title:
Efficient computation of first passage times in Kou's jump-diffusion
  model

abstract:
  S. G. Kou and H. Wang [First Passage times of a Jump Diffusion Process
\textit{Ann. Appl. Probab.} {\bf 35} (2003) 504--531] give expressions of both
the (real) Laplace transform of the distribution of first passage time and the
(real) Laplace transform of the joint distribution of the first passage time
and the running maxima of a jump-diffusion model called Kou model. %However, to
invert the last Laplace transform it is needed Kuo and Wang invert the first
Laplace transform by using Gaver-Stehfest algorithm, and the inversion of
second one involves a large computing time with an algebra computer system. In
the present paper, we give a much simpler expression of the Laplace transform
of the joint distribution, and we also show, using Complex Analysis techniques,
that both Laplace transform can be extended to the complex plane. Hence, we can
use variants of the Fourier-series methods to invert that Laplace transfoms,
which are very efficent. The improvement in the computing times and accuracy is
remarkable.


title: On Tjurina Transform and Resolution of Determinantal Singularities

abstract:
  Determinantal singularities are an important class of singularities,
generalizing complete intersections, which recently have seen a large amount of
interest. They are defined as preimage of $M^{t}_{m,n}$ the sets of matrices of
rank less than $t$. The linear algebraic structure $M^{t}_{m,n}$ gives rise to
some interesting structures on determinantal singularities. In this article we
will focus on one of these, namely the Tjurina transform. We will show some
properties of it, and discuss how it can and how can not be used to find
resolutions of determinantal singularities.


title:
Dynamic Input/Output Automata: a Formal and Compositional Model for
  Dynamic Systems

abstract:
  We present dynamic I/O automata (DIOA), a compositional model of dynamic
systems. In DIOA, automata can be created and destroyed dynamically, as
computation proceeds, and an automaton can dynamically change its signature,
i.e., the set of actions in which it can participate.
  DIOA features operators for parallel composition, action hiding, action
renaming, a notion of automaton creation, and a notion of behavioral subtyping
by means of trace inclusion. DIOA can model mobility, using signature
modification, and is hierarchical: a dynamically changing system of interacting
automata is itself modeled as a single automaton.
  We also show that parallel composition, action hiding, action renaming, and
(subject to some technical conditions) automaton creation are all monotonic
with respect to trace inclusion: if one component is replaced by another whose
traces are a subset of the former, then the set of traces of the system as a
whole can only be reduced.


abstract:
  We prove a conjecture of Boston that if $p\geq 5$, all $p$-central quotients
of the free group on two generators and of the free product of two cyclic
groups of order $p$ are Beauville groups. In the case of the free product, we
also determine Beauville structures in $p$-central quotients when $p=3$. As a
consequence, we give an explicit infinite family of Beauville $3$-groups, which
is different from the only one that was known up to date.


title: A study guide for the $l^2$ Decoupling Theorem

abstract:
  This paper contains a detailed, self contained and more streamlined proof of
our $l^2$ decoupling theorem for hypersurfaces.


title: A Lindblad Model of Quantum Brownian Motion

abstract:
  The theory of quantum Brownian motion describes the properties of a large
class of open quantum systems. Nonetheless, its description in terms of a
Born-Markov master equation, widely used in the literature, is known to violate
the positivity of the density operator at very low temperatures. We study an
extension of existing models, leading to an equation in the Lindblad form,
which is free of this problem. We study the dynamics of the model, including
the detailed properties of its stationary solution, for both constant and
position-dependent coupling of the Brownian particle to the bath, focusing in
particular on the correlations and the squeezing of the probability
distribution induced by the environment


title: New basis functions for wave equation

abstract:
  The Differential Transfer Matrix Method is extended to the complex plane,
which allows dealing with singularities at turning points. The result for
real-valued systems are simplified and a pair of basis functions is found.
These bases are a bit less accurate than WKB solutions but much easier to work
with because of their algebraic form. Furthermore, these bases exactly satisfy
the initial conditions and may go over the turning points without the divergent
behavior of WKB solutions. The findings of this paper allow explicit evaluation
of eigenvalues of confined modes with high precision, as demonstrated by few
examples.


title:
The validity of Whitham's approximation for a Klein-Gordon-Boussinesq
  model

abstract:
  In this paper we prove the validity of a long wave Whitham approximation for
a system consisting of a Boussinesq equation coupled with a Klein-Gordon
equation. The proof is based on an infinite series of normal form
transformations and an energy estimate. We expect that the concepts of this
paper will be a part of a general approximation theory for Whitham's equations
which are especially used in the description of slow modulations in time and
space of periodic wave trains in general dispersive wave systems.


title:
Random Projection Estimation of Discrete-Choice Models with Large Choice
  Sets

abstract:
  We introduce sparse random projection, an important dimension-reduction tool
from machine learning, for the estimation of discrete-choice models with
high-dimensional choice sets. Initially, high-dimensional data are compressed
into a lower-dimensional Euclidean space using random projections.
Subsequently, estimation proceeds using cyclic monotonicity moment inequalities
implied by the multinomial choice model; the estimation procedure is
semi-parametric and does not require explicit distributional assumptions to be
made regarding the random utility errors. The random projection procedure is
justified via the Johnson-Lindenstrauss Lemma -- the pairwise distances between
data points are preserved during data compression, which we exploit to show
convergence of our estimator. The estimator works well in simulations and in an
application to a supermarket scanner dataset.


title: Commutative pseudo equality algebras

abstract:
  Pseudo equality algebras were initially introduced by Jenei and $\rm
K\acute{o}r\acute{o}di$ as a possible algebraic semantic for fuzzy type theory,
and they have been revised by Dvure\v{c}enskij and Zahiri under the name of
JK-algebras. In this paper we define and study the commutative pseudo equality
algebras. We give a characterization of commutative pseudo equality algebras
and we prove that an invariant pseudo equality algebra is commutative if and
only if its corresponding pseudo BCK(pC)-meet-semilattice is commutative. Other
results consist of proving that every commutative pseudo equality algebra is a
distributive lattice and every finite invariant commutative pseudo equality
algebra is a symmetric pseudo equality algebra. We also introduce and
investigate the commutative deductive systems of pseudo equality algebras. As
applications of these notions and results we define and study the measures and
measure-morphisms on pseudo equality algebras, we prove new properties of state
pseudo equality algebras, and we introduce and investigate the
pseudo-valuations on pseudo equality algebras.


title: Two-variable Logic with Counting and a Linear Order

abstract:
  We study the finite satisfiability problem for the two-variable fragment of
first-order logic extended with counting quantifiers (C2) and interpreted over
linearly ordered structures. We show that the problem is undecidable in the
case of two linear orders (in the presence of two other binary symbols). In the
case of one linear order it is NEXPTIME-complete, even in the presence of the
successor relation. Surprisingly, the complexity of the problem explodes when
we add one binary symbol more: C2 with one linear order and in the presence of
other binary predicate symbols is equivalent, under elementary reductions, to
the emptiness problem for multicounter automata.


title:
Symmetry, quantitative Liouville theorems and analysis of large
  solutions of conformally invariant fully nonlinear elliptic equations

abstract:
  We establish blow-up profiles for any blowing-up sequence of solutions of
general conformally invariant fully nonlinear elliptic equations on Euclidean
domains. We prove that (i) the distance between blow-up points is bounded from
below by a universal positive number, (ii) the solutions are very close to a
single standard bubble in a universal positive distance around each blow-up
point, and (iii) the heights of these bubbles are comparable by a universal
factor. As an application of this result, we establish a quantitative Liouville
theorem.


title:
Ground state structure of BaFeO$_{3}$: Density Functional Theory
  Calculations

abstract:
  Using density functional theory calculations, the ground state structure of
BaFeO$_3$ (BFO) is investigated with local spin density approximation (LSDA).
Cubic, tetragonal, orthorhombic, and rhombohedral types BFO are considered to
calculate the formation enthalpy. The formation enthalpies reveal that cubic is
the most stable structure of BFO. Small energy difference between the cubic and
tetragonal suggests a possible tetragonal BFO. Ferromagnetic(FM) and
anitiferromagnetic (AFM) coupling between the Fe atoms show that all the
striochmetric BFO are FM. The energy difference between FM and AFM shows room
temperature ferromagnetism in cubic BFO in agreement with the experimental
work. The LSDA calculated electronic structures are metallic in all studied
crystallographic phases of BFO. Calculations including the Hubbard potential
$U,i.e.$ LSDA+$U$, show that all phases of BFO are half-metallic consistent
with the integer magnetic moments. The presence of half-metallicity is
discussed in terms of electronic band structures of BFO.


title:
The GTC exoplanet transit spectroscopy survey. IV. Confirmation of the
  flat transmission spectrum of HAT-P-32b

abstract:
  We observed the hot Jupiter HAT-P-32b (also known as HAT-P-32Ab) to determine
its optical transmission spectrum by measuring the wavelength-dependent
planet-to-star radius ratios in the region between 518 - 918 nm. We used the
OSIRIS instrument at the GTC in long slit spectroscopy mode, placing HAT-P-32
and a reference star in the same slit and obtaining a time series of spectra
covering two transit events. Using the best quality data set, we were able to
yield 20 narrow-band transit light curves, with each passband spanning a 20 nm
wide interval. After removal of all systematic noise signals and light curve
modeling the uncertainties for the resulting radius ratios lie between 337 and
972 ppm. The radius ratios show little variation with wavelength suggesting a
high altitude cloud layer masking any atmospheric features. Alternatively, a
strong depletion in alkali metals or a much smaller than expected planetary
atmospheric scale height could be responsible for the lack of atmospheric
features. Our result of a flat transmission spectrum is consistent with a
previous ground-based study of the optical spectrum of this planet. This
agreement between independent results demonstrates that ground-based
measurements of exoplanet atmospheres can give reliable and reproducible
results despite the fact that the data often is heavily affected by systematic
noise, as long as the noise source is well understood and properly corrected.
We also extract an optical spectrum of the M-dwarf companion HAT-P-32B. Using
PHOENIX stellar atmosphere models we determine an effective temperature of
$T_\mathrm{eff}= 3187^{+60}_{-71}$ K, slightly colder than previous studies
relying only on broadband infra-red data.


title: On the maximal mean curvature of a smooth surface

abstract:
  Given a smooth simply connected planar domain, the area is bounded away from
zero in terms of the maximal curvature alone. We show that in higher dimensions
this is not true, and for a given maximal mean curvature we provide smooth
embeddings of the ball with arbitrary small volume.


title:
M(s)stab(L): A Generalization of IDR(s)stab(L) for Sequences of Linear
  Systems

abstract:
  We propose Mstab, a novel Krylov subspace recycling method for the iterative
solution of sequences of linear systems with fixed system matrix and changing
right-hand sides. This new method is a straight and simple generalization of
IDRstab. IDRstab in turn is a very efficient method and generalization of
BiCGStab.
  The theory of Mstab is based on a generalization of the IDR theorem and
Sonneveld spaces.
  Numerical experiments indicate that Mstab can solve sequences of linear
systems faster than its corresponding IDRstab variant. Instead, when solving a
single system both methods are identical.


title: On cuts in ultraproducts of linear orders II

abstract:
  We continue our study of the class $\mathscr{C}(D)$, where $D$ is a uniform
ultrafilter on a cardinal $\kappa$ and $\mathscr{C}(D)$ is the class of all
pairs $(\theta_1, \theta_2),$ where $(\theta_1, \theta_2)$ is the cofinality of
a cut in $J^\kappa /D$ and $J$ is some $(\theta_1+\theta_2)^+$-saturated dense
linear order. We give a combinatorial characterization of the class
$\mathscr{C}(D)$. We also show that if $(\theta_1, \theta_2) \in
\mathscr{C}(D)$ and $D$ is $\aleph_1$-complete or $\theta_1 + \theta_2 >
2^\kappa,$ then $\theta_1=\theta_2.$


title: Dialog-based Language Learning

abstract:
  A long-term goal of machine learning research is to build an intelligent
dialog agent. Most research in natural language understanding has focused on
learning from fixed training sets of labeled data, with supervision either at
the word level (tagging, parsing tasks) or sentence level (question answering,
machine translation). This kind of supervision is not realistic of how humans
learn, where language is both learned by, and used for, communication. In this
work, we study dialog-based language learning, where supervision is given
naturally and implicitly in the response of the dialog partner during the
conversation. We study this setup in two domains: the bAbI dataset of (Weston
et al., 2015) and large-scale question answering from (Dodge et al., 2015). We
evaluate a set of baseline learning strategies on these tasks, and show that a
novel model incorporating predictive lookahead is a promising approach for
learning from a teacher's response. In particular, a surprising result is that
it can learn to answer questions correctly without any reward-based supervision
at all.


title:
Stationary configurations of the Standard Model Higgs potential:
  electroweak stability and rising inflection point

abstract:
  We study the gauge-independent observables associated with two interesting
stationary configurations of the Standard Model Higgs potential (extrapolated
to high energy according to the present state of the art, namely the NNLO): i)
the value of the top mass ensuring stability of the SM electroweak minimum, and
ii) the value of the Higgs potential at a rising inflection point. We examine
in detail and reappraise the experimental and theoretical uncertainties which
plague their determination, finding that: i) stability of the SM is compatible
with the present data at the 1.5 sigma level; ii) despite the large theoretical
error plaguing the value of the Higgs potential at a rising inflection point,
application of such configuration to models of primordial inflation displays a
3 sigma tension with the recent bounds on the tensor-to-scalar ratio of
cosmological perturbations.


title: A note on surgery obstructions and hyperbolic integer homology spheres

abstract:
  Auckly gave two examples of irreducible integer homology spheres (one
toroidal and one hyperbolic) which are not surgery on a knot in the
three-sphere. Using Heegaard Floer homology, the authors and Karakurt provided
infinitely many small Seifert fibered examples. In this note, we extend those
results to give infinitely many hyperbolic examples, as well as infinitely many
examples with arbitrary JSJ decomposition.


title: Magnon Inflation: Slow Roll with Steep Potentials

abstract:
  We find multi-scalar effective field theories (EFTs) that can achieve a slow
inflationary roll despite having a scalar potential that does not satisfy the
usual slow-roll condition (d V)^2 << V^2/Mp^2. They evade the usual slow-roll
conditions on $V$ because their kinetic energies are dominated by
single-derivative terms rather than the usual two-derivative terms. Single
derivatives dominate during slow roll and so do not require a breakdown of the
usual derivative expansion that underpins calculational control in much of
cosmology. The presence of such terms requires some sort of UV Lorentz-symmetry
breaking during inflation (besides the usual cosmological breaking).
Chromo-natural inflation provides an example of a UV theory that can generate
the multi-field single-derivative terms we consider, and we argue that the EFT
we find indeed captures the slow-roll conditions for the background evolution
for Chromo-natural inflation. We also show that our EFT can be understood as a
multi-field generalization of the single-field Cuscuton models. The multi-field
case introduces a new feature, however: the scalar kinetic terms define a
target-space 2-form, F_{ab}, whose antisymmetry gives new ways for slow roll to
be achieved.


title:
High-Capacity Angularly-Multiplexed Holographic Memory Operating at the
  Single Photon Level

abstract:
  We experimentally demonstrate an angularly-multiplexed holographic memory
capable of intrinsic generation, storage and retrieval of multiple photons,
based on off-resonant Raman interaction in warm rubidium-87 vapors. The memory
capacity of up to 60 independent atomic spin-wave modes is evidenced by
analyzing angular distributions of coincidences between Stokes and time-delayed
anti-Stokes light, observed down to the level of single spin-wave excitation
during several-$\mu$s memory lifetime. We also propose how to practically
enhance rates of single and multiple photons generation by combining our
multimode emissive memory with existing fast optical switches.


title:
Multimode Strong Coupling in Superconducting Cavity
  Piezo-electromechanics

abstract:
  High frequency mechanical resonators subjected to low thermal phonon
occupancy are easier to be prepared to the ground state by direct cryogenic
cooling. Their extreme stiffness, however, poses a significant challenge for
external interrogations. Here we demonstrate a superconducting cavity
piezo-electromechanical system in which multiple modes of a bulk acoustic
resonator oscillating at $10\,\textrm{GHz}$ are coupled to a planar microwave
superconducting resonator with a cooperativity exceeding $2\times10^{3}$, deep
in the strong coupling regime. By implementation of the non-contact coupling
scheme to reduce mechanical dissipation, the system exhibits excellent
coherence characterized by a frequency-quality factor product of
$7.5\times10^{15}\,\textrm{Hz}$. Interesting dynamics of temporal oscillations
of the microwave energy is observed, implying the coherent conversion between
phonons and photons. The demonstrated high frequency cavity
piezo-electromechanics is compatible with superconducting qubits, representing
an important step towards hybrid quantum systems.


title: Radiative Screening of Fifth Forces

abstract:
  We describe a symmetron model in which the screening of fifth forces arises
at the one-loop level through the Coleman-Weinberg mechanism of spontaneous
symmetry breaking. We show that such a theory can avoid current constraints on
the existence of fifth forces but still has the potential to give rise to
observable deviations from general relativity, which could be seen in cold atom
experiments.


title:
Caloric Effects in Methylammonium Lead Iodide from Molecular Dynamics
  Simulations

abstract:
  Organic-inorganic hybrid perovskite architecture could serve as a robust
platform for materials design to realize functionalities beyond photovoltaic
applications. We explore caloric effects in organometal halide perovskites,
taking methylammonium lead iodide (MAPbI$_3$) as an example, using all-atom
molecular dynamics simulations with a first-principles based interatomic
potential. The adiabatic thermal change is estimated directly by introducing
different driving fields in the simulations. We find that MAPbI$_3$ exhibits
both electrocaloric and mechanocaloric effects at room temperature. Local
structural analysis reveals that the rearrangement of molecular cations in
response to electric and stress fields is responsible for the caloric effects.
The enhancement of caloric response could be realized through strain
engineering and chemical doping.


title:
Decomposition and Analysis of Technological domains for better
  understanding of Technological Structure

abstract:
  Patents represent one of the most complete sources of information related to
technological change. This paper presents three months of research on U.S.
patents in the field of patent analysis. The methodology consists of using
search terms to locate the most representative international and US patent
classes and determines the overlap of those classes to arrive at the final set
of patents and using the prediction model developed by Benson and Magee to
calculate the technological improvement rate for the technological domains. My
research focused on the Biochemical Pharmacology technological area and
selecting relevant patents for technological domains and sub-domains within
this area. The goal is to better understand structure of technology domain and
understand how fast the domains and their sub-domains progress. The method I
used is developed by Benson and Magee which is called the Classification
Overlap Method1, it provides a reliable and largely automated way to break the
patent database into understandable technological domains where progress can be
measured.


title: Direct evaluation of overlap integrals between Slater-type-orbitals

abstract:
  We derive direct single-stage numerical evaluation of the electronic overlap
integral between arbitrary atomic orbitals (including STOs). Integration is
over cartesian co-ordinates, and replaces previous sums over 'special'
functions. The results, in Mathematica 10 and Maple 18, agree with the
literature to 8 digits. We briefly discuss possible use in quantum chemistry,
including accuracy, algorithmic suitability and operating-system
machine-implementation as an intrinsic function.


title: Topological Varma superfluid in optical lattices

abstract:
  Topological states of matter are peculiar quantum phases showing different
edge and bulk transport properties connected by the bulk-boundary
correspondence. While non-interacting fermionic topological insulators are well
established by now and have been classified according to a ten-fold scheme, the
possible realisation of topological states for bosons has not been much
explored yet. Furthermore, the role of interactions is far from being
understood. Here, we show that a topological state of matter exclusively driven
by interactions may occur in the p-band of a Lieb optical lattice filled with
ultracold bosons. The single-particle spectrum of the system displays a
remarkable parabolic band-touching point, with both bands exhibiting
non-negative curvature. Although the system is neither topological at the
single-particle level, nor for the interacting ground state, on-site
interactions induce an anomalous Hall effect for the excitations, carrying a
non-zero Chern number. Our work introduces an experimentally realistic strategy
for the formation of interaction-driven topological states of bosons.


title:
A single-exponential fixed-parameter algorithm for Distance-Hereditary
  Vertex Deletion

abstract:
  Vertex deletion problems ask whether it is possible to delete at most $k$
vertices from a graph so that the resulting graph belongs to a specified graph
class. Over the past years, the parameterized complexity of vertex deletion to
a plethora of graph classes has been systematically researched. Here we present
the first single-exponential fixed-parameter tractable algorithm for vertex
deletion to distance-hereditary graphs, a well-studied graph class which is
particularly important in the context of vertex deletion due to its connection
to the graph parameter rank-width. We complement our result with matching
asymptotic lower bounds based on the exponential time hypothesis. As an
application of our algorithm, we show that a vertex deletion set to
distance-hereditary graphs can be used as a parameter which allows
single-exponential fixed-parameter tractable algorithms for classical NP-hard
problems.


title:
Hierarchical Deep Reinforcement Learning: Integrating Temporal
  Abstraction and Intrinsic Motivation

abstract:
  Learning goal-directed behavior in environments with sparse feedback is a
major challenge for reinforcement learning algorithms. The primary difficulty
arises due to insufficient exploration, resulting in an agent being unable to
learn robust value functions. Intrinsically motivated agents can explore new
behavior for its own sake rather than to directly solve problems. Such
intrinsic behaviors could eventually help the agent solve tasks posed by the
environment. We present hierarchical-DQN (h-DQN), a framework to integrate
hierarchical value functions, operating at different temporal scales, with
intrinsically motivated deep reinforcement learning. A top-level value function
learns a policy over intrinsic goals, and a lower-level function learns a
policy over atomic actions to satisfy the given goals. h-DQN allows for
flexible goal specifications, such as functions over entities and relations.
This provides an efficient space for exploration in complicated environments.
We demonstrate the strength of our approach on two problems with very sparse,
delayed feedback: (1) a complex discrete stochastic decision process, and (2)
the classic ATARI game `Montezuma's Revenge'.


title: Succinct Choice Dictionaries

abstract:
  The choice dictionary is introduced as a data structure that can be
initialized with a parameter $n\in\mathbb{N}=\{1,2,\ldots\}$ and subsequently
maintains an initially empty subset $S$ of $\{1,\ldots,n\}$ under insertion,
deletion, membership queries and an operation choice that returns an arbitrary
element of $S$. The choice dictionary appears to be fundamental in
space-efficient computing. We show that there is a choice dictionary that can
be initialized with $n$ and an additional parameter $t\in\mathbb{N}$ and
subsequently occupies $n+O(n(t/w)^t+\log n)$ bits of memory and executes each
of the four operations insert, delete, contains (i.e., a membership query) and
choice in $O(t)$ time on a word RAM with a word length of $w=\Omega(\log n)$
bits. In particular, with $w=\Theta(\log n)$, we can support insert, delete,
contains and choice in constant time using $n+O(n/(\log n)^t)$ bits for
arbitrary fixed $t$. We extend our results to maintaining several pairwise
disjoint subsets of $\{1,\ldots,n\}$.
  We study additional space-efficient data structures for subsets $S$ of
$\{1,\ldots,n\}$, including one that supports only insertion and an operation
extract-choice that returns and deletes an arbitrary element of $S$. All our
main data structures can be initialized in constant time and support efficient
iteration over the set $S$, and we can allow changes to $S$ while an iteration
over $S$ is in progress. We use these abilities crucially in designing the most
space-efficient algorithms known for solving a number of graph and other
combinatorial problems in linear time. In particular, given an undirected graph
$G$ with $n$ vertices and $m$ edges, we can output a spanning forest of $G$ in
$O(n+m)$ time with at most $(1+\epsilon)n$ bits of working memory for arbitrary
fixed $\epsilon>0$.


title:
$\mu$Kummer: efficient hyperelliptic signatures and key exchange on
  microcontrollers

abstract:
  We describe the design and implementation of efficient signature and
key-exchange schemes for the AVR ATmega and ARM Cortex M0 microcontrollers,
targeting the 128-bit security level. Our algorithms are based on an efficient
Montgomery ladder scalar multiplication on the Kummer surface of Gaudry and
Schost's genus-2 hyperelliptic curve, combined with the Jacobian point recovery
technique of Costello, Chung, and Smith. Our results are the first to show the
feasibility of software-only hyperelliptic cryptography on constrained
platforms, and represent a significant improvement on the elliptic-curve
state-of-the-art for both key exchange and signatures on these architectures.
Notably, our key-exchange scalar-multiplication software runs in under 9740k
cycles on the ATmega, and under 2650k cycles on the Cortex M0.


title: Brane realization of q-theory and the cosmological constant problem

abstract:
  We discuss the cosmological constant problem using the properties of a
freely-suspended two-dimensional condensed-matter film, i.e., an explicit
realization of a 2D brane. The large contributions of vacuum fluctuations to
the surface tension of this film are cancelled in equilibrium by the
thermodynamic potential arising from the conservation law for particle number.
In short, the surface tension of the film vanishes in equilibrium due to a
thermodynamic identity. This 2D brane can be generalized to a 4D brane with
gravity. For the 4D brane, the analogue of the 2D surface tension is the 4D
cosmological constant, which is also nullified in full equilibrium. The 4D
brane theory provides an alternative description of the phenomenological
$q$-theory of the quantum vacuum. As for other realizations of the vacuum
variable $q$, such as the 4-form field-strength realization, the main
ingredient is the conservation law for the variable $q$, which makes the vacuum
a self-sustained system. For a vacuum within this class, the nullification of
the cosmological constant takes place automatically in equilibrium. Out of
equilibrium, the cosmological constant can be as large as suggested by naive
estimates based on the summation of zero-point energies. In this brane
description, $q$-theory also corresponds to a generalization of unimodular
gravity.


title: Compositionality and String Diagrams for Game Theory

abstract:
  We introduce string diagrams as a formal mathematical, graphical language to
represent, compose, program and reason about games. The language is well
established in quantum physics, quantum computing and quantum linguistic with
the semantics given by category theory. We apply this language to the game
theoretical setting and show examples how to use it for some economic games
where we highlight the compositional nature of our higher-order game theory.


title:
Diophantine equations, Platonic solids, McKay correspondence, equivelar
  maps and Vogel's universality

abstract:
  We notice that one of the Diophantine equations, $knm=2kn+2km+2nm$, arising
in the universality originated Diophantine classification of simple Lie
algebras, has interesting interpretations for two different sets of signs of
variables. In both cases it describes "regular polyhedrons" with $k$ edges in
each vertex, $n$ edges of each face, with total number of edges $|m|$, and
Euler characteristics $\chi=\pm 2$. In the case of negative $m$ this equation
corresponds to $\chi=2$ and describes true regular polyhedrons, Platonic
solids. The case with positive $m$ corresponds to Euler characteristic
$\chi=-2$ and describes the so called equivelar maps (charts) on the surface of
genus $2$. In the former case there are two routes from Platonic solids to
simple Lie algebras - abovementioned Diophantine classification and McKay
correspondence. We compare them for all solutions of this type, and find
coincidence in the case of icosahedron (dodecahedron), corresponding to $E_8$
algebra. In the case of positive $k$, $n$ and $m$ we obtain in this way the
interpretation of (some of) the mysterious solutions (Y-objects), appearing in
the Diophantine classification and having some similarities with simple Lie
algebras.


title: Fermi Gases in the Two-Dimensional to Quasi-Two-Dimensional Crossover

abstract:
  We tune the dimensionality of pancake-shaped strongly-interacting $^6$Li
Fermi gas clouds from two-dimensional (2D) to quasi-2D, by controlling the
ratio of the radial Fermi energy $E_F$ to the harmonic oscillator energy
$h\nu_z$ in the tightly confined direction. In the 2D regime, where
$E_F<<h\nu_z$, the measured radio frequency resonance spectra are in agreement
with 2D-BCS theory. In the quasi-2D regime, where $E_F\simeq h\nu_z$, the
measured spectra deviate significantly from 2D-BCS theory. For both regimes,
the measured cloud radii disagree with 2D-BCS mean field theory, but agree
approximately with predictions using a free energy derived from the
Bethe-Goldstone equation.


title:
The Role of Tensorial Electronic Friction in Energy Transfer at Metal
  Surfaces

abstract:
  An accurate description of nonadiabatic energy relaxation is crucial for
modeling atomistic dynamics at metal surfaces. Interfacial energy transfer due
to electron-hole pair excitations coupled to motion of molecular adsorbates is
often simulated by Langevin molecular dynamics with electronic friction. Here,
we present calculations of the full electronic friction tensor by using first
order time-dependent perturbation theory (TDPT) at the density functional
theory (DFT) level. We show that the friction tensor is generally anisotropic
and non-diagonal, as found for hydrogen atom on Pd(100) and CO on a Cu(100)
surfaces. This implies that electron-hole pair induced nonadiabatic coupling at
metal surfaces leads to friction-induced mode coupling, therefore opening an
additional channel for energy redistribution. We demonstrate the robustness and
accuracy of our results by direct comparison to established methods and
experimental data.


title: gevolution: a cosmological N-body code based on General Relativity

abstract:
  We present a new N-body code, gevolution, for the evolution of large scale
structure in the Universe. Our code is based on a weak field expansion of
General Relativity and calculates all six metric degrees of freedom in Poisson
gauge. N-body particles are evolved by solving the geodesic equation which we
write in terms of a canonical momentum such that it remains valid also for
relativistic particles. We validate the code by considering the Schwarzschild
solution and, in the Newtonian limit, by comparing with the Newtonian N-body
codes Gadget-2 and RAMSES. We then proceed with a simulation of large scale
structure in a Universe with massive neutrinos where we study the gravitational
slip induced by the neutrino shear stress. The code can be extended to include
different kinds of dark energy or modified gravity models and going beyond the
usually adopted quasi-static approximation. Our code is publicly available.


title: On the Galois correspondence for Hopf Galois structures

abstract:
  We study the question of the surjectivity of the Galois correspondence from
subHopf algebras to subfields given by the Fundamental Theorem of Galois Theory
for abelian Hopf Galois structures on a Galois extension of fields with Galois
group G', a finite abelian p-group. Applying the connection between regular
subgroups of the holomorph of a finite abelian p-group (G, +) and associative,
commutative nilpotent algebra structures A on (G, +) of Caranti, et. al., we
show that if A gives rise to a H-Hopf Galois structure on L/K, then the
K-subHopf algebras of H correspond to the ideals of A. Among the applications,
we show that if G and G' are both elementary abelian p-groups, then the only
Hopf Galois structure on L/K of type G for which the Galois correspondence is
surjective is the classical Galois structure on L/K.


title: Cuckoo Filter: Simplification and Analysis

abstract:
  The cuckoo filter data structure of Fan, Andersen, Kaminsky, and Mitzenmacher
(CoNEXT 2014) performs the same approximate set operations as a Bloom filter in
less memory, with better locality of reference, and adds the ability to delete
elements as well as to insert them. However, until now it has lacked
theoretical guarantees on its performance. We describe a simplified version of
the cuckoo filter using fewer hash function calls per query. With this
simplification, we provide the first theoretical performance guarantees on
cuckoo filters, showing that they succeed with high probability whenever their
fingerprint length is large enough.


title:
Reconstruction for multiwave imaging in attenuating media with large
  damping coefficient

abstract:
  In this article we study the reconstruction problem in TAT/PAT on an
attenuating media. Namely, we prove a reconstruction procedure of the initial
condition for the damped wave equation via Neumann series that works for
arbitrary large smooth attenuation coefficients extending the result of Homan
in [1]. We also illustrate the theoretical result by including some numerical
experiments at the end of the paper.


title: An infinitesimal approach to a conjecture of Eisenbud and Harris

abstract:
  Eisenbud and Harris conjectured in 1982 that an algebraic curve of high genus
lies on a surface of low degree (which they proved for curves of very large
degree). They observed constraints on the Hilbert function of a general
hyperplane section which imply that the hyperplane section lies on a curve of
low degree. We investigate this situation under deformation. Given a set of
sufficiently many points (as postulated by the conjecture) on a linearly normal
curve, we show that if the number of conditions on quadrics remains constant,
then for every deformation of the points the curve deforms along with them.


title: On Induced Colourful Paths in Triangle-free Graphs

abstract:
  Given a graph $G=(V,E)$ whose vertices have been properly coloured, we say
that a path in $G$ is "colourful" if no two vertices in the path have the same
colour. It is a corollary of the Gallai-Roy-Vitaver Theorem that every properly
coloured graph contains a colourful path on $\chi(G)$ vertices. We explore a
conjecture that states that every properly coloured triangle-free graph $G$
contains an induced colourful path on $\chi(G)$ vertices and prove its
correctness when the girth of $G$ is at least $\chi(G)$. Recent work on this
conjecture by Gy\'arf\'as and S\'ark\"ozy, and Scott and Seymour has shown the
existence of a function $f$ such that if $\chi(G)\geq f(k)$, then an induced
colourful path on $k$ vertices is guaranteed to exist in any properly coloured
triangle-free graph $G$.


title:
A supernova feedback implementation for the astrophysical simulation
  software Arepo

abstract:
  Supernova (SN) explosions play an important role in the development of
galactic structures. The energy and momentum imparted on the interstellar
medium (ISM) in so-called "supernova feedback" drives turbulence, heats the
gas, enriches it with heavy elements, can lead to the formation of new stars or
even suppress star formation by disrupting stellar nurseries. In the numerical
simulation at the sub-galactic level, not including the energy and momentum of
supernovas in the physical description of the problem can also lead to several
problems that might partially be resolved by including a description of
supernovas. In this thesis such an implementation is attempted for the combined
numerical hydrodynamics and N-body simulation software Arepo (Springel, 2010)
for the high density gas in the ISM only. This allows supernova driven
turbulence in boxes of 400pc cubed to be studied. In a stochastic process a
large amount of thermal energy is imparted on a number of neighbouring cells,
mimicking the effect of a supernova explosions. We test this approach by
modelling the explosion of a single supernova in a uniform density medium and
comparing the evolution of the resulting supernova remnant to the
theoretically-predicted behaviour. We also run a simulation with our feedback
code and a fixed supernova rate derived from the Kennicutt-Schmidt relation
(Kennicutt, 1998) for a duration of about 20 Myrs. We describe our method in
detail in this text and discuss the properties of our implementation. vii


title: An effective bound for the gonality conjecture

abstract:
  Ein and Lazarsfeld have shown that one can read off the gonality of an
algebraic curve from its syzygies in the embedding defined by any one line
bundle of sufficiently large degree. This note extends their approach and shows
that the gonality can be detected from the syzygies of an embedding by any line
bundle of degree at least 4g-3.


title:
Bayesian Analysis of Two Stellar Populations in Galactic Globular
  Clusters I: Statistical and Computational Methods

abstract:
  We develop a Bayesian model for globular clusters composed of multiple
stellar populations, extending earlier statistical models for open clusters
composed of simple (single) stellar populations (vanDyk et al. 2009, Stein et
al. 2013). Specifically, we model globular clusters with two populations that
differ in helium abundance. Our model assumes a hierarchical structuring of the
parameters in which physical properties---age, metallicity, helium abundance,
distance, absorption, and initial mass---are common to (i) the cluster as a
whole or to (ii) individual populations within a cluster, or are unique to
(iii) individual stars. An adaptive Markov chain Monte Carlo (MCMC) algorithm
is devised for model fitting that greatly improves convergence relative to its
precursor non-adaptive MCMC algorithm. Our model and computational tools are
incorporated into an open-source software suite known as BASE-9. We use
numerical studies to demonstrate that our method can recover parameters of
two-population clusters, and also show model misspecification can potentially
be identified. As a proof of concept, we analyze the two stellar populations of
globular cluster NGC 5272 using our model and methods. (BASE-9 is available
from GitHub: https://github.com/argiopetech/base/releases).


title:
Bayesian Analysis of Two Stellar Populations in Galactic Globular
  Clusters II: NGC 5024, NGC 5272, and NGC 6352

abstract:
  We use Cycle 21 Hubble Space Telescope (HST) observations and HST archival
ACS Treasury observations of Galactic Globular Clusters to find and
characterize two stellar populations in NGC 5024 (M53), NGC 5272 (M3), and NGC
6352. For these three clusters, both single and double-population analyses are
used to determine a best fit isochrone(s). We employ a sophisticated Bayesian
analysis technique to simultaneously fit the cluster parameters (age, distance,
absorption, and metallicity) that characterize each cluster. For the
two-population analysis, unique population level helium values are also fit to
each distinct population of the cluster and the relative proportions of the
populations are determined. We find differences in helium ranging from
$\sim$0.05 to 0.11 for these three clusters. Model grids with solar
$\alpha$-element abundances ([$\alpha$/Fe] =0.0) and enhanced $\alpha$-elements
([$\alpha$/Fe]=0.4) are adopted.


title:
Heat flow of extrinsic biharmonic maps from a four dimensional manifold
  with boundary

abstract:
  Let $(M,g)$ be a four dimensional compact Riemannian manifold with boundary
and $(N,h)$ be a compact Riemannian manifold without boundary. We show the
existence of a unique, global weak solution of the heat flow of extrinsic
biharmonic maps from $M$ to $N$ under the Dirichlet boundary condition, which
is regular with the exception of at most finitely many time slices. We also
discuss the behavior of solution near the singular times. As an immediate
application, we prove the existence of a smooth extrinsic biharmonic map from
$M$ to $N$ under any Dirichlet boundary condition.


title:
Question Answering via Integer Programming over Semi-Structured
  Knowledge

abstract:
  Answering science questions posed in natural language is an important AI
challenge. Answering such questions often requires non-trivial inference and
knowledge that goes beyond factoid retrieval. Yet, most systems for this task
are based on relatively shallow Information Retrieval (IR) and statistical
correlation techniques operating on large unstructured corpora. We propose a
structured inference system for this task, formulated as an Integer Linear
Program (ILP), that answers natural language questions using a semi-structured
knowledge base derived from text, including questions requiring multi-step
inference and a combination of multiple facts. On a dataset of real, unseen
science questions, our system significantly outperforms (+14%) the best
previous attempt at structured reasoning for this task, which used Markov Logic
Networks (MLNs). It also improves upon a previous ILP formulation by 17.7%.
When combined with unstructured inference methods, the ILP system significantly
boosts overall performance (+10%). Finally, we show our approach is
substantially more robust to a simple answer perturbation compared to
statistical correlation methods.


title:
Two-Dimensional Flow Nanometry of Biological Nanoparticles for Accurate
  Determination of Their Size and Emission Intensity

abstract:
  Biological nanoparticles (BNPs) are of high interest due to their key role in
various biological processes and use as biomarkers. BNP size and molecular
composition are decisive for their functions, but simultaneous determination of
both properties with high accuracy remains challenging, which is a severe
limitation. Surface-sensitive microscopy allows one to precisely determine
fluorescence or scattering intensity, but not the size of individual BNPs. The
latter is better determined by tracking their random motion in bulk, but the
limited illumination volume for tracking this motion impedes reliable intensity
determination. We here show that attaching BNPs (specifically, vesicles and
functionalized gold NPs) to a supported lipid bilayer, subjecting them to a
hydrodynamic flow, and tracking their motion via surface-sensitive imaging
enable to determine their diffusion coefficients and flow-induced drift
velocities and to accurately quantify both BNP size and emission intensity. For
vesicles, the high accuracy is demonstrated by resolving the expected
radius-squared dependence of their fluorescence intensity.


title: Remarks on approximate harmonic maps in dimension two

abstract:
  For the class of approximate harmonic maps $u\in W^{1,2}(\Sigma,N)$ from a
closed Riemmanian surface $(\Sigma,g)$ to a compact Riemannian manifold $(N,
h)$, we show that (i) the so-called energy identity holds for weakly convergent
approximate harmonic maps $\{u_n\}:\Sigma\to N$, with tension fields
$\tau(u_n)$ bounded in the Morrey space $M^{1,\delta}(\Sigma)$ for some
$0\le\delta<2$; and (ii) if an approximate harmonic map $u$ has tension field
$\tau(u)\in L\log L(\Sigma)\cap M^{1,\delta}(\Sigma)$ for some $0\le\delta<2$,
then $u\in W^{2,1}(\Sigma, N)$. Based on these estimates, we further establish
the bubble tree convergence, referring to energy identity both $L^{2,1}$ of
gradients and $L^1$-norm of hessians and the oscillation convergence, for a
weakly convergent sequence of approximate harmonic maps $\{u_n\}$, with tension
fields $\tau(u_n)$ uniformly bounded in $M^{1,\delta}(\Sigma)$ for some
$0\le\delta<2$ and uniformly integrable in $L\log L(\Sigma)$.


title: Symmetry-aware Depth Estimation using Deep Neural Networks

abstract:
  Due to the abundance of 2D product images from the Internet, developing
efficient and scalable algorithms to recover the missing depth information is
central to many applications. Recent works have addressed the single-view depth
estimation problem by utilizing convolutional neural networks. In this paper,
we show that exploring symmetry information, which is ubiquitous in man made
objects, can significantly boost the quality of such depth predictions.
Specifically, we propose a new convolutional neural network architecture to
first estimate dense symmetric correspondences in a product image and then
propose an optimization which utilizes this information explicitly to
significantly improve the quality of single-view depth estimations. We have
evaluated our approach extensively, and experimental results show that this
approach outperforms state-of-the-art depth estimation techniques.


title: Spectral Properties of Schwarzschild Instantons

abstract:
  We study spectral properties of the Dirac and scalar Laplace operator on the
Euclidean Schwarzschild space, both twisted by a family of abelian connections
with anti-self-dual curvature. We show that the zero-modes of the gauged Dirac
operator, first studied by Pope, take a particularly simple form in terms of
the radius of the Euclidean time orbits, and interpret them in the context of
geometric models of matter. For the gauged Laplace operator, we study the
spectrum of bound states numerically and observe that it can be approximated
with remarkable accuracy by that of the exactly solvable gauged Laplace
operator on the Euclidean Taub-NUT space.


title:
Characteristic properties of the Casimir free energy for metal films
  deposited on metallic plates

abstract:
  The Casimir free energy and pressure of thin metal films deposited on
metallic plates are considered using the Lifshitz theory and the Drude and
plasma model approaches to the role of conduction electrons. The bound
electrons are taken into account by using the complete optical data of film and
plate metals. It is shown that for films of several tens of nanometers
thickness the Casimir free energy and pressure calculated using these
approaches differ by hundreds and thousands percent and can be easily
discriminated experimentally. According to our results, the free energy of a
metal film does not vanish in the limiting case of ideal metal if the Drude
model approach is used in contradiction with the fact that the fluctuating
field cannot penetrate in its interior. Numerical computations of the Casimir
free energy and pressure of Ag and Au films deposited on Cu and Al plates have
been performed using both theoretical approaches. It is shown that the free
energy of a film can be both negative and positive depending on the metals
used. For a Au film on a Ag plate and vice versa the Casimir energy of a film
changes its sign with increasing film thickness. Applications of the obtained
results for resolving the Casimir puzzle and the problem of stability of thin
films are discussed.


title: Topological bound states of a quantum walk with cold atoms

abstract:
  We suggest a method for engineering a quantum walk, with cold atoms as
walkers, which presents topologically non-trivial properties. We derive the
phase diagram, and show that we are able to produce a boundary between
topologically distinct phases using the finite beam width of the applied
lasers. A topologically protected bound state can then be observed, which is
pinned to the interface and is robust to perturbations. We show that it is
possible to identify this bound state by averaging over spin sensitive measures
of the atom's position, based on the spin distribution that these states
display. Interestingly, there exists a parameter regime in which our system
maps on to the Creutz ladder.


title:
Automatic Graphic Logo Detection via Fast Region-based Convolutional
  Networks

abstract:
  Brand recognition is a very challenging topic with many useful applications
in localization recognition, advertisement and marketing. In this paper we
present an automatic graphic logo detection system that robustly handles
unconstrained imaging conditions. Our approach is based on Fast Region-based
Convolutional Networks (FRCN) proposed by Ross Girshick, which have shown
state-of-the-art performance in several generic object recognition tasks
(PASCAL Visual Object Classes challenges). In particular, we use two CNN models
pre-trained with the ILSVRC ImageNet dataset and we look at the selective
search of windows `proposals' in the pre-processing stage and data augmentation
to enhance the logo recognition rate. The novelty lies in the use of transfer
learning to leverage powerful Convolutional Neural Network models trained with
large-scale datasets and repurpose them in the context of graphic logo
detection. Another benefit of this framework is that it allows for multiple
detections of graphic logos using regions that are likely to have an object.
Experimental results with the FlickrLogos-32 dataset show not only the
promising performance of our developed models with respect to noise and other
transformations a graphic logo can be subject to, but also its superiority over
state-of-the-art systems with hand-crafted models and features.


title:
Entanglement Density Tunes Microscale Nonlinear Response of Entangled
  Actin

abstract:
  We optically drive a microsphere at constant speed through entangled actin
networks of 0.2 - 1.4 mg/ml at rates faster than the critical rate controlling
the onset of a nonlinear response. By measuring the resistive force exerted on
the microsphere during and following strain we reveal a critical concentration
$c^{*}\simeq0.4$ mg/ml for nonlinear features to emerge. For $c>c^{*}$,
entangled actin stiffens at short times with the degree of stiffening $S$ and
corresponding timescale $t_{stiff}$ scaling with the entanglement tube density,
i.e. $S\sim t_{stiff}\sim d_t^{-1}\sim c^{3/5}$. The network subsequently
yields to a viscous regime with the yield distance $d_y$ scaling linearly with
yield force $f_y$ and inversely with the entanglement length ($f_y\sim d_y\sim
l_{e}^{-1} \sim c^{2/5}$). Stiffening and yielding dynamics are consistent with
recent theoretical predictions for nonlinear cohesive breakdown of
entanglements. We further show that above $c^{*}$ force relaxation proceeds via
slow filament disengagement from dilated tubes coupled with $\sim$10x faster
lateral hopping, with the corresponding concentration dependences in agreement
with recent theoretical predictions for entangled rigid rods.


title: The screening Horndeski cosmologies

abstract:
  We present a systematic analysis of homogeneous and isotropic cosmologies in
a particular Horndeski model with Galileon shift symmetry, containing also a
$\Lambda$-term and a matter. The model, sometimes called Fab Five, admits a
rich spectrum of solutions. Some of them describe the standard late time
cosmological dynamic dominated by the $\Lambda$-term and matter, while at the
early times the universe expands with a constant Hubble rate determined by the
value of the scalar kinetic coupling. For other solutions the $\Lambda$-term
and matter are screened at all times but there are nevertheless the early and
late accelerating phases. The model also admits bounces, as well as peculiar
solutions describing "the emergence of time". Most of these solutions contain
ghosts in the scalar and tensor sectors. However, a careful analysis reveals
three different branches of ghost-free solutions, all showing a late time
acceleration phase. We analyze the dynamical stability of these solutions and
find that all of them are stable in the future, since all their perturbations
stay bounded at late times. However, they all turn out to be unstable in the
past, as their perturbations grow violently when one approaches the initial
spacetime singularity. We therefore conclude that the model has no viable
solutions describing the whole of the cosmological history, although it may
describe the current acceleration phase. We also check that the flat space
solution is ghost-free in the model, but it may acquire ghost in more general
versions of the Horndeski theory.


title:
Spin glass in semiconducting KFe$_{1.05}$Ag$_{0.88}$Te$_{2}$ single
  crystals

abstract:
  We report discovery of KFe$_{1.05}$Ag$_{0.88}$Te$_{2}$ single crystals with
semiconducting spin glass ground state. Composition and structure analysis
suggest nearly stoichiometric I4/mmm space group but allow for the existence of
vacancies, absent in long range semiconducting antiferromagnet
KFe$_{0.85}$Ag$_{1.15}$Te$_{2}$. The subtle change in stoichometry in Fe/Ag
sublattice changes magnetic ground state but not conductivity, giving further
insight into the semiconducting gap mechanism.


title:
Study of Time Evolution for Approximation of Two-Body Spinless-Salpeter
  Equation

abstract:
  We approximate the two-body spinless Salpeter equation with the one which is
valid in heavy quarks limit. We consider the resulting semi-relativistic
equation in a time-dependent formulation. We use the Lewis- Riesenfeld
dynamical invariant method and series solution to obtain the solutions of the
differential equation. We have also done some calculations in order to derive
the time evolution operator for the considered problem.


title:
Inflationary universe from higher derivative quantum gravity coupled
  with scalar electrodynamics

abstract:
  We study inflation for a quantum scalar electrodynamics model in curved
space-time and for higher-derivative quantum gravity (QG) coupled with scalar
electrodynamics. The corresponding renormalization-group (RG) improved
potential is evaluated for both theories in Jordan frame where non-minimal
scalar-gravitational coupling sector is explicitly kept. The role of one-loop
quantum corrections is investigated by showing how these corrections enter in
the expressions for the slow-roll parameters, the spectral index and the
tensor-to-scalar ratio and how they influence the bound of the Hubble parameter
at the beginning of the primordial acceleration. We demonstrate that the viable
inflation maybe successfully realized, so that it turns out to be consistent
with last Planck and BICEP2/Keck Array data.


title:
Towards a fully predictive model of flight paths in pigeons navigating
  in the familiar area: prediction across differing individuals

abstract:
  This paper will detail the basis of our previously developed predictive model
for pigeon flight paths based on observations of the specific individual being
predicted. We will then describe how this model can be adapted to predict the
flight of a new, unobserved bird, based on observations of other individuals
from the same release site. We will test the accuracy of these predictions
relative to naive models with no previous flight information and those trained
on the focal bird's own previous flights, and discuss the implications of these
results for the nature of navigational cue use in the familiar area. Finally we
will discuss how visual cues may be explicitly encoded in the model in future
work.


title: Precision decay rate calculations in quantum field theory

abstract:
  Tunneling in quantum field theory is worth understanding properly, not least
because it controls the long term fate of our universe. There are however, a
number of features of tunneling rate calculations which lack a desirable
transparency, such as the necessity of analytic continuation, the
appropriateness of using an effective instead of classical potential, and the
sensitivity to short-distance physics. This paper attempts to review in
pedagogical detail the physical origin of tunneling and its connection to the
path integral. Both the traditional potential-deformation method and a recent
more direct propagator-based method are discussed. Some new insights from using
approximate semi-classical solutions are presented. In addition, we explore the
sensitivity of the lifetime of our universe to short distance physics, such as
quantum gravity, emphasizing a number of important subtleties.


title:
Habitability of planets on eccentric orbits: the limits of the mean flux
  approximation

abstract:
  Contrary to Earth, which has a small orbital eccentricity, some exoplanets
discovered in the insolation habitable zone (HZ) have high orbital
eccentricities (e.g., up to an eccentricity of $\sim0.97$ for HD~20782~b). This
raises the question of the capacity of these planets to host surface liquid
water. In order to assess the habitability of an eccentric planet, the mean
flux approximation is often used. It states that a planet on an eccentric orbit
is called habitable if it receives on average a flux compatible with the
presence of surface liquid water. However, as the planets do experience
important insolation variations over one orbit and even spend some time outside
the HZ for high eccentricities, the question of their habitability might not be
as straightforward. We performed a set of simulations using the Global Climate
Model LMDz, exploring the limits of the mean flux approximation when varying
the luminosity of the host star and the eccentricity of the planet. We computed
the climate of tidally locked ocean covered planets with orbital eccentricity
from 0 to 0.9 receiving a mean flux equal to Earth's, around stars of
luminosity ranging from $L_\odot$ to $10^{-4}~L_\odot$. Using here a definition
of habitability based on the presence of surface liquid water, we find that
most of the planets considered can sustain surface liquid water on the dayside
with an ice cap on the nightside. However, for high eccentricity and high
luminosity, planets cannot sustain surface liquid water during the whole
orbital period. They completely freeze at apoastron and when approaching
periastron an ocean appears around the substellar point. We conclude that the
higher the eccentricity and the higher the luminosity of the star, the less
reliable the mean flux approximation.


title:
Exoplanetary Atmospheres - Chemistry, Formation Conditions, and
  Habitability

abstract:
  Characterizing the atmospheres of extrasolar planets is the new frontier in
exoplanetary science. The last two decades of exoplanet discoveries have
revealed that exoplanets are very common and extremely diverse in their orbital
and bulk properties. We now enter a new era as we begin to investigate the
chemical diversity of exoplanets, their atmospheric and interior processes, and
their formation conditions. Recent developments in the field have led to
unprecedented advancements in our understanding of atmospheric chemistry of
exoplanets and the implications for their formation conditions. We review these
developments in the present work. We review in detail the theory of atmospheric
chemistry in all classes of exoplanets discovered to date, from highly
irradiated gas giants, ice giants, and super-Earths, to directly imaged giant
planets at large orbital separations. We then review the observational
detections of chemical species in exoplanetary atmospheres of these various
types using different methods, including transit spectroscopy, doppler
spectroscopy, and direct imaging. In addition to chemical detections, we
discuss the advances in determining chemical abundances in these atmospheres
and how such abundances are being used to constrain exoplanetary formation
conditions and migration mechanisms. Finally, we review recent theoretical work
on the atmospheres of habitable exoplanets, followed by a discussion of future
outlook of the field.


title: Hello Darkness My Old Friend: The Fading of the Nearby TDE ASASSN-14ae

abstract:
  We present late-time optical spectroscopy taken with the Large Binocular
Telescope's Multi-Object Double Spectrograph, an improved ASAS-SN pre-discovery
non-detection, and late-time SWIFT observations of the nearby ($d=193$ Mpc,
$z=0.0436$) tidal disruption event (TDE) ASASSN-14ae. Our observations span
from $\sim$20 days before to $\sim$750 days after discovery. The proximity of
ASASSN-14ae allows us to study the optical evolution of the flare and the
transition to a host dominated state with exceptionally high precision. We
measure very weak H$\alpha$ emission 300 days after discovery ($L_{\rm H\alpha}
\simeq 4\times 10^{39}$ ergs s$^{-1}$) and the most stringent upper limit to
date on the H$\alpha$ luminosity $\sim$750 days after discovery ($L_{\rm
H\alpha} \lesssim 10^{39}$ ergs s$^{-1}$), suggesting that the optical emission
arising from a TDE can vanish on a timescale as short as 1 year. Our results
have important implications for both spectroscopic detection of TDE candidates
at late times, as well as the nature of TDE host galaxies themselves.


title:
The crucial role of higher-order multiplicity in wide binary formation:
  A case study using the $\beta$-Pictoris moving group

abstract:
  The "in-situ" formation of very wide binaries is hard to explain as their
physical separations are beyond the typical size of a collapsing cloud core
($\approx$5000-10,000 au). Here we investigate the formation process of such
systems. We compute population statistics such as the multiplicity fraction
(MF), companion-star fraction (CSF) and physical separation distribution of
companions in the $\beta$-Pictoris moving group (BPMG). We compare previous
multiplicity studies in younger and older regions and show that the dynamic
evolution of a young population with a high degree of primordial multiplicity
can lead to a processed separation distribution, similar to the field
population. The evolution of outer components is attributed to the dynamical
unfolding of higher-order (triple) systems; a natural consequence of which is
the formation of wide binaries. We find a strong preference for wide systems to
contain three or more components ($>$1000 au: 11 / 14, 10,000 au: 6 / 7). We
argue that the majority of wide binaries identified in young moving groups are
primordial. Under the assumption that stellar populations, within our galaxy,
have statistically similar primordial multiplicity, we can infer that the
paucity of wide binaries in the field is the result of dynamical evolution.


title: Zoomed cosmological simulations of Milky Way sized halos in f(R)-gravity

abstract:
  We investigate the impact of f(R) modified gravity on the internal properties
of Milky Way sized dark matter halos in a set of cosmological zoom simulations
of seven halos from the Aquarius suite, carried out with our code MG-GADGET in
the Hu & Sawicki f(R) model. Also, we calculate the fifth forces in ideal
NFW-halos as well as in our cosmological simulations and compare them against
analytic model predictions for the fifth force inside spherical objects. We
find that these theoretical predictions match the forces in the ideal halos
very well, whereas their applicability is somewhat limited for realistic
cosmological halos. Our simulations show that f(R) gravity significantly
affects the dark matter density profile of Milky Way sized objects as well as
their circular velocities. In unscreened regions, the velocity dispersions are
increased by up to 40% with respect to LCDM for viable f(R) models. This
difference is larger than reported in previous works. The Solar circle is fully
screened in $f_{R0} = -10^{-6}$ models for Milky Way sized halos, while this
location is unscreened for slightly less massive objects. Within the scope of
our limited halo sample size, we do not find a clear dependence of the
concentration parameter of dark matter halos on $f_{R0}$.


title:
Angular observables for spin discrimination in boosted diboson final
  states

abstract:
  We investigate the prospects for spin determination of a heavy diboson
resonance using angular observables. Focusing in particular on boosted fully
hadronic final states, we detail both the differences in signal efficiencies
and distortions of differential distributions resulting from various jet
substructure techniques. We treat the 2 TeV diboson excess as a case study, but
our results are generally applicable to any future discovery in the diboson
channel. Scrutinizing ATLAS and CMS analyses at 8 TeV and 13 TeV, we find that
the specific cuts employed in these analyses have a tremendous impact on the
discrimination power between different signal hypotheses. We discuss modified
cuts that can offer a significant boost to spin sensitivity in a post-discovery
era. Even without altered cuts, we show that CMS, and partly also ATLAS, will
be able to distinguish between spin 0, 1, or 2 new physics diboson resonances
at the $2\sigma$ level with 30 fb$^{-1}$ of 13 TeV data, for our 2 TeV case
study.


title:
Detection and Characterization of Exoplanets using Projections on
  Karhunen-Loeve Eigenimages: Forward Modeling

abstract:
  A new class of high-contrast image analysis algorithms that empirically fit
and subtract systematic noise has lead to recent discoveries of faint exoplanet
/substellar companions and scattered light images of circumstellar disks. These
methods are extremely efficient at enhancing the detectability of faint
astrophysical signal, but they do generally create systematic biases in their
observed properties. This paper provides a general solution for this
outstanding problem. We present the analytical derivation of a linear expansion
that captures the impact of astrophysical over-subtraction and/or
self-subtraction these image analysis techniques. We examine the general case
for which the reference images of the astrophysical scene move azimuthally
and/or radially across the field of view as a result of the observation
strategy. Our new method is based on perturbing the covariance matrix
underlying any least-squares speckles problem, and propagating this
perturbation through the data analysis algorithm. We then demonstrate practical
applications of this new algorithm. We first consider the case of the spectral
extraction of faint point sources in IFS data and illustrate, using public
Gemini Planet Imager commissioning data, that our novel perturbation-based
Karhunen-Lo\`eve Image Processing Forward Modeling (KLIP-FM) can indeed
alleviate algorithmic biases. We then apply KLIP-FM to the problem associated
with the detection of point sources. We show how it decreases the rate of false
negatives (e.g missed planets) while keeping the rate of false positives
unchanged when compared to classical least-squares fitting methods. This can
potentially have important consequences on the design of follow-up strategies
of ongoing direct imaging surveys.


title:
Generating Ray Class Fields of Real Quadratic Fields via Complex
  Equiangular Lines

abstract:
  For certain real quadratic fields $K$ with sufficiently small discriminant we
produce explicit unit generators for specific ray class fields of $K$ using a
numerical method that arose in the study of complete sets of equiangular lines
in $\mathbb{C}^d$ (known in quantum information as symmetric informationally
complete measurements or SICs). The construction in low dimensions suggests a
general recipe for producing unit generators in infinite towers of ray class
fields above arbitrary real quadratic $K$, and we summarise this in a
conjecture. There are indications [19,20] that the logarithms of these
canonical units are related to the values of $L$-functions associated to the
extensions, following the programme laid out in the Stark Conjectures.


title: Shedding Light on Neutrino Masses with Dark Forces

abstract:
  Heavy right-handed neutrinos (RHNs) provide the simplest explanation for the
origin of light neutrino masses and mixings. If the RHN masses are at or below
the weak scale, direct experimental discovery of these states is possible at
accelerator experiments such as the LHC or new dedicated beam dump experiments;
in such experiments, the RHN decays after traversing a macroscopic distance
from the collision point. The experimental sensitivity to RHNs is significantly
enhanced if there is a new "dark" gauge force connecting them to the Standard
Model (SM), and detection of RHNs can be the primary discovery mode for the new
dark force itself. We take the well-motivated example of a B-L gauge symmetry
and analyze the sensitivity to displaced decays of the RHNs produced via the
new gauge interaction in two experiments: the LHC and the proposed SHiP beam
dump experiment. In the most favorable case in which the mediator can be
produced on-shell and decays to RHNs, the sensitivity reach is controlled by
the square of the B-L gauge coupling. We demonstrate that these experiments
could access neutrino parameters responsible for the observed SM neutrino
masses and mixings in the most straightforward implementation of the see-saw
mechanism.


title: Mixed Dark Matter in Left-Right Symmetric Models

abstract:
  Motivated by the recently reported diboson and dijet excesses in Run 1 data
at ATLAS and CMS, we explore models of mixed dark matter in left-right
symmetric theories. In this study, we calculate the relic abundance and the
elastic scattering cross section with nuclei for a number of dark matter
candidates that appear within the fermionic multiplets of left-right symmetric
models. In contrast to the case of pure multiplets, WIMP-nucleon scattering
proceeds at tree-level, and hence the projected reach of future direct
detection experiments such as LUX-ZEPLIN and XENON1T will cover large regions
of parameter space for TeV-scale thermal dark matter. Decays of the heavy
charged W' boson to particles in the dark sector can potentially shift the
right-handed gauge coupling to larger values when fixed to the rate of the Run
1 excesses, moving towards the theoretically attractive scenario, gR = gL. This
region of parameter space may be probed by future collider searches for new
Higgs bosons or electroweak fermions.


title: Spurious Long-range Entanglement and Replica Correlation Length

abstract:
  Topological entanglement entropy has been regarded as a smoking-gun signature
of topological order in two dimensions, capturing the total quantum dimension
of the topological particle content. An extrapolation method on cylinders has
been used frequently to measure the topological entanglement entropy. Here, we
show that a class of short-range entangled 2D states, when put on an infinite
cylinder of circumference $L$, exhibits the entanglement R\'enyi entropy of any
integer index $\alpha \ge 2$ that obeys $S_\alpha = a L - \gamma$ where $a,
\gamma > 0 $. Under the extrapolation method, the subleading term $\gamma$
would be identified as the topological entanglement entropy, which is spurious.
A nonzero $\gamma$ is always present if the 2D state reduces to a certain
symmetry-protected topological 1D state, upon disentangling spins that are far
from the entanglement cut. The internal symmetry that stabilizes $\gamma > 0$
is not necessarily a symmetry of the 2D state, but should be present after the
disentangling reduction. If the symmetry is absent, $\gamma$ decays
exponentially in $L$ with a characteristic length, termed as a replica
correlation length, which can be arbitrarily large compared to the two-point
correlation length of the 2D state. We propose a simple numerical procedure to
measure the replica correlation length through replica correlation functions.
We also calculate the replica correlation functions for representative wave
functions of abelian discrete gauge theories and the double semion theory in
2D, to show that they decay abruptly to zero. This supports a conjecture that
the replica correlation length being small implies that the subleading term
from the extrapolation method determines the total quantum dimension.


title: Extending Velocity Channel Analysis for Studying Turbulence Anisotropies

abstract:
  We extend the velocity channel analysis (VCA), introduced by Lazarian &
Pogosyan, of the intensity fluctuations in the velocity slices of
position-position-velocity (PPV) spectroscopic data from Doppler broadened
lines to study statistical anisotropy of the underlying velocity and density
that arises in a turbulent medium from the presence of magnetic field. In
particular, we study analytically how the anisotropy of the intensity
correlation in the channel maps changes with the thickness of velocity
channels. In agreement with the earlier VCA studies we find that the anisotropy
in the thick channels reflects the anisotropy of the density field, while the
relative contribution of density and velocity fluctuations to the thin velocity
channels depends on the density spectral slope. We show that the anisotropies
arising from Alfven, slow and fast magnetohydrodynamical modes are different,
in particular, the anisotropy in PPV created by fast modes is opposite to that
created by Alfven and slow modes, and this can be used to separate their
contributions. We successfully compare our results with the recent numerical
study of the PPV anisotropies measured with synthetic observations. We also
extend our study to the medium with self-absorption as well as to the case of
absorption lines. In addition, we demonstrate how the studies of anisotropy can
be performed using interferometers.


title:
The KMOS Redshift One Spectroscopic Survey (KROSS): The Tully-Fisher
  Relation at z ~ 1

abstract:
  We present the stellar mass ($M_{*}$), and K-corrected $K$-band absolute
magnitude ($M_{K}$) Tully-Fisher relations (TFRs) for sub-samples of the 584
galaxies spatially resolved in H$\alpha$ emission by the KMOS Redshift One
Spectroscopic Survey (KROSS). We model the velocity field of each of the KROSS
galaxies and extract a rotation velocity, $V_{80}$ at a radius equal to the
major axis of an ellipse containing 80% of the total integrated H$\alpha$ flux.
The large sample size of KROSS allowed us to select 210 galaxies with well
measured rotation speeds. We extract from this sample a further 56 galaxies
that are rotationally supported, using the stringent criterion $V_{80}/\sigma >
3$, where $\sigma$ is the flux weighted average velocity dispersion. We find
the $M_{K}$ and $M_{*}$ TFRs for this sub-sample to be $M_{K} / \rm{mag}= (-7.3
\pm 0.9) \times [(\log(V_{80}/\rm{km\ s^{-1}})-2.25]- 23.4 \pm 0.2$ , and
$\log(M_{*} / M_{\odot})= (4.7 \pm 0.4) \times [(\log(V_{80}/\rm{km\ s^{-1}}) -
2.25] + 10.0 \pm 0.3$, respectively. We find an evolution of the $M_{*}$ TFR
zero-point of $-0.41 \pm 0.08$ dex over the last $\sim $8 billion years.
However, we measure no evolution in the $M_{K}$ TFR zero-point over the same
period. We conclude that rotationally supported galaxies of a given dynamical
mass had less stellar mass at $z \sim 1$ than the present day, yet emitted the
same amounts of $K$-band light. The ability of KROSS to differentiate, using
integral field spectroscopy with KMOS, between those galaxies that are
rotationally supported and those that are not explains why our findings are at
odds with previous studies without the same capabilities.


title:
The Role of Radiation Pressure in the Narrow Line Regions of Seyfert
  Host Galaxies

abstract:
  We investigate the relative significance of radiation pressure and gas
pressure in the extended narrow line regions (ENLRs) of four Seyfert galaxies
from the integral field Siding Spring Southern Seyfert Spectroscopic Snapshot
Survey (S7). We demonstrate that there exist two distinct types of
starburst-AGN mixing curves on standard emission line diagnostic diagrams which
reflect the balance between gas pressure and radiation pressure in the ENLR. In
two of the galaxies the ENLR is radiation pressure dominated throughout and the
ionization parameter remains constant (log U ~ 0). In the other two galaxies
radiation pressure is initially important, but gas pressure becomes dominant as
the ionization parameter in the ENLR decreases from log U ~ 0 to -3.4 <= log U
<= -3.2. Where radiation pressure is dominant, the AGN regulates the density of
the interstellar medium on kpc scales and may therefore have a direct impact on
star formation activity and/or the incidence of outflows in the host galaxy to
scales far beyond the zone of influence of the black hole. We find that both
radiation pressure dominated and gas pressure dominated ENLRs are dynamically
active with evidence for outflows, indicating that radiation pressure may be an
important source of AGN feedback even when it is not dominant over the entire
ENLR.


title:
Induced spectral gap and pairing correlations from superconducting
  proximity effect

abstract:
  We theoretically consider superconducting proximity effect, using the
Bogoliubov-de Gennes theory, in heterostructure sandwich-type geometries
involving a normal s-wave superconductor and a non-superconducting material
with the proximity effect being driven by Cooper pairs tunneling from the
superconducting slab to the non-superconducting slab. Applications of the
superconducting proximity effect may rely on an induced spectral gap or induced
pairing correlations without any spectral gap. We clarify that in a
non-superconducting material the induced spectral gap and pairing correlations
are independent physical quantities arising from the proximity effect. This is
a crucial issue in proposals to create topological superconductivity through
the proximity effect. Heterostructures of 3D topological insulator (TI) slabs
on conventional s-wave superconductor (SC) substrates provide a platform, with
proximity-induced topological superconductivity expected to be observed on the
"naked" top surface of a thin TI slab. We theoretically study the induced
superconducting gap on this naked surface. In addition, we compare against the
induced spectral gap in heterostructures of SC with a normal metal or a
semiconductor with strong spin orbit coupling and a Zeeman splitting potential
(another platform for topological superconductivity). We find that for any
model for the non-SC metal (including metallic TI) the induced spectral gap on
the naked surface decays as $L^{-3}$ as the thickness ($L$) of the non-SC slab
is increased in contrast to the slower $1/L$ decay of the pairing correlations.
Our distinction between proximity-induced spectral gap (with its faster spatial
decay) and pairing correlation (with its slower spatial decay) has important
implications for the currently active search for topological superconductivity
and Majorana fermions in various superconducting heterostructures.


title:
No evidence for younger stellar generations within the intermediate age
  massive clusters NGC 1783, NGC 1696 and NGC 411

abstract:
  Recently, Li et al. (2016) claimed to have found evidence for multiple
generations of stars in the intermediate age clusters NGC 1783, NGC 1696 and
NGC 411 in the Large and Small Magellanic Clouds (LMC/SMC). Here we show that
these young stellar populations are present in the field regions around these
clusters and are not likely associated with the clusters themselves. Using the
same datasets, we find that the background subtraction method adopted by the
authors does not adequately remove contaminating stars in the small number
Poisson limit. Hence, we conclude that their results do not provide evidence of
young generations of stars within these clusters.


title:
Joint signal extraction from galaxy clusters in X-ray and SZ surveys: A
  matched-filter approach

abstract:
  The hot ionized gas of the intra-cluster medium emits thermal radiation in
the X-ray band and also distorts the cosmic microwave radiation through the
Sunyaev-Zel'dovich (SZ) effect. Combining these two complementary sources of
information through innovative techniques can therefore potentially improve the
cluster detection rate when compared to using only one of the probes. Our aim
is to build such a joint X-ray-SZ analysis tool, which will allow us to detect
fainter or more distant clusters while maintaining high catalogue purity. We
present a method based on matched multifrequency filters (MMF) for extracting
cluster catalogues from SZ and X-ray surveys. We first designed an X-ray
matched-filter method, analogous to the classical MMF developed for SZ
observations. Then, we built our joint X-ray-SZ algorithm by combining our
X-ray matched filter with the classical SZ-MMF, for which we used the physical
relation between SZ and X-ray observations. We show that the proposed X-ray
matched filter provides correct photometry results, and that the joint matched
filter also provides correct photometry when the $F_{\rm X}/Y_{500}$ relation
of the clusters is known. Moreover, the proposed joint algorithm provides a
better signal-to-noise ratio than single-map extractions, which improves the
detection rate even if we do not exactly know the $F_{\rm X}/Y_{500}$ relation.
The proposed methods were tested using data from the ROSAT all-sky survey and
from the Planck survey.


title:
Chiral Lagrangian from Duality and Monopole Operators in Compactified
  QCD

abstract:
  We show that there exists a special compactification of QCD on $\mathbb{R}^3
\times S^1$ in which the theory has a domain where continuous chiral symmetry
breaking is analytically calculable. We give a microscopic derivation of the
chiral lagrangian, the chiral condensate, and the Gell-Mann-Oakes-Renner
relation $m_{\pi}^2 f_{\pi}^2 = m_q \langle \bar{q} q \rangle$. Abelian
duality, monopole operators, and flavor-twisted boundary conditions, or a
background flavor holonomy, play the main roles. The flavor twisting leads to
the new effect of fractional jumping of fermion zero modes among
monopole-instantons. Chiral symmetry breaking is induced by monopole-instanton
operators, and the Nambu-Goldstone pions arise by color-flavor transmutation
from gapless "dual photons". We also give a microscopic picture of the
"constituent quark" masses. Our results are consistent with expectations from
chiral perturbation theory at large $S^1$, and yield strong support for
adiabatic continuity between the small-$S^1$ and large-$S^1$ regimes. We also
find concrete microscopic connections between ${\cal N}=1$ and ${\cal N}=2$
supersymmetric gauge theory dynamics and non-supersymmetric QCD dynamics.


title: Competition between Kondo effect and RKKY physics in graphene magnetism

abstract:
  The cooperative behavior of quantum impurities on 2D materials, such as
graphene and bilayer graphene, is characterized by a non-trivial competition
between screening (Kondo effect), and Ruderman-Kittel-Kasuya-Yosida (RKKY)
magnetism. In addition, due to the small density of states at the Fermi level,
impurities may not couple to the conduction electrons at all, behaving as free
moments. Employing a recently developed {\em{exact}} numerical method to study
multi-impurity lattice systems, we obtain non-perturbative results that
dramatically depart from expectations based on the conventional RKKY theory. At
half-filling and for weak coupling, impurities remain in the local moment
regime when they are on opposite sublattices, up to a critical value of the
interactions when they start coupling anti-ferromagnetically with correlations
that decay very slowly with inter-impurity distance. At finite doping, away
from half-filling, ferromagnetism is completely absent and the physics is
dominated by a competition between anti-ferromagnetism and Kondo effect. In
bilayer graphene, impurities on opposite layers behave as free moments, unless
the interaction is of the order of the hopping or larger.


title: Dynamics of two coupled semiconductor spin qubits in a noisy environment

abstract:
  We theoretically consider the temporal dynamics of two coupled spin qubits
(e.g., semiconductor quantum dots) driven by the inter-qubit spin-spin
coupling. The presence of environmental noise (e.g., charge traps, nuclear
spins, random magnetic impurities) is accounted for by including random
magnetic field and random inter-qubit coupling terms in the Hamiltonian. Both
Heisenberg coupling and Ising coupling between the spin qubits are considered,
corresponding respectively to exchange and capacitive gates as appropriate for
single spin and singlet-triplet semiconductor qubit systems, respectively. Both
exchange (Heisenberg) and capacitive (Ising) coupling situations can be solved
numerically exactly even in the presence of noise, leading to the key findings
that (i) the steady-state return probability to the initial state remains close
to unity in the presence of strong noise for many, but not all, starting spin
configurations, and (ii) the return probability as a function of time is
oscillatory with a characteristic noise-controlled decay toward the
steady-state value. We also provide results for the magnetization dynamics of
the coupled two-qubit system. Our predicted dynamics can be directly tested in
the already existing semiconductor spin qubit setups providing insight into
their coherent interaction dynamics. Retention of the initial state spin memory
even in the presence of strong environmental noise has important implications
for quantum computation using spin qubits.


title: IGLOO: Integrating global and local biological network alignment

abstract:
  Analogous to genomic sequence alignment, biological network alignment (NA)
aims to find regions of similarities between molecular networks (rather than
sequences) of different species. NA can be either local (LNA) or global (GNA).
LNA aims to identify highly conserved common subnetworks, which are typically
small, while GNA aims to identify large common subnetworks, which are typically
suboptimally conserved. We recently showed that LNA and GNA yield complementary
results: LNA has high functional but low topological alignment quality, while
GNA has high topological but low functional alignment quality. Thus, we propose
IGLOO, a new approach that integrates GNA and LNA in hope to reconcile the two.
We evaluate IGLOO against state-of-the-art LNA (NetworkBLAST, NetAligner,
AlignNemo, and AlignMCL) and GNA (GHOST, NETAL, GEDEVO, MAGNA++, WAVE, and
L-GRAAL) methods. We show that IGLOO allows for a trade-off between topological
and functional alignment quality better than the existing LNA and GNA methods
considered in our study.


title:
Convex Hull Calculations: a Matlab Implementation and Correctness Proofs
  for the lrs-Algorithm

abstract:
  This paper provides full \Matlab-code and informal correctness proofs for the
lexicographic reverse search algorithm for convex hull calculations. The
implementation was tested on a 1993 486-PC for various small and some larger,
partially highly degenerate combinatorial polytopes, one of which (a certain
13-dimensional 24 vertex polyhedron) occurs naturally in the study of a well
known problem posed by Professor Graciano de Oliveira: see end of section 1.


title:
Speaker Cluster-Based Speaker Adaptive Training for Deep Neural Network
  Acoustic Modeling

abstract:
  A speaker cluster-based speaker adaptive training (SAT) method under deep
neural network-hidden Markov model (DNN-HMM) framework is presented in this
paper. During training, speakers that are acoustically adjacent to each other
are hierarchically clustered using an i-vector based distance metric. DNNs with
speaker dependent layers are then adaptively trained for each cluster of
speakers. Before decoding starts, an unseen speaker in test set is matched to
the closest speaker cluster through comparing i-vector based distances. The
previously trained DNN of the matched speaker cluster is used for decoding
utterances of the test speaker. The performance of the proposed method on a
large vocabulary spontaneous speech recognition task is evaluated on a training
set of with 1500 hours of speech, and a test set of 24 speakers with 1774
utterances. Comparing to a speaker independent DNN with a baseline word error
rate of 11.6%, a relative 6.8% reduction in word error rate is observed from
the proposed method.


title:
Chandra and XMM-Newton X-ray Observations of the Hyperactive T Tauri
  Star RY Tau

abstract:
  We present results of pointed X-ray observations of the accreting jet-driving
T Tauri star RY Tau using Chandra and XMM-Newton. We obtained high-resolution
grating spectra and excellent-quality CCD spectra and light curves with the
objective of identifying the physical mechanisms underlying RY Tau's bright
X-ray emission. Grating spectra reveal numerous emission lines spanning a broad
range of temperature superimposed on a hot continuum. The X-ray emission
measure distribution is dominated by very hot plasma at T_hot ~ 50 MK but
higher temperatures were present during flares. A weaker cool plasma component
is also present as revealed by low-temperature lines such as O VIII. X-ray
light curves show complex variability consisting of short-duration (~hours)
superhot flares accompanied by fluorescent Fe emission at 6.4 keV superimposed
on a slowly-varying (~one day) component that may be tied to stellar rotation.
The hot flaring component is undoubtedly of magnetic (e.g. coronal) origin.
Soft and hard-band light curves undergo similar slow variability implying that
at least some of the cool plasma shares a common magnetic origin with the hot
plasma. Any contribution to the X-ray emission from cool shocked plasma is
small compared to the dominant hot component but production of individual
low-temperature lines such as O VIII in an accretion shock is not ruled out.


title: iQ Cavity for Material Permittivity Characterization

abstract:
  We present an X-band waveguide (WR90) and UHF waveguide (WR1500) measurement
method that permits the extraction of the complex permittivity for low
dielectric loss tangent material specimen. The extraction method relies on
computational electromagnetic (CEM) simulations; coupled with a genetic
algorithm; to fit the experimental measurement and the simulated transmitted
scattering parameter (S21) of the TE10 mode through the waveguide with the
material specimen partially filling the cross-section. This technique provides
the material measurement community with the ability to accurately extract
material properties of low-loss material specimen.


title:
Gromov--Hausdorff Distance, Irreducible Correspondences, Steiner
  Problem, and Minimal Fillings

abstract:
  We introduce irreducible correspondences that enables us to calculate the
Gromov--Hausdorff distances effectively. By means of these correspondences, we
show that the set of all metric spaces each consisting of no more than $3$
points is isometric to a polyhedral cone in the space $R^3$ endowed with the
maximum norm. We prove that for any $3$-point metric space such that all the
triangle inequalities are strict in it, there exists a neighborhood such that
the Steiner minimal trees (in Gromov-Hausdorff space) with boundaries from this
neighborhood are minimal fillings, i.e., it is impossible to decrease the
lengths of these trees by isometrically embedding their boundaries into any
other ambient metric space. On the other hand, we construct an example of
$3$-point boundary whose points are $3$-point metric spaces such that its
Steiner minimal tree in the Gromov-Hausdorff space is not a minimal filling.
The latter proves that the Steiner subratio of the Gromov-Hausdorff space is
less than 1. The irreducible correspondences enabled us to create a quick
algorithm for calculating the Gromov-Hausdorff distance between finite metric
spaces. We carried out a numerical experiment and obtained more precise upper
estimate on the Steiner subratio: we have shown that it is less than $0.857$.


title: Nonexistence of a few binary orthogonal arrays

abstract:
  We develop and apply combinatorial algorithms for investigation of the
feasible distance distributions of binary orthogonal arrays with respect to a
point of the ambient binary Hamming space utilizing constraints imposed from
the relations between the distance distributions of connected arrays. This
turns out to be strong enough and we prove the nonexistence of binary
orthogonal arrays of parameters (length, cardinality, strength)$\
=(9,6.2^4=96,4)$, $(10,6.2^5,5)$, $(10,7.2^4=112,4)$, $(11,7.2^5,5)$,
$(11,7.2^4,4)$ and $(12,7.2^5,5)$, resolving the first cases where the
existence was undecided so far. For the existing arrays our approach allows
substantial reduction of the number of feasible distance distributions which
could be helpful for classification results (uniqueness, for example).


title:
XPL: An extended probabilistic logic for probabilistic transition
  systems

abstract:
  Generalized Probabilistic Logic (GPL) is a temporal logic, based on the modal
mu-calculus, for specifying properties of reactive probabilistic systems. We
explore XPL, an extension to GPL allowing the semantics of nondeterminism
present in Markov decision processes (MDPs). XPL is expressive enough that a
number of independently studied problems--- such as termination of Recursive
MDPs (RMDPs), PCTL* model checking of MDPs, and reachability for Branching
MDPs--- can all be cast as model checking over XPL. Termination of multi-exit
RMDPs is undecidable; thus, model checking in XPL is undecidable in general. We
define a subclass, called separable XPL, for which model checking is decidable.
Decidable problems such as termination of 1-exit RMDPs, PCTL* model checking of
MDPs, and reachability for Branching MDPs can be reduced to model checking
separable XPL. Thus, XPL forms a uniform framework for studying problems
involving systems with non-deterministic and probabilistic behaviors, while
separable XPL provides a way to solve decidable fragments of these problems.


title: Network of Experts for Large-Scale Image Categorization

abstract:
  We present a tree-structured network architecture for large scale image
classification. The trunk of the network contains convolutional layers
optimized over all classes. At a given depth, the trunk splits into separate
branches, each dedicated to discriminate a different subset of classes. Each
branch acts as an expert classifying a set of categories that are difficult to
tell apart, while the trunk provides common knowledge to all experts in the
form of shared features. The training of our "network of experts" is completely
end-to-end: the partition of categories into disjoint subsets is learned
simultaneously with the parameters of the network trunk and the experts are
trained jointly by minimizing a single learning objective over all classes. The
proposed structure can be built from any existing convolutional neural network
(CNN). We demonstrate its generality by adapting 4 popular CNNs for image
categorization into the form of networks of experts. Our experiments on
CIFAR100 and ImageNet show that in every case our method yields a substantial
improvement in accuracy over the base CNN, and gives the best result achieved
so far on CIFAR100. Finally, the improvement in accuracy comes at little
additional cost: compared to the base network, the training time is only
moderately increased and the number of parameters is comparable or in some
cases even lower.