title: All-in all-out magnetic order and propagating spin-waves in Sm2Ir2O7

abstract:
  Using resonant magnetic x-ray scattering we address the unresolved nature of
the magnetic groundstate and the low-energy effective Hamiltonian of
Sm$_2$Ir$_2$O$_7$, a prototypical pyrochlore iridate with a finite temperature
metal-insulator transition. Through a combination of elastic and inelastic
measurements, we show that the magnetic ground state is an all-in all-out
(AIAO) antiferromagnet. The magnon dispersion indicates significant electronic
correlations and can be well-described by a minimal Hamiltonian that includes
Heisenberg exchange ($J=27.3(6)$ meV) and Dzyaloshinskii-Moriya interaction
($D=4.9(3)$ meV), which provides a consistent description of the magnetic order
and excitations. In establishing that Sm$_2$Ir$_2$O$_7$ has the requisite
inversion symmetry preserving AIAO magnetic groundstate, our results support
the notion that pyrochlore iridates may host correlated Weyl semimetals.


title: Black holes and stars in Horndeski theory

abstract:
  We review black hole and star solutions for Horndeski theory. For non-shift
symmetric theories, black holes involve a Kaluza-Klein reduction of higher
dimensional Lovelock solutions. On the other hand, for shift symmetric theories
of Horndeski and beyond Horndeski, black holes involve two classes of
solutions: those that include, at the level of the action, a linear coupling to
the Gauss-Bonnet term and those that involve time dependence in the galileon
field. We analyze the latter class in detail for a specific subclass of
Horndeski theory, discussing the general solution of a static and spherically
symmetric spacetime. We then discuss stability issues, slowly rotating
solutions as well as black holes coupled to matter. The latter case involves a
conformally coupled scalar field as well as an electromagnetic field and the
(primary) hair black holes thus obtained. We review and discuss the recent
results on neutron stars in Horndeski theories.


title:
Classical nature of ordered quantum phases and origin of spontaneous
  symmetry breaking

abstract:
  We analyse the nature of spontaneous symmetry breaking in complex quantum
systems by investigating the long-standing conjecture that the maximally
symmetry-breaking quantum ground states are the most classical ones
corresponding to a globally ordered phase. We make this argument quantitatively
precise by comparing different local and global indicators of classicality and
quantumness, respectively in symmetry-breaking and symmetry-preserving quantum
ground states. We first discuss how naively comparing local, pairwise
entanglement and discord apparently leads to the opposite conclusion. Indeed,
we show that in symmetry-preserving ground states the two-body entanglement
captures only a modest portion of the total two-body quantum correlations,
while, on the contrary, in maximally symmetry-breaking ground states it
contributes the largest amount to the total two-body quantum correlations. We
then put to test the conjecture by looking at the global, macroscopic
correlation properties of quantum ground states. We prove that the ground
states which realize the maximum breaking of the Hamiltonian symmetries,
associated to a globally ordered phase, are the only ones that: I) are always
locally convertible, i.e. can be obtained from all other ground states by only
applying LOCC transformations (local operations and classical communication),
while the reverse is never possible; II) minimize the monogamy inequality on
the globally shared, macroscopic bipartite entanglement.

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


title:
Ruin probabilities with dependence on the number of claims within a
  fixed time window

abstract:
  We analyse the ruin probabilities for a renewal insurance risk process with
inter-arrival time distributions depending on the claims that arrived within a
fixed (past) time window. This dependence could be explained through a
regenerative structure. The main inspiration of the model comes from the
Bonus-Malus feature. We discuss first asymptotic results of ruin probabilities
for different regimes of claim distributions. For numerical results, we
recognise an embedded Markov additive process. Via an appropriate change of
measure, ruin probabilities could be computed to a closed form formulae.
Additionally, we present simulated results via the importance sampling method,
which further permit an in-depth analysis of a few concrete cases.


title: Failure of local thermal equilibrium in quantum friction

abstract:
  Recent progress in manipulating atomic and condensed matter systems has
instigated a surge of interest in non-equilibrium physics, including many-body
dynamics of trapped ultracold atoms and ions, near-field radiative heat
transfer, and quantum friction. Under most circumstances the complexity of such
non-equilibrium systems requires a number of approximations to make theoretical
descriptions tractable. In particular, it is often assumed that spatially
separated components of a system thermalize with their immediate surroundings,
although the global state of the system is out of equilibrium. This powerful
assumption reduces the complexity of non-equilibrium systems to the local
application of well-founded equilibrium concepts. While this technique appears
to be consistent for the description of some phenomena, we show that it fails
for quantum friction by underestimating by approximately $80 \%$ the magnitude
of the drag force. Our results show that the correlations among components of
driven, but steady-state, quantum systems invalidate the assumption of local
thermal equilibrium, calling for a critical reexamination of this approach for
describing the physics of non-equilibrium systems.


title:
A computer code for forward calculation and inversion of the H/V
  spectral ratio under the diffuse field assumption

abstract:
  During a quarter of a century, the main characteristics of the
horizontal-to-vertical spectral ratio of ambient noise HVSRN have been
extensively used for site effect assessment. In spite of the uncertainties
about the optimum theoretical model to describe these observations, several
schemes for inversion of the full HVSRN curve for near surface surveying have
been developed over the last decade.
  In this work, a computer code for forward calculation of H/V spectra based on
the diffuse field assumption (DFA) is presented and tested.It takes advantage
of the recently stated connection between the HVSRN and the elastodynamic
Green's function which arises from the ambient noise interferometry theory.
  The algorithm allows for (1) a natural calculation of the Green's functions
imaginary parts by using suitable contour integrals in the complex wavenumber
plane, and (2) separate calculation of the contributions of Rayleigh, Love,
P-SV and SH waves as well. The stability of the algorithm at high frequencies
is preserved by means of an adaptation of the Wang's orthonormalization method
to the calculation of dispersion curves, surface-waves medium responses and
contributions of body waves.
  This code has been combined with a variety of inversion methods to make up a
powerful tool for passive seismic surveying.


title: Jacques Tits' motivic measure

abstract:
  Making use of the recent theory of noncommutative motives, we construct a new
motivic measure, which we call the Tits' motivic measure. As a first
application, we prove that two Severi-Brauer varieties (or more generally
twisted Grassmannian varieties), associated to central simple algebras of
period 2, have the same Grothendieck class if and only if they are isomorphic.
As a second application, we show that if two Severi-Brauer varieties,
associated to central simple algebras of period 2, 3, 4, 5 or 6, have the same
Grothendieck class, then they are necessarily birational. As a third
application, we prove that two quadric hypersurfaces (or more generally
involution varieties), associated to quadratic forms of degree 6, have the same
Grothendieck class if and only if they are isomorphic. This latter result also
holds for products of such quadrics. Finally, as a fourth application, we show
in certain cases that two products of conics have the same Grothendieck class
if and only if they are isomorphic; this refines a result of Kollar.


title: Probing the ultimate limits of metal plasticity

abstract:
  Along with high strength, plasticity is what makes metals so widely usable in
our material world. Both strength and plasticity properties of a metal are
defined by the motion of dislocations - line defects in the crystal lattice
that divide areas of atomic planes displaced relative to each other by an
interatomic distance. Here we present first fully dynamic atomistic simulations
of single crystal plasticity in metal tantalum predicting that above certain
maximum rate of straining - the ultimate limit - the dislocations can no longer
relieve mechanical loads and another mechanism, twinning, comes into play and
takes over as the dominant mode of dynamic response. At straining rates below
the ultimate limit, the metal attains a path-independent stationary state of
plastic flow in which both flow stress and dislocation density remain constant
indefinitely for as long as the straining conditions remain unchanged. In this
distinct state tantalum flows like a viscous fluid while still remaining a
strong and stiff metal.


title: On the Capacity of Diffusion-Based Molecular Timing Channels

abstract:
  This work introduces capacity limits for molecular timing (MT) channels,
where information is modulated on the release timing of small information
particles, and decoded from the time of arrival at the receiver. It is shown
that the random time of arrival can be represented as an additive noise
channel, and for the diffusion-based MT (DBMT) channel, this noise is
distributed according to the L\'evy distribution. Lower and upper bounds on the
capacity of the DBMT channel are derived for the case where the delay
associated with the propagation of information particles in the channel is
finite. These bounds are also shown to be tight.


title: Cdh descent in equivariant homotopy K-theory

abstract:
  We construct geometric models for classifying spaces of linear algebraic
groups in G-equivariant motivic homotopy theory, where G is a tame group
scheme. As a consequence, we show that the equivariant motivic spectrum
representing the homotopy K-theory of G-schemes (which we construct as an
E-infinity-ring) is stable under arbitrary base change, and we deduce that
homotopy K-theory of G-schemes satisfies cdh descent.


title:
The Equivariant Tamagawa Number Conjecture for modular motives with
  coefficients in Hecke algebras

abstract:
  Under mild hypotheses on the residual representation, we prove the
Equivariant Tamagawa Number Conjecture for modular motives with coefficients in
universal deformation rings and Hecke algebras using a novel combination of the
methods of Euler systems and Taylor-Wiles systems. We also prove the
compatibility of this conjecture with specialization.


title: The data, they are a-changin'

abstract:
  The cost of deriving actionable knowledge from large datasets has been
decreasing thanks to a convergence of positive factors: low cost data
generation, inexpensively scalable storage and processing infrastructure
(cloud), software frameworks and tools for massively distributed data
processing, and parallelisable data analytics algorithms. One observation that
is often overlooked, however, is that each of these elements is not immutable,
rather they all evolve over time. This suggests that the value of such
derivative knowledge may decay over time, unless it is preserved by reacting to
those changes. Our broad research goal is to develop models, methods, and tools
for selectively reacting to changes by balancing costs and benefits, i.e.
through complete or partial re-computation of some of the underlying processes.
In this paper we present an initial model for reasoning about change and
re-computations, and show how analysis of detailed provenance of derived
knowledge informs re-computation decisions. We illustrate the main ideas
through a real-world case study in genomics, namely on the interpretation of
human variants in support of genetic diagnosis.


title:
$p$-adic properties of motivic fundamental lines (Kato's conjecture is
  (probably) false for (not so) trivial reasons)

abstract:
  We prove the conjectured compatibility of $p$-adic fundamental lines with
specializations at motivic points for a wide class of $p$-adic families of
$p$-adic Galois representations (for instance, the families which arise from
$p$-adic families of automorphic representations of the unit group of a
quaternion algebra or of a totally definite unitary groups) and deduce the
compatibility of the Equivariant Tamagawa Number Conjectures for them. However,
we also show that fundamental lines are not compatible with arbitrary
characteristic zero specializations with values in a domain in general. This
points to the need to modify some conjectures on $p$-adic variation of special
values using completed cohomology.


title: FlashR: R-Programmed Parallel and Scalable Machine Learning using SSDs

abstract:
  R is one of the most popular programming languages for statistics and machine
learning, but the R framework is relatively slow and unable to scale to large
datasets. The general approach for speeding up an implementation in R is to
implement the algorithms in C or FORTRAN and provide an R wrapper. FlashR takes
a different approach: it executes R code in parallel and scales the code beyond
memory capacity by utilizing solid-state drives (SSDs) automatically. It
provides a small number of generalized operations (GenOps) upon which we
reimplement a large number of matrix functions in the R base package. As such,
FlashR parallelizes and scales existing R code with little/no modification. To
reduce data movement between CPU and SSDs, FlashR evaluates matrix operations
lazily, fuses operations at runtime, and uses cache-aware, two-level matrix
partitioning. We evaluate FlashR on a variety of machine learning and
statistics algorithms on inputs of up to four billion data points. FlashR
out-of-core tracks closely the performance of FlashR in-memory. The R code for
machine learning algorithms executed in FlashR outperforms the in-memory
execution of H2O and Spark MLlib by a factor of 2-10 and outperforms Revolution
R Open by more than an order of magnitude.


title:
Energy, centrality and momentum dependence of dielectron production at
  collider energies in a coarse-grained transport approach

abstract:
  Dilepton production in heavy-ion collisions at collider energies - i.e., for
the Relativistic Heavy-Ion Collider (RHIC) and the Large Hadron Collider (LHC)
- is studied within an approach that uses coarse-grained transport simulations
to calculate thermal dilepton emission applying in-medium spectral functions
from hadronic many-body theory and partonic production rates based on lattice
calculations. The microscopic output from the Ultra-relativistic Quantum
Molecular Dynamics (UrQMD) model is hereby put on a grid of space-time cells
which allows to extract the local temperature and chemical potential in each
cell via an equation of state. The resulting dilepton spectra are in good
agreement with the experimental results for the range of RHIC energies,
$\sqrt{s_{NN}}=19.6 - 200$ GeV. The comparison of data and model outcome shows
that the newest measurements by the PHENIX and STAR collaborations are
consistent and that the low-mass spectra can be described by a cocktail of
hadronic decay contributions together with thermal emission from broadened
vector-meson spectral functions and from the Quark-Gluon Plasma phase.
Predictions for dilepton results at LHC energies show no significant change of
the spectra as compared to RHIC, but a higher fraction of thermal contribution
and harder slopes of the transverse momentum distributions due to the higher
temperatures and flow obtained.


title:
Computationally Efficient Calculations of Target Performance of the
  Normalized Matched Filter Detector for Hydrocoustic Signals

abstract:
  Detection of hydroacoustic transmissions is a key enabling technology in
applications such as depth measurements, detection of objects, and undersea
mapping. To cope with the long channel delay spread and the low signal-to-noise
ratio, hydroacoustic signals are constructed with a large time-bandwidth
product, $N$. A promising detector for hydroacoustic signals is the normalized
matched filter (NMF). For the NMF, the detection threshold depends only on $N$,
thereby obviating the need to estimate the characteristics of the sea ambient
noise which are time-varying and hard to estimate. While previous works
analyzed the characteristics of the normalized matched filter (NMF), for
hydroacoustic signals with large $N$ values the expressions available are
computationally complicated to evaluate. Specifically for hydroacoustic signals
of large $N$ values, this paper presents approximations for the probability
distribution of the NMF. These approximations are found extremely accurate in
numerical simulations. We also outline a computationally efficient method to
calculate the receiver operating characteristic (ROC) which is required to
determine the detection threshold. Results from an experiment conducted in the
Mediterranean sea at depth of 900~m agree with the analysis.


title: Fractionalized Fermi Liquid in a Kondo-Heisenberg Model

abstract:
  The Kondo-Heisenberg model is used for a microscopic demonstration of
existence of a peculiar metallic state with unbroken translational symmetry
where the Fermi surface volume is not controlled by the total electron density.
I use a non-perturbative approach where the strongest interactions are taken
into account by means of exact solution, and corrections are controllable. In
agreement with the general requirements formulated in (T. Senthil {\it et.al.}
Phys. Rev. Lett. {\bf 90}, 216403 (2003)), the resulting metallic state
represents a fractionalized Fermi liquid where well defined quasiparticles
coexist with gapped fractionalized collective excitations. The system undergoes
a phase transition to an ordered phase (charge density wave or
superconducting), at the transition temperature which is parametrically small
in comparison to the quasiparticle Fermi energy.


title:
Weak Concentration for First Passage Percolation Times on Graphs and
  General Increasing Set-valued Processes

abstract:
  A simple lemma bounds $\mathrm{s.d.}(T)/\mathbb{E} T$ for hitting times $T$
in Markov chains with a certain strong monotonicity property. We show how this
lemma may be applied to several increasing set-valued processes. Our main
result concerns a model of first passage percolation on a finite graph, where
the traversal times of edges are independent Exponentials with arbitrary rates.
Consider the percolation time $X$ between two arbitrary vertices. We prove that
$\mathrm{s.d.}(X)/\mathbb{E} X$ is small if and only if $\Xi/\mathbb{E} X$ is
small, where $\Xi$ is the maximal edge-traversal time in the percolation path
attaining $X$.


title: Bell Correlations in a Bose-Einstein Condensate

abstract:
  Characterizing many-body systems through the quantum correlations between
their constituent particles is a major goal of quantum physics. Although
entanglement is routinely observed in many systems, we report here the
detection of stronger correlations - Bell correlations - between the spins of
about 480 atoms in a Bose-Einstein condensate. We derive a Bell correlation
witness from a many-particle Bell inequality involving only one- and two-body
correlation functions. Our measurement on a spin-squeezed state exceeds the
threshold for Bell correlations by 3.8 standard deviations. Our work shows that
the strongest possible non-classical correlations are experimentally accessible
in many-body systems, and that they can be revealed by collective measurements.


title:
A Laplace Principle for Hermitian Brownian Motion and Free Entropy I:
  the convex functional case

abstract:
  This paper is part of a series aiming at proving that the $\limsup$ and
$\liminf$ variants of Voiculescu's free entropy coincide. This is based on a
Laplace principle (implying a large deviation principle) for hermitian brownian
motion on $[0,1]$. In the current paper, we show that microstates free entropy
$\chi(X_1,...,X_m)$ and non-microstate free entropy $\chi^*(X_1,...,X_m)$
coincide for self-adjoint variables $(X_1,...,X_m)$ satisfying a
Schwinger-Dyson equation for subquadratic, bounded below, strictly convex
potentials with Lipschitz derivative sufficiently approximable by
non-commutative polynomials. Our results are based on Dupuis-Ellis weak
convergence approach to large deviations where one shows a Laplace principle in
obtaining a stochastic control formulation for exponential functionals. In the
non-commutative context, ultrapoduct analysis replaces weak-convergence of the
stochastic control problems.


title: Space-time fractional Dirichlet problems

abstract:
  This paper establishes explicit solutions for fractional diffusion problems
on bounded domains. It also gives stochastic solutions, in terms of Markov
processes time-changed by an inverse stable subordinator whose index equals the
order of the fractional time derivative. Some applications are given, to
demonstrate how to specify a well-posed Dirichlet problem for space-time
fractional diffusions in one or several variables. This solves an open problem
in numerical analysis.


title: Black Hole Spindown by Light Bosons

abstract:
  The saturation mechanism for the fastest-growing instability of massive
scalar field in Kerr metric is identified, assuming saturation by cubic or
quartic nonlinearities of the field potential. The resulting spindown rate of
the black hole is calculated. The (rather involved) saturation scenario is
confirmed by numerical simulations.


title:
Superresolution in the maximum entropy approach to invert Laplace
  transforms

abstract:
  The method of maximum entropy has proven to be a rather powerful way to solve
the inverse problem consisting of determining a probability density $f_S(s)$ on
$[0,\infty)$ from the knowledge of the expected value of a few generalized
moments, that is, of functions $g_i(S)$ of the variable $S.$ A version of this
problem, of utmost relevance for banking, insurance, engineering and the
physical sciences, corresponds to the case in which $S \geq 0$ and
$g_i(s)=\exp(-\alpha_i s),$ th expected values $E[\exp-\alpha_i S)]$ are the
values of the Laplace transform of $S$ the points $\alpha_i$ on the real line.
Since inverting the Laplace transform is an ill-posed problem, to devise
numerical tecniques that are efficient is of importance for many applications,
specially in cases where all we know is the value of the transform at a few
points along the real axis. A simple change of variables transforms the Laplace
inversion problem into a fractional moment problem on $[0,1].$ It is remarkable
that the maximum entropy procedure allows us to determine the density on
$[0,1]$ with high accuracy. In this note, we examine why this might be so.


title:
Single mode lasing in transversely multi-moded PT-symmetric microring
  resonators

abstract:
  Single mode lasing is experimentally demonstrated in a transversely
multi-moded InP-based semiconductor microring arrangement. In this system, mode
discrimination is attained by judiciously utilizing the exceptional points in a
parity-time (PT) symmetric double microring configuration. The proposed scheme
is versatile, robust to small fabrication errors, and enables the device to
operate in a stable manner considerably above threshold while maintaining
spatial and spectral purity. The results presented here pave the way towards a
new class of chip-scale semiconductor lasers that utilize gain/loss contrast as
a primary mechanism for mode selection.


title: Why all the fuss about 2D semiconductors?

abstract:
  Graphene is no longer alone; a family of atomically thin 2D semiconductors
has emerged. Optoelectronics and photonics applications are in their
experimental infancy but the future holds much promise.


title: Reflection Quasilattices and the Maximal Quasilattice

abstract:
  We introduce the concept of a {\it reflection quasilattice}, the
quasiperiodic generalization of a Bravais lattice with irreducible reflection
symmetry. Among their applications, reflection quasilattices are the reciprocal
(i.e. Bragg diffraction) lattices for quasicrystals and quasicrystal tilings,
such as Penrose tilings, with irreducible reflection symmetry and discrete
scale invariance. In a follow-up paper, we will show that reflection
quasilattices can be used to generate tilings in real space with properties
analogous to those in Penrose tilings, but with different symmetries and in
various dimensions. Here we explain that reflection quasilattices only exist in
dimensions two, three and four, and we prove that there is a unique reflection
quasilattice in dimension four: the "maximal reflection quasilattice" in terms
of dimensionality and symmetry. Unlike crystallographic Bravais lattices, all
reflection quasilattices are invariant under rescaling by certain discrete
scale factors. We tabulate the complete set of scale factors for all reflection
quasilattices in dimension $d>2$, and for all those with quadratic irrational
scale factors in $d=2$.

categories: math-ph cond-mat.mtrl-sci hep-th math.MP


title:
Analysis of the Entropy-guided Switching Trimmed Mean Deviation-based
  Anisotropic Diffusion filter

abstract:
  This report describes the experimental analysis of a proposed switching
filter-anisotropic diffusion hybrid for the filtering of the fixed value (salt
and pepper) impulse noise (FVIN). The filter works well at both low and high
noise densities though it was specifically designed for high noise density
levels. The filter combines the switching mechanism of decision-based filters
and the partial differential equation-based formulation to yield a powerful
system capable of recovering the image signals at very high noise levels.
Experimental results indicate that the filter surpasses other filters,
especially at very high noise levels. Additionally, its adaptive nature ensures
that the performance is guided by the metrics obtained from the noisy input
image. The filter algorithm is of both global and local nature, where the
former is chosen to reduce computation time and complexity, while the latter is
used for best results.


title: Massless Fermions in anisotropic Bianchi type I spacetimes

abstract:
  The behavior of spin - 1/2 - particles in anisotropic Bianchi type I
backgrounds is investigated utilizing the concept of differential forms and
orthonormal frames. Specializing to the massless case and power law scale
factors $\alpha_j(t) = t^{q_j}$ of the metric where $q_1 = q_2 $, an analytical
outcome for the time evolution operator in terms of Bessel functions is
presented.


title:
Local unitary representations of the braid group and their applications
  to quantum computing

abstract:
  We provide an elementary introduction to topological quantum computation
based on the Jones representation of the braid group. We first cover the Burau
representation and Alexander polynomial. Then we discuss the Jones
representation and Jones polynomial and their application to anyonic quantum
computation. Finally we outline the approximation of the Jones polynomial and
explicit localizations of braid group representations.


title: Quasi Yukawa Unification and Fine-Tuning in U(1) Extended SSM

abstract:
  We consider the low scale implications in the U(1)' extended MSSM (UMSSM). We
restrict the parameter space such that the lightest supersymmetric particle
(LSP) is always the lightest neutralino. In addition, we impose quasi Yukawa
unification (QYU) at the grand unification scale (M_GUT). QYU strictly requires
the ratios among the yukawa couplings as y_t/y_b ~ 1.2, y_tau/y_b ~ 1.4, and
y_t/y_tau ~ 0.8. We find that the need of fine-tuning over the fundamental
parameter space of QYU is in the acceptable range (Delta_EW <= 10^3), even if
the universal boundary conditions are imposed at M_ GUT, in contrast to CMSSM
and NUHM. UMSSM with the universal boundary conditions yields heavy stops
(m_{stop} >~ 2.5 TeV), gluinos (m_gluino >~ 2 TeV), and squarks from the first
two families (m_squarks >~ 4 TeV). Similarly the stau mass is bounded from
below at about 1.5 TeV. Despite this heavy spectrum, we find Delta_EW >~ 300,
which is much lower than that needed for the minimal supersymmetric models. In
addition, UMSSM yield relatively small mu-term, and the LSP neutralio is mostly
form by the Higgsinos of mass >~ 700 GeV. We obtain also bino-like dark matter
(DM) of mass about 400 GeV. Wino is usually found to be heavier than Higgsinos
and binos, but there is a small region where mu ~ M_1 ~ M_2 ~ 1 TeV. We also
identify chargino-neutralino coannihilation channel and A-resonance solutions
which reduce the relic abundance of LSP neutralino down to the ranges
compatible with the current WMAP measurements.


title: No occurrence obstructions in geometric complexity theory

abstract:
  The permanent versus determinant conjecture is a major problem in complexity
theory that is equivalent to the separation of the complexity classes VP_{ws}
and VNP. Mulmuley and Sohoni (SIAM J. Comput., 2001) suggested to study a
strengthened version of this conjecture over the complex numbers that amounts
to separating the orbit closures of the determinant and padded permanent
polynomials. In that paper it was also proposed to separate these orbit
closures by exhibiting occurrence obstructions, which are irreducible
representations of GL_{n^2}(C), which occur in one coordinate ring of the orbit
closure, but not in the other. We prove that this approach is impossible.
However, we do not rule out the general approach to the permanent versus
determinant problem via multiplicity obstructions as proposed by Mulmuley and
Sohoni.


title:
Comment on "Lifshitz-Matsubara sum formula for the Casimir pressure
  between magnetic metallic mirrors"

abstract:
  Recently Guerout et al. [Phys. Rev. E, v.93, 022108 (2016)] advocated that
the lossless plasma model has to be redefined as the limit of the Drude model
when the relaxation parameter goes to zero. It was claimed that the previously
used plasma model cannot correctly describe the Casimir pressure between two
plates made of both nonmagnetic and magnetic metals and has to be replaced with
the redefined one. We show that the suggested redefinition does not satisfy
necessary physical requirements imposed on the dielectric permittivity. We also
present a plausible explanation to the fact that the lossless plasma model
describes the Casimir pressure correctly even though it does not match the
optical and electrical properties of metals.


title:
Walk and Learn: Facial Attribute Representation Learning from Egocentric
  Video and Contextual Data

abstract:
  The way people look in terms of facial attributes (ethnicity, hair color,
facial hair, etc.) and the clothes or accessories they wear (sunglasses, hat,
hoodies, etc.) is highly dependent on geo-location and weather condition,
respectively. This work explores, for the first time, the use of this
contextual information, as people with wearable cameras walk across different
neighborhoods of a city, in order to learn a rich feature representation for
facial attribute classification, without the costly manual annotation required
by previous methods. By tracking the faces of casual walkers on more than 40
hours of egocentric video, we are able to cover tens of thousands of different
identities and automatically extract nearly 5 million pairs of images connected
by or from different face tracks, along with their weather and location
context, under pose and lighting variations. These image pairs are then fed
into a deep network that preserves similarity of images connected by the same
track, in order to capture identity-related attribute features, and optimizes
for location and weather prediction to capture additional facial attribute
features. Finally, the network is fine-tuned with manually annotated samples.
We perform an extensive experimental analysis on wearable data and two standard
benchmark datasets based on web images (LFWA and CelebA). Our method
outperforms by a large margin a network trained from scratch. Moreover, even
without using manually annotated identity labels for pre-training as in
previous methods, our approach achieves results that are better than the state
of the art.


title: Estimating the gap of finite metric spaces of strict p-negative type

abstract:
  Let (X,d) be a finite metric space. This paper first discusses the spectrum
of the p-distance matrix of a finite metric space of p-negative type and then
gives upper and lower bounds for the so called gap of a finite metric space of
strict p-negative type. Furthermore estimations for the gap under a certain
glueing construction for finite metric spaces are given and finally be applied
to finite ultrametric spaces.


title:
Long-term orbital stability of exosolar planetary systems with highly
  eccentric orbits

abstract:
  Nowadays, many extrasolar planetary systems possessing at least one planet on
a highly eccentric orbit have been discovered. In this work, we study the
possible long-term stability of such systems. We consider the general three
body problem as our model. Highly eccentric orbits are out of the Hill
stability regions. However, mean motion resonances can provide phase protection
and orbits with long-term stability exist. We construct maps of dynamical
stability based on the computation of chaotic indicators and we figure out
regions in phase space, where the long-term stability is guaranteed. We focus
on regions where at least one planet is highly eccentric and attempt to
associate them with the existence of stable periodic orbits. The values of the
orbital elements, which are derived from observational data, are often given
with very large deviations. Generally, phase space regions of high
eccentricities are narrow and thus, our dynamical analysis may restrict
considerably the valid domain of the system's location.


title:
Raman-assisted coherent, mid-infrared frequency combs in silicon
  microresonators

abstract:
  We demonstrate the first low-noise mid-IR frequency comb source using a
silicon microresonator. Our observation of strong Raman scattering lines in the
generated comb suggests that Raman and four-wave mixing interactions play a
role in assisting the transition to the low-noise state. In addition, we
characterize, the intracavity comb generation dynamics using an integrated PIN
diode, which takes advantage of the inherent three-photon absorption process in
silicon.


title: Heterotic-Type IIA Duality and Degenerations of K3 Surfaces

abstract:
  We study the duality between four-dimensional N=2 compactifications of
heterotic and type IIA string theories. Via adiabatic fibration of the duality
in six dimensions, type IIA string theory compactified on a K3-fibred
Calabi-Yau threefold has a potential heterotic dual compactification. This
adiabatic picture fails whenever the K3 fibre degenerates into multiple
components over points in the base of the fibration. Guided by monodromy, we
identify such degenerate K3 fibres as solitons generalizing the NS5-brane in
heterotic string theory. The theory of degenerations of K3 surfaces can then be
used to find which solitons can be present on the heterotic side. Similar to
small instanton transitions, these solitons escort singular transitions between
different Calabi-Yau threefolds. Starting from well-known examples of
heterotic--type IIA duality, such transitions can take us to type IIA
compactifications with unknown heterotic duals.


title: Leaders should not be conformists in evolutionary social dilemmas

abstract:
  The most common assumption in evolutionary game theory is that players should
adopt a strategy that warrants the highest payoff. However, recent studies
indicate that the spatial selection for cooperation is enhanced if an
appropriate fraction of the population chooses the most common rather than the
most profitable strategy within the interaction range. Such conformity might be
due to herding instincts or crowd behavior in humans and social animals. In a
heterogeneous population where individuals differ in their degree, collective
influence, or other traits, an unanswered question remains who should conform.
Selecting conformists randomly is the simplest choice, but it is neither a
realistic nor the optimal one. We show that, regardless of the source of
heterogeneity and game parametrization, socially the most favorable outcomes
emerge if the masses conform. On the other hand, forcing leaders to conform
significantly hinders the constructive interplay between heterogeneity and
coordination, leading to evolutionary outcomes that are worse still than if
conformists were chosen randomly. We conclude that leaders must be able to
create a following for network reciprocity to be optimally augmented by
conformity. In the opposite case, when leaders are castrated and made to
follow, the failure of coordination impairs the evolution of cooperation.


title: Holographic Collisions in Non-conformal Theories

abstract:
  We numerically simulate gravitational shock wave collisions in a holographic
model dual to a non-conformal four-dimensional gauge theory. We find two novel
effects associated to the non-zero bulk viscosity of the resulting plasma.
First, the hydrodynamization time increases. Second, if the bulk viscosity is
large enough then the plasma becomes well described by hydrodynamics before the
energy density and the average pressure begin to obey the equilibrium equation
of state. We discuss implications for the quark-gluon plasma created in heavy
ion collision experiments.


title: An end-to-end construction of doubly periodic minimal surfaces

abstract:
  Using Traizet's regeneration method, we prove that for each positive integer
n there is a family of embedded, doubly periodic minimal surfaces with parallel
ends in Euclidean space of genus 2n-1 and 4 ends in the quotient by the maximal
group of translations. The genus 2n-1 family converges smoothly to 2n copies of
Scherk's doubly periodic minimal surface. The only previously known doubly
periodic minimal surfaces with parallel ends and genus greater than 3 limit in
a foliation of Euclidean space by parallel planes.


title: Model for multi-shot all-thermal all-optical switching in ferromagnets

abstract:
  All optical magnetic switching (AOS) is a recently observed rich and puzzling
phenomenon that offers promis- ing technological applications. However,
fundamental understanding of the underlying mechanisms remains elusive. Here we
present a new model for multi-shot helicity-dependent AOS in ferromagnetic
materials based on a purely heat-driven mechanism in the presence of Magnetic
Circular Dichroism (MCD). We predict that AOS should be possible with as little
as 0.5% of MCD, after a minimum number of laser shots. Finally, we re- produce
previous AOS results by simulating the sweeping of a laser beam on an FePtC
granular ferromagnetic film.


title: Chiral SUSY Theories with a Suppressed SUSY Charge

abstract:
  The well-known Chiral and Gauge SUSY Actions realize the SUSY charge in terms
of transformations among the Fields. These transformations are included in the
Master Equation by coupling them to Sources. Here we show that there are new
local SUSY Actions where the Chiral SUSY transformations are realized in terms
of transformations among both Fields and Sources. These Actions can be easily
obtained from the Chiral case by a very simple and local `Exchange
Transformation', which carries along all the interactions without difficulty.
For these new SUSY Actions, the SUSY charge does not exist in the relevant
sector, because Sources do not satisfy Equations of Motion.
  Nevertheless, the `Exchange Transformation' ensures that the new Master
Equation is true for the new Action. As a consequence, the Master Equation also
is true for the new 1PI Generating Functional. This implies that a `Suppressed
SUSY Charge' version of SUSY is still present. SUSY certainly becomes more
obscure and less constrained in this case. But it is still very restrictive.
  The new theories can be obtained from the old theories by using a special
technique, but it is not true that they are a sort of `broken version of
supersymmetry'. They are simply a new type of theory that is governed by
Supersymmetry, but without the use of Supercharges (except perhaps in some
sectors).
  In particular the number of physical Bosonic and Fermionic degrees of Freedom
are not equal for these new (sub)-Actions, although there is still
Boson/Fermion mass degeneracy in a (sub)-Action, so long as there is still a
Boson present. Notably, there is even a SUSY (sub)-Action where the physical
Scalars are not present, so that the (sub)-Action contains physical Fermions
only. In this theory the degeneracy of Bosonic and Fermionic masses is
obviously not present.


title:
Robust Estimators in High Dimensions without the Computational
  Intractability

abstract:
  We study high-dimensional distribution learning in an agnostic setting where
an adversary is allowed to arbitrarily corrupt an $\varepsilon$-fraction of the
samples. Such questions have a rich history spanning statistics, machine
learning and theoretical computer science. Even in the most basic settings, the
only known approaches are either computationally inefficient or lose
dimension-dependent factors in their error guarantees. This raises the
following question:Is high-dimensional agnostic distribution learning even
possible, algorithmically?
  In this work, we obtain the first computationally efficient algorithms with
dimension-independent error guarantees for agnostically learning several
fundamental classes of high-dimensional distributions: (1) a single Gaussian,
(2) a product distribution on the hypercube, (3) mixtures of two product
distributions (under a natural balancedness condition), and (4) mixtures of
spherical Gaussians. Our algorithms achieve error that is independent of the
dimension, and in many cases scales nearly-linearly with the fraction of
adversarially corrupted samples. Moreover, we develop a general recipe for
detecting and correcting corruptions in high-dimensions, that may be applicable
to many other problems.

categories: cs.DS cs.IT cs.LG math.IT math.ST stat.ML stat.TH


title:
On the Validity of the Effective Field Theory Approach to SM Precision
  Tests

abstract:
  We discuss the conditions for an effective field theory (EFT) to give an
adequate low-energy description of an underlying physics beyond the Standard
Model (SM). Starting from the EFT where the SM is extended by dimension-6
operators, experimental data can be used without further assumptions to measure
(or set limits on) the EFT parameters. The interpretation of these results
requires instead a set of broad assumptions (e.g. power counting rules) on the
UV dynamics. This allows one to establish, in a bottom-up approach, the
validity range of the EFT description, and to assess the error associated with
the truncation of the EFT series. We give a practical prescription on how
experimental results could be reported, so that they admit a maximally broad
range of theoretical interpretations. Namely, the experimental constraints on
dimension-6 operators should be reported as functions of the kinematic
variables that set the relevant energy scale of the studied process. This is
especially important for hadron collider experiments where collisions probe a
wide range of energy scales.


title:
Electronic and magnetic properties of single-layer MPX$_3$ metal
  phosphorous trichalcogenides

abstract:
  We systematically investigate the electronic structure and magnetic
properties of two dimensional (2D) MPX$_3$ (M= V, Cr, Mn, Fe, Co, Ni, Cu, Zn,
and X = S, Se, Te) transition metal chacogenophosphates to examine their
potential role as single-layer van der Waals materials that exhibit magnetic
order. Our {\em ab initio} calculations predict that most of these single-layer
materials are antiferromagnetic semiconductors. The band gaps of the
antiferromagnetic states decrease as the atomic number of the chalcogen atom
increases (from S to Se, Te), leading in some cases to half-metallic
ferromagnetic states or to non-magnetic metallic states. We find that the phase
transition from antiferromagnetic semiconductor to ferromagnetic half-metal can
be controlled by gating or by strain engineering. The sensitive interdependence
we find between magnetic, structural, and electronic properties establishes the
potential of this 2D materials class for applications in spintronics.


title: Digamma, what next?

abstract:
  If the 750 GeV resonance in the diphoton channel is confirmed, what are the
measurements necessary to infer the properties of the new particle and
understand its nature? We address this question in the framework of a single
new scalar particle, called digamma ($\digamma$). We describe it by an
effective field theory, which allows us to obtain general and model-independent
results, and to identify the most useful observables, whose relevance will
remain also in model-by-model analyses. We derive full expressions for the
leading-order processes and compute rates for higher-order decays, digamma
production in association with jets, gauge or Higgs bosons, and digamma pair
production. We illustrate how measurements of these higher-order processes can
be used to extract couplings, quantum numbers, and properties of the new
particle.


title:
Higgs boson pair production in gluon fusion at NLO with full top-quark
  mass dependence

abstract:
  We present the calculation of the cross section and invariant mass
distribution for Higgs boson pair production in gluon fusion at next-to-leading
order (NLO) in QCD. Top-quark masses are fully taken into account throughout
the calculation. The virtual two-loop amplitude has been generated using an
extension of the program GoSam supplemented with an interface to Reduze for the
integral reduction. The occurring integrals have been calculated numerically
using the program SecDec. Our results, including the full top-quark mass
dependence for the first time, allow us to assess the validity of various
approximations proposed in the literature, which we also recalculate. We find
substantial deviations between the NLO result and the different approximations,
which emphasizes the importance of including the full top-quark mass dependence
at NLO.


title: Topological Fukaya category and mirror symmetry for punctured surfaces

abstract:
  In this paper we establish a version of homological mirror symmetry for
punctured Riemann surfaces. Following a proposal of Kontsevich we model
A-branes on a punctured surface $\Sigma$ via the topological Fukaya category.
We prove that the topological Fukaya category of $\Sigma$ is equivalent to the
category of matrix factorizations of the mirror LG model $(X,W)$. Along the way
we establish new gluing results for the topological Fukaya category of
punctured surfaces which might be of independent interest.


title:
Critical local moment fluctuations and enhanced pairing correlations in
  a cluster Anderson model

abstract:
  The appearance of unconventional superconductivity near heavy-fermion quantum
critical points (QCPs) motivates investigation of pairing correlations close to
a ``beyond Landau'' Kondo-destruction QCP. We focus on a two-Anderson-impurity
cluster in which Kondo destruction is induced by a pseudogap in the
conduction-electron density of states. Analysis via continuous-time quantum
Monte-Carlo and the numerical renormalization group reveals a previously
unstudied QCP that both displays the critical-local moment fluctuations
characteristic of Kondo destruction and leads to a strongly enhanced
singlet-pairing susceptibility. Our results provide new insights into the
mechanism for superconductivity in quantum critical metals.


title:
Evolution of the Pauli spin-paramagnetic effect on the upper critical
  fields of K$_{x}$Fe$_{2-y}$Se$_{2-z}$S$_{z}$ single crystals

abstract:
  We have studied the temperature dependence of the upper critical fields,
$\mu_{0}H_{c2}$, of K$_{x}$Fe$_{2-y}$Se$_{2-z}$S$_{z}$ single crystals up to 60
T. The $\mu _{0}H_{c2}$ for $H\parallel ab$ and $H\parallel c$ decrease with
increasing sulfur content. The detailed analysis using
Werthamer-Helfand-Hohenberg (WHH) theory including the Pauli spin-paramagnetic
effect shows that $\mu _{0}H_{c2}$ for $H\parallel ab$ is dominated by the
spin-paramagnetic effect, which diminishes with higher S content, whereas $\mu
_{0}H_{c2}$ for $H\parallel c$ shows a linear temperature dependence with an
upturn at high fields. The latter observation can be ascribed to multiband
effects that become weaker for higher S content. This results in an enhanced
anisotropy of $\mu _{0}H_{c2}$ for high S content due to the different trends
of the spin-paramagnetic and multiband effect for $H\parallel ab$ and
$H\parallel c$, respectively.


title:
Lithography-Free, Low-Cost Method for Improving Photodiode Performance
  by Etching Silicon Nanocones as Antireflection Layer

abstract:
  A three-step process has been demonstrated to improve the performance of
photodiode by creating nanocone forest on the surface of photodiode as an
antireflection layer. This high-throughput, low-cost process has been shown to
decrease the reflectivity by 66.1%, enhance the quantum efficiency by 27%, and
increase the responsivity by 25.7%. This low-cost manufacture process can be
applied to increase the responsivity of silicon based photonic devices.


title: Weighted domination number of cactus graphs

abstract:
  In the paper, we write a linear algorithm for calculating the weighted
domination number of a vertex-weighted cactus. The algorithm is based on the
well known depth first search (DFS) structure. Our algorithm needs less than
$12n+5b$ additions and $9n+2b$ $\min$-operations where $n$ is the number of
vertices and $b$ is the number of blocks in the cactus.


title: The first positive eigenvalue of the sub-laplacian on cr spheres

abstract:
  We prove that the first positive eigenvalue, normalized by the volume, of the
sub-Laplacian associated with a strictly pseudoconvex pseudo-Hermitian
structure $\\theta$ on the CR sphere S 2n+1 $\subset$ C n+1 , achieves its
maximum when $\\theta$ is the standard contact form.


title:
Measurable Steinhaus sets do not exist for finite sets or the integers
  in the plane

abstract:
  A Steinhaus set $S \subseteq \RR^d$ for a set $A \subseteq \RR^d$ is a set
such that $S$ has exactly one point in common with $\tau A$, for every rigid
motion $\tau$ of $\RR^d$. We show here that if $A$ is a finite set of at least
two points then there is no such set $S$ which is Lebesgue measurable.
  An old result of Komj\'ath says that there exists a Steinhaus set for $A =
\ZZ\times\Set{0}$ in $\RR^2$. We also show here that such a set cannot be
Lebesgue measurable.


title:
An enhanced fraction of starbursting galaxies among high Eddington ratio
  AGNs

abstract:
  We investigate the star-forming properties of 1620 X-ray selected AGN host
galaxies as a function of their specific X-ray luminosity (i.e., X-ray
luminosity per unit host stellar mass) -- a proxy of the Eddington ratio. Our
motivation is to determine whether there is any evidence of a suppression of
star-formation at high Eddington ratios, which may hint toward "AGN feedback"
effects. Star-formation rates (SFRs) are derived from fits to Herschel-measured
far-infrared spectral energy distributions, taking into account any
contamination from the AGN. Herschel-undetected AGNs are included via stacking
analyses to provide average SFRs in bins of redshift and specific X-ray
luminosity (spanning $0.01 \lesssim L_{\rm X}/M_{\ast} \lesssim 100~L_{\odot}
~M_{\odot}^{-1}$). After normalising for the effects of mass and redshift
arising from the evolving galaxy main sequence, we find that the SFRs of high
specific luminosity AGNs are slightly enhanced compared to their lower specific
luminosity counterparts. This suggests that the SFR distribution of AGN hosts
changes with specific X-ray luminosity, a result reinforced by our finding of a
significantly higher fraction of starbursting hosts among high specific
luminosity AGNs compared to that of the general star-forming galaxy population
(i.e., 8-10 per cent vs. 3 per cent). Contrary to our original motivation, our
findings suggest that high specific luminosity AGNs are more likely to reside
in galaxies with enhanced levels of star-formation.


title: The Close Companion Mass-Ratio Distribution of Intermediate-Mass Stars

abstract:
  Binary stars and higher-order multiple systems are an ubiquitous outcome of
star formation, especially as the system mass increases. The companion
mass-ratio distribution is a unique probe into the conditions of the collapsing
cloud core and circumstellar disk(s) of the binary fragments. Inside $a \sim
1000$ AU the disks from the two forming stars can interact, and additionally
companions can form directly through disk fragmentation. We should therefore
expect the mass-ratio distribution of close companions ($a \lesssim 100$ AU) to
differ from that of wide companions. This prediction is difficult to test using
traditional methods, especially with intermediate-mass primary stars, for a
variety of observational reasons. We present the results of a survey searching
for companions to A- and B-type stars using the direct spectral detection
method, which is sensitive to late-type companions within $\sim 1"$ of the
primary and which has no inner working angle. We estimate the temperatures and
surface gravity of most of the 341 sample stars, and derive their masses and
ages. We additionally estimate the temperatures and masses of the 64 companions
we find, 23 of which are new detections. We find that the mass-ratio
distribution for our sample has a maximum near $q \sim 0.3$. Our mass-ratio
distribution has a very different form than in previous work, where it is
usually well-described by a power law, and indicates that close companions to
intermediate-mass stars experience significantly different accretion histories
or formation mechanisms than wide companions.


title: The tetrahexahedric Calogero model

abstract:
  We consider the spherical reduction of the rational Calogero model (of type
$A_{n-1}$, without the center of mass) as a maximally superintegrable quantum
system. It describes a particle on the $(n{-}2)$-sphere in a very special
potential. A detailed analysis is provided of the simplest non-separable case,
$n{=}4$, whose potential blows up at the edges of a spherical tetrahexahedron,
tesselating the two-sphere into 24 identical right isosceles spherical
triangles in which the particle is trapped. We construct a complete set of
independent conserved charges and of Hamiltonian intertwiners and elucidate
their algebra. The key structure is the ring of polynomials in Dunkl-deformed
angular momenta, in particular the subspaces invariant and antiinvariant under
all Weyl reflections, respectively.


title: Exoplanet Atmospheres and Giant Ground-Based Telescopes

abstract:
  The study of extrasolar planets has rapidly expanded to encompass the search
for new planets, measurements of sizes and masses, models of planetary
interiors, planetary demographics and occurrence frequencies, the
characterization of planetary orbits and dynamics, and studies of these worlds'
complex atmospheres. Our insights into exoplanets dramatically advance whenever
improved tools and techniques become available, and surely the largest tools
now being planned are the optical/infrared Extremely Large Telescopes (ELTs).
Two themes summarize the advantages of atmospheric studies with the ELTs: high
angular resolution when operating at the diffraction limit and high spectral
resolution enabled by the unprecedented collecting area of these large
telescopes. This brief review describes new opportunities afforded by the ELTs
to study the composition, structure, dynamics, and evolution of these planets'
atmospheres, while specifically focusing on some of the most compelling
atmospheric science cases for four qualitatively different planet populations:
highly irradiated gas giants, young, hot giant planets, old, cold gas giants,
and small planets and Earth analogs.


title: Surface density effects in quenching: cause or effect?

abstract:
  There are very strong observed correlations between the specific
star-formation rates (sSFR) of galaxies and their mean surface mass densities,
{\Sigma}, as well as other aspects of their internal structure. These strong
correlations have often been taken to indicate that the internal structure of a
galaxy must play a major physical role, directly or indirectly, in the control
of star-formation. In this paper we show by means of a very simple toy model
that these correlations can arise naturally without any such physical role once
the observed evolution of the size-mass relation for star-forming galaxies is
taken into account. In particular, the model reproduces the sharp threshold in
{\Sigma} between galaxies that are star-forming and those that are quenched,
and the evolution of this threshold with redshift. Similarly, it produces
iso-quenched-fraction contours in the ${f_Q(m,R_e)}$ plane that are almost
exactly parallel to lines of constant {\Sigma} for centrals and shallower for
satellites. It does so without any dependence on quenching on size or {\Sigma},
and without invoking any differences between centrals and satellites, beyond
the different mass-dependences of their quenching laws. The toy-model also
reproduces several other observations, including the sSFR gradients within
galaxies and the appearance of inside-out build-up of passive galaxies.
Finally, it is shown that curvature in the Main Sequence sSFR-mass relation can
produce curvature in the apparent B/T ratios with mass. Our analysis therefore
suggests that many of the strong correlations that are observed between galaxy
structure and sSFR may well be a consequence of things unrelated to quenching
and should not be taken as evidence of the physical processes that drive
quenching.


title: High Performance Emulation of Quantum Circuits

abstract:
  As quantum computers of non-trivial size become available in the near future,
it is imperative to develop tools to emulate small quantum computers. This
allows for validation and debugging of algorithms as well as exploring
hardware-software co-design to guide the development of quantum hardware and
architectures. The simulation of quantum computers entails multiplications of
sparse matrices with very large dense vectors of dimension $2^n$, where $n$
denotes the number of qubits, making this a memory-bound and network
bandwidth-limited application. We introduce the concept of a quantum computer
\textit{emulator} as a component of a software framework for quantum computing,
enabling a significant performance advantage over simulators by emulating
quantum algorithms at a high level rather than simulating individual gate
operations. We describe various optimization approaches and present
benchmarking results, establishing the superiority of quantum computer
emulators in terms of performance.


title:
The Evolution of Normal Galaxy X-ray Emission Through Cosmic History:
  Constraints from the 6 Ms Chandra Deep Field-South

abstract:
  We present measurements of the evolution of normal-galaxy X-ray emission from
$z \approx$ 0-7 using local galaxies and galaxy samples in the 6 Ms Chandra
Deep Field-South (CDF-S) survey. The majority of the CDF-S galaxies are
observed at rest-frame energies above 2 keV, where the emission is expected to
be dominated by X-ray binary (XRB) populations; however, hot gas is expected to
provide small contributions to the observed- frame < 1 keV emission at $z < 1$.
We show that a single scaling relation between X-ray luminosity ($L_{\rm X}$)
and star-formation rate (SFR) is insufficient for characterizing the average
X-ray emission at all redshifts. We establish that scaling relations involving
not only SFR, but also stellar mass ($M_\star$) and redshift, provide
significantly improved characterizations of the average X-ray emission from
normal galaxy populations at $z \approx$ 0-7. We further provide the first
empirical constraints on the redshift evolution of X-ray emission from both
low-mass XRB (LMXB) and high-mass XRB (HMXB) populations and their scalings
with $M_\star$ and SFR, respectively. We find $L_{\rm 2-10 keV}({\rm
LMXB})/M_\star \propto (1 + z)^{2-3}$ and $L_{\rm 2-10 keV}({\rm HMXB})$/SFR
$\propto (1 + z)$, and show that these relations are consistent with XRB
population-synthesis model predictions, which attribute the increase in LMXB
and HMXB scaling relations with redshift as being due to declining host galaxy
stellar ages and metallicities, respectively. We discuss how emission from XRBs
could provide an important source of heating to the intergalactic medium in the
early Universe, exceeding that of active galactic nuclei.


title:
The Next Generation Virgo Cluster Survey (NGVS). XIII. The Luminosity
  and Mass Function of Galaxies in the Core of the Virgo Cluster and the
  Contribution from Disrupted Satellites

abstract:
  We present measurements of the galaxy luminosity and stellar mass function in
a 3.71 deg$^2$ (0.3 Mpc$^2$) area in the core of the Virgo cluster, based on
$ugriz$ data from the Next Generation Virgo Cluster Survey (NGVS). The galaxy
sample consists of 352 objects brighter than $M_g=-9.13$ mag, the 50%
completeness limit of the survey. Using a Bayesian analysis, we find a best-fit
faint end slope of $\alpha=-1.33 \pm 0.02$ for the g-band luminosity function;
consistent results are found for the stellar mass function as well as the
luminosity function in the other four NGVS bandpasses. We discuss the
implications for the faint-end slope of adding 92 ultra compact dwarfs galaxies
(UCDs) -- previously compiled by the NGVS in this region -- to the galaxy
sample, assuming that UCDs are the stripped remnants of nucleated dwarf
galaxies. Under this assumption, the slope of the luminosity function (down to
the UCD faint magnitude limit, $M_g = -9.6$ mag) increases dramatically, up to
$\alpha = -1.60 \pm 0.06$ when correcting for the expected number of disrupted
non-nucleated galaxies. We also calculate the total number of UCDs and globular
clusters that may have been deposited in the core of Virgo due to the
disruption of satellites, both nucleated and non-nucleated. We estimate that
~150 objects with $M_g\lesssim-9.6$ mag and that are currently classified as
globular clusters, might, in fact, be the nuclei of disrupted galaxies. We
further estimate that as many as 40% of the (mostly blue) globular clusters in
the core of Virgo might once have belonged to such satellites; these same
disrupted satellites might have contributed ~40% of the total luminosity in
galaxies observed in the core region today. Finally, we use an updated Local
Group galaxy catalog to provide a new measurement of the luminosity function of
Local Group satellites, $\alpha=-1.21\pm0.05$.


title:
Quantifying Tensions between CMB and Distance Datasets in Models with
  Free Curvature or Lensing Amplitude

abstract:
  Recent measurements of the Cosmic Microwave Background (CMB) by the Planck
Collaboration have produced arguably the most powerful observational evidence
in support of the standard model of cosmology, i.e. the spatially flat
$\Lambda$CDM paradigm. In this work, we perform model selection tests to
examine whether the base CMB temperature and large scale polarization
anisotropy data from Planck 2015 (P15) prefer any of eight commonly used
one-parameter model extensions with respect to flat $\Lambda$CDM. We find a
clear preference for models with free curvature, $\Omega_\mathrm{K}$, or free
amplitude of the CMB lensing potential, $A_\mathrm{L}$. We also further develop
statistical tools to measure tension between datasets. We use a Gaussianization
scheme to compute tensions directly from the posterior samples using an
entropy-based method, the surprise, as well as a calibrated evidence ratio
presented here for the first time. We then proceed to investigate the
consistency between the base P15~CMB data and six other CMB and distance
datasets. In flat $\Lambda$CDM we find a $4.8\sigma$ tension between the base
P15~CMB data and a distance ladder measurement, whereas the former are
consistent with the other datasets. In the curved $\Lambda$CDM model we find
significant tensions in most of the cases, arising from the well-known low
power of the low-$\ell$ multipoles of the CMB data. In the flat $\Lambda$CDM
$+A_\mathrm{L}$ model, however, all datasets are consistent with the base
P15~CMB observations except for the CMB lensing measurement, which remains in
significant tension. This tension is driven by the increased power of the CMB
lensing potential derived from the base P15~CMB constraints in both models,
pointing at either potentially unresolved systematic effects or the need for
new physics beyond the standard flat $\Lambda$CDM model.


title: The infrared spectral properties of Magellanic carbon stars

abstract:
  The Infrared Spectrograph on the Spitzer Space Telescope observed 184 carbon
stars in the Magellanic Clouds. This sample reveals that the dust-production
rate (DPR) from carbon stars generally increases with the pulsation period of
the star. The composition of the dust grains follows two condensation
sequences, with more SiC condensing before amorphous carbon in metal-rich
stars, and the order reversed in metal-poor stars. MgS dust condenses in
optically thicker dust shells, and its condensation is delayed in more
metal-poor stars. Metal-poor carbon stars also tend to have stronger absorption
from C2H2 at 7.5 um. The relation between DPR and pulsation period shows
significant apparent scatter, which results from the initial mass of the star,
with more massive stars occupying a sequence parallel to lower-mass stars, but
shifted to longer periods. Accounting for differences in the mass distribution
between the carbon stars observed in the Small and Large Magellanic Clouds
reveals a hint of a subtle decrease in the DPR at lower metallicities, but it
is not statistically significant. The most deeply embedded carbon stars have
lower variability amplitudes and show SiC in absorption. In some cases they
have bluer colors at shorter wavelengths, suggesting that the central star is
becoming visible. These deeply embedded stars may be evolving off of the AGB
and/or they may have non-spherical dust geometries.


title: Evidence for an Electrifying Violation of Cosmic Censorship

abstract:
  We present a plausible counterexample to cosmic censorship in four
dimensional Einstein-Maxwell theory with asymptotically anti-de Sitter boundary
conditions. Smooth initial data evolves to a region of arbitrarily large
curvature that is visible to distant observers. Our example is based on a
holographic model of an electrically charged, localised defect which was
previously studied at zero temperature. We partially extend those results to
nonzero temperatures.


title:
Microwave control of the superconducting proximity effect and minigap in
  magnetic and normal metals

abstract:
  We demonstrate theoretically that shining light on superconducting proximity
structures controls the minigap and triplet proximity effect in normal and
magnetic metals, respectively. Considering both a bilayer and Josephson
junction geometry, we show that microwave irradiation with frequency $\omega$
qualitatively alters the spectral properties of the system, controlling the
minigap size $E_\text{mg}$ and even replacing the minigap with a strong peak of
quasiparticle accumulation at zero energy when $\omega=E_\text{mg}$. The
interaction between light and Cooper pairs may thus open a route to active
control of quantum coherent phenomena in superconducting proximity structures.


title: Gauge theories of Partial Compositeness: Scenarios for Run-II of the LHC

abstract:
  We continue our investigation of gauge theories in which the Higgs boson
arises as a pseudo-Nambu-Goldstone boson (pNGB) and top-partners arise as bound
states of three hyperfermions. All models have additional pNGBs in their
spectrum that should be accessible at LHC. We analyze the patterns of symmetry
breaking and present all relevant couplings of the pNGBs with the gauge fields.
We discuss how vacuum misalignment and a mass for the pNGBs is generated by a
loop-induced potential. Finally, we paint a very broad, qualitative, picture of
the kind of experimental signatures these models give rise to, setting the
stage for further analysis.


title:
Swift J1644+57: an Ideal Test Bed of Radiation Mechanisms in a
  Relativistic Super-Eddington Jet

abstract:
  Within the first 10 days after Swift discovered the jetted tidal disruption
event (TDE) Sw J1644+57, simultaneous observations in the radio, near-infrared,
optical, X-ray and gamma-ray bands were carried out. These multiwavelength data
provide a unique opportunity to constrain the emission mechanism and make-up of
a relativistic super-Eddington jet. We consider an exhaustive variety of
radiation mechanisms for the generation of X-rays in this TDE, and rule out
many processes such as SSC, photospheric and proton synchrotron. The infrared
to gamma-ray data for Sw J1644+57 are consistent with synchrotron and
external-inverse-Compton (EIC) processes provided that electrons in the jet are
continuously accelerated on a time scale shorter than ~1% of the dynamical time
to maintain a power-law distribution. The requirement of continuous electron
acceleration points to magnetic reconnection in a Poynting flux dominated jet.
The EIC process may require fine tuning to explain the observed temporal decay
of the X-ray lightcurve, whereas the synchrotron process in a magnetic jet
needs no fine tuning for this TDE.


title: Quantum dynamics of ultracold Bose polarons

abstract:
  We analyze the dynamics of Bose polarons in the vicinity of a Feshbach
resonance between the impurity and host atoms. We compute the radio-frequency
absorption spectra for the case when the initial state of the impurity is
non-interacting and the final state is strongly interacting. We compare results
of different theoretical approaches including a single excitation expansion, a
self-consistent T-matrix method, and a time-dependent coherent state approach.
Our analysis reveals sharp spectral features arising from metastable states
with several Bogoliubov excitations bound to the impurity atom. This surprising
result of the interplay of many-body and few-body Efimov type bound state
physics can only be obtained by going beyond the commonly used Fr\"ohlich model
and including quasiparticle scattering processes. Close to the resonance we
find that strong fluctuations lead to a broad, incoherent absorption spectrum
where no quasi-particle peak can be assigned.

categories: cond-mat.quant-gas cond-mat.mes-hall cond-mat.other cond-mat.str-el quant-ph


title:
Thermodynamics of the two-dimensional XY model from functional
  renormalization

abstract:
  We solve the nonperturbative renormalization-group flow equations for the
two-dimensional XY model at the truncation level of the (complete) second-order
derivative expansion. We compute the thermodynamic properties in the
high-temperature phase and compare the non-universal features specific to the
XY model with results from Monte Carlo simulations. In particular, we study the
position and magnitude of the specific heat peak as a function of temperature.
The obtained results compare well with Monte Carlo simulations. We additionally
gauge the accuracy of simplified nonperturbative renormalization-group
treatments relying on $\phi^4$-type truncations. Our computation indicates that
such an approximation is insufficient in the high-$T$ phase and a correct
analysis of the specific heat profile requires account of an infinite number of
interaction vertices.

categories: cond-mat.stat-mech cond-mat.quant-gas cond-mat.supr-con hep-th


title:
Non-Archimedean Reaction-Ultradiffusion Equations and Complex Hierarchic
  Systems

abstract:
  We initiate the study of non-Archimedean reaction-ultradiffusion equations
and their connections with models of complex hierarchic systems. From a
mathematical perspective, the equations studied here are the p-adic counterpart
of the integro-differential models for phase separation introduced by Bates and
Chmaj. Our equations are also generalizations of the ultradiffusion equations
on trees studied in the 80's by Ogielski, Stein, Bachas, Huberman, among
others, and also generalizations of the master equations of the Avetisov et al.
models, which describe certain complex hierarchic systems. From a physical
perspective, our equations are gradient flows of non-Archimedean free energy
functionals and their solutions describe the macroscopic density profile of a
bistable material whose space of states has an ultrametric structure. Some of
our results are p-adic analogs of some well-known results in the Archimedean
settting, however, the mechanism of diffusion is completely different due to
the fact that it occurs in an ultrametric space.


title: The wind nebula around magnetar Swift J1834.9-0846

abstract:
  We report on the analysis of two deep XMM-Newton observations of the magnetar
Swift J1834.9-0846 and its surrounding extended emission taken in March 2014
and October 2014, 2.5 and 3.1 years after the source went into outburst. The
magnetar is only weakly detected in the first observation with an absorption
corrected flux $F_{\rm 0.5-10 keV}\approx4\times10^{-14}$ erg s$^{-1}$
cm$^{-2}$, and a $3\sigma$ upper limit during the second observation of about
$3\times10^{-14}$ erg s$^{-1}$ cm$^{-2}$. This flux level is more than 3 orders
of magnitude lower than the flux measured at the outburst onset on September
2011. The extended emission, centered at the magnetar position and elongated
towards the south-west, is clearly seen in both observations; it is best fit by
a highly absorbed power-law (PL), with a hydrogen column density of $N_{\rm
H}=8.0\times10^{22}$ cm$^{-2}$ and PL photon index $\Gamma=2.2\pm0.2$. Its flux
is constant between the two observations at $F_{\rm 0.5-10
keV}=1.3\times10^{-12}$ erg s$^{-1}$ cm$^{-2}$. We find no statistically
significant changes in the spectral shape or the flux of this extended emission
over a period of 9 years from 2005 to 2014. These new results strongly support
the extended emission nature as a wind nebula and firmly establish Swift
J1834.9-0846 as the first magnetar to show a surrounding wind nebula. Further,
our results imply that such nebulae are no longer exclusive to rotation-powered
pulsars and narrow the gap between these two sub-populations of isolated
neutron stars. The size and spectrum of the nebula are compatible with those of
pulsar-wind nebulae but its radiative efficiency $\eta_{\rm X}=L_{\rm
X}/\dot{E}\approx0.1$ is markedly high, possibly pointing to an additional wind
component in Swift J1834.9-0846.


title:
Testing Models of Quasar Hosts With Strong Gravitational Lensing by
  Quasar Hosts

abstract:
  We perform a statistical analysis of strong gravitational lensing by quasar
hosts of background galaxies, in the two competing models of dark matter halos
of quasars, HOD and CS models. Utilizing the BolshoiP Simulation we demonstrate
that strong gravitational lensing provides a potentially very powerful test of
models of quasar hosting halos. For quasars at $z=0.5$, the lensing probability
by quasars of background galaxies in the HOD model is higher than that of the
CS model by two orders of magnitude or more for lensing image separations in
the range of $\theta\sim 1.2-12~$arcsec. To observationally test this, we show
that, as an example, at the depth of the CANDELS wide field survey and with a
quasar sample of $1000$ at $z=0.5$, the two models can be differentiated at
$3-4\sigma$ confidence level.


title:
On Detection and Structural Reconstruction of Small-World Random
  Networks

abstract:
  In this paper, we study detection and fast reconstruction of the celebrated
Watts-Strogatz (WS) small-world random graph model \citep{watts1998collective}
which aims to describe real-world complex networks that exhibit both high
clustering and short average length properties. The WS model with neighborhood
size $k$ and rewiring probability probability $\beta$ can be viewed as a
continuous interpolation between a deterministic ring lattice graph and the
Erd\H{o}s-R\'{e}nyi random graph. We study both the computational and
statistical aspects of detecting the deterministic ring lattice structure (or
local geographical links, strong ties) in the presence of random connections
(or long range links, weak ties), and for its recovery. The phase diagram in
terms of $(k,\beta)$ is partitioned into several regions according to the
difficulty of the problem. We propose distinct methods for the various regions.


title: Detection of emission lines from z ~ 3 DLAs towards the QSO J2358+0149

abstract:
  Using VLT/X-shooter we searched for emission line galaxies associated to four
damped Lyman-$\alpha$ systems (DLAs) and one sub-DLA at 2.73<=z<=3.25 towards
QSO J2358+0149. We detect [O III] emission from a "low-cool" DLA at z_abs =
2.9791 (having log N(HI)=21.69+\-0.10, [Zn/H] = -1.83+\-0.18) at an impact
parameter of, $\rho$ ~12 kpc. The associated galaxy is compact with a dynamical
mass of (1-6)x10^9 M_solar, very high excitation ([O III]/[O II] and [O
III]/[H$\beta$] both greater than 10), 12+[O/H]<=8.5 and moderate star
formation rate (SFR <=2 M_solar yr^{-1}). Such properties are typically seen in
the low-z extreme blue compact dwarf galaxies. The kinematics of the gas is
inconsistent with that of an extended disk and the gas is part of either a
large scale wind or cold accretion. We detect Ly$\alpha$ emission from the
z_abs = 3.2477 DLA (having log N(HI)=21.12+\-0.10 and [Zn/H]=-0.97+\-0.13).The
Ly$\alpha$ emission is redshifted with respect to the metal absorption lines by
320 km s^{-1}, consistent with the location of the red hump expected in
radiative transport models. We derive SFR ~0.2-1.7 M_solar yr^{-1} and
Ly$\alpha$ escape fraction of >=10 per cent. No other emission line is detected
from this system. Because the DLA has a small velocity separation from the
quasar (~500 km s^{-1}) and the DLA emission is located within a small
projected distance ($\rho<5$ kpc), we also explore the possibility that the
Ly$\alpha$ emission is being induced by the QSO itself. QSO induced Ly$\alpha$
fluorescence is possible if the DLA is within a physical separation of 340 kpc
to the QSO. Detection of stellar continuum light and/or the oxygen emission
lines would disfavor this possibility. We do not detect any emission line from
the remaining three systems.


title:
Group transformations and entangled-state quantum gates with
  directionally unbiased linear-optical multiports

abstract:
  The concept of directionally unbiased optical multiports is introduced, in
which photons may reflect back out the input direction. A linear-optical
implementation is described, and the simplest three-port version studied.
Symmetry arguments demonstrate potential for unusual quantum information
processing applications. The devices impose group structures on two-photon
entangled Bell states and act as universal Bell-state processors to implement
probabilistic quantum gates acting on state symmetries. These multiports allow
optical scattering experiments to be carried out on arbitrary undirected graphs
via linear optics and raise the possibility of linear-optical information
processing using group structures formed by optical qudit states.


title:
Fitting the Low Energy Spectra of Cosmic Ray Primary Nuclei from C to Fe
  as Measured on Voyager 1

abstract:
  The intensities of the low energy part of the spectra of primary cosmic ray
nuclei including C, O, Ne, Mg, Si and Fe measured by Voyager 1 beyond the
heliopause are deficient relative to the spectra measured at energies above
~100 MeV/nuc as calculated using a standard Leaky Box Model with the path
length a function of rigidity. Modifications to the normal exponential
distribution of path lengths at a single rigidity as is used in a simple LBM
will provide a good fit to this new Voyager 1 data at low energies. These
modifications, sometimes called a truncation, lead to a deficiency of short
path lengths relative to an exponential distribution. This deficiency in the
intensities can be described by a truncation parameter = 0.12. This
modification can be produced in several ways including a non-uniform local
distribution of cosmic ray sources. A uniform source distribution in the
galactic plane that is deficient in sources within 0.2-0.4 Kpc of the Sun is
indicated by the data. Further studies of these low energy spectra in more
detail will improve these estimates and help define other features of the local
galactic distribution of these cosmic rays.


title: General Theory of Spontaneous Emission Near Exceptional Points

abstract:
  We present a general theory of spontaneous emission at exceptional points
(EPs)---exotic degeneracies in non-Hermitian systems. Our theory extends beyond
spontaneous emission to any light--matter interaction described by the local
density of states (e.g., absorption, thermal emission, and nonlinear frequency
conversion). Whereas traditional spontaneous-emission theories imply infinite
enhancement factors at EPs, we derive finite bounds on the enhancement, proving
maximum enhancement of 4 in passive systems with second-order EPs and
significantly larger enhancements (exceeding $400\times$) in gain-aided and
higher-order EP systems. In contrast to non-degenerate resonances, EPs are
associated with non-Lorentzian emission curves, leading to enhancements that
scale polynomially with the resonance quality factor.


title:
Stratospheric aftermath of the 2010 Storm on Saturn as observed by the
  TEXES instrument. I. Temperature structure

abstract:
  We report on spectroscopic observations of Saturn's stratosphere in July 2011
with the Texas Echelon Cross Echelle Spectrograph (TEXES) mounted on the NASA
InfraRed Telescope Facility (IRTF). The observations, targeting several lines
of the CH$_4$ $\nu_4$ band and the H$_2$ S(1) quadrupolar line, were designed
to determine how Saturn's stratospheric thermal structure was disturbed by the
2010 Great White Spot. A study of Cassini Composite Infrared Spectrometer
(CIRS) spectra had already shown the presence of a large stratospheric
disturbance centered at a pressure of 2~hPa, nicknamed the beacon B0, and a
tail of warm air at lower pressures (Fletcher et al. 2012. Icarus 221,
560--586). Our observations confirm that the beacon B0 vertical structure
determined by CIRS, with a maximum temperature of $180\pm1$K at 2~hPa, is
overlain by a temperature decrease up to the 0.2-hPa pressure level. Our
retrieved maximum temperature of $180\pm1$K is colder than that derived by CIRS
($200\pm1$K), a difference that may be quantitatively explained by terrestrial
atmospheric smearing. We propose a scenario for the formation of the beacon
based on the saturation of gravity waves emitted by the GWS. Our observations
also reveal that the tail is a planet-encircling disturbance in Saturn's upper
stratosphere, oscillating between 0.2 and 0.02~hPa, showing a distinct
wavenumber-2 pattern. We propose that this pattern in the upper stratosphere is
either the signature of thermal tides generated by the presence of the warm
beacon in the mid-stratosphere, or the signature of Rossby wave activity.


title:
LOH and behold: Web-scale visual search, recommendation and clustering
  using Locally Optimized Hashing

abstract:
  We propose a novel hashing-based matching scheme, called Locally Optimized
Hashing (LOH), based on a state-of-the-art quantization algorithm that can be
used for efficient, large-scale search, recommendation, clustering, and
deduplication. We show that matching with LOH only requires set intersections
and summations to compute and so is easily implemented in generic distributed
computing systems. We further show application of LOH to: a) large-scale search
tasks where performance is on par with other state-of-the-art hashing
approaches; b) large-scale recommendation where queries consisting of thousands
of images can be used to generate accurate recommendations from collections of
hundreds of millions of images; and c) efficient clustering with a graph-based
algorithm that can be scaled to massive collections in a distributed
environment or can be used for deduplication for small collections, like search
results, performing better than traditional hashing approaches while only
requiring a few milliseconds to run. In this paper we experiment on datasets of
up to 100 million images, but in practice our system can scale to larger
collections and can be used for other types of data that have a vector
representation in a Euclidean space.


title: Visual Congruent Ads for Image Search

abstract:
  The quality of user experience online is affected by the relevance and
placement of advertisements. We propose a new system for selecting and
displaying visual advertisements in image search result sets. Our method
compares the visual similarity of candidate ads to the image search results and
selects the most visually similar ad to be displayed. The method further
selects an appropriate location in the displayed image grid to minimize the
perceptual visual differences between the ad and its neighbors. We conduct an
experiment with about 900 users and find that our proposed method provides
significant improvement in the users' overall satisfaction with the image
search experience, without diminishing the users' ability to see the ad or
recall the advertised brand.


title: Wi-Fi Scaling and Performance in Dense Frequency Planned Networks

abstract:
  The capacity scaling of a Wi-Fi network with fixed transmit power is
investigated. The 802.11 MAC appears to impose a hard limit on the area
capacity by enforcing single transmissions in overlapped cell coverage areas.
However due to the difficulty reading the packet header when transmissions
either overlap or are faded, stations in different cells may lose
synchronization with each other. A large frequency planned network with full
propagation impairments of fast and slow fading is simulated in NS-3 with an
upgraded receiver model supporting packet capture. Downlink Wi-Fi performance
is compared to an equivalent LTE network on the same cell centers. Results show
that Wi-Fi downlink throughput grows with densification limited by decreasing
SINR and partially operational virtual carrier sense. LTE area capacity grows
faster as it is only constrained by SINR.


title: On Stronger Calculi for QBFs

abstract:
  Quantified Boolean formulas (QBFs) generalize propositional formulas by
admitting quantifications over propositional variables. QBFs can be viewed as
(restricted) formulas of first-order predicate logic and easy translations of
QBFs into first-order formulas exist. We analyze different translations and
show that first-order resolution combined with such translations can
polynomially simulate well-known deduction concepts for QBFs. Furthermore, we
extend QBF calculi by the possibility to instantiate a universal variable by an
existential variable of smaller level. Combining such an enhanced calculus with
the propositional extension rule results in a calculus with a universal
quantifier rule which essentially introduces propositional formulas for
universal variables. In this way, one can mimic a very general quantifier rule
known from sequent systems.


title: Parallel Strategies Selection

abstract:
  We consider the problem of selecting the best variable-value strategy for
solving a given problem in constraint programming. We show that the recent
Embarrassingly Parallel Search method (EPS) can be used for this purpose. EPS
proposes to solve a problem by decomposing it in a lot of subproblems and to
give them on-demand to workers which run in parallel. Our method uses a part of
these subproblems as a simple sample as defined in statistics for comparing
some strategies in order to select the most promising one that will be used for
solving the remaining subproblems. For each subproblem of the sample, the
parallelism helps us to control the running time of the strategies because it
gives us the possibility to introduce timeouts by stopping a strategy when it
requires more than twice the time of the best one. Thus, we can deal with the
great disparity in solving times for the strategies. The selections we made are
based on the Wilcoxon signed rank tests because no assumption has to be made on
the distribution of the solving times and because these tests can deal with the
censored data that we obtain after introducing timeouts. The experiments we
performed on a set of classical benchmarks for satisfaction and optimization
problems show that our method obtain good performance by selecting almost all
the time the best variable-value strategy and by almost never choosing a
variable-value strategy which is dramatically slower than the best one. Our
method also outperforms the portfolio approach consisting in running some
strategies in parallel and is competitive with the multi armed bandit
framework.


title:
A review of the effects of chemical and phase segregation on the
  mechanical behaviour of multi-phase steels

abstract:
  In the drive towards higher strength alloys, a diverse range of alloying
elements is employed to enhance their strength and ductility. Limited solid
solubility of these elements in steel leads to segregation during casting which
affects the entire down-stream processing and eventually the mechanical
properties of the finished product. Although it is thought that the presence of
continuous bands lead to premature failure, it has not been possible to verify
this link. This poses as increasingly greater risk for higher alloyed, higher
strength steels which are prone to centre-line segregation: it is thus vital to
be able to predict the mechanical behaviour of multi-phase (MP) steels under
loading.
  This review covers the microstructure and properties of galvanised advanced
high strength steels with particular emphasis to their use in automotive
applications. In order to understand the origins of banding, the origins of
segregation of alloying elements during casting and partitioning in the solid
state will be discussed along with the effects on the mechanical behaviour and
damage evolution under (tensile) loading. Attention will also be paid to the
application of microstructural models in tailoring the production process to
enable suppression of the effects of segregation upon banding. Finally, the
theory and application of the experimental techniques used in this work to
elucidate the structure and properties will be examined.


title:
Humans and deep networks largely agree on which kinds of variation make
  object recognition harder

abstract:
  View-invariant object recognition is a challenging problem, which has
attracted much attention among the psychology, neuroscience, and computer
vision communities. Humans are notoriously good at it, even if some variations
are presumably more difficult to handle than others (e.g. 3D rotations). Humans
are thought to solve the problem through hierarchical processing along the
ventral stream, which progressively extracts more and more invariant visual
features. This feed-forward architecture has inspired a new generation of
bio-inspired computer vision systems called deep convolutional neural networks
(DCNN), which are currently the best algorithms for object recognition in
natural images. Here, for the first time, we systematically compared human
feed-forward vision and DCNNs at view-invariant object recognition using the
same images and controlling for both the kinds of transformation as well as
their magnitude. We used four object categories and images were rendered from
3D computer models. In total, 89 human subjects participated in 10 experiments
in which they had to discriminate between two or four categories after rapid
presentation with backward masking. We also tested two recent DCNNs on the same
tasks. We found that humans and DCNNs largely agreed on the relative
difficulties of each kind of variation: rotation in depth is by far the hardest
transformation to handle, followed by scale, then rotation in plane, and
finally position. This suggests that humans recognize objects mainly through 2D
template matching, rather than by constructing 3D object models, and that DCNNs
are not too unreasonable models of human feed-forward vision. Also, our results
show that the variation levels in rotation in depth and scale strongly modulate
both humans' and DCNNs' recognition performances. We thus argue that these
variations should be controlled in the image datasets used in vision research.


title: On generalization of Zermelo navigation problem on Riemannian manifolds

abstract:
  We generalize the Zermelo navigation problem and its solution on Riemannian
manifolds $(M, h)$ admitting a space dependence of a ship's own speed
$|u(x)|_h\leq1$ in the presence of a perturbation $W$ determined by a mild
velocity vector field $|W(x)|_h<|u(x)|_h$, with application of Finsler metric
of Randers type.


title:
Uncertain for A Century: Quantum Mechanics and The Dilemma of
  Interpretation

abstract:
  Quantum Mechanics, the physical theory describing the microworld, represents
one of science's greatest triumphs. It lies at the root of all modern digital
technologies and offers unparalleled correspondence between prediction and
experiments. Remarkably, however, after more than 100 years it is still unclear
what quantum mechanics means in terms of basic philosophical questions about
the nature of reality. While there are many interpretations of the mathematical
machinery of quantum physics, there remains no experimental means to
distinguish between most of them.
  In this contribution, (based on a discussion at the NYAS), I wish to consider
the ways in which the enduring lack of an agreed upon interpretation of quantum
physics influences a number of critical philosophical debates about physics and
reality. I briefly review two problems effected by quantum interpretations: the
meaning of the term 'Universe' and the nature of consciousness. In what follows
I am explicitly not advocating for any particular quantum interpretation.
Instead, I am interested in how the explicit inability of modern physics to
experimentally distinguish between interpretations with wildly divergent
ontological/epistemological implications plays into discussions of physics and
its description of the world.


title: Free Will - A road less travelled in quantum information

abstract:
  Conway and Kochen's Free Will Theory is examined as an important foundational
element in a new area of activity in computer science - developing protocols
for quantum computing


title:
Personal recollections: Frascati and the search for gravitational waves
  at the Istituto Nazionale di Fisica Nucleare (INFN)

abstract:
  The history of the gravitational wave experiments at the Frascati National
Laboratories of INFN is described, from the early suggestion of Edoardo Amaldi
to the realization of NAUTILUS, the most sensitive detector at the end of the
XXth century.


title: Is General Relativity a (partial) Return of Aristotelian Physics?

abstract:
  Aristotle has split physics at the sphere of the moon; above this sphere
there is no change except eternal spherical motion, below are two different
kinds of motion: Natural motion (without specific cause) and enforced motion.
In modern view motion is caused by gravity and by other forces. The split at
the sphere of the moon has been definitely overcome through the observation of
a supernova and several comets by Tycho Brahe. The second distinction was
eradicated by Isaak Newton who showed that gravitational motion was caused by a
force proportional to the inverse square of the distance. By the theory of
General Relativity, Albert Einstein showed that there is no gravitational force
but motion under gravity (i.e. Aristotles <natural motion>) is caused by the
curved geometry of spacetime. In this way, the Aristotelian distinction between
natural motion and enforced motion has come back in the form of two great
theories: General Relativity and Quantum Field Theory which are today
incompatible. To find a way out of this dilemma is the challenge of modern
physics.


title: Dynamic of the extended Mandelbrots equation

abstract:
  The paper deals with the mathematical - numerical analysis of the Mandelbrot
equation extended by the dynamic continuous term. The possibilities of
generation of fractal patterns with the mathematical form, defined in such a
manner, were investigated. The decay of fractal structure with time was
demonstrated.


title: Laser-heating-based active optics for synchrotron radiation applications

abstract:
  Active optics has attracted considerable interest from researchers in
synchrotron radiation facilities, because of its capacity for x-ray wavefront
correction. Here, we report a novel and efficient technique for correcting or
modulating a mirror surface profile based on laser-heating-induced thermal
expansion. An experimental study of the characteristics of the surface thermal
deformation response indicates that the power of a milliwatt laser yields a
bump height as low as sub-nanometer scale, and that variation of the spot size
modulates the response function width effectively. In addition, the capacity of
the laser-heating technique for free-form surface modulation is demonstrated
via a surface correction experiment. The developed method is a promising new
approach towards effective x-ray active optics coupled with at-wavelength
metrology techniques.


title: Characterization of the Companion to $\mu$ Her

abstract:
  $\mu$ Her is a nearby quadruple system with a G-subgiant primary and several
low mass companions arranged in a 2+2 architecture. While the BC components
have been well characterized, the Ab component has been detected
astrometrically and with direct imaging but there has been some confusion over
its nature, in particular whether the companion is stellar or substellar. Using
near-infrared spectroscopy we are able to estimate the spectral type of the
companion as a M4$\pm$1V star. In addition, we have measured the astrometry of
the system for over a decade. We combined the astrometry with archival radial
velocity measurements to compute an orbit of the system. From the combined
orbit, we are able to compute the mass sum of the system. Using the estimated
mass of the primary, we estimate the mass of the secondary as 0.32 M_sun, which
agrees with the estimated spectral type. Our computed orbit is preliminary due
to the incomplete orbital phase coverage, but it should be sufficient to
predict ephemerides over the next decade.