title: Higgs EFT for 2HDM and beyond

abstract:
  We discuss the validity of the Standard Model Effective Field Theory (SM EFT)
as the low-energy effective theory for the two-Higgs-doublet Model (2HDM).
Using the up-to-date Higgs signal strength measurements at the LHC, one can
obtain a likelihood function for the Wilson coefficients of dimension-6
operators in the EFT Lagrangian. Given the matching between the 2HDM and the
EFT, the constraints on the Wilson coefficients can be translated into
constraints on the parameters of the 2HDM Lagrangian. We discuss under which
conditions such a procedure correctly reproduces the true limits on the 2HDM.
Finally, we employ the SM EFT to identify the pattern of the Higgs boson
couplings that are needed to improve the fit to the current Higgs data. To this
end, one needs, simultaneously, to increase the top Yukawa coupling, decrease
the bottom Yukawa coupling, and induce a new contact interaction of the Higgs
boson with gluons. We comment on how these modifications can be realized in the
2HDM extended by new colored particles.


title: Pulsations and outbursts in Be stars: Small differences - big impacts

abstract:
  New high-cadence observations with BRITE covering many months confirm that
coupled pairs of nonradial pulsation modes are widespread among early-type Be
stars. With the difference frequency between the parental variations they may
form a roughly sinusoidal variability or the amplitude may cyclicly vary. A
first - amplified - beat pattern is also found. In all three cases the
amplitudes of difference frequencies can exceed the amplitude sum of the base
frequencies, and modulations of the star-to-circumstellar-disk mass-transfer
rate may be associated with these slow variations. This suggests more strongly
than any earlier observations that significant dissipation of pulsational
energy in the atmosphere may be a cause of mass ejections from Be stars. A
unifying interpretative concept is presented.


title:
Efficient and accurate causal inference with hidden confounders from
  genome-transcriptome variation data

abstract:
  Mapping gene expression as a quantitative trait using whole genome-sequencing
and transcriptome analysis allows to discover the functional consequences of
genetic variation. We developed a novel method and ultra-fast software Findr
for higly accurate causal inference between gene expression traits using
cis-regulatory DNA variations as causal anchors, which improves current methods
by taking into account hidden confounders and weak regulations. Findr
outperformed existing methods on the DREAM5 Systems Genetics challenge and on
the prediction of microRNA and transcription factor targets in human
lymphoblastoid cells, while being nearly a million times faster. Findr is
publicly available at https://github.com/lingfeiwang/findr


title: Phase Coexistence for the Hard-Core Model on ${\mathbb Z}^2$

abstract:
  The hard-core model has attracted much attention across several disciplines,
representing lattice gases in statistical physics and independent sets in
discrete mathematics and computer science. On finite graphs, we are given a
parameter $\lambda$, and an independent set $I$ arises with probability
proportional to $\lambda^{|I|}$. On infinite graphs a Gibbs measure is defined
as a suitable limit with the correct conditional probabilities, and we are
interested in determining when this limit is unique and when there is phase
coexistence, i.e., existence of multiple Gibbs measures.
  It has long been conjectured that on ${\mathbb Z}^2$ this model has a
critical value $\lambda_c \approx 3.796$ with the property that if $\lambda <
\lambda_c$ then it exhibits uniqueness of phase, while if $\lambda > \lambda_c$
then there is phase coexistence. Much of the work to date on this problem has
focused on the regime of uniqueness, with the state of the art being recent
work of Sinclair, Srivastava, \v{S}tefankovi\v{c} and Yin showing that there is
a unique Gibbs measure for all $\lambda < 2.538$. Here we give the first
non-trivial result in the other direction, showing that there are multiple
Gibbs measures for all $\lambda > 5.3506$. There is some potential for lowering
this bound, but with the methods we are using we cannot hope to replace
$5.3506$ with anything below about $4.8771$.
  Our proof begins along the lines of the standard Peierls argument, but we add
two innovations. First, following ideas of Koteck\'y and Randall, we construct
an event that distinguishes two boundary conditions and always has long
contours associated with it, obviating the need to accurately enumerate short
contours. Second, we obtain improved bounds on the number of contours by
relating them to a new class of self-avoiding walks on an oriented version of
${\mathbb Z}^2$.


title: Binary Paragraph Vectors

abstract:
  Recently Le & Mikolov described two log-linear models, called Paragraph
Vector, that can be used to learn state-of-the-art distributed representations
of documents. Inspired by this work, we present Binary Paragraph Vector models:
simple neural networks that learn short binary codes for fast information
retrieval. We show that binary paragraph vectors outperform autoencoder-based
binary codes, despite using fewer bits. We also evaluate their precision in
transfer learning settings, where binary codes are inferred for documents
unrelated to the training corpus. Results from these experiments indicate that
binary paragraph vectors can capture semantics relevant for various
domain-specific documents. Finally, we present a model that simultaneously
learns short binary codes and longer, real-valued representations. This model
can be used to rapidly retrieve a short list of highly relevant documents from
a large document collection.


title: Nuclear parton distributions from the nCTEQ group

abstract:
  We present the nCTEQ15 global analysis of nuclear parton distribution
functions (nPDFs). The main addition to the previous nCTEQ PDFs is the
introduction of PDF uncertainties based on the Hessian method. Another
important improvement is the inclusion of pion production data from RHIC giving
us a handle to constrain gluon PDF. In this presentation we briefly discuss the
framework of our analysis and concentrate on the comparison of our results with
those of other groups. Additionally we show a first estimate of the impact of
the LHC pPb W/Z boson production data on the presented nCTEQ15 PDFs.


title: The bizarre anti-de Sitter spacetime

abstract:
  Anti--de Sitter spacetime is important in general relativity and modern field
theory. We review its geometrical features and properties of light signals and
free particles moving in it. Applying only elementary tools of tensor calculus
we derive \textit{ab initio\/} all these properties and show that they are
really weird. One finds superluminal velocities of light and particles,
infinite particle energy necessary to escape at infinite distance and spacetime
regions inaccessible by a free fall, though reachable by an accelerated
spaceship. Radial timelike geodesics are identical to the circular ones and
actually all timelike geodesics are identical to one circle in a fictitious
five--dimensional space. Employing the latter space one is able to explain
these bizarre features of anti--de Sitter spacetime; in this sense the
spacetime is not self--contained. This is not a physical world.


title:
Infinite-sample consistent estimations of parameters of the Wiener
  process with drift

abstract:
  We consider the Wiener process with drift $$ dX_t=\mu dt +\sigma d W_t $$
with initial value problem $X_0=x_0$, where $x_0 \in R$, $ \mu \in R$ and
$\sigma > 0$ are parameters. By use values $(z_k)_{k \in N}$ of corresponding
trajectories at a fixed positive moment $t$, the infinite-sample consistent
estimates of each unknown parameter of the Wiener process with drift are
constructed under assumption that all another parameters are known. Further, we
propose a certain approach for estimation of unknown parameters
$x_0,\mu,\sigma$ of the Wiener process with drift by use the values
$(z^{(1)}_k)_{k \in N}$ and $(z^{(2)}_k)_{k \in N}$ being the results of
observations on the $2k$-th and $2k+1$-th trajectories of the Wiener process
with drift at moments $t_1$ and $t_2$ , respectively.


title: Generating Families of Practical Fast Matrix Multiplication Algorithms

abstract:
  Matrix multiplication (GEMM) is a core operation to numerous scientific
applications. Traditional implementations of Strassen-like fast matrix
multiplication (FMM) algorithms often do not perform well except for very large
matrix sizes, due to the increased cost of memory movement, which is
particularly noticeable for non-square matrices. Such implementations also
require considerable workspace and modifications to the standard BLAS
interface. We propose a code generator framework to automatically implement a
large family of FMM algorithms suitable for multiplications of arbitrary matrix
sizes and shapes. By representing FMM with a triple of matrices [U,V,W] that
capture the linear combinations of submatrices that are formed, we can use the
Kronecker product to define a multi-level representation of Strassen-like
algorithms. Incorporating the matrix additions that must be performed for
Strassen-like algorithms into the inherent packing and micro-kernel operations
inside GEMM avoids extra workspace and reduces the cost of memory movement.
Adopting the same loop structures as high-performance GEMM implementations
allows parallelization of all FMM algorithms with simple but efficient data
parallelism without the overhead of task parallelism. We present a simple
performance model for general FMM algorithms and compare actual performance of
20+ FMM algorithms to modeled predictions. Our implementations demonstrate a
performance benefit over conventional GEMM on single core and multi-core
systems. This study shows that Strassen-like fast matrix multiplication can be
incorporated into libraries for practical use.


title:
The impact of (n,$\gamma$) reaction rate uncertainties of unstable
  isotopes near $N=50$ on the i process nucleosynthesis in He-shell flash white
  dwarfs

abstract:
  The first peak s-process elements Rb, Sr, Y and Zr in the post-AGB star
Sakurai's object (V4334 Sagittarii) have been proposed to be the result of
i-process nucleosynthesis in a post-AGB very-late thermal pulse event. We
estimate the nuclear physics uncertainties in the i-process model predictions
to determine whether the remaining discrepancies with observations are
significant and point to potential issues with the underlying astrophysical
model. We find that the dominant source in the nuclear physics uncertainties
are predictions of neutron capture rates on unstable neutron rich nuclei, which
can have uncertainties of more than a factor 20 in the band of the i-process.
We use a Monte Carlo variation of 52 neutron capture rates and a 1D multi-zone
post-processing model for the i-process in Sakurai's object to determine the
cumulative effect of these uncertainties on the final elemental abundance
predictions. We find that the nuclear physics uncertainties are large and
comparable to observational errors. Within these uncertainties the model
predictions are consistent with observations. A correlation analysis of the
results of our MC simulations reveals that the strongest impact on the
predicted abundances of Rb, Sr, Y and Zr is made by the uncertainties in the
(n,$\gamma$) reaction rates of $^{85}$Br, $^{86}$Br, $^{87}$Kr, $^{88}$Kr,
$^{89}$Kr, $^{89}$Rb, $^{89}$Sr, and $^{92}$Sr. (abridged)


title:
Parameter estimation for heavy binary-black holes with networks of
  second-generation gravitational-wave detectors

abstract:
  The era of gravitational-wave astronomy has started with the discovery of the
binary black hole coalescences (BBH) GW150914 and GW151226 by the LIGO
instruments. These systems allowed for the first direct measurement of masses
and spins of black holes. The component masses in each of the systems have been
estimated with uncertainties of over 10\%, with only weak constraints on the
spin magnitude and orientation. In this paper we show how these uncertainties
will be typical for this type of source when using advanced detectors. Focusing
in particular on heavy BBH of masses similar to GW150914, we find that typical
uncertainties in the estimation of the source-frame component masses will be
around 40\%. We also find that for most events the magnitude of the component
spins will be estimated poorly: for only 10\% of the systems the uncertainties
in the spin magnitude of the primary (secondary) BH will be below 0.7 (0.8).
Conversely, the effective spin along the angular momentum can be estimated more
precisely than either spins, with uncertainties below 0.16 for 10\% of the
systems. We also quantify how often large or negligible primary spins can be
excluded, and how often the sign of the effective spin can be measured. We show
how the angle between the spin and the orbital angular momentum can only seldom
be measured with uncertainties below 60$^\circ$. We then investigate how the
measurement of spin parameters depends on the inclination angle and the total
mass of the source. We find that when precession is present, uncertainties are
smaller for systems observed close to edge-on. Contrarily to what happens for
low-mass, inspiral dominated, sources, for heavy BBH we find that large spins
aligned with the orbital angular momentum can be measured with small
uncertainty. We also show how spin uncertainties increase with the total mass.
Finally...


title:
On the impact of large angle CMB polarization data on cosmological
  parameters

abstract:
  (abridged) We study the impact of the large-angle CMB polarization datasets
publicly released by the WMAP and Planck satellites on the estimation of
cosmological parameters of the $\Lambda$CDM model. To complement large-angle
polarization, we consider the high-resolution CMB datasets from either WMAP or
Planck, as well as CMB lensing as traced by Planck. In the case of WMAP, we
compute the large-angle polarization likelihood starting over from
low-resolution frequency maps and their covariance matrices, and perform our
own foreground mitigation technique, which includes as a possible alternative
Planck 353 GHz data to trace polarized dust. We find that the latter choice
induces a downward shift in the optical depth $\tau$, of order ~$2\sigma$,
robust to the choice of the complementary high-l dataset. When the Planck 353
GHz is consistently used to minimize polarized dust emission, WMAP and Planck
70 GHz large-angle polarization data are in remarkable agreement: by combining
them we find $\tau = 0.066 ^{+0.012}_{-0.013}$, again very stable against the
particular choice for high-$\ell$ data. We find that the amplitude of
primordial fluctuations $A_s$, notoriously degenerate with $\tau$, is the
parameter second most affected by the assumptions on polarized dust removal,
but the other parameters are also affected, typically between $0.5$ and
$1\sigma$. In particular, cleaning dust with \planck's 353 GHz data imposes a
$1\sigma$ downward shift in the value of the Hubble constant $H_0$,
significantly contributing to the tension reported between CMB based and direct
measurements of $H_0$. On the other hand, we find that the appearance of the
so-called low $\ell$ anomaly, a well-known tension between the high- and
low-resolution CMB anisotropy amplitude, is not significantly affected by the
details of large-angle polarization, or by the particular high-$\ell$ dataset
employed.


title:
Relations between dynamical degrees, Weil's Riemann hypothesis and the
  standard conjectures

abstract:
  Let $\mathbb{K}$ be an algebraically closed field, $X$ a smooth projective
variety over $\mathbb{K}$ and $f:X\rightarrow X$ a dominant regular morphism.
Let $N^i(X)$ be the group of algebraic cycles modulo numerical equivalence. Let
$\chi (f)$ be the spectral radius of the pullback
$f^*:H^*(X,\mathbb{Q}_l)\rightarrow H^*(X,\mathbb{Q}_l)$ on $l$-adic cohomology
groups, and $\lambda (f)$ the spectral radius of the pullback
$f^*:N^*(X)\rightarrow N^*(X)$. We prove in this paper, by using consequences
of Deligne's proof of Weil's Riemann hypothesis, that $\chi (f)=\lambda (f)$.
This answers affirmatively a question posed by Esnault and Srinivas.
Consequently, the algebraic entropy $\log \chi (f)$ of an endomorphism is both
a birational invariant and \'etale invariant. More general results are proven
if either $\mathbb{K}=\overline{\mathbb{F}_p}$ or the Fundamental Conjecture D
(numerical equivalence vs homological equivalence) holds. Among other results
in the paper, we show that if some properties of dynamical degrees, known in
the case $\mathbb{K}=\mathbb{C}$, hold in positive characteristics, then simple
proofs of Weil's Riemann hypothesis follow.


title: Bayesian fractional posteriors

abstract:
  We consider the fractional posterior distribution that is obtained by
updating a prior distribution via Bayes theorem with a fractional likelihood
function, a usual likelihood function raised to a fractional power. First, we
analyze the contraction property of the fractional posterior in a general
misspecified framework. Our contraction results only require a prior mass
condition on certain Kullback-Leibler (KL) neighborhood of the true parameter
(or the KL divergence minimizer in the misspecified case), and obviate
constructions of test functions and sieves commonly used in the literature for
analyzing the contraction property of a regular posterior. We show through a
counterexample that some condition controlling the complexity of the parameter
space is necessary for the regular posterior to contract, rendering additional
flexibility on the choice of the prior for the fractional posterior. Second, we
derive a novel Bayesian oracle inequality based on a PAC-Bayes inequality in
misspecified models. Our derivation reveals several advantages of averaging
based Bayesian procedures over optimization based frequentist procedures. As an
application of the Bayesian oracle inequality, we derive a sharp oracle
inequality in the convex regression problem under an arbitrary dimension. We
also illustrate the theory in Gaussian process regression and density
estimation problems.


title:
Quantum Floquet anomalous Hall states and quantized ratchet effect in
  one-dimensional dimer chain driven by two ac electric fields

abstract:
  In condensed matter physics, one of the major topics is to find out and
classify interesting novel topological matters and phenomena. Topologically
nontrivial systems can also be achieved by using periodical driving fields. On
the other hand, ratchet effect can be used to collect useful work from
fluctuations or realize directed transport in periodically-driven systems.
Here, we promote a dimer chain by applying two mutually-perpendicular ac
electric fields, and obtain an effective two-dimensional Hamiltonian in the
low-frequency regime. We thereby derive quantum Floquet anomalous Hall (QFAH)
conductance and then find a quantized ratchet effect in the resulting current
along the chain. Our further analysis shows that these originate from the
electric fields only. This lengthwise quantized ratchet effect without magnetic
field should be useful to designing novel high-performance electronic
applications.


title: Plasma Waves as a Benchmark Problem

abstract:
  A large number of wave modes exist in a magnetized plasma. Their properties
are determined by the interaction of particles and waves. In a simulation code,
the correct treatment of field quantities and particle behavior is essential to
correctly reproduce the wave properties. Consequently, plasma waves provide
test problems that cover a large fraction of the simulation code.
  The large number of possible wave modes and the freedom to choose parameters
make the selection of test problems time consuming and comparison between
different codes difficult. This paper therefore aims to provide a selection of
test problems, based on different wave modes and with well defined parameter
values, that is accessible to a large number of simulation codes to allow for
easy benchmarking and cross validation.
  Example results are provided for a number of plasma models. For all plasma
models and wave modes that are used in the test problems, a mathematical
description is provided to clarify notation and avoid possible misunderstanding
in naming.


title:
Room temperature multiferroism in polycrystalline thin films of gallium
  ferrite

abstract:
  Sol-gel deposited (010) textured polycrystalline thin films of gallium
ferrite (GaFeO3 or GFO) on n-Si(100) and Pt/Si(111) substrates are
characterized for room temperature multiferroism. Structural characterization
using X-ray diffraction and Raman spectroscopy confirms formation of single
phase with nano-sized crystallites. Temperature dependent magnetization study
demonstrates ferri to paramagnetic transition at ~300 K. Room temperature
piezoresponse force microscopic analysis reveals local 180 degree phase
switching of ferroelectric domains at very high coercive field EC, ~ 1350 kV/cm
consistent with recent experimental and first-principles studies. Our study
opens up possibility of integrating polycrystalline GFO in novel room
temperature multiferroic devices.


title: Cross: Efficient Low-rank Tensor Completion

abstract:
  The completion of tensors, or high-order arrays, attracts significant
attention in recent research. Current literature on tensor completion primarily
focuses on recovery from a set of uniformly randomly measured entries, and the
required number of measurements to achieve recovery is not guaranteed to be
optimal. In addition, the implementation of some previous methods is NP-hard.
In this article, we propose a framework for low-rank tensor completion via a
novel tensor measurement scheme we name Cross. The proposed procedure is
efficient and easy to implement. In particular, we show that a third order
tensor of Tucker rank-$(r_1, r_2, r_3)$ in $p_1$-by-$p_2$-by-$p_3$ dimensional
space can be recovered from as few as $r_1r_2r_3 + r_1(p_1-r_1) + r_2(p_2-r_2)
+ r_3(p_3-r_3)$ noiseless measurements, which matches the sample complexity
lower-bound. In the case of noisy measurements, we also develop a theoretical
upper bound and the matching minimax lower bound for recovery error over
certain classes of low-rank tensors for the proposed procedure. The results can
be further extended to fourth or higher-order tensors. Simulation studies show
that the method performs well under a variety of settings. Finally, the
procedure is illustrated through a real dataset in neuroimaging.


title:
Pilot Distribution Optimization and Power Control in Multi-Cellular
  Large Scale MIMO Systems

abstract:
  Massive MIMO communication systems have been identified as one of the most
prominent technologies of the next generation wireless standards, such as 5G,
due to the large gains in energy and spectral efficiency that can be achieved.
In the asymptotic condition of infinite number of antennas at the base station
(BS), the performance bottleneck of these systems is due to the pilot
contamination effect, i.e., the directional interference arising from users in
adjacent cells that reuse the same set of orthogonal training sequences, and
thus the interference seen by each user is determined by the pilot sequence
assigned to him. We show in this paper that the system performance can be
improved by appropriately assigning the pilot sequences to the users, in the
so-called pilot allocation scheme. Depending on the optimization metric
adopted, it is more advantageous to a user with certain long- term fading
coefficient be assigned to a specific pilot sequence, whose interference can be
completely estimated in advance by the BS by only knowing the long term fading
coefficients of users in adjacent cells. Besides, if the objective is to
maximize the number of users with a target quality of service, we have shown
that the pilot allocation schemes can be combined with power control
algorithms, resulting in much more improvements for the system. For unitary
frequency reuse factor, we have found that the data throughput provided for 95%
of the users increases when applying power control algorithm from 134kbps to
1.461Mbps with no pilot allocation, while this performance gain provided by
power control changes from 793kbps to 6.743Mbps when pilot allocation is
employed. If the reuse factor increases to 3, a 95%-likely data throughput of
17.310Mbps can be assured when pilot allocation and power control are suitably
combined.


title: Thermodynamic Volume of Cosmological Solitons

abstract:
  We present explicit expressions of the thermodynamic volume inside and
outside the cosmological horizon of Eguchi-Hanson solitons in general odd
dimensions. These quantities are calculable and well-defined regardless of
whether or not the regularity condition for the soliton is imposed. For the
inner case, we show that the reverse isoperimetric inequality is not satisfied
for general values of the soliton parameter $a$, though a narrow range exists
for which the inequality does hold. For the outer case, we find that the mass
$M_{out}$ satisfies the maximal mass conjecture and the volume is positive. We
also show that, by requiring $M_{out}$ to yield the mass of dS spacetime when
the soliton parameter vanishes, the associated cosmological volume is always
positive.


title: Boundary relative extremal functions

abstract:
  We give alternative definitions of the boundary relative extremal function
and show that Edwards' theorem does not hold in open sets.


title: Defects and boundary RG flows in $\mathbb{C}/\mathbb{Z}_d$

abstract:
  We show that topological defects in the language of Landau-Ginzburg models
carry information about the RG flow between the non-compact orbifolds
$\mathbb{C}/\mathbb{Z}_d$. We show that such defects correctly implement the
bulk-induced RG flow on the boundary.


title:
Pairwise entanglement and the Mott transition for correlated electrons
  in nanochains

abstract:
  Pairwise entanglement, calculated separately for charge and spin degrees of
freedom, is proposed as a ground-state signature of the Mott transition in
correlated nanoscopic systems. Utilizing the exact diagonalization - ab initio
method (EDABI), for chains containing $N\leqslant{}16$ hydrogenic-like atoms
(at the half filling), we find that the vanishing of the nearest-neighbor
charge concurrence indicates the crossover from a partly-localized quantum
liquid to the Mott insulator. Spin concurrence remains nonzero at the
insulating phase, showing that the decopling of spin and charge degrees of
freedom may manifest itself by wavefunctions entangled in spin, but separable
in charge coordinates. At the quarter filling, the analysis for
$N\leqslant{}20$ shows that spin concurrence vanishes immediately when the
charge-energy gap obtained from the scaling with $1/N\rightarrow{}0$ vanishes,
constituting a finite-system version of the Mott transition. Analytic
derivations of the formulas expressing either charge or spin concurrence in
terms of ground-state correlation functions are also provided.


title:
Contribution to the neutrino magnetic moment coming from 2HDM in
  presence of magnetic fields

abstract:
  The confirmation of the neutrino mass by oscillation phenomena converts the
study of the magnetic dipole moment (MDM) of the neutrino, in vacuum and
regions where existing external magnetic fields, a topic of particular interest
from the theoretical point of view. The MDM has an implicit relation with
neutrino masses, and this is a possible benchmark from new physics in the
solution of open questions in neutrino physics. Besides we know that this kind
of phenomena has significant consequences on cosmology and astrophysics, e.g.,
under the influence of combined effects of neutrinos in the compact objects
formation and evolution of primordials magnetic fields. We calculate and
analyze such effects introducing charged Higgs bosons based on the parameter
space of several 2HDMs with and without flavor conservation in neutral
currents.


title: Study Of Boosted W-Jets And Higgs-Jets With the SiFCC Detector

abstract:
  We study the detector performance in the reconstruction of
hadronically-decaying W bosons and Higgs bosons at very high energy proton
colliders using a full GEANT4 simulation of the SiFCC detector. The W and Higgs
bosons carry transverse momentum in the multi-TeV range, which results in
collimated decay products that are reconstructed as a single jet. We present a
measurement of the energy response and resolution of boosted W-jets and
Higgs-jets and show the separation of two sub-jets within the boosted boson
jet.


title: A Memory Bandwidth-Efficient Hybrid Radix Sort on GPUs

abstract:
  Sorting is at the core of many database operations, such as index creation,
sort-merge joins, and user-requested output sorting. As GPUs are emerging as a
promising platform to accelerate various operations, sorting on GPUs becomes a
viable endeavour. Over the past few years, several improvements have been
proposed for sorting on GPUs, leading to the first radix sort implementations
that achieve a sorting rate of over one billion 32-bit keys per second. Yet,
state-of-the-art approaches are heavily memory bandwidth-bound, as they require
substantially more memory transfers than their CPU-based counterparts.
  Our work proposes a novel approach that almost halves the amount of memory
transfers and, therefore, considerably lifts the memory bandwidth limitation.
Being able to sort two gigabytes of eight-byte records in as little as 50
milliseconds, our approach achieves a 2.32-fold improvement over the
state-of-the-art GPU-based radix sort for uniform distributions, sustaining a
minimum speed-up of no less than a factor of 1.66 for skewed distributions.
  To address inputs that either do not reside on the GPU or exceed the
available device memory, we build on our efficient GPU sorting approach with a
pipelined heterogeneous sorting algorithm that mitigates the overhead
associated with PCIe data transfers. Comparing the end-to-end sorting
performance to the state-of-the-art CPU-based radix sort running 16 threads,
our heterogeneous approach achieves a 2.06-fold and a 1.53-fold improvement for
sorting 64 GB key-value pairs with a skewed and a uniform distribution,
respectively.


title: Revealing the Hidden Structural Phases of FeRh

abstract:
  ${\it Ab}$ ${\it initio}$ electronic structure calculations reveal that
tetragonal distortion has a dramatic effect on the relative stability of the
various magnetic structures (C-, A-, G-, A$'$-AFM, and FM) of FeRh giving rise
to a wide range of novel stable/metastable structures and magnetic phase
transitions between these states. We predict that the ${\it cubic}$ G-AFM
structure, which was believed thus far to be the ground state, is metastable
and that the ${\it tetragonally}$ expanded G-AFM is the stable structure. The
low energy barrier separating these states suggests phase coexistence at room
temperature. We propose a novel A$'$-AFM phase to be the ${\it global}$ ground
state among all magnetic phases which arises from the strain-induced tuning of
the exchange interactions. The results elucidate the underlying mechanism for
the recent experimental findings of electric-field control of magnetic phase
transition driven via tetragonal strain. The novel magnetic phase transitions
open interesting prospects for exploiting strain engineering for the
next-generation memory devices.


title: High-rate field demonstration of large-alphabet quantum key distribution

abstract:
  Quantum key distribution (QKD) exploits the quantum nature of light to share
provably secure keys, allowing secure communication in the presence of an
eavesdropper. The first QKD schemes used photons encoded in two states, such as
polarization. Recently, much effort has turned to large-alphabet QKD schemes,
which encode photons in high-dimensional basis states. Compared to
binary-encoded QKD, large-alphabet schemes can encode more secure information
per detected photon, boosting secure communication rates, and also provide
increased resilience to noise and loss. High-dimensional encoding may also
improve the efficiency of other quantum information processing tasks, such as
performing Bell tests and implementing quantum gates. Here, we demonstrate a
large-alphabet QKD protocol based on high-dimensional temporal encoding. We
achieve record secret-key rates and perform the first field demonstration of
large-alphabet QKD. This demonstrates a new, practical way to optimize
secret-key rates and marks an important step towards transmission of
high-dimensional quantum states in deployed networks.


title:
The structure of fixed-point tensor network states characterizes
  patterns of long-range entanglement

abstract:
  The algebraic structure of representation theory naturally arises from 2D
fixed-point tensor network states, which conceptually formulates the pattern of
long-range entanglement realized in such states. In 3D, the same underlying
structure is also shared by Turaev-Viro state-sum topological quantum field
theory (TQFT). We show that a 2D fixed-point tensor network state arises
naturally on the boundary of the 3D manifold on which the TQFT is defined, and
the fact that exactly the same information is needed to construct either the
tensor network or the TQFT is made explicit in a form of holography.
Furthermore, the entanglement of the fixed-point states leads to an emergence
of pre-geometry in the 3D TQFT bulk. We further extend these ideas to the case
where an additional global onsite unitary symmetry is imposed on the tensor
network states.


title: Extension Theorems for Various Weight Functions over Frobenius Bimodules

abstract:
  In this paper we study codes where the alphabet is a finite Frobenius
bimodule over a finite ring. We discuss the extension property for various
weight functions. Employing an entirely character-theoretic approach and a
duality theory for partitions on Frobenius bimodules we derive alternative
proofs for the facts that the Hamming weight and the homogeneous weight satisfy
the extension property. We also use the same techniques to derive the extension
property for other weights, such as the Rosenbloom-Tsfasman weight.


title: Using a Deep Reinforcement Learning Agent for Traffic Signal Control

abstract:
  Ensuring transportation systems are efficient is a priority for modern
society. Technological advances have made it possible for transportation
systems to collect large volumes of varied data on an unprecedented scale. We
propose a traffic signal control system which takes advantage of this new, high
quality data, with minimal abstraction compared to other proposed systems. We
apply modern deep reinforcement learning methods to build a truly adaptive
traffic signal control agent in the traffic microsimulator SUMO. We propose a
new state space, the discrete traffic state encoding, which is information
dense. The discrete traffic state encoding is used as input to a deep
convolutional neural network, trained using Q-learning with experience replay.
Our agent was compared against a one hidden layer neural network traffic signal
control agent and reduces average cumulative delay by 82%, average queue length
by 66% and average travel time by 20%.


title: Quasiparticle decay in a one-dimensional Bose-Fermi mixture

abstract:
  In a one-dimensional weakly interacting Bose-Fermi mixture one branch of
elementary excitations is well described by the Bogoliubov spectrum. Here we
use the microscopic theory to study the decay of such quasiparticle
excitations. The main scattering process which leads to their decay is the
backscattering of a Bogoliubov quasiparticle off the Fermi sea, where a
particle-hole pair is excited. For a low-momentum quasiparticle (phonon) of
momentum $q$, we find that the decay rate scales as $q^3$ provided $q$ is
smaller than the Fermi momentum $k_F$, while in the opposite case the decay
behaves as $q^2$. If the ratio of the masses of fermions and bosons equals to
the ratio of the boson-fermion and the boson-boson interaction strengths, the
decay rate changes dramatically. It scales as $q^7$ for $q<k_F$ while we find
$q^6$ scaling at $q>k_F$. For a high momentum Bogoliubov quasiparticle, we find
a constant decay rate for $q<k_F$, while it scales as $1/q$ for $q>k_F$. We
also find an analytic expression for the decay rate in the crossover region
between low and high momenta. The decay rate is a continuous, but nonanalytic
function of the momentum at $q=k_F$. In the special case when the parameters of
our system correspond to the integrable model, we observe that the decay rate
vanishes.


title: Categorical Reparameterization with Gumbel-Softmax

abstract:
  Categorical variables are a natural choice for representing discrete
structure in the world. However, stochastic neural networks rarely use
categorical latent variables due to the inability to backpropagate through
samples. In this work, we present an efficient gradient estimator that replaces
the non-differentiable sample from a categorical distribution with a
differentiable sample from a novel Gumbel-Softmax distribution. This
distribution has the essential property that it can be smoothly annealed into a
categorical distribution. We show that our Gumbel-Softmax estimator outperforms
state-of-the-art gradient estimators on structured output prediction and
unsupervised generative modeling tasks with categorical latent variables, and
enables large speedups on semi-supervised classification.


title: Exploring the Kibble-Zurek mechanism with homogeneous Bose gases

abstract:
  Out-of-equilibrium phenomena is a subject of considerable interest in many
fields of physics. Ultracold quantum gases, which are extremely clean,
well-isolated and highly controllable systems, offer ideal platforms to
investigate this topic. The recent progress in tailoring trapping potentials
now allows the experimental production of homogeneous samples in custom
geometries, which is a key advance for studies of the emergence of coherence in
interacting quantum systems. Here we review recent experiments in which
temperature quenches have been performed across the Bose-Einstein condensation
(BEC) phase transition in an annular geometry and in homogeneous 3D and
quasi-2D gases. Combined, these experiments give a comprehensive picture of the
Kibble-Zurek (KZ) scenario through complementary measurements of correlation
functions and topological defects density. They also allow the measurement of
KZ scaling laws, the direct confirmation of the "freeze-out" hypothesis that
underlies the KZ theory, and the extraction of critical exponents of the
Bose-Einstein condensation transition.


title: Finding Approximate Local Minima Faster than Gradient Descent

abstract:
  We design a non-convex second-order optimization algorithm that is guaranteed
to return an approximate local minimum in time which scales linearly in the
underlying dimension and the number of training examples. The time complexity
of our algorithm to find an approximate local minimum is even faster than that
of gradient descent to find a critical point. Our algorithm applies to a
general class of optimization problems including training a neural network and
other non-convex objectives arising in machine learning.


title: Quasi-polynomial mixing of critical 2D random cluster models

abstract:
  We study the Glauber dynamics for the random cluster (FK) model on the torus
$(\mathbb{Z}/n\mathbb{Z})^2$ with parameters $(p,q)$, for $q \in (1,4]$ and $p$
the critical point $p_c$. The dynamics is believed to undergo a critical
slowdown, with its continuous-time mixing time transitioning from $O(\log n)$
for $p\neq p_c$ to a power-law in $n$ at $p=p_c$. This was verified at $p\neq
p_c$ by Blanca and Sinclair, whereas at the critical $p=p_c$, with the
exception of the special integer points $q=2,3,4$ (where the model corresponds
to the Ising/Potts models) the best-known upper bound on mixing was exponential
in $n$. Here we prove an upper bound of $n^{O(\log n)}$ at $p=p_c$ for all
$q\in (1,4]$, where a key ingredient is bounding the number of nested
long-range crossings at criticality.


title: Can Big Media Data Revolutionarize Gun Violence Prevention?

abstract:
  The scientific method drives improvements in public health, but a strategy of
obstructionism has impeded scientists from gathering even a minimal amount of
information to address America's gun violence epidemic. We argue that in spite
of a lack of federal investment, large amounts of publicly available data offer
scientists an opportunity to measure a range of firearm-related behaviors.
Given the diversity of available data - including news coverage, social media,
web forums, online advertisements, and Internet searches (to name a few) -
there are ample opportunities for scientists to study everything from trends in
particular types of gun violence to gun-related behaviors (such as purchases
and safety practices) to public understanding of and sentiment towards various
gun violence reduction measures. Science has been sidelined in the gun violence
debate for too long. Scientists must tap the big media data stream and help
resolve this crisis.


title:
Band Excitations in CePd$_3$: A Comparison of Neutron Scattering and ab
  initio Theory

abstract:
  Intermediate valence compounds containing rare earth or actinide ions are
archetypal systems for the investigation of strong electron correlations. Their
effective electron masses of 10 to 50 times the free electron mass result from
a hybridization of the highly localized $f$-electrons with the more itinerant
$d$-electrons, which is strong enough that their properties are dominated by
on-site electron correlations. To a remarkable degree, this can be modeled by
the Anderson Impurity Model, even though the $f$-electrons are situated on a
periodic lattice. However, in recent years, there has been increasing evidence
that the dynamic magnetic susceptibility of intermediate valence compounds is
not purely local, but shows variations across the Brillouin zone that have been
ascribed to $f$-band coherence. So far, this has been based on simplified
qualitative models. In this article, we present a quantitative comparison of
inelastic neutron scattering from a single crystal of CePd$_3$, measured in
four-dimensional (Q,$\omega$)-space, with ab initio calculations, which are in
excellent agreement on an absolute scale. Our results establish that the
Q-dependence of the scattering is caused by particle-hole excitations within
$f$-$d$ hybridized bands that grow in coherence with decreasing temperature.


title: Generalized master equations leading to completely positive dynamics

abstract:
  We provide a general construction of quantum generalized master equations
with memory kernel leading to well defined, that is completely positive and
trace preserving, time evolutions. The approach builds on an operator
generalization of memory kernels appearing in the description of non-Markovian
classical processes, and puts into evidence the non uniqueness of the
relationship arising due to the typical quantum issue of operator ordering. The
approach provides a physical interpretation of the structure of the kernels,
and its connection with the classical viewpoint allows for a trajectory
description of the dynamics. Previous apparently unrelated results are now
connected in a unified framework, which further allows to phenomenologically
construct a large class of non-Markovian evolutions taking as starting point
collections of time dependent maps and instantaneous transformations describing
the microscopic interaction dynamics.


title:
Common Origin of Two RR Lyrae Populations and the Double Red Clump in
  the Milky Way Bulge

abstract:
  A recent survey toward the Milky Way bulge has discovered two sequences of RR
Lyrae stars on the period-amplitude diagram with a maximum period-shift of
{\Delta}log P = 0.015 between the two populations. Here we show, from our
synthetic horizontal-branch models, that this period-shift is most likely due
to the small difference in helium abundance ({\Delta}Y = 0.012) between the
first and second-generation stars (G1 and G2), as is the case in our models for
the inner halo globular clusters with similar metallicity ([Fe/H] = -1.1). We
further show that the observed double red clump (RC) in the bulge is naturally
reproduced when these models are extended to solar metallicity following
{\Delta}Y/{\Delta}Z = 6 for G2, as would be expected from the chemical
evolution models. Therefore, the two populations of RR Lyrae stars and the
double RC observed in the bulge appear to be different manifestations of the
same multiple population phenomenon in the metal-poor and metal-rich regimes
respectively.


title:
Visualisation of massive data from scholarly Article and Journal
  Database A Novel Scheme

abstract:
  Scholarly articles publishing and getting cited has become a way of life for
academicians. These scholarly publications shape up the career growth of not
only the authors but also of the country, continent and the technological
domains. Author affiliations, country and other information of an author
coupled with data analytics can provide useful and insightful results. However,
massive and complete data is required to perform this research. Google scholar
which is a comprehensive and free repository of scholarly articles has been
used as a data source for this purpose. Data scraped from Google scholar when
stored as a graph and visualized in the form of nodes and relationships, can
offer discerning and concealed information. Such as, evident domain shift of an
author, various research domains spread for an author, prediction of emerging
domain and sub domains, detection of journal and author level citation cartel
behaviors etc. The data from graph database is also used in computation of
scholastic indicators for the journals. Eventually, econometric model, named
Cobb Douglas model is used to compute the journals Modeling "Internationality"
Index based on these scholastic indicators.


title: On Perfectness of Intersection Graph of Ideals of $\mathbb{Z}_n$

abstract:
  In this paper, we characterize the positive integers $n$ for which
intersection graph of ideals of $\mathbb{Z}_n$ is perfect.


title:
Dualities of Deformed $\mathcal{N=2}$ SCFTs from Link Monodromy on
  D3-brane States

abstract:
  We study D3-brane theories that are dually described as deformations of two
different $\mathcal{N}=2$ superconformal theories with massless monopoles and
dyons. These arise at the self-intersection of a seven-brane in F-theory, which
cuts out a link on a small three-sphere surrounding the self-intersection. The
spectrum is studied by taking small loops in the three-sphere, yielding a
link-induced monodromy action on string junction D3-brane states, and
subsequently quotienting by the monodromy. This reduces the differing flavor
algebras of the $\mathcal{N}=2$ theories to the same flavor algebra, as
required by duality, and projects out charged states, yielding an
$\mathcal{N}=1$ superconformal theory on the D3-brane. In one, a deformation of
a rank one Argyres-Douglas theory retains its $SU(2)$ flavor symmetry and
exhibits a charge neutral flavor triplet that is comprised of electron, dyon,
and monopole string junctions. From duality we argue that the monodromy
projection should also be imposed away from the conformal point, in which case
the D3-brane field theory appears to exhibit confinement of electrons, dyons,
and monopoles. We will address the mathematical counterparts in a companion
paper.


title: Central stars of mid-infrared nebulae discovered with Spitzer and WISE

abstract:
  Searches for compact mid-IR nebulae with the Spitzer Space Telescope and the
Wide-field Infrared Survey Explorer (WISE), accompanied by spectroscopic
observations of central stars of these nebulae led to the discovery of many
dozens of massive stars at different evolutionary stages, of which the most
numerous are candidate luminous blue variables (LBVs). In this paper, we give a
census of candidate and confirmed Galactic LBVs revealed with Spitzer and WISE,
and present some new results of spectroscopic observations of central stars of
mid-IR nebulae.


title:
Merger-induced Shocks in the Nearby LIRG VV 114 through Methanol
  Observations with ALMA

abstract:
  We report the detection of two CH$_3$OH lines (J$_K$ = 2$_K$-1$_K$ and
3$_K$-2$_K$) between the progenitor's disks ("Overlap") of the mid-stage
merging galaxy VV 114 obtained using the Atacama Large Millimeter/submillimeter
Array (ALMA) Band 3 and Band 4. The detected CH$_3$OH emission show an extended
filamentary structure (~ 3 kpc) across the progenitor's disks with relatively
large velocity width (FWZI ~ 150 km/s). The emission is only significant in the
"overlap" and not detected in the two merging nuclei. Assuming optically-thin
emission and local thermodynamic equilibrium (LTE), we found the CH$_3$OH
column density relative to H$_2$ ($X_{\rm CH_3OH}$) peaks at the "Overlap" (~ 8
$\times$ 10$^{-9}$), which is almost an order of magnitude larger than that at
the eastern nucleus. We suggest that kpc-scale shocks driven by galaxy-galaxy
collision may play an important role to enhance the CH$_3$OH abundance at the
"Overlap". This scenario is consistent with that shock-induced large velocity
dispersion components of ionized gas have been detected in optical wavelength
at the same region. Conversely, low $X_{\rm CH_3OH}$ at the nuclear regions
might be attributed to the strong photodissociation by nuclear starbursts
and/or putative active galactic nucleus (AGN), or inefficient production of
CH$_3$OH on dust grains due to initial high temperature conditions (i.e.,
desorption of the precursor molecule, CO, into gas-phase before forming
CH$_3$OH on dust grains). These ALMA observations demonstrate that CH$_3$OH is
a unique tool to address kpc-scale shock-induced gas dynamics and star
formation in merging galaxies.


title: The Black Hole Mass Function from Gravitational Wave Measurements

abstract:
  We examine how future gravitational-wave measurements from merging black
holes (BHs) can be used to infer the shape of the black-hole mass function,
with important implications for the study of star formation and evolution and
the properties of binary BHs. We model the mass function as a power law,
inherited from the stellar initial mass function, and introduce lower and upper
mass cutoff parameterizations in order to probe the minimum and maximum BH
masses allowed by stellar evolution, respectively. We initially focus on the
heavier BH in each binary, to minimize model dependence. Taking into account
the experimental noise, the mass measurement errors and the uncertainty in the
redshift-dependence of the merger rate, we show that the mass function
parameters, as well as the total rate of merger events, can be measured to <10%
accuracy within a few years of advanced LIGO observations at its design
sensitivity. This can be used to address important open questions such as the
upper limit on the stellar mass which allows for BH formation and to confirm or
refute the currently observed mass gap between neutron stars and BHs. In order
to glean information on the progenitors of the merging BH binaries, we then
advocate the study of the two-dimensional mass distribution to constrain
parameters that describe the two-body system, such as the mass ratio between
the two BHs, in addition to the merger rate and mass function parameters. We
argue that several years of data collection can efficiently probe models of
binary formation, and show, as an example, that the hypothesis that some
gravitational-wave events may involve primordial black holes can be tested.
Finally, we point out that in order to maximize the constraining power of the
data, it may be worthwhile to lower the signal-to-noise threshold imposed on
each candidate event and amass a larger statistical ensemble of BH mergers.


title:
The K2 M67 Study: An Evolved Blue Straggler in M67 from K2 Mission
  Asteroseismology

abstract:
  Yellow straggler stars (YSSs) fall above the subgiant branch in optical
color-magnitude diagrams, between the blue stragglers and the red giants. YSSs
may represent a population of evolved blue stragglers, but none have the direct
and precise mass and radius measurements needed to determine their evolutionary
states and formation histories. Here we report the first asteroseismic mass and
radius measurements of such a star, the yellow straggler S1237 in the open
cluster M67. We apply asteroseismic scaling relations to a frequency analysis
of the Kepler K2 light curve and find a mass of 2.9 $\pm$ 0.2 M$_{\odot}$ and a
radius of 9.2 $\pm$ 0.2 R$_{\odot}$. This is more than twice the mass of the
main- sequence turnoff in M67, suggesting S1237 is indeed an evolved blue
straggler. S1237 is the primary in a spectroscopic binary. We update the binary
orbital solution and use spectral energy distribution (SED) fitting to
constrain the color-magnitude diagram (CMD) location of the secondary star. We
find that the secondary is likely an upper main-sequence star near the turnoff,
but a slightly hotter blue straggler companion is also possible. We then
compare the asteroseismic mass of the primary to its mass from CMD fitting,
finding the photometry implies a mass and radius more than 2$\sigma$ below the
asteroseismic measurement. Finally, we consider formation mechanisms for this
star and suggest that S1237 may have formed from dynamical encounters resulting
in stellar collisions or a binary merger.


title:
Dynamical ejecta from precessing neutron star-black hole mergers with a
  hot, nuclear-theory based equation of state

abstract:
  Neutron star-black hole binaries are among the strongest sources of
gravitational waves detectable by current observatories. They can also power
bright electromagnetic signals (gamma-ray bursts, kilonovae), and may be a
significant source of production of r-process nuclei. A misalignment of the
black hole spin with respect to the orbital angular momentum leads to
precession of that spin and of the orbital plane, and has a significant effect
on the properties of the post-merger remnant and of the material ejected by the
merger. We present a first set of simulations of precessing neutron star-black
hole mergers using a hot, composition dependent, nuclear-theory based equation
of state (DD2). We show that the mass of the remnant and of the dynamical
ejecta are broadly consistent with the result of simulations using simpler
equations of state, while differences arise when considering the dynamics of
the merger and the velocity of the ejecta. We show that the latter can easily
be understood from assumptions about the composition of low-density, cold
material in the different equations of state, and propose an updated estimate
for the ejecta velocity which takes those effects into account. We also present
an updated mesh-refinement algorithm which allows us to improve the numerical
resolution used to evolve neutron star-black hole mergers.


title:
Cosmology with Phase Statistics: Parameter Forecasts and Detectability
  of BAO

abstract:
  We consider an alternative to conventional three-point statistics such as the
bispectrum, which is purely based on the Fourier phases of the density field:
the line correlation function. This statistic directly probes the non-linear
clustering regime and contains information highly complementary to that
contained in the power spectrum. In this work, we determine, for the first
time, its potential to constrain cosmological parameters and detect baryon
acoustic oscillations (hereafter BAOs). We show how to compute the line
correlation function for a discrete sampled set of tracers that follow a local
Lagrangian biasing scheme and demonstrate how it breaks the degeneracy between
the amplitude of density fluctuations and the bias parameters of the model. We
then derive analytic expressions for its covariance and show that it can be
written as a sum of a Gaussian piece plus non-Gaussian corrections. We compare
our predictions with a large ensemble of $N$-body simulations and confirm that
BAOs do indeed modulate the signal of the line correlation function for scales
$50$-$100\,h^{-1}\,\mathrm{Mpc}$, and that the characteristic S-shape feature
would be detectable in upcoming Stage IV surveys at the level of $\sim4\sigma$.
We then focus on the cosmological information content and compute Fisher
forecasts for an idealized Stage III galaxy redshift survey of volume $V\sim
10\,h^{-3}\,\mathrm{Gpc}^3$ and out to $z=1$. We show that, combining the line
correlation function with the galaxy power spectrum and a Planck-like microwave
background survey, yields improvements up to a factor of two for parameters
such as $\sigma_8$, $b_1$ and $b_2$, compared to using only the two-point
information alone.


title:
From Mirrors to Windows: Lyman-Alpha Radiative Transfer in a Very Clumpy
  Medium

abstract:
  Lyman-Alpha (Ly$\alpha$) is the strongest emission line in the Universe and
is frequently used to detect and study the most distant galaxies. Because Lya
is a resonant line, photons typically scatter prior to escaping; this
scattering process complicates the interpretation of Ly$\alpha$ spectra, but
also encodes a wealth of information about the structure and kinematics of
neutral gas in the galaxy. Modeling the Ly$\alpha$ line therefore allows us to
study tiny-scale features of the gas, even in the most distant galaxies.
Curiously, observed Ly$\alpha$ spectra can be modeled successfully with very
simple, homogeneous geometries (such as an expanding, spherical shell), whereas
more realistic, multiphase geometries often fail to reproduce the observed
spectra. This seems paradoxical since the gas in galaxies is known to be
multiphase. In this Letter, we show that spectra emerging from extremely clumpy
geometries with many clouds along the line of sight converge to the predictions
from simplified, homogeneous models. We suggest that this resolves the apparent
discrepancy, and may provide a way to study the gas structure in galaxies on
scales far smaller than can be probed in either cosmological simulations or
direct (i.e., spatially-resolved) observations.


title: Type Ia Supernovae: Colors, Rates, and Progenitors

abstract:
  The rate of type Ia supernovae (SNe Ia) in a galaxy depends not only on
stellar mass, but also on star formation history. Here we show that two simple
observational quantities ($g-r$ or $u-r$ host galaxy color, and $r$-band
luminosity), coupled with an assumed delay time distribution (the rate of SNe
Ia as a function of time for an instantaneous burst of star formation), are
sufficient to accurately determine a galaxy's SN Ia rate, with very little
sensitivity to the precise details of the star formation history. Using this
result, we compare observed and predicted color distributions of SN Ia hosts
for the MENeaCS cluster supernova survey, and for the SDSS Stripe 82 supernova
survey. The observations are consistent with a continuous delay time
distribution (DTD), without any cutoff. For old progenitor systems the
power-law slope for the DTD is found to be $-1.50 ^{+0.19} _{-0.15}$. This
result favours the double degenerate scenario for SN Ia, though other
interpretations are possible. We find that the late-time slopes of the delay
time distribution are different at the 1$\sigma$ level for low and high stretch
supernova, which suggest a single degenerate scenario for the latter. However,
due to ambiguity in the current models' DTD predictions, single degenerate
progenitors can neither be confirmed as causing high stretch supernovae nor
ruled out from contributing to the overall sample.


title:
Strongly anomalous non-thermal fixed point in a quenched two-dimensional
  Bose gas

abstract:
  Universal scaling behavior in the relaxation dynamics of an isolated
two-dimensional Bose gas is studied by means of semi-classical stochastic
simulations of the Gross-Pitaevskii model. The system is quenched far out of
equilibrium by imprinting vortex defects into an otherwise phase-coherent
condensate. A strongly anomalous non-thermal fixed point is identified,
associated with a slowed decay of the defects in the case that the dissipative
coupling to the thermal background noise is suppressed. At this fixed point, a
large anomalous exponent $\eta \simeq -3$ and, related to this, a large
dynamical exponent $z \simeq 5$ are identified. The corresponding power-law
decay is found to be consistent with three-vortex-collision induced loss. The
article discusses these aspects of non-thermal fixed points in the context of
phase-ordering kinetics and coarsening dynamics, thus relating phenomenological
and analytical approaches to classifying far-from-equilibrium scaling dynamics
with each other. In particular, a close connection between the anomalous
scaling exponent $\eta$, introduced in a quantum-field theoretic approach, and
conservation-law induced scaling in classical phase-ordering kinetics is
revealed. Moreover, the relation to superfluid turbulence as well as to driven
stationary systems is discussed.

categories: cond-mat.quant-gas cond-mat.stat-mech hep-ph physics.flu-dyn


title: Sensitive Dependence of Optimal Network Dynamics on Network Structure

abstract:
  The relation between network structure and dynamics is determinant for the
behavior of complex systems in numerous domains. An important long-standing
problem concerns the properties of the networks that optimize the dynamics with
respect to a given performance measure. Here we show that such optimization can
lead to sensitive dependence of the dynamics on the structure of the network.
Specifically, using diffusively coupled systems as examples, we demonstrate
that the stability of a dynamical state can exhibit sensitivity to unweighted
structural perturbations (i.e., link removals and node additions) for
undirected optimal networks and to weighted perturbations (i.e., small changes
in link weights) for directed optimal networks. As mechanisms underlying this
sensitivity, we identify discontinuous transitions occurring in the complement
of undirected optimal networks and the prevalence of eigenvector degeneracy in
directed optimal networks. These findings establish a unified characterization
of networks optimized for dynamical stability, which we illustrate using Turing
instability in activator-inhibitor systems, synchronization in power-grid
networks, network diffusion, and several other network processes. Our results
suggest that the network structure of a complex system operating near an
optimum can potentially be fine-tuned for a significantly enhanced stability
compared to what one might expect from simple extrapolation. On the other hand,
they also suggest constraints on how close to the optimum the system can be in
practice. Finally, the results have potential implications for biophysical
networks, which have evolved under the competing pressures of optimizing
fitness while remaining robust against perturbations.


title: Sharpening the shape analysis for higher-dimensional operator searches

abstract:
  When the Standard Model is interpreted as the renormalizable sector of a
low-energy effective theory, the effects of new physics are encoded into a set
of higher dimensional operators. These operators potentially deform the shapes
of Standard Model differential distributions of final states observable at
colliders. We describe a simple and systematic method to obtain optimal
estimations of these deformations when using numerical tools, like Monte Carlo
simulations. A crucial aspect of this method is minimization of the estimation
uncertainty: we demonstrate how the operator coefficients have to be set in the
simulations in order to get optimal results. The uncertainty on the
interference term turns out to be the most difficult to control and grows very
quickly when the interference is suppressed. We exemplify our method by
computing the deformations induced by the ${\cal O}_{3W}$ operator in $W^+W^-$
production at the LHC, and by deriving a bound on ${\cal O}_{3W}$ using $8$ TeV
CMS data.


title:
The COSMOS [OII] Survey: Evolution of Electron Density with Star
  Formation Rate

abstract:
  Star-forming galaxies at $z > 1$ exhibit significantly different properties
to local galaxies of equivalent stellar mass. Not only are high-redshift
star-forming galaxies characterized by higher star formation rates and gas
fractions than their local counterparts, they also appear to host star-forming
regions with significantly different physical conditions, including greater
electron densities. To understand what physical mechanisms are responsible for
the observed evolution of star-forming conditions we have assembled the largest
sample of star-forming galaxies at $z\sim 1.5$ with emission-line measurements
of the $\mathrm{[OII]} \lambda \lambda 3726,3729$ doublet. By comparing our
$z\sim 1.5$ sample to local galaxy samples with equivalent distributions of
stellar mass, star formation rate and specific star formation rate we
investigate the proposed evolution in electron density and its dependence on
global properties. We measure an average electron density of $114_{-27}^{+28}
\, \mathrm {cm}^{-3} $ for our $z\sim 1.5$ sample, a factor of five greater
than the typical electron density of local star-forming galaxies. However, we
find no offset between the typical electron densities of local and
high-redshift galaxies with equivalent star-formation rates. Our work indicates
that the average electron density of a sample is highly sensitive to the star
formation rates, implying that the previously observed evolution is mainly the
result of selection effects.


title:
Non-ideal teleportation of tripartite entanglement:
  Einstein-Podolsky-Rosen versus Greenberger-Horne-Zeilinger schemes

abstract:
  Channels composed by Einstein-Podolsky-Rosen (EPR) pairs are capable of
teleporting arbitrary multipartite states. The question arises whether EPR
channels are also optimal against imperfections. In particular, the
teleportation of Greenberger-Horne-Zeilinger states (GHZ) requires three EPR
states as the channel and full measurements in the Bell basis. We show that, by
using two GHZ states as the channel, it is possible to transport any unknown
three-qubit state of the form $c_0|000\rangle+c_1|111\rangle$. The
teleportation is made through measurements in the GHZ basis, and, to obtain
deterministic results, in most of the investigated scenarios, four out of the
eight elements of the basis need to be unambiguously distinguished. Most
importantly, we show that when both, systematic errors and noise are
considered, the fidelity of the teleportation protocol is higher when a GHZ
channel is used in comparison to that of a channel composed by EPR pairs.


title:
ALMA observations of the $\eta$ Corvi debris disc: inward scattering of
  CO-rich exocomets by a chain of 3-30 M$_\oplus$ planets?

abstract:
  While most of the known debris discs present cold dust at tens of AU, a few
young systems exhibit hot dust analogous to the Zodiacal dust. $\eta$ Corvi is
particularly interesting as it is old and it has both, with its hot dust
significantly exceeding the maximum luminosity of an in-situ collisional
cascade. Previous work suggested that this system could be undergoing an event
similar to the Late Heavy Bombardment (LHB) soon after or during a dynamical
instability. Here we present ALMA observations of $\eta$ Corvi with a
resolution of 1."2 (~22au) to study its outer belt. The continuum emission is
consistent with an axisymmetric belt, with a mean radius of 152au and radial
FWHM of 46au, which is too narrow compared to models of inward scattering of an
LHB-like scenario. Instead, the hot dust could be explained as material passed
inwards in a rather stable planetary configuration. We also report a 4sigma
detection of CO at ~ 20au. CO could be released in situ from icy planetesimals
being passed in when crossing the H$_2$O or CO$_2$ ice lines. Finally, we place
constraints on hidden planets in the disc. If a planet is sculpting the disc's
inner edge, this should be orbiting at 75-100au, with a mass of 3-30 M$_\oplus$
and an eccentricity < 0.08. Such a planet would be able to clear its chaotic
zone on a timescale shorter than the age of the system and scatter material
inwards from the outer belt to the inner regions, thus feeding the hot dust.


title:
A Minimalist Feedback-Regulated Model for Galaxy Formation During the
  Epoch of Reionization

abstract:
  Near-infrared surveys have now determined the luminosity functions of
galaxies at 6<z<9 to impressive precision and identified a number of candidates
at even earlier times. Here we develop a simple analytic model to describe
these populations that allows physically-motivated extrapolation to earlier
times and fainter luminosities. We assume that galaxies grow through accretion
onto dark matter halos, which we model by matching halos at fixed number
density across redshift, and that stellar feedback limits the star formation
rate. We allow for a variety of feedback mechanisms, including regulation
through supernova energy and momentum from radiation pressure. We show that
reasonable choices for the feedback parameters can fit the available galaxy
data, which in turn substantially limits the range of plausible extrapolations
of the luminosity function to earlier times and fainter luminosities: for
example, the global star formation rate declines rapidly at z>10, but the
bright galaxies accessible to observations decline much faster than the total.
Deviations from our predictions would provide evidence for new astrophysics
within the first generations of galaxies. We also provide predictions for
galaxy measurements by future facilities, including JWST and WFIRST.


title:
PrivLogit: Efficient Privacy-preserving Logistic Regression by Tailoring
  Numerical Optimizers

abstract:
  Safeguarding privacy in machine learning is highly desirable, especially in
collaborative studies across many organizations. Privacy-preserving distributed
machine learning (based on cryptography) is popular to solve the problem.
However, existing cryptographic protocols still incur excess computational
overhead. Here, we make a novel observation that this is partially due to naive
adoption of mainstream numerical optimization (e.g., Newton method) and failing
to tailor for secure computing. This work presents a contrasting perspective:
customizing numerical optimization specifically for secure settings. We propose
a seemingly less-favorable optimization method that can in fact significantly
accelerate privacy-preserving logistic regression. Leveraging this new method,
we propose two new secure protocols for conducting logistic regression in a
privacy-preserving and distributed manner. Extensive theoretical and empirical
evaluations prove the competitive performance of our two secure proposals while
without compromising accuracy or privacy: with speedup up to 2.3x and 8.1x,
respectively, over state-of-the-art; and even faster as data scales up. Such
drastic speedup is on top of and in addition to performance improvements from
existing (and future) state-of-the-art cryptography. Our work provides a new
way towards efficient and practical privacy-preserving logistic regression for
large-scale studies which are common for modern science.


title:
Topological exciton Fermi surfaces in two-component fractional quantized
  Hall insulators

abstract:
  A wide variety of two-dimensional electron systems (2DES) allow for
independent control of the total and relative charge density of two-component
fractional quantum Hall (FQH) states. In particular, a recent experiment on
bilayer graphene (BLG) observed a continuous transition between a compressible
and incompressible phase at total filling $\nu_T = \frac{1}{2}$ as charge is
transferred between the layers, with the remarkable property that the
incompressible phase has a finite interlayer polarizability. We argue that this
occurs because the topological order of $\nu_T = \frac{1}{2}$ systems supports
a novel type of interlayer exciton that carries Fermi statistics. If the
fermionic excitons are lower in energy than the conventional bosonic excitons
(i.e., electron-hole pairs), they can form an emergent neutral Fermi surface,
providing a possible explanation of an incompressible yet polarizable state at
$\nu_T = \frac{1}{2}$. We perform exact diagonalization studies which
demonstrate that fermionic excitons are indeed lower in energy than bosonic
excitons. This suggests that a "topological exciton metal" hidden inside a FQH
insulator may have been realized experimentally in BLG. We discuss several
detection schemes by which the topological exciton metal can be experimentally
probed.


title:
Multiple-Speaker Localization Based on Direct-Path Features and
  Likelihood Maximization with Spatial Sparsity Regularization

abstract:
  This paper addresses the problem of multiple-speaker localization in noisy
and reverberant environments, using binaural recordings of an acoustic scene. A
Gaussian mixture model (GMM) is adopted, whose components correspond to all the
possible candidate source locations defined on a grid. After optimizing the
GMM-based objective function, given an observed set of binaural features, both
the number of sources and their locations are estimated by selecting the GMM
components with the largest priors. This is achieved by enforcing a sparse
solution, thus favoring a small number of speakers with respect to the large
number of initial candidate source locations. An entropy-based penalty term is
added to the likelihood, thus imposing sparsity over the set of GMM priors. In
addition, the direct-path relative transfer function (DP-RTF) is used to build
robust binaural features. The DP-RTF, recently proposed for single-source
localization, was shown to be robust to reverberations, since it encodes
inter-channel information corresponding to the direct-path of sound
propagation. In this paper, we extend the DP-RTF estimation to the case of
multiple sources. In the short-time Fourier transform domain, a consistency
test is proposed to check whether a set of consecutive frames is associated to
the same source or not. Reliable DP-RTF features are selected from the frames
that pass the consistency test to be used for source localization. Experiments
carried out using both simulation data and real data gathered with a robotic
head confirm the efficiency of the proposed multi-source localization method.


title:
Vortex arrays and ciliary tangles underlie the feeding-swimming tradeoff
  in starfish larvae

abstract:
  Many marine invertebrates have larval stages covered in linear arrays of
beating cilia, which propel the animal while simultaneously entraining
planktonic prey. These bands are strongly conserved across taxa spanning four
major superphyla, and they are responsible for the unusual morphologies of many
invertebrate larvae. However, few studies have investigated their underlying
hydrodynamics. Here, we study the ciliary bands of starfish larvae, and
discover a beautiful pattern of slowly-evolving vortices that surrounds the
swimming animals. Closer inspection of the bands reveals unusual ciliary
"tangles" analogous to topological defects that break up and re-form as the
animal adjusts its swimming stroke. Quantitative experiments and modeling
demonstrate that these vortices create a physical tradeoff between feeding and
swimming in heterogenous environments, which manifests as distinct flow
patterns or "eigen-strokes" representing each behavior---potentially
implicating neuronal control of cilia. This quantitative interplay between
larval form and hydrodynamic function may generalize to other invertebrates
with ciliary bands, and illustrates the potential effects of active boundary
conditions in other biological and synthetic systems.


title:
Hausdorff Dimension, Lagrange and Markov Dynamical Spectra for Geometric
  Lorenz Attractors

abstract:
  In this paper, we show that geometric Lorenz attractors have Hausdorff
dimension strictly greater than $2$. We use this result to show that for a
"large" set of real functions the Lagrange and Markov Dynamical spectrum
associated to these attractors has persistently non-empty interior.


title: The Borel equivariant cohomology of real Grassmannians

abstract:
  Recent work of Chen He has determined through GKM methods the Borel
equivariant cohomology with rational coefficients of the isotropy action on a
real Grassmannian and an real oriented Grassmannian through GKM methods. In
this expository note, we propound a less involved approach, due essentially to
Vitali Kapovitch, to computing equivariant cohomology rings $H^*_K(G/H)$ for
$G,K,H$ connected Lie groups, and apply it to recover the equivariant
cohomology of the Grassmannians. The bulk is setup and commentary; once one
believes in the model, the proof itself is under a page.


title: Geometric realization of algebraic conformal field theories

abstract:
  We explore new connections between the fields and local observables in two
dimensional chiral conformal field theory. We show that in a broad class of
examples, the von Neumann algebras of local observables (a conformal net) can
be obtained from the fields (a unitary vertex operator algebra) via a
continuous geometric interpolation procedure involving Graeme Segal's
functorial definition of conformal field theory. In particular, we construct
conformal nets from these unitary vertex operator algebras by showing that
'geometrically mollified' versions of the fields yield bounded, local operators
on the Hilbert space completion of the vertex algebra. This work is inspired by
Henriques' picture of conformal nets arising from degenerate Riemann surfaces.


title:
Multiplicity results for the Yamabe equation by Lusternik-Schnirelmann
  theory

abstract:
  Let $(M,g)$ be any closed Riemannianan manifold and $(N,h)$ be a Riemannian
manifold of constant positive scalar curvature. We prove that the Yamabe
equation on the Riemannian product $(M\times N , g + \delta h)$ has at least
$Cat(M) +1 $ solutions for $\delta$ small enough, where $Cat(M)$ denotes the
Lusternik-Schnirelmann-category of $M$. Cat(M) of the solutions obtained have
energy arbitrarily close to the minimum.


title: Equivalence of two definitions of set-theoretic Yang-Baxter homology

abstract:
  In 2004, Carter, Elhamdadi and Saito defined a homology theory for
set-theoretic Yang-Baxter operators(we will call it the "algebraic" version in
this article). In 2012, Przytycki defined another homology theory for
pre-Yang-Baxter operators which has a nice graphic visualization(we will call
it the "graphic" version in this article). We show that they are equivalent.
The "graphic" homology is also defined for pre-Yang-Baxter operators, and we
give some examples of it's one-term and two-term homologies. In the two-term
case, we have found torsion in homology of Yang-Baxter operator that yields the
Jones polynomial.


title:
Adaptive Geometric Multiscale Approximations for Intrinsically
  Low-dimensional Data

abstract:
  We consider the problem of efficiently approximating and encoding
high-dimensional data sampled from a probability distribution $\rho$ in
$\mathbb{R}^D$, that is nearly supported on a $d$-dimensional set $\mathcal{M}$
- for example supported on a $d$-dimensional Riemannian manifold. Geometric
Multi-Resolution Analysis (GMRA) provides a robust and computationally
efficient procedure to construct low-dimensional geometric approximations of
$\mathcal{M}$ at varying resolutions. We introduce a thresholding algorithm on
the geometric wavelet coefficients, leading to what we call adaptive GMRA
approximations. We show that these data-driven, empirical approximations
perform well, when the threshold is chosen as a suitable universal function of
the number of samples $n$, on a wide variety of measures $\rho$, that are
allowed to exhibit different regularity at different scales and locations,
thereby efficiently encoding data from more complex measures than those
supported on manifolds. These approximations yield a data-driven dictionary,
together with a fast transform mapping data to coefficients, and an inverse of
such a map. The algorithms for both the dictionary construction and the
transforms have complexity $C n \log n$ with the constant linear in $D$ and
exponential in $d$. Our work therefore establishes adaptive GMRA as a fast
dictionary learning algorithm with approximation guarantees. We include several
numerical experiments on both synthetic and real data, confirming our
theoretical results and demonstrating the effectiveness of adaptive GMRA.


title: Complex spectrum of spin models for finite-density QCD

abstract:
  We consider the spectrum of transfer matrix eigenvalues associated with
Polyakov loops in lattice QCD at strong coupling. The transfer matrix at finite
density is non-Hermitian, and its eigenvalues become complex as a manifestation
of the sign problem. We show that the symmetry under charge conjugation and
complex conjugation ensures that the eigenvalues are either real or part of a
complex conjugate pair, and the complex pairs lead to damped oscillatory
behavior in Polyakov loop correlation functions, which also appeared in our
previous phenomenological models using complex saddle points. We argue that
this effect should be observable in lattice simulations of QCD at finite
density.


title:
Current crowding mediated large contact noise in graphene field-effect
  transistors

abstract:
  The impact of the intrinsic time-dependent fluctuations in the electrical
resistance at the graphene-metal interface or the contact noise, on the
performance of graphene field effect transistors, can be as adverse as the
contact resistance itself, but remains largely unexplored. Here we have
investigated the contact noise in graphene field effect transistors of varying
device geometry and contact configuration, with carrier mobility ranging from
5,000 to 80,000$~$cm$^{2}$V$^{-1}$s$^{-1}$. Our phenomenological model for
contact noise due to current crowding in purely two dimensional conductors,
confirms that the contacts dominate the measured resistance noise in all
graphene field effect transistors in the two-probe or invasive four probe
configurations, and surprisingly, also in nearly noninvasive four probe (Hall
bar) configuration in the high mobility devices. The microscopic origin of
contact noise is directly linked to the fluctuating electrostatic environment
of the metal-channel interface, which could be generic to two dimensional
material-based electronic devices.


title: Golden-Ratio-Based Rectangular Tilings

abstract:
  A golden-ratio-based rectangular tiling of the first quadrant of the
Euclidean plane is constructed by drawing vertical and horizontal grid lines
which are located at all even powers of $\phi$ along one axis, and at all odd
powers of $\phi$ on the other axis. The vertices of the rectangles formed by
these lines can be connected by rays starting at the origin having slopes that
are odd powers of $\phi$. A refinement of this tiling results in the familiar
one with horizontal and vertical grid lines at every power of $\phi$ along each
axis. Geometric proofs of the convergence of several known power series' in
$\phi$ are provided.


title:
Unconventional superfluids of fermionic polar molecules in a bilayer
  system

abstract:
  We study unconventional superfluids of fermionic polar molecules in a
two-dimensional bilayer system with dipoles are head-to-tail across the layers.
We analyze the critical temperature of several unconventional pairings as a
function of different system parameters. The peculiar competition between the
$d$- and the $s$- wave pairings is discussed. We show that the experimental
observation of such unconventional superfluids requires ulralow temperatures,
which opens up new possibilities to realize several topological phases.


title: Large data analysis for Kolmogorov's two-equation model of turbulence

abstract:
  We establish long-time and large-data existence of a suitable weak solution
to three-dimensional internal unsteady flows described by Kolmogorov's
two-equation model of turbulence. The governing system of equations is
completed by initial and boundary conditions; concerning the velocity we
consider generalized stick-slip boundary conditions. The fact that the
admissible class of boundary conditions includes various types of slipping
mechanisms on the boundary makes the result robust from the point of view of
possible applications.


title: Runaway Dwarf Carbon Stars as Candidate Supernova Ejecta

abstract:
  The dwarf carbon (dC) star SDSS J112801.67+004034.6 has an unusually high
radial velocity, 531$\pm 4$ km s$^{-1}$. We present proper motion and new
spectroscopic observations which imply a large Galactic rest frame velocity,
425$\pm 9$ km s$^{-1}$. Several other SDSS dC stars are also inferred to have
very high galactocentric velocities, again each based on both high heliocentric
radial velocity and also confidently detected proper motions. Extreme
velocities and the presence of $C_2$ bands in the spectra of dwarf stars are
both rare. Passage near the Galactic center can accelerate stars to such
extreme velocities, but the large orbital angular momentum of SDSS J1128
precludes this explanation. Ejection from a supernova in a binary system or
disruption of a binary by other stars are possibilities, particularly as dC
stars are thought to obtain their photospheric $C_2$ via mass transfer from an
evolved companion.


title: Demystifying ResNet

abstract:
  The Residual Network (ResNet), proposed in He et al. (2015), utilized
shortcut connections to significantly reduce the difficulty of training, which
resulted in great performance boosts in terms of both training and
generalization error.
  It was empirically observed in He et al. (2015) that stacking more layers of
residual blocks with shortcut 2 results in smaller training error, while it is
not true for shortcut of length 1 or 3. We provide a theoretical explanation
for the uniqueness of shortcut 2.
  We show that with or without nonlinearities, by adding shortcuts that have
depth two, the condition number of the Hessian of the loss function at the zero
initial point is depth-invariant, which makes training very deep models no more
difficult than shallow ones. Shortcuts of higher depth result in an extremely
flat (high-order) stationary point initially, from which the optimization
algorithm is hard to escape. The shortcut 1, however, is essentially equivalent
to no shortcuts, which has a condition number exploding to infinity as the
number of layers grows. We further argue that as the number of layers tends to
infinity, it suffices to only look at the loss function at the zero initial
point.
  Extensive experiments are provided accompanying our theoretical results. We
show that initializing the network to small weights with shortcut 2 achieves
significantly better results than random Gaussian (Xavier) initialization,
orthogonal initialization, and shortcuts of deeper depth, from various
perspectives ranging from final loss, learning dynamics and stability, to the
behavior of the Hessian along the learning process.


title: Simplified Limits on New LHC Resonances

abstract:
  If an excess potentially heralding new physics is noticed in collider data,
it would be useful to be able to compare the data with entire classes of models
at once. This talk discusses a method that applies when the new physics
corresponds to the production and decay of a single, relatively narrow,
s-channel resonance. A simplifed model of the resonance allows us to convert an
estimated signal cross section into model-independent bounds on the product of
the branching ratios corresponding to production and decay. This quickly
reveals whether a given class of models could possibly produce a signal of the
observed size. We will describe how to apply our analysis framework to cases of
current experimental interest, including resonances decaying to dibosons,
diphotons, dileptons, or dijets.


title: On the well-posedness of the hyperelastic rod equation

abstract:
  In this paper we consider the hyperelastic rod equation on the Sobolev spaces
$H^s(\R)$, $s > 3/2$. Using a geometric approach we show that for any $T > 0$
the corresponding solution map, $u(0) \mapsto u(T)$, is nowhere locally
uniformly continuous. The method applies also to the periodic case $H^s(\mathbb
T)$, $s > 3/2$.


title: Experimentally exploring compressed sensing quantum tomography

abstract:
  In the light of the progress in quantum technologies, the task of verifying
the correct functioning of processes and obtaining accurate tomographic
information about quantum states becomes increasingly important. Compressed
sensing, a machinery derived from the theory of signal processing, has emerged
as a feasible tool to perform robust and significantly more resource-economical
quantum state tomography for intermediate-sized quantum systems. In this work,
we provide a comprehensive analysis of compressed sensing tomography in the
regime in which tomographically complete data is available with reliable
statistics from experimental observations of a multi-mode photonic
architecture. Due to the fact that the data is known with high statistical
significance, we are in a position to systematically explore the quality of
reconstruction depending on the number of employed measurement settings,
randomly selected from the complete set of data, and on different model
assumptions. We present and test a complete prescription to perform efficient
compressed sensing and are able to reliably use notions of model selection and
cross-validation to account for experimental imperfections and finite counting
statistics. Thus, we establish compressed sensing as an effective tool for
quantum state tomography, specifically suited for photonic systems.


title:
Conspiracies between Learning Algorithms, Circuit Lower Bounds and
  Pseudorandomness

abstract:
  We prove several results giving new and stronger connections between
learning, circuit lower bounds and pseudorandomness. Among other results, we
show a generic learning speedup lemma, equivalences between various learning
models in the exponential time and subexponential time regimes, a dichotomy
between learning and pseudorandomness, consequences of non-trivial learning for
circuit lower bounds, Karp-Lipton theorems for probabilistic exponential time,
and NC$^1$-hardness for the Minimum Circuit Size Problem.


title: Forbidden M1 and E2 transitions in monovalent atoms and ions

abstract:
  We carried out a systematic high-precision relativistic study of the
forbidden magnetic-dipole and electric-quadrupole transitions in Ca+, Rb, Sr+,
Cs, Ba+, Fr, Ra+, Ac2+, and Th3+. This work is motivated by the importance of
these transitions for tests of fundamental physics and precision measurements.
The relative importance of the relativistic, correlation, Breit correction, and
contributions of negative-energy states is investigated. Recommended values of
reduced matrix elements are presented together with their uncertainties. The
matrix elements and resulting lifetimes are compared with other theoretical
values and with experiment where available.


title: Powerful numbers and the ABC-conjecture

abstract:
  The $abc$ conjecture is a very deep concept in number theory with wide
application to many areas of number theory. In this article we introduce the
conjecture and give examples of its applications. In particular we apply the
$abc$ conjecture to the location of powerful numbers.


title: Algorithms for Disconnected Diagrams in Lattice QCD

abstract:
  Computing disconnected diagrams in Lattice QCD (operator insertion in a quark
loop) entails the computationally demanding problem of taking the trace of the
all to all quark propagator. We first outline the basic algorithm used to
compute a quark loop as well as improvements to this method. Then, we motivate
and introduce an algorithm based on the synergy between hierarchical probing
and singular value deflation. We present results for the chiral condensate
using a 2+1-flavor clover ensemble and compare estimates of the nucleon charges
with the basic algorithm.


title:
Convex set of quantum states with positive partial transpose analysed by
  hit and run algorithm

abstract:
  The convex set of quantum states of a composite $K \times K$ system with
positive partial transpose is analysed. A version of the hit and run algorithm
is used to generate a sequence of random points covering this set uniformly and
an estimation for the convergence speed of the algorithm is derived. For $K\ge
3$ this algorithm works faster than sampling over the entire set of states and
verifying whether the partial transpose is positive. The level density of the
PPT states is shown to differ from the Marchenko-Pastur distribution, supported
in [0,4] and corresponding asymptotically to the entire set of quantum states.
Based on the shifted semi--circle law, describing asymptotic level density of
partially transposed states, and on the level density for the Gaussian unitary
ensemble with constraints for the spectrum we find an explicit form of the
probability distribution supported in [0,3], which describes well the level
density obtained numerically for PPT states.


title:
Integrating Atlas and Graph Cut Methods for LV Segmentation from Cardiac
  Cine MRI

abstract:
  Magnetic Resonance Imaging (MRI) has evolved as a clinical standard-of-care
imaging modality for cardiac morphology, function assessment, and guidance of
cardiac interventions. All these applications rely on accurate extraction of
the myocardial tissue and blood pool from the imaging data. Here we propose a
framework for left ventricle (LV) segmentation from cardiac cine-MRI. First, we
segment the LV blood pool using iterative graph cuts, and subsequently use this
information to segment the myocardium. We formulate the segmentation procedure
as an energy minimization problem in a graph subject to the shape prior
obtained by label propagation from an average atlas using affine registration.
The proposed framework has been validated on 30 patient cardiac cine-MRI
datasets available through the STACOM LV segmentation challenge and yielded
fast, robust, and accurate segmentation results.


title: Attractors of sequences of iterated function systems

abstract:
  If $F$ and $G$ are iterated function systems, then any infinite word $W$ in
the symbols $F$ and $G$ induces a limit set. It is natural to ask whether this
Cantor set can also be realized as the limit set of a single $C^{1 + \alpha}$
iterated function system $H$. We prove that under certain assumptions on $F$,
$G$ and $H$, the answer is no. This problem is motivated by the spectral theory
of one-dimensional quasicrystals.


title: The dynamics of filament assembly define cytoskeletal network morphology

abstract:
  The actin cytoskeleton is a key component in the machinery of eukaryotic
cells, and it selfassembles out of equilibrium into a wide variety of
biologically crucial structures. While the molecular mechanisms involved are
well characterized, the physical principles governing the spatial arrangement
of actin filaments are not understood. Here we propose that the dynamics of
actin network assembly from growing filaments results from a competition
between diffusion, bundling, and steric hindrance, and is responsible for the
range of observed morphologies. Our model and simulations thus predict an
abrupt dynamical transition between homogeneous and strongly bundled networks
as a function of the actin polymerization rate. This suggests that cells may
effect dramatic changes to their internal architecture through minute
modifications of their nonequilibrium dynamics. Our results are consistent with
available experimental data.


title: Galilean Geometry in Condensed Matter Systems

abstract:
  We present a systematic means to impose Galilean invariance within field
theory. We begin by defining the most general background geometries consistent
with Galilean invariance and then turn to applications within effective field
theory, fluid dynamics, and the quantum Hall effect.


title: Capacity-Achieving Rate-Compatible Polar Codes for General Channels

abstract:
  We present a rate-compatible polar coding scheme that achieves the capacity
of any family of channels. Our solution generalizes the previous results [1],
[2] that provide capacity-achieving rate-compatible polar codes for a degraded
family of channels. The motivation for our extension comes from the fact that
in many practical scenarios, e.g., MIMO systems and non-Gaussian interference,
the channels cannot be ordered by degradation. The main technical contribution
of this paper consists in removing the degradation condition. To do so, we
exploit the ideas coming from the construction of universal polar codes.
  Our scheme possesses the usual attractive features of polar codes: low
complexity code construction, encoding, and decoding; super-polynomial scaling
of the error probability with the block length; and absence of error floors. On
the negative side, the scaling of the gap to capacity with the block length is
slower than in standard polar codes, and we prove an upper bound on the scaling
exponent.


title: On well quasi-order of graph classes under homomorphic image orderings

abstract:
  In this paper we consider the question of well quasi-order for classes
defined by a single obstruction within the classes of all graphs, digraphs and
tournaments, under the homomorphic image ordering (in both its standard and
strong forms). The homomorphic image ordering was introduced by the authors in
a previous paper and corresponds to the existence of a surjective homomorphism
between two structures. We obtain complete characterizations in all cases
except for graphs under the strong ordering, where some open questions remain.


title: Can a quantum critical state represent a blackbody?

abstract:
  The blackbody theory of Planck played a seminal role in the development of
quantum theory at the turn of the past century. A blackbody cavity is generally
thought to be a collection of photons in thermal equilibrium; the radiation
emitted is at all wavelengths, and the intensity follows a scaling law, which
is Planck's characteristic distribution law. These photons arise from
non-interacting normal modes. Here we suggest that certain quantum critical
states when heated emit "radiation" at all wavelengths and satisfy all the
criteria of a blackbody. An important difference is that the "radiation" does
not necessarily consist of non-interacting photons, but also emergent
relativistic bosons or fermions. The examples we provide include emergent
relativistic fermions at a topological quantum critical point. This perspective
on a quantum critical state may be illuminating in many unforeseen ways.