.


title: The Inflation Technique for Causal Inference with Latent Variables

abstract:
  The problem of causal inference is to determine if a given probability
distribution on observed variables is compatible with some causal structure.
The difficult case is when the causal structure includes latent variables. We
here introduce the $\textit{inflation technique}$ for tackling this problem. An
inflation of a causal structure is a new causal structure that can contain
multiple copies of each of the original variables, but where the ancestry of
each copy mirrors that of the original. To every distribution of the observed
variables that is compatible with the original causal structure, we assign a
family of marginal distributions on certain subsets of the copies that are
compatible with the inflated causal structure. It follows that compatibility
constraints for the inflation can be translated into compatibility constraints
for the original causal structure. Even if the constraints at the level of
inflation are weak, such as observable statistical independences implied by
disjoint causal ancestry, the translated constraints can be strong. We apply
this method to derive new inequalities whose violation by a distribution
witnesses that distribution's incompatibility with the causal structure (of
which Bell inequalities and Pearl's instrumental inequality are prominent
examples). We describe an algorithm for deriving all such inequalities for the
original causal structure that follow from ancestral independences in the
inflation. For three observed binary variables with pairwise common causes, it
yields inequalities that are stronger in at least some aspects than those
obtainable by existing methods. We also describe an algorithm that derives a
weaker set of inequalities but is more efficient. Finally, we discuss which
inflations are such that the inequalities one obtains from them remain valid
even for quantum (and post-quantum) generalizations of the notion of a causal
model.

categories: quant-ph math.ST stat.ME stat.ML stat.TH


title: Helical Kink Instability in a Confined Solar Eruption

abstract:
  A model for strongly writhing confined solar eruptions suggests an origin in
the helical kink instability of a coronal flux rope which remains stable
against the torus instability. This model is tested against the well observed
filament eruption on 2002 May 27 in a parametric MHD simulation study which
comprises all phases of the event. Good agreement with the essential observed
properties is obtained. These include the confinement, terminal height,
writhing, distortion, and dissolution of the filament, and the flare loops. The
agreement is robust against variations in a representative range of parameter
space. Careful comparisons with the observation data constrain the ratio of the
external toroidal and poloidal field components to
$B_\mathrm{et}/B_\mathrm{ep}\approx1$ and the initial flux rope twist to
$\Phi\approx4\pi$. Different from ejective eruptions, two distinct phases of
strong magnetic reconnection can occur. First, the erupting flux is cut by
reconnection with overlying flux in the helical current sheet formed by the
instability. If the resulting flux bundles are linked as a consequence of the
erupting rope's strong writhing, they subsequently reconnect in the vertical
current sheet between them. This reforms the overlying flux and a far less
twisted flux rope, offering a pathway to homologous eruptions.


title: On the representation number of a crown graph

abstract:
  A graph $G=(V,E)$ is word-representable if there exists a word $w$ over the
alphabet $V$ such that letters $x$ and $y$ alternate in $w$ if and only if $xy$
is an edge in $E$. It is known that any word-representable graph $G$ is
$k$-word-representable for some $k$, that is, there exists a word $w$
representing $G$ such that each letter occurs exactly $k$ times in $w$. The
minimum such $k$ is called $G$'s representation number.
  A crown graph $H_{n,n}$ is a graph obtained from the complete bipartite graph
$K_{n,n}$ by removing a perfect matching. In this paper we show that for $n\geq
5$, $H_{n,n}$'s representation number is $\lceil n/2 \rceil$. This result not
only provides a complete solution to the open Problem 7.4.2 in \cite{KL}, but
also gives a negative answer to the question raised in Problem 7.2.7 in
\cite{KL} on 3-word-representability of bipartite graphs. As a byproduct we
obtain a new example of a graph class with a high representation number.


title:
Limiting empirical distribution of zeros and critical points of random
  polynomials agree in general

abstract:
  In this article, we study critical points (zeros of derivative) of random
polynomials. Take two deterministic sequences $\{a_n\}_{n\geq1}$ and
$\{b_n\}_{n\geq1}$ of complex numbers whose limiting empirical measures are
same. By choosing $\xi_n = a_n$ or $b_n$ with equal probability, define the
sequence of polynomials by $P_n(z)=(z-\xi_1)\dots(z-\xi_n)$. We show that the
limiting measure of zeros and critical points agree for this sequence of random
polynomials under some assumption. We also prove a similar result for
triangular array of numbers. A similar result for zeros of generalized
derivative (can be thought as random rational function) is also proved.
Pemantle and Rivin initiated the study of critical points of random
polynomials. Kabluchko proved the result considering the zeros to be i.i.d.
random variables.


title:
A Search for the LHCb Charmed 'Pentaquark' using Photo-Production of
  $J/{\psi}$ at Threshold in Hall C at Jefferson Lab

abstract:
  We propose to measure the photo-production cross section of $J/{\psi}$ near
threshold, in search of the recently observed LHCb hidden-charm resonances
$P_c$(4380) and $P_c$(4450) consistent with 'pentaquarks'. The observation of
these resonances in photo-production will provide strong evidence of the true
resonance nature of the LHCb states, distinguishing them from kinematic
enhancements. A bremsstrahlung photon beam produced with an 11 GeV electron
beam at CEBAF covers the energy range of $J/{\psi}$ production from the
threshold photo-production energy of 8.2 GeV, to an energy beyond the presumed
$P_c$(4450) resonance. The experiment will be carried out in Hall C at
Jefferson Lab using a 50{\mu}A electron beam incident on a 9% copper radiator.
The resulting photon beam passes through a 15 cm liquid hydrogen target,
producing $J/{\psi}$ mesons through a diffractive process in the $t$-channel,
or through a resonant process in the $s$- and $u$-channel. The decay $e^+e^-$
pair of the $J/{\psi}$ will be detected in coincidence using the two
high-momentum spectrometers of Hall C. The spectrometer settings have been
optimized to distinguish the resonant $s$- and $u$-channel production from the
diffractive $t$-channel $J/{\psi}$ production. The $s$- and $u$-channel
production of the charmed 5-quark resonance dominates the $t$-distribution at
large $t$. The momentum and angular resolution of the spectrometers is
sufficient to observe a clear resonance enhancement in the total cross section
and $t$-distribution. We request a total of 11 days of beam time with 9 days to
carry the main experiment and 2 days to acquire the needed $t$-channel elastic
$J/{\psi}$ production data for a calibration measurement. This calibration
measurement in itself will greatly enhance our knowledge of $t$-channel elastic
$J/{\psi}$ production near threshold.


title:
Detection and Estimation of Multiple DoA Targets with Single Snapshot
  Measurements

abstract:
  In this paper, we explore the problems of detecting the number of
narrow-band, far-field targets and estimating their corresponding directions of
arrivals (DoAs) from single snapshot measurements. We use the principles of
sparse signal recovery (SSR) for detection and estimation of multiple targets.
In the SSR framework, the DoA estimation problem is grid based and can be posed
as the lasso optimization problem. The corresponding DoA detection problem
reduces to estimating the optimal regularization parameter ($\tau$) of the
lasso problem for achieving the required probability of correct detection
($P_c$). We propose finite sample and asymptotic test statistics for detecting
the number of sources with the required $P_c$ at moderate to high signal to
noise ratios. Once the number of sources are detected, or equivalently the
optimal $\hat{\tau}$ is estimated, the corresponding DoAs can be estimated by
solving the lasso with regularization parameter set to $\hat{\tau}$.


title: Particle dynamics and Stochastic Resonance in Periodic potentials

abstract:
  We have studied the dynamics of a particle in a periodically driven
underdamped periodic potential. Recent studies have reported the occurrence of
Stochastic Resonance (SR) in such systems in the high frequency regime, using
input energy per period of external drive as a quantifier. The particle
trajectories in these systems can be in two dynamical states characterised by
their definite energy and phase relation with the external drive. SR is due to
the noise assisted transition of the particles between these two states. We
study the role of damping on the occurrence of SR. We show that a driven
underdamped periodic system exhibits SR only if the damping is below a
particular limit. To explain this we study the syatem in the deterministic
regime. The existence of the two dynamical states in the deterministic regime
is dependent on the amount of damping and the amplitude od external drive. We
also study the input energy distributions and phase difference of the response
amplitude with the external drive as afunction of the friction parameter.


title: G64-12 and G64-37 are Carbon-Enhanced Metal-Poor Stars

abstract:
  We present new high-resolution chemical-abundance analyses for the well-known
high proper-motion subdwarfs G64-12 and G64-37, based on very high
signal-to-noise spectra (S/N ~ 700/1) with resolving power R ~ 95,000. These
high-quality data enable the first reliable determination of the carbon
abundances for these two stars; we classify them as carbon-enhanced metal-poor
(CEMP) stars based on their carbonicities, which both exceed [C/Fe] = +1.0.
They are sub-classified as CEMP- no Group-II stars, based on their location in
the Yoon-Beers diagram of absolute carbon abundance, A(C) vs. [Fe/H], as well
as on the conventional diagnostic [Ba/Fe]. The relatively low absolute carbon
abundances of CEMP-no stars, in combination with the high effective
temperatures of these two stars (Teff ~ 6500 K) weakens their CH molecular
features to the point that accurate carbon abundances can only be estimated
from spectra with very high S/N. A comparison of the observed abundance
patterns with the predicted yields from massive, metal-free supernova models
reduces the inferred progenitor masses by factors of ~ 2-3, and explosion
energies by factors of ~ 10-15, compared to those derived using previously
claimed carbon abundance estimates. There are certainly many more warm CEMP-no
stars near the halo main-sequence turnoff that have been overlooked in past
studies, directly impacting the derived frequencies of CEMP-no stars as a
function of metallicity, a probe that provides important constraints on
Galactic chemical evolution models, the initial mass function in the early
Universe, and first-star nucleosynthesis.


title:
Accurate De Novo Prediction of Protein Contact Map by Ultra-Deep
  Learning Model

abstract:
  Recently exciting progress has been made on protein contact prediction, but
the predicted contacts for proteins without many sequence homologs is still of
low quality and not very useful for de novo structure prediction. This paper
presents a new deep learning method that predicts contacts by integrating both
evolutionary coupling (EC) and sequence conservation information through an
ultra-deep neural network formed by two deep residual networks. This deep
neural network allows us to model very complex sequence-contact relationship as
well as long-range inter-contact correlation. Our method greatly outperforms
existing contact prediction methods and leads to much more accurate
contact-assisted protein folding. Tested on three datasets of 579 proteins, the
average top L long-range prediction accuracy obtained our method, the
representative EC method CCMpred and the CASP11 winner MetaPSICOV is 0.47, 0.21
and 0.30, respectively; the average top L/10 long-range accuracy of our method,
CCMpred and MetaPSICOV is 0.77, 0.47 and 0.59, respectively. Ab initio folding
using our predicted contacts as restraints can yield correct folds (i.e.,
TMscore>0.6) for 203 test proteins, while that using MetaPSICOV- and
CCMpred-predicted contacts can do so for only 79 and 62 proteins, respectively.
Further, our contact-assisted models have much better quality than
template-based models. Using our predicted contacts as restraints, we can (ab
initio) fold 208 of the 398 membrane proteins with TMscore>0.5. By contrast,
when the training proteins of our method are used as templates, homology
modeling can only do so for 10 of them. One interesting finding is that even if
we do not train our prediction models with any membrane proteins, our method
works very well on membrane protein prediction. Finally, in recent blind CAMEO
benchmark our method successfully folded 5 test proteins with a novel fold.


title: Fractal basin boundaries and escape dynamics in a multiwell potential

abstract:
  The escape dynamics in a two-dimensional multiwell potential is explored. A
thorough numerical investigation is conducted in several types of
two-dimensional planes and also in a three-dimensional subspace of the entire
four-dimensional phase space in order to distinguish between non-escaping
(ordered and chaotic) and escaping orbits. The determination of the location of
the basins of escape towards the different escape channels and their
correlations with the corresponding escape time of the orbits is undoubtedly an
issue of paramount importance. It was found that in all examined cases regions
of non-escaping motion coexist with several basins of escape. Furthermore, we
monitor how the percentages of all types of orbits evolve when the total
orbital energy varies. The larger escape periods have been measured for orbits
with initial conditions in the fractal basin boundaries, while the lowest
escape rates belong to orbits with initial conditions inside the basins of
escape. The Newton-Raphson basins of attraction of the equilibrium points of
the system have also been determined. We hope that our numerical analysis will
be useful for a further understanding of the escape mechanism of orbits in open
Hamiltonian systems with two degrees of freedom.


title:
Unifying Markov Chain Approach for Disease and Rumor Spreading in
  Complex Networks

abstract:
  Spreading processes are ubiquitous in natural and artificial systems. They
can be studied via a plethora of models, depending on the specific details of
the phenomena under study. Disease contagion and rumor spreading are among the
most important of these processes due to their practical relevance. However,
despite the similarities between them, current models address both spreading
dynamics separately. In this paper, we propose a general information spreading
model that is based on discrete time Markov chains. The model includes all the
transitions that are plausible for both a disease contagion process and rumor
propagation. We show that our model not only covers the traditional spreading
schemes, but that it also contains some features relevant in social dynamics,
such as apathy, forgetting, and lost/recovering of interest. The model is
evaluated analytically to obtain the spreading thresholds and the early time
dynamical behavior for the contact and reactive processes in several scenarios.
Comparison with Monte Carlo simulations shows that the Markov chain formalism
is highly accurate while it excels in computational efficiency. We round off
our work by showing how the proposed framework can be applied to the study of
spreading processes occurring on social networks.


title: Pairwise, Magnitude, or Stars: What's the Best Way for Crowds to Rate?

abstract:
  We compare three popular techniques of rating content: the ubiquitous five
star rating, the less used pairwise comparison, and the recently introduced (in
crowdsourcing) magnitude estimation approach. Each system has specific
advantages and disadvantages, in terms of required user effort, achievable user
preference prediction accuracy and number of ratings required.
  We design an experiment where the three techniques are compared in an
unbiased way. We collected 39'000 ratings on a popular crowdsourcing platform,
allowing us to release a dataset that will be useful for many related studies
on user rating techniques.


title: Attaining the quantum limit of passive imaging

abstract:
  We consider the problem, where a camera is tasked with determining one of two
hypotheses: first with an incoherently-radiating quasi-monochromatic point
source and the second with two identical closely spaced point sources. We are
given that the total number of photons collected over an integration time is
assumed to be the same under either hypothesis. For the one-source hypothesis,
the source is taken to be on-axis along the line of sight and for the
two-source hypothesis, we give ourselves the prior knowledge of the angular
separation of the sources, and they are assumed to be identical and located
symmetrically off-axis. This problem was studied by Helstrom in 1973, who
evaluated the probability of error achievable using a sub-optimal optical
measurement, with an unspecified structured realization. In this paper, we
evaluate the quantum Chernoff bound, a lower bound on the minimum probability
of error achievable by any physically-realizable receiver, which is
exponentially tight in the regime that the integration time is high. We give an
explicit structured receiver that separates three orthogonal spatial modes of
the aperture field followed by quantum-noise-limited time-resolved photon
measurement and show that this achieves the quantum Chernoff bound. In other
words, the classical Chernoff bound of our mode-resolved detector exactly
matches the quantum Chernoff bound for this problem. Finally, we evaluate the
classical Chernoff bound on the error probability achievable using an ideal
focal plane array---a signal shot-noise limited continuum photon-detection
receiver with infinitely many infinitesimally-tiny pixels---and quantify its
performance gap with the quantum limit.


title: Majorana quasiparticles of inhomogeneous Rashba chain

abstract:
  We investigate the inhomogeneous Rashba chain coupled to a superconducting
substrate, hosting the Majorana quasiparticles near its edges. We discuss its
subgap spectrum and study how robust are the zero-energy quasiparticles against
the diagonal and off-diagonal disorder. Studying the $\mathbb{Z}_2$ topological
invariant we show that disorder induced transition from the topologically
non-trivial to trivial phases is manifested by characteristic features in the
spatially-resolved quasiparticle spectrum at zero energy. We provide evidence
for the non-local nature of the zero-energy Majorana quasiparticles, that are
well preserved upon partitioning the chain into separate pieces. Even though
the Majorana quasiparticles are not completely immune to inhomogeneity we show
that they can spread onto other (normal) nanoscopic objects via the proximity
effect.


title:
Single photon in hierarchical architecture for physical reinforcement
  learning: Photon intelligence

abstract:
  Understanding and using natural processes for intelligent functionalities,
referred to as natural intelligence, has recently attracted interest from a
variety of fields, including post-silicon computing for artificial intelligence
and decision making in the behavioural sciences. In a past study, we
successfully used the wave-particle duality of single photons to solve the
two-armed bandit problem, which constitutes the foundation of reinforcement
learning and decision making. In this study, we propose and confirm a
hierarchical architecture for single-photon-based reinforcement learning and
decision making that verifies the scalability of the principle. Specifically,
the four-armed bandit problem is solved given zero prior knowledge in a
two-layer hierarchical architecture, where polarization is autonomously adapted
in order to effect adequate decision making using single-photon measurements.
In the hierarchical structure, the notion of layer-dependent decisions emerges.
The optimal solutions in the coarse layer and in the fine layer, however,
conflict with each other in some contradictive problems. We show that while
what we call a tournament strategy resolves such contradictions, the
probabilistic nature of single photons allows for the direct location of the
optimal solution even for contradictive problems, hence manifesting the
exploration ability of single photons. This study provides insights into photon
intelligence in hierarchical architectures for future artificial intelligence
as well as the potential of natural processes for intelligent functionalities.


title:
An invariance principle for sums and record times of regularly varying
  stationary sequences

abstract:
  We prove a sequence of limiting results about weakly dependent stationary and
regularly varying stochastic processes in discrete time. After deducing the
limiting distribution for individual clusters of extremes, we present a new
type of point process convergence theorem. It is designed to preserve the
entire information about the temporal ordering of observations which is
typically lost in the limit after time scaling. By going beyond the existing
asymptotic theory, we are able to prove a new functional limit theorem. Its
assumptions are satisfied by a wide class of applied time series models, for
which standard limiting theory in the space $D$ of \cadlag\ functions does not
apply.
  To describe the limit of partial sums in this more general setting, we use
the space~$E$ of so--called decorated \cadlag\ functions. We also study the
running maximum of partial sums for which a corresponding functional theorem
can be still expressed in the familiar setting of space $D$.
  We further apply our method to analyze record times in a sequence of
dependent stationary observations, even when their marginal distribution is not
necessarily regularly varying. Under certain restrictions on dependence among
the observations, we show that the record times after scaling converge to a
relatively simple compound scale invariant Poisson process.


title:
Boltzmann-Gibbs states in topological quantum walks and associated
  many-body systems: Fidelity and Uhlmann parallel transport analysis of Phase
  Transitions

abstract:
  We perform the fidelity analysis for Boltzmann-Gibbs-like states in order to
investigate whether the topological order of 1D fermionic systems at zero
temperature is maintained at finite temperatures. We use quantum walk protocols
that are known to simulate topological phases and the respective quantum phase
transitions for chiral symmetric Hamiltonians. Using the standard approaches of
the fidelity analysis and the study of edge states, we conclude that no
thermal-like phase transitions occur as temperature increases, i.e., the
topological behaviour is washed out gradually. We also show that the behaviour
of the Uhlmann geometric factor associated to the considered fidelity exhibits
the same behaviour as the latter, thus confirming the results obtained using
the previously established approaches.


title: Ensemble Learned Vaccination Uptake Prediction using Web Search Queries

abstract:
  We present a method that uses ensemble learning to combine clinical and
web-mined time-series data in order to predict future vaccination uptake. The
clinical data is official vaccination registries, and the web data is query
frequencies collected from Google Trends. Experiments with official vaccine
records show that our method predicts vaccination uptake effectively (4.7 Root
Mean Squared Error). Whereas performance is best when combining clinical and
web data, using solely web data yields comparative performance. To our
knowledge, this is the first study to predict vaccination uptake using web data
(with and without clinical data).


title:
Integrability of the hyperbolic reduced Maxwell-Bloch equations for
  strongly correlated Bose-Einstein condensates

abstract:
  We derive and study the hyperbolic reduced Maxwell-Bloch equations (HRMB), a
simplified model for the dynamics of strongly correlated Bose-Einstein
condensates (BECs), and in particular for the interaction between the BEC atoms
and its evaporated atoms under the strong interactions. This equation is one
among four which are proven to be integrable via the existence of a Lax pair,
and thus the method of inverse scattering transform. Another equation is the
reduced Maxwell-Bloch equation of quantum optics and the two others do not have
physical applications yet. By studying the linear stability of the constant
solutions of these four equations we observe various regimes, from stable, to
modulational unstable and unstable at all frequencies. The finite dimensional
reduction of the RMB equations is also used to give more insight into the
constant solutions of these equations. From this study, we find that the HRMB
equation arising from strongly correlated BECS is stable under the particular
condition that the transition rate of evaporation is not too large compared to
the number of evaporated atoms. We then derive explicit soliton solutions of
the RMB equations and use numerical simulations to show collisions of solitons
and kink solitons.

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


title: Multilevel Monte Carlo for Reliability Theory

abstract:
  As the size of engineered systems grows, problems in reliability theory can
become computationally challenging, often due to the combinatorial growth in
the cut sets. In this paper we demonstrate how Multilevel Monte Carlo (MLMC) -
a simulation approach which is typically used for stochastic differential
equation models - can be applied in reliability problems by carefully
controlling the bias-variance tradeoff in approximating large system behaviour.
In this first exposition of MLMC methods in reliability problems we address the
canonical problem of estimating the expectation of a functional of system
lifetime and show the computational advantages compared to classical Monte
Carlo methods. The difference in computational complexity can be orders of
magnitude for very large or complicated system structures.


title:
Review of recent results on heavy-ion physics and astroparticle physics
  in ALICE at the LHC

abstract:
  In this work we present a summary of the most relevant results on heavy-ion
and astroparticle physics in ALICE. The summary includes a brief overview of
the current status on the characterization of the hot and dense QCD medium
created in the heavy-ion collisions produced at the LHC, as well as the
intriguing finding of collective-like phenomena in small collision systems.


title:
Tunneling Conductance in Normal-Insulator-Superconductor junctions of
  Silicene

abstract:
  We theoretically investigate the transport properties of a
normal-insulator-superconductor (NIS) junction of silicene in the thin barrier
limit. Similar to graphene the tunneling conductance in such NIS structure
exhibits an oscillatory behavior as a function of the strength of the barrier
in the insulating region. However, unlike in graphene, the tunneling
conductance in silicene can be controlled by an external electric field owing
to its buckled structure. We also demonstrate the change in behavior of the
tunneling conductance across the NIS junction as we change the chemical
potential in the normal silicene region. In addition, at high doping levels in
the normal region, the period of oscillation of the tunneling conductance as a
function of the barrier strength changes from $\pi/2$ to $\pi$ with the
variation of doping in the superconducting region of silicene.


title:
Two computationally efficient polynomial-iteration infeasible
  interior-point algorithms for linear programming

abstract:
  Since the beginning of the development of interior-point methods, there
exists a puzzling gap between the results in theory and the observations in
numerical experience, i.e., algorithms with good polynomial bound are not
computationally efficient and algorithms demonstrated efficiency in computation
do not have a good or any polynomial bound. Todd raised a question in 2002:
"Can we find a theoretically and practically efficient way to reoptimize?" This
paper is an effort to close the gap. We propose two arc-search infeasible
interior-point algorithms with infeasible central path neighborhood wider than
all existing infeasible interior-point algorithms that are proved to be
convergent. We show that the first algorithm is polynomial and its simplified
version, if it terminates in finite iterations, has a complexity bound equal to
the best known complexity bound for all (feasible or infeasible) interior-point
algorithms. We demonstrate the computational efficiency of the proposed
algorithms by testing all Netlib linear programming problems in standard form
and comparing the numerical results to those obtained by Mehrotra's
predictor-corrector algorithm and a recently developed more efficient
arc-search algorithm (the convergence of these two algorithms is unknown). We
conclude that the newly proposed algorithms are not only polynomial but also
computationally competitive comparing to both Mehrotra's predictor-corrector
algorithm and the efficient arc-search algorithm.


title:
MRT-SS Calculator: An R Shiny Application for Sample Size Calculation in
  Micro-Randomized Trials

abstract:
  The micro-randomized trial (MRT) is a new experimental design which allows
for the investigation of the proximal effects of a "just-in-time" treatment,
often provided via a mobile device as part of a mobile health intervention. As
with a traditional randomized controlled trial, computing the minimum required
sample size to achieve a desired power is a crucial step in designing an MRT.
We present MRT-SS Calculator, an online sample-size calculator for
micro-randomized trials, built with R Shiny. MRT-SS Calculator requires
specification of time-varying patterns for the proximal treatment effect and
expected treatment availability. We illustrate the implementation of MRT-SS
Calculator using a mobile health trial, HeartSteps. The application can be
accessed from https://pengliao.shinyapps.io/mrt-calculator.


title:
Adaptive Bayesian Spectral Analysis of Nonstationary Biomedical Time
  Series

abstract:
  Many studies of biomedical time series signals aim to measure the association
between frequency-domain properties of time series and clinical and behavioral
covariates. However, the time-varying dynamics of these associations are
largely ignored due to a lack of methods that can assess the changing nature of
the relationship through time. This article introduces a method for the
simultaneous and automatic analysis of the association between the time-varying
power spectrum and covariates. The procedure adaptively partitions the grid of
time and covariate values into an unknown number of approximately stationary
blocks and nonparametrically estimates local spectra within blocks through
penalized splines. The approach is formulated in a fully Bayesian framework, in
which the number and locations of partition points are random, and fit using
reversible jump Markov chain Monte Carlo techniques. Estimation and inference
averaged over the distribution of partitions allows for the accurate analysis
of spectra with both smooth and abrupt changes. The proposed methodology is
used to analyze the association between the time-varying spectrum of heart rate
variability and self-reported sleep quality in a study of older adults serving
as the primary caregiver for their ill spouse.


title:
Deterministic and Stochastic Becker-D\"oring equations: Past and Recent
  Mathematical Developments

abstract:
  We present a survey on the results on a particular coagulation-fragmentation
model given by the Becker-D\"oring equations. For both the deterministic and
stochastic versions, we include well-posedness, long-time behavior, convergence
rate towards equilibrium, coarsening and relation to transport equations,
time-dependent properties, metastability and classical nucleation theory. All
along this survey, we highlight recent results and open questions.


title: Photothermal effects in ultra-precisely stabilized tunable microcavities

abstract:
  We study the mechanical stability of a tunable high-finesse microcavity under
ambient conditions and investigate light-induced effects that can both suppress
and excite mechanical fluctuations. As an enabling step, we demonstrate the
ultra-precise electronic stabilization of a microcavity. We then show that
photothermal mirror expansion can provide high-bandwidth feedback and improve
cavity stability by almost two orders of magnitude. At high intracavity power,
we observe self-oscillations of mechanical resonances of the cavity. We explain
the observations by a dynamic photothermal instability, leading to parametric
driving of mechanical motion. For an optimized combination of electronic and
photothermal stabilization, we achieve a feedback bandwidth of $500\,$kHz and a
noise level of $1.1 \times 10^{-13}\,$m rms.


title:
Approximate orthogonality of powers for ergodic affine unipotent
  diffeomorphisms on nilmanifolds

abstract:
  Let $ G $ be a connected, simply connected nilpotent Lie group and $ \Gamma <
G $ a lattice. We prove that each ergodic diffeomorphism $
\phi(x\Gamma)=uA(x)\Gamma $ on the nilmanifold $ G/\Gamma $, where $ u\in G $
and $ A:G\to G $ is a unipotent automorphism satisfying $ A(\Gamma)=\Gamma $,
enjoys the property of asymptotically orthogonal powers (AOP). Two consequences
follow:
  (i) Sarnak's conjecture on M\"obius orthogonality holds in every uniquely
ergodic model of an ergodic affine unipotent diffeomorphism;
  (ii) For ergodic affine unipotent diffeomorphisms themselves, the M\"obius
orthogonality holds on so called typical short interval: $ \frac1 M\sum_{M\leq
m<2M}\left|\frac1H\sum_{m\leq n<m+H} f(\phi^n(x\Gamma))\mu (n)\right|\to 0$ as
$ H\to\infty $ and $ H/M\to0 $ for each $ x\Gamma\in G/\Gamma $ and each $ f\in
C(G/\Gamma) $.
  In particular, the results in (i) and (ii) hold for ergodic nil-translations.
Moreover, we prove that each nilsequence is orthogonal to the M\"obius function
$\mu$ on a typical short interval. We also study the problem of lifting of the
AOP property to induced actions and derive some applications on uniform
distribution.


title: Towards the Quantization of Eddington-inspired-Born-Infeld Theory

abstract:
  The quantum effects close to the classical big rip singularity within the
Eddington-inspired-Born-Infeld theory (EiBI) are investigated through quantum
geometrodynamics. It is the first time that this approach is applied to a
modified theory constructed upon Palatini formalism. The Wheeler-DeWitt (WDW)
equation is obtained and solved based on an alternative action proposed in
Ref.[1], under two different factor ordering choices. This action is
dynamically equivalent to the original EiBI action while it is free of square
root of the spacetime curvature. We consider a homogeneous, isotropic and
spatially flat universe, which is assumed to be dominated by a phantom perfect
fluid whose equation of state is a constant. We obtain exact solutions of the
WDW equation based on some specific conditions. In more general cases, we
propose a qualitative argument with the help of a Wentzel-Kramers-Brillouin
(WKB) approximation to get further solutions. Besides, we also construct an
effective WDW equation by simply promoting the classical Friedmann equations.
We find that for all the approaches considered, the DeWitt condition hinting
singularity avoidance is satisfied. Therefore the big rip singularity can be
avoided through the quantum approach within the EiBI theory.


title: High-frequency, scaled MoS2 transistors

abstract:
  The interest in MoS2 for radio-frequency (RF) application has recently
increased. However, little is known on the scaling behavior of transistors made
from MoS2 for RF applications, which is important for establishing performance
limits for electronic circuits based on 2D semiconductors on flexible and rigid
substrates. Here, we present a systematic study of top-gated trilayer MoS2 RF
transistors with gate lengths scaled down to 70 and 40 nm. In addition, by
introducing edge-contacted injection of electrons in trilayer MoS2 devices, we
decrease the contact resistance and as a result obtain the highest cutoff
frequency of 6 GHz before the de-embedding procedure and 25 GHz after the
de-embedding procedure.


title:
Numerical solution of a semilinear parabolic degenerate
  Hamilton-Jacobi-Bellman equation with singularity

abstract:
  We consider a semilinear parabolic degenerated Hamilton-Jacobi-Bellman (HJB)
equation with singularity which is related to a stochastic control problem with
fuel constraint. The fuel constraint translates into a singular initial
condition for the HJB equation. We first propose a transformation based on a
change of variables that gives rise to an equivalent HJB equation with
nonsingular initial condition but irregular coefficients. We then construct
explicit and implicit numerical schemes for solving the transformed HJB
equation and prove their convergences by establishing an extension to the
result of Barles and Souganidis (1991).


title: Slanted snaking of localized Faraday waves

abstract:
  We report on an experimental, theoretical and numerical study of slanted
snaking of spatially localized parametrically excited waves on the surface of a
water-surfactant mixture in a Hele-Shaw cell. We demonstrate experimentally the
presence of a hysteretic transition to spatially extended parametrically
excited surface waves when the acceleration amplitude is varied, as well as the
presence of spatially localized waves exhibiting slanted snaking. The latter
extend outside the hysteresis loop. We attribute this behavior to the presence
of a conserved quantity, the liquid volume, and introduce a universal model
based on symmetry arguments, which couples the wave amplitude with such a
conserved quantity. The model captures both the observed slanted snaking and
the presence of localized waves outside the hysteresis loop, as demonstrated by
numerical integration of the model equations.


title:
A comparison of Redlich-Kister polynomial and cubic spline
  representations of the chemical potential in phase field computations

abstract:
  Free energies play a central role in many descriptions of equilibrium and
non-equilibrium properties of solids. Continuum partial differential equations
(PDEs) of atomic transport, phase transformations and mechanics often rely on
first and second derivatives of a free energy function. The stability, accuracy
and robustness of numerical methods to solve these PDEs are sensitive to the
particular functional representations of the free energy. In this communication
we investigate the influence of different representations of thermodynamic data
on phase field computations of diffusion and two-phase reactions in the solid
state. First-principles statistical mechanics methods were used to generate
realistic free energy data for HCP titanium with interstitially dissolved
oxygen. While Redlich-Kister polynomials have formed the mainstay of
thermodynamic descriptions of multi-component solids, they require high order
terms to fit oscillations in chemical potentials around phase transitions. Here
we demonstrate that high fidelity fits to rapidly fluctuating free energy
functions are obtained with spline functions. Spline functions that are many
degrees lower than Redlich-Kister polynomials provide equal or superior fits to
chemical potential data and, when used in phase field computations, result in
solution times approaching an order of magnitude speed up relative to the use
of Redlich-Kister polynomials.


title:
Classification of the stable solution to the fractional $2<s<3$
  Lane-Emden equation

abstract:
  We classify the stable solutions (positive or sign-changing, radial or not)
to the following nonlocal Lane-Emden equation: $(-\Delta)^s u=|u|^{p-1}u$ in
$\mathbb{R}^n$ for $2<s<3$.


title: Families from Supergroups and Predictions for Leptonic CP Violation

abstract:
  As was shown in 1984 by Caneschi, Farrar, and Schwimmer, decomposing
representations of the supergroup SU(M|N), can give interesting anomaly-free
sets of fermion representations of SU(M) x SU(N) x U(1). It is shown here that
such groups can be used to construct realistic grand unified models with
non-abelian gauged family symmetries. A particularly simple three-family
example based on SU(5) x SU(2) x U(1) is studied. The forms of the mass
matrices, including that of the right-handed neutrinos, are determined in terms
of SU(2) Clebsch coefficients; and the model is able to fit the lepton sector
and predict the Dirac CP-violating phase of the neutrinos.. Models of this type
would have a rich phenomenology if part of the family symmetry is broken near
the electroweak scale.


title: Magnetic properties of Proxima Centauri b analogues

abstract:
  The discovery of a planet around the closest star to our Sun, Proxima
Centauri, represents a quantum leap in the testability of exoplanetary models.
Unlike any other discovered exoplanet, models of Proxima b could be contrasted
against near future telescopic observations and far future in-situ
measurements. In this paper we aim at predicting the planetary radius and the
magnetic properties (dynamo lifetime and magnetic dipole moment) of Proxima b
analogues (solid planets with masses of $\sim 1-3\,M_\oplus$, rotation periods
of several days and habitable conditions). For this purpose we build a grid of
planetary models with a wide range of compositions and masses. For each point
in the grid we run the planetary evolution model developed in
\citet{Zuluaga2013}. Our model assumes small orbital eccentricity, negligible
tidal heating and earth-like radiogenic mantle elements abundances. We devise a
statistical methodology to estimate the posterior distribution of the desired
planetary properties assuming simple prior distributions for the orbital
inclination and bulk composition. Our model predicts that Proxima b would have
a mass $1.3\leq M_{\rm p}\leq 2.3\,M_{\oplus}$ and a radius $R_{\rm
p}=1.4^{+0.3}_{-0.2}\,R_{\oplus}$. In our simulations, most Proxima b analogues
develop intrinsic dynamos that last for $\geq$4 Gyr (the estimated age of the
host star). If alive, the dynamo of Proxima b have a dipole moment ${\cal
M}_{\rm dip}>0.32^{\times 2.3}_{\div 2.9}{\cal M}_{\rm dip,\oplus}$. These
results are not restricted to Proxima b but they also apply to earth-like
planets having similar observed properties.


title: Operators and higher genus mirror curves

abstract:
  We perform further tests of the correspondence between spectral theory and
topological strings, focusing on mirror curves of genus greater than one with
nontrivial mass parameters. In particular, we analyze the geometry relevant to
the SU(3) relativistic Toda lattice, and the resolved C^3/Z_6 orbifold.
Furthermore, we give evidence that the correspondence holds for arbitrary
values of the mass parameters, where the quantization problem leads to resonant
states. We also explore the relation between this correspondence and cluster
integrable systems.


title: Scientific Return of a Lunar Elevator

abstract:
  The concept of a space elevator dates back to Tsilokovsky, but they are not
commonly considered in near-term plans for space exploration, perhaps because a
terrestrial elevator would not be possible without considerable improvements in
tether material. A Lunar Space Elevator (LSE), however, can be built with
current technology using commercially available tether polymers. This paper
considers missions leading to infrastructure capable of shortening the time,
lowering the cost and enhancing the capabilities of robotic and human
explorers. These missions use planetary scale tethers, strings many thousands
of kilometers long stabilized either by rotation or by gravitational gradients.
These systems promise major reduction in transport costs versus chemical
rockets, in a rapid timeframe, for a modest investment. Science will thus
benefit as well as commercial activities.


title: Flexible Bayesian Quantile Regression in Ordinal Models

abstract:
  The paper introduces an estimation method for flexible Bayesian quantile
regression in ordinal (FBQROR) models i.e., an ordinal quantile regression
where the error follows a generalized asymmetric Laplace (GAL) distribution.
The GAL distribution, unlike the asymmetric Laplace (AL) distribution, allows
to fix specific quantiles while simultaneously letting the mode, skewness and
tails to vary. We also introduce the cumulative distribution function
(necessary for constructing the likelihood) and the moment generating function
of the GAL distribution. The algorithm is illustrated in multiple simulation
studies and implemented to analyze public opinion on homeownership as the best
long-term investment in the United States.


title:
Generalized Spatial and Spatiotemporal Autoregressive Conditional
  Heteroscedasticity

abstract:
  In this paper, we introduce a new spatial model that incorporates
heteroscedastic variance depending on neighboring locations. The proposed
process is regarded as the spatial equivalent to the temporal autoregressive
conditional heteroscedasticity (ARCH) model. We show additionally how the
introduced spatial ARCH model can be used in spatiotemporal settings. In
contrast to the temporal ARCH model, in which the distribution is known given
the full information set of the prior periods, the distribution is not
straightforward in the spatial and spatiotemporal setting. However, it is
possible to estimate the parameters of the model using the maximum-likelihood
approach. Via Monte Carlo simulations, we demonstrate the performance of the
estimator for a specific spatial weighting matrix. Moreover, we combine the
known spatial autoregressive model with the spatial ARCH model assuming
heteroscedastic errors. Eventually, the proposed autoregressive process is
illustrated using an empirical example. Specifically, we model lung cancer
mortality in 3108 U.S. counties and compare the introduced model with two
benchmark approaches.


title: Model structures on the category of complexes of quiver representations

abstract:
  In this paper, we study the category $\mathbb{C}(\text{Rep}(\mathcal{Q},
\mathcal{G}))$ of complexes of representations of quiver $\mathcal{Q}$ with
values in a Grothendieck category $\mathcal{G}$. We develop a method for
constructing some model structures on $\mathbb{C}(\text{Rep}(\mathcal{Q},
\mathcal{G}))$ based on componentwise notion. Moreover we also show that these
model structures are monoidal. As an application of these model structure we
introduce some descriptions of the derived category of complexes of
representations of $\mathcal{Q}$ in $\text{Mod-} R$. In particular we set
$\mathcal{Q}=A_2$ and consider the morphism category $\mathbf{H}(R)$ and its
two full subcategories, monomorphism category $\mathbf{S}(R)$ and epimorphism
category $\mathbf{F}(R)$. We show that the well know equivalence between
$\mathbf{S}(R)$ and $\mathbf{F}(R)$ can be extended to an auto-equivalence of
derived category of $\mathbf{H}(R)$.


title:
Superdense coding over optical fiber links with complete Bell-state
  measurements

abstract:
  Adopting quantum communication to modern networking requires transmitting
quantum information through fiber-based infrastructure. We report the first
demonstration of superdense coding over optical fiber links, taking advantage
of a complete Bell-state measurement enabled by time-polarization
hyperentanglement, linear optics, and common single-photon detectors. We
demonstrate the highest single-qubit channel capacity to date utilizing linear
optics, $1.665 \pm 0.018$, and we provide a full experimental implementation of
a hybrid, quantum-classical communication protocol for image transfer.


title: Analytical On-shell Calculation of Low Energy Higher Order Scattering

abstract:
  We demonstrate that the use of analytical on-shell methods involving
calculation of the discontinuity across the t-channel cut associated with the
exchange of a pair of massless particles (photons or gravitons) can be used to
evaluate one-loop contributions to electromagnetic and gravitational
scattering, with and without polarizability, reproducing via simple algebraic
manipulations, results obtained previously, generally using Feynman diagram
techniques. In the gravitational case the use of factorization permits a
straightforward and algebraic calculation of higher order scattering without
consideration of ghost contributions or of triple-graviton couplings, which
made previous evaluations considerably more arduous.


title: Rarefied elliptic hypergeometric functions

abstract:
  Two exact evaluation formulae for multiple rarefied elliptic beta integrals
related to the simplest lens space are proved. They generalize evaluations of
the type I and II elliptic beta integrals attached to the root system $C_n$. In
a special $n=1$ case, the simplest $p\to 0$ limit is shown to lead to a new
class of $q$-hypergeometric identities. Symmetries of a rarefied elliptic
analogue of the Euler-Gauss hypergeometric function are described and the
respective generalization of the hypergeometric equation is constructed. Some
extensions of the latter function to $C_n$ and $A_n$ root systems and
corresponding symmetry transformations are considered. An application of the
rarefied type II $C_n$ elliptic hypergeometric function to some eigenvalue
problems is briefly discussed.


title: Lectures on Inflation

abstract:
  Planning to explore the beginning of the Universe? A lightweight introductory
guide to the theory of Inflation.


title: Very Massive Tracers and Higher Derivative Biases

abstract:
  Most of the upcoming cosmological information will come from analyzing the
clustering of the Large Scale Structures (LSS) of the universe through LSS or
CMB observations. It is therefore essential to be able to understand their
behavior with exquisite precision. The Effective Field Theory of Large Scale
Structures (EFTofLSS) provides a consistent framework to make predictions for
LSS observables in the mildly non-linear regime. In this paper we focus on
biased tracers. We argue that in calculations at a given order in the dark
matter perturbations, highly biased tracers will underperform because of their
larger higher derivative biases. A natural prediction of the EFTofLSS is
therefore that by simply adding higher derivative biases, all tracers should
perform comparably well. We implement this prediction for the halo-halo and the
halo-matter power spectra at one loop, and the halo-halo-halo,
halo-halo-matter, and halo-matter-matter bispectra at tree-level, and compare
with simulations. We find good agreement with the prediction: for all tracers,
we are able to match the bispectra up to $k\simeq0.17\,h/$Mpc at $z=0$ and the
power spectra to a higher wavenumber.


title:
Convolutional Neural Networks for Text Categorization: Shallow
  Word-level vs. Deep Character-level

abstract:
  This paper reports the performances of shallow word-level convolutional
neural networks (CNN), our earlier work (2015), on the eight datasets with
relatively large training data that were used for testing the very deep
character-level CNN in Conneau et al. (2016). Our findings are as follows. The
shallow word-level CNNs achieve better error rates than the error rates
reported in Conneau et al., though the results should be interpreted with some
consideration due to the unique pre-processing of Conneau et al. The shallow
word-level CNN uses more parameters and therefore requires more storage than
the deep character-level CNN; however, the shallow word-level CNN computes much
faster.


title:
Peacock Bundles: Bundle Coloring for Graphs with Globality-Locality
  Trade-off

abstract:
  Bundling of graph edges (node-to-node connections) is a common technique to
enhance visibility of overall trends in the edge structure of a large graph
layout, and a large variety of bundling algorithms have been proposed. However,
with strong bundling, it becomes hard to identify origins and destinations of
individual edges. We propose a solution: we optimize edge coloring to
differentiate bundled edges. We quantify strength of bundling in a flexible
pairwise fashion between edges, and among bundled edges, we quantify how
dissimilar their colors should be by dissimilarity of their origins and
destinations. We solve the resulting nonlinear optimization, which is also
interpretable as a novel dimensionality reduction task. In large graphs the
necessary compromise is whether to differentiate colors sharply between locally
occurring strongly bundled edges ("local bundles"), or also between the weakly
bundled edges occurring globally over the graph ("global bundles"); we allow a
user-set global-local tradeoff. We call the technique "peacock bundles".
Experiments show the coloring clearly enhances comprehensibility of graph
layouts with edge bundling.


title:
Characterization of single layer anti-reflective coatings for
  bolometer-based rare event searches

abstract:
  Combining analysis from phonon signals and photon signals is a powerful
technique for reducing backgrounds in bolometer-based rare event searches.
Anti-reflective coatings can significantly increase the performance of the
secondary light-sensing bolometer in these experiments. As a first step toward
these improvements, coatings of SiO$_2$, HfO$_2$, and TiO$_2$ on Ge and Si
wafers were fabricated and characterized at room temperature and multiple
angles of incidence.


title: Motivic splitting principle

abstract: A variation on the splitting principle


title: Quantum walks and gravitational waves

abstract:
  A new family of discrete-time quantum walks (DTQWs) propagating on a regular
$(1+2)$D spacetime lattice is introduced. The continuous limit of these DTQWs
is shown to coincide with the dynamics of a Dirac fermion interacting with an
arbitrary relativistic gravitational field. This family is used to model the
influence of arbitrary linear gravitational waves (GWs) on DTQWs. Pure shear
GWs are studied in detail. On large spatial scales, pure shear GWs do not
modify the polarizations of the fermion eigen-modes, but rescale all energies
by a common factor. On smaller scales typically comparable to two or three
lattice steps, both polarizations and energies are modified in a non-trivial
way. This effect is particularly salient on interference patterns between the
fermion eigen-modes.