title: On the Profitability of Optimal Mean Reversion Trading Strategies

abstract:
  We study the profitability of optimal mean reversion trading strategies in
the US equity market. Different from regular pair trading practice, we apply
maximum likelihood method to construct the optimal static pairs trading
portfolio that best fits the Ornstein-Uhlenbeck process, and rigorously
estimate the parameters. Therefore, we ensure that our portfolios match the
mean-reverting process before trading. We then generate contrarian trading
signals using the model parameters. We also optimize the thresholds and the
length of in-sample period by multiple tests. In nine good pair examples, we
can see that our pairs exhibit high Sharpe ratio (above 1.9) over the in-sample
period and out-of-sample period. In particular, Crown Castle International
Corp. (CCI) and HCP, Inc. (HCP) achieve a Sharpe ratio of 2.326 during
in-sample period and a Sharpe ratio of 2.425 in out-of-sample test. Crown
Castle International Corp. (CCI) and Realty Income Corporation (O) achieve a
Sharpe ratio of 2.405 and 2.903 respectively during in-sample period and
out-of-sample period.


title: Detailed ultraviolet asymptotics for AdS scalar field perturbations

abstract:
  We present a range of methods suitable for accurate evaluation of the leading
asymptotics for integrals of products of Jacobi polynomials in limits when the
degrees of some or all polynomials inside the integral become large. The
structures in question have recently emerged in the context of effective
descriptions of small amplitude perturbations in anti-de Sitter (AdS)
spacetime. The limit of high degree polynomials corresponds in this situation
to effective interactions involving extreme short-wavelength modes, whose
dynamics is crucial for the turbulent instabilities that determine the ultimate
fate of small AdS perturbations. We explicitly apply the relevant asymptotic
techniques to the case of a self-interacting probe scalar field in AdS and
extract a detailed form of the leading large degree behavior, including closed
form analytic expressions for the numerical coefficients appearing in the
asymptotics.


title: Dubinin and the Brouers-Sotolongo family isotherms

abstract:
  We show how the Dubinin isotherm and its extensions can be related to the
isotherms derived from the general BrouersSotolongo isotherm. We compare them
using benzene vapor adsorbed on activated carbon data from one of the original
Dubinin paper. We use the same procedure to analyze data from the thesis of
MarquezMontesino on the adsorption on activated carbon prepared from pinus
caribaea saw dust. We conclude by proposing a simple methodology to determine
the macroscopic information given by genuine statistical isotherms.


title: Remarks on Wolff's inequality for hypersurfaces

abstract:
  We run an iteration argument due to Pramanik and Seeger, to provide a proof
of sharp decoupling inequalities for conical surfaces and for $k$-cones. These
are extensions of results \L aba and Pramanik to sharp exponents.


title: On sequences of consecutive squares on elliptic curves

abstract:
  Let $C$ be an elliptic curve defined over $\mathbb Q$ by the equation
$y^2=x^3+Ax+B$ where $A,B\in\mathbb Q$. A sequence of rational points
$(x_i,y_i)\in C(\mathbb Q),\,i=1,2,\ldots,$ is said to form a sequence of
consecutive squares on $C$ if the sequence of $x$-coordinates,
$x_i,i=1,2,\ldots$, consists of consecutive squares. We produce an infinite
family of elliptic curves $C$ with a $5$-term sequence of consecutive squares.
Furthermore, this sequence consists of five independent rational points in
$C(\mathbb Q)$. In particular, the rank $r$ of $C(\mathbb Q)$ satisfies $r\ge
5$.


title:
Conditional purity and quantum correlation measures in two qubit mixed
  states

abstract:
  We analyze and show experimental results of the conditional purity, the
quantum discord and other related measures of quantum correlation in mixed
two-qubit states constructed from a pair of photons in identical polarization
states. The considered states are relevant for the description of spin pair
states in interacting spin chains in a transverse magnetic field. We derive
clean analytical expressions for the conditional local purity and other
correlation measures obtained as a result of a remote local projective
measurement, which are fully verified by the experimental results. A simple
exact expression for the quantum discord of these states in terms of the
maximum conditional purity is also derived.


title:
Two-dimensional radiation-hydrodynamics simulations of super-luminous
  interacting supernovae of type IIn

abstract:
  Some interacting supernovae (SNe) of type IIn show a sizeable continuum
polarisation suggestive of a large scale asymmetry in the circumstellar medium
(CSM) and/or the SN ejecta. Here, we extend the recent work of Dessart et al.
on super-luminous SNe IIn and perform axially-symmetric (i.e., 2D) multi-group
radiation hydrodynamics simulations to explore the impact of an imposed large
scale density asymmetry. When the CSM is asymmetric, the latitudinal variation
of the radial optical depth $\tau$ introduces a strong flux redistribution from
the higher-density CSM regions, where the shock luminosity is larger, towards
the lower-density CSM regions where photons escape more freely --- this
redistribution ceases when $\tau<$1. Along directions where the CSM density is
larger, the shock deceleration is stronger and its progression slower,
producing a non-spherical cold-dense shell (CDS). For an oblate CSM density
distribution, the photosphere (CDS) has an oblate (prolate) morphology when
$\tau>$1. When the CSM is symmetric and the ejecta asymmetric, the flux
redistribution within the CSM now tends to damp the latitudinal variation of
the luminosity at the shock. It then requires a larger ejecta asymmetry to
produce a sizeable latitudinal variation in the emergent flux. When the
interaction is between a SN ejecta and a relic disk, the luminosity boost at
early times scales with the disk opening angle -- forming a super-luminous SN
IIn this way requires an unrealistically thick disk. In contrast, interaction
with a disk of modest thickness/mass can yield a power that rivals radioactive
decay of a standard SN II at nebular times.


title: Partially Multiplicative Biquandles and Handlebody-Knots

abstract:
  We introduce several algebraic structures related to handlebody-knots,
including $G$-families of biquandles, partially multiplicative biquandles and
group decomposable biquandles. These structures can be used to color the
semiarcs in $Y$-oriented spatial trivalent graph diagrams representing
$S^1$-oriented handlebody-knots to obtain computable invariants for
handlebody-knots and handlebody-links. In the case of $G$-families of
biquandles, we enhance the counting invariant using the group $G$ to obtain a
polynomial invariant of handlebody-knots.


title:
ABRA: Approximating Betweenness Centrality in Static and Dynamic Graphs
  with Rademacher Averages

abstract:
  We present ABRA, a suite of algorithms that compute and maintain
probabilistically-guaranteed, high-quality, approximations of the betweenness
centrality of all nodes (or edges) on both static and fully dynamic graphs. Our
algorithms rely on random sampling and their analysis leverages on Rademacher
averages and pseudodimension, fundamental concepts from statistical learning
theory. To our knowledge, this is the first application of these concepts to
the field of graph analysis. The results of our experimental evaluation show
that our approach is much faster than exact methods, and vastly outperforms, in
both speed and number of samples, current state-of-the-art algorithms with the
same quality guarantees.


title: Infrared light emission from atomic point contacts

abstract:
  Gold atomic point contacts are prototype systems to evidence ballistic
electron transport. The typical dimension of the nanojunction being smaller
than the electron-phonon interaction length, even at room temperature,
electrons transfer their excess energy to the lattice only far from the
contact. At the contact however, favored by huge current densities,
electron-electron interactions result in a nano hot electron gas acting as a
source of photons. Using a home built Mechanically Controlled Break Junction,
it is reported here, for the first time, that this hot electron gas also
radiates in the infrared range (0.2eV to 1.2eV). Moreover, in agreement with
the pioneering work of Tomchuk, we show that this radiation is compatible with
a blackbody like spectrum emitted from an electron gas at temperatures of
several thousands of Kelvin given by $(kB.Te)^2 = \alpha. I.V$ where $\alpha$,
$I$ and $V$ are respectively a fitting parameter, the current flowing and the
applied bias.


title:
Two bi-stability jumps in theoretical wind models for massive stars and
  the implications for Luminous Blue Variable supernovae

abstract:
  Luminous Blue Variables have been suggested to be the direct progenitors of
supernova types IIb and IIn, with enhanced mass loss prior to explosion.
However, the mechanism of this mass loss is not yet known. Here, we investigate
the qualitative behaviour of theoretical stellar wind mass-loss as a function
of Teff across two bi-stability jumps in blue supergiant regime and also in
proximity to the Eddington limit, relevant for LBVs. To investigate the
physical ingredients that play a role in the radiative acceleration we
calculate blue supergiant wind models with the CMFGEN non-LTE model atmosphere
code over an effective temperature range between 30000 and 8800 K. Although our
aim is not to provide new mass-loss rates for BA supergiants, we study and
confirm the existence of two bi-stability jumps in mass-loss rates predicted by
Vink, de Koter, & Lamers (1999). However, they are found to occur at somewhat
lower Teff (20000 and 9000 K, respectively) than found previously, which would
imply that stars may evolve towards lower Teff before strong mass-loss is
induced by the bi-stability jumps. When the combined effects of the second
bi-stability jump and the proximity to Eddington limit are accounted for, we
find a dramatic increase in the mass-loss rate by up to a factor of 30. Further
investigation of both bi-stability jumps is expected to lead to a better
understanding of discrepancies between empirical modelling and theoretical
mass-loss rates reported in the literature, and to provide key inputs for the
evolution of both normal AB supergiants and LBVs, as well as their subsequent
supernova type II explosions.


title:
Kinetic Monte Carlo Simulations for Birefringence Relaxation of
  Photo-Switchable Molecules on a Surface

abstract:
  Recent experiments have demonstrated that in a dense monolayer of
photo-switchable dye Methyl-Red molecules the relaxation of an initial
birefringence follows a power-law decay, typical for glass-like dynamics. The
slow relaxation can efficiently be controlled and accelerated by illuminating
the monolayer with circularly polarized light, which induces trans-cis
isomerization cycles. To elucidate the microscopic mechanism, we develop a
two-dimensional molecular model in which the trans and cis isomers are
represented by straight and bent needles, respectively. As in the experimental
system, the needles are allowed to rotate and to form overlaps but they cannot
translate. The out-of-equilibrium rotational dynamics of the needles is
generated using kinetic Monte Carlo simulations. We demonstrate that, in a
regime of high density and low temperature, the power-law relaxation can be
traced to the formation of spatio-temporal correlations in the rotational dy-
namics, i.e., dynamic heterogeneity. We also show that the nearly isotropic cis
isomers can prevent dynamic heterogeneity from forming in the monolayer and
that the relaxation then becomes exponential.


title: Applications of graph containers in the Boolean lattice

abstract:
  We apply the graph container method to prove a number of counting results for
the Boolean lattice $\mathcal P(n)$. In particular, we: (i) Give a partial
answer to a question of Sapozhenko estimating the number of $t$ error
correcting codes in $\mathcal P(n)$, and we also give an upper bound on the
number of transportation codes; (ii) Provide an alternative proof of Kleitman's
theorem on the number of antichains in $\mathcal P(n)$ and give a two-coloured
analogue; (iii) Give an asymptotic formula for the number of $(p,q)$-tilted
Sperner families in $\mathcal P(n)$; (iv) Prove a random version of Katona's
$t$-intersection theorem.
  In each case, to apply the container method, we first prove corresponding
supersaturation results. We also give a construction which disproves two
conjectures of Ilinca and Kahn on maximal independent sets and antichains in
the Boolean lattice. A number of open questions are also given.


title: The local vicinity of spins sum for certain mass dimension one spinors

abstract:
  It is well known that the usual formulation of Elko spinor fields leads to a
subtle Lorentz symmetry break encoded in the spin sums. Recently it was
proposed a redefinition in the dual structure, along with a given mathematical
device, which eliminate the Lorentz breaking term in the spin sums. In this
work we delve into the analysis of this mathematical device providing a solid
framework to the used method.


title: Rational and Polynomial Density on Compact Real Manifolds

abstract:
  We establish a characterization for an $m$-manifold $M$ to admit $n$
functions $f_1$,...,$f_n$ and $n'$ functions $g_1,...,g_{n'}$ in
$\mathcal{C}^\infty(M)$ so that every element of $\mathcal{C}^k(M)$ can be
approximated by rational combinations of $f_1,...,f_n$ and polynomial
combinations of $g_1,...,g_{n'}$. As an application, we show that the optimal
value of $n$ and $n'$ for all manifolds of dimension $m$ is [3m/2], when $k\geq
1$ and $m\geq 2$.


title: Dynamical zeta functions

abstract:
  These are notes from a course given in Orsay in 2002 explaining carefully the
Milnor-Thurston kneading determinant approach to dynamical zeta functions as
interpreted by Baladi and Ruelle (Invent. Math. 1996). We make them available
in view of the recent renewed interest in this approach. (see arXiv:1501.00294,
The Milnor-Thurston determinant and the Ruelle transfer operator, HH Rugh,
Comm. Math. Phys. 342 (2016) 603-614, and arXiv:1407.5313, Kneading with
weights, HH Rugh, Lei Tan, J. Fractal Geom. 2 (2015) 339-375)


title: Delving into the Security Issues of Mobile Cloud Computing

abstract:
  Looking at the last decade, progress in technology has made a huge impact on
our lifestyles. Enhanced use of mobile phones has provided a technological
breakthrough, with the latest smartphones capturing the market. The word
smartphone is enough for everyone to understand the tremendous potential it
brought to the market in terms of economics as well as usability. Not only
this, this ever growing mobile mania has a lot more to offer. The familiarity
of applications like dropbox etc is a clear indication of the popularity of
mobile and cloud computing. But where we get all the benefits from this
computing platform, there are some of the challenges too. However, with the
enhanced facilities and luxuries, some challenges are always accompanied.


title:
Convolutional RNN: an Enhanced Model for Extracting Features from
  Sequential Data

abstract:
  Traditional convolutional layers extract features from patches of data by
applying a non-linearity on an affine function of the input. We propose a model
that enhances this feature extraction process for the case of sequential data,
by feeding patches of the data into a recurrent neural network and using the
outputs or hidden states of the recurrent units to compute the extracted
features. By doing so, we exploit the fact that a window containing a few
frames of the sequential data is a sequence itself and this additional
structure might encapsulate valuable information. In addition, we allow for
more steps of computation in the feature extraction process, which is
potentially beneficial as an affine function followed by a non-linearity can
result in too simple features. Using our convolutional recurrent layers we
obtain an improvement in performance in two audio classification tasks,
compared to traditional convolutional layers. Tensorflow code for the
convolutional recurrent layers is publicly available in
https://github.com/cruvadom/Convolutional-RNN.


title: Derived Categories of BHK Mirrors

abstract:
  We prove a derived analogue to the results of Borisov, Clarke, Kelly, and
Shoemaker on the birationality of Berglund-Hubsch-Krawitz mirrors. Heavily
bootstrapping off work of Seidel and Sheridan, we obtain Homological Mirror
Symmetry for Berglund-Hubsch-Krawitz mirror pencils to hypersurfaces in
projective space.


title: Modelling modal gating of ion channels with hierarchical Markov models

abstract:
  Many ion channels spontaneously switch between different levels of activity.
Although this behaviour known as modal gating has been observed for a long time
it is currently not well understood. Despite the fact that appropriately
representing activity changes is essential for accurately capturing time course
data from ion channels, systematic approaches for modelling modal gating are
currently not available. In this paper, we develop a modular approach for
building such a model in an iterative process. First, stochastic switching
between modes and stochastic opening and closing within modes are represented
in separate aggregated Markov models. Second, the continuous-time hierarchical
Markov model, a new modelling framework proposed here, then enables us to
combine these components so that in the integrated model both mode switching as
well as the kinetics within modes are appropriately represented. A mathematical
analysis reveals that the behaviour of the hierarchical Markov model naturally
depends on the properties of its components. We also demonstrate how a
hierarchical Markov model can be parameterised using experimental data and show
that it provides a better representation than a previous model of the same data
set. Because evidence is increasing that modal gating reflects underlying
molecular properties of the channel protein, it is likely that biophysical
processes are better captured by our new approach than in earlier models.


title:
Signatures of Topological Phase Transition in 3d Topological Insulators
  from Dynamical Axion Response

abstract:
  Axion electrodynamics, first proposed in the context of particle physics,
manifests itself in condensed matter physics in the topological field theory
description of 3d topological insulators and gives rise to magnetoelectric
effect, where applying magnetic (electric) field $\mathbf{B}(\mathbf{E})$
induces polarization (magnetization) $\mathbf{p}(\mathbf{m})$. We use linear
response theory to study the associated topological current using the
Fu-Kane-Mele model of 3d topological insulators in the presence of
time-dependent uniform weak magnetic field. By computing the dynamical current
susceptibility $\chi^{\mathbf{j}_p\mathbf{j}_p}_{ij}(\omega)$, we discover from
its static limit an `order parameter' of the topological phase transition
between weak topological (or ordinary) insulator and strong topological
insulator, found to be continuous. The
$\chi^{\mathbf{j}_p\mathbf{j}_p}_{ij}(\omega)$ shows a sign-changing
singularity at a critical frequency with suppressed strength in the topological
insulating state. Our results can be verified in current noise experiment on 3d
TI candidate materials for the detection of such topological phase transition.


title: Folding and escape of nascent proteins at ribosomal exit tunnel

abstract:
  We investigate the interplay between post-translational folding and escape of
two small single-domain proteins at the ribosomal exit tunnel by using Langevin
dynamics with coarse-grained models. It is shown that at temperatures lower or
near the temperature of the fastest folding, folding proceeds concomitantly
with the escape process, resulting in vectorial folding and enhancement of
foldability of nascent proteins. The concomitance between the two processes,
however, deteriorates as temperature increases. Our folding simulations as well
as free energy calculation by using umbrella sampling show that, at low
temperatures, folding at the tunnel follows one or two specific pathways
without kinetic traps. It is shown that the escape time can be mapped to a
one-dimensional diffusion model with two different regimes for temperatures
above and below the folding transition temperature. Attractive interactions
between amino acids and attractive sites on the tunnel wall lead to a free
energy barrier along the escape route of protein. It is suggested that this
barrier slows down the escape process and consequently promotes correct folding
of the released nascent protein.


title: Generalised row and column removal phenomena and $p$-Kostka numbers

abstract:
  We explain and generalise row-removal phenomena for Schur algebras via
isomorphisms between subquotients of these algebras. In particular, we prove a
new reduction formulae for $p$-Kostka numbers and extension groups between Weyl
and simple modules.


title:
Emergent Friedmann dynamics with a quantum bounce from quantum gravity
  condensates

abstract:
  We study the effective cosmological dynamics, emerging as the hydrodynamics
of simple condensate states, of a group field theory model for quantum gravity
coupled to a massless scalar field and reduced to its isotropic sector. The
quantum equations of motion for these group field theory condensate states are
given in relational terms with respect to the scalar field, from which
effective dynamics for spatially flat, homogeneous and isotropic space-times
can be extracted. The result is a generalization of the Friedmann equations,
including quantum gravity modifications, in a specific regime of the theory
corresponding to a Gross-Pitaevskii approximation where interactions are
subdominant. The classical Friedmann equations of general relativity are
recovered in a suitable semi-classical limit for some range of parameters of
the microscopic dynamics. An important result is that the quantum geometries
associated with these GFT condensate states are non-singular: a bounce
generically occurs in the Planck regime. For some choices of condensate states,
these modified Friedmann equations are very similar to those of loop quantum
cosmology.


title:
Testing the speed of gravitational waves over cosmological distances
  with strong gravitational lensing

abstract:
  Probing the relative speeds of gravitational waves and light acts as an
important test of General Relativity and alternative theories of gravity.
Measuring the arrival time of gravitational waves and electromagnetic
counterparts can be used to measure the relative speeds, but only if the
intrinsic time-lag between emission of the photons and gravitational waves is
well understood. Here we suggest a method that does not make such an
assumption, using future strongly lensed GW events and EM counterparts;
Biesiada et al forecast that 50-100 strongly lensed GW events will be observed
each year with the Einstein Telescope. A single strongly lensed GW event would
produce robust constraints on the ratio of speeds of GWs and light at the
$10^{-7}$ level, if a high energy EM counterpart is observed within the
field-of-view of an observing gamma ray burst monitor.


title: Pathways towards instability in financial networks

abstract:
  Following the financial crisis of 2007-2008, a deep analogy between the
origins of instability in financial systems and complex ecosystems has been
pointed out: in both cases, topological features of network structures
influence how easily distress can spread within the system. However, in
financial network models, the details of how financial institutions interact
typically play a decisive role, and a general understanding of precisely how
network topology creates instability remains lacking. Here we show how
processes that are widely believed to stabilise the financial system, i.e.
market integration and diversification, can actually drive it towards
instability, as they contribute to create cyclical structures which tend to
amplify financial distress, thereby undermining systemic stability and making
large crises more likely. This result holds irrespective of the details of how
institutions interact, showing that policy-relevant analysis of the factors
affecting financial stability can be carried out while abstracting away from
such details.


title:
An explicit relation between knot groups in lens spaces and those in
  $S^3$

abstract:
  For a cyclic covering map $(\Sigma,K) \to (\Sigma',K')$ between two pairs of
a 3-manifold and a knot each, we describe the fundamental group $\pi_1(\Sigma
\setminus K)$ in terms of $\pi_1(\Sigma' \setminus K')$. As a consequence, we
give an alternative proof for the fact that certain knots in $S^3$ cannot be
represented as the preimage of any knot in a lens space, which is related to
free periods of knots. In our proofs, the subgroup of a group $G$ generated by
the commutators and the $p$th power of each element of $G$ plays a key role.


title: Goodness-of-Fit Test: Khmaladze Transformation vs Empirical Likelihood

abstract:
  This paper compares two asymptotic distribution free methods for
goodness-of-fit test of one sample of location-scale family: Khmaladze
transformation and empirical likelihood methods. The comparison is made from
the perspective of empirical level and power obtained from simulations. When
testing for normal and logistic null distributions, we try various alternative
distributions and find that Khmaladze transformation method has better power in
most cases. R-package which was used for the simulation is available online.
See section 5 for the detail.


title:
Photonic Crystals Engineering For Light Manipulation: Low Symmetry,
  Graded Index and Parity Time Symmetry

abstract:
  The great interest to the two and three dimensionally periodic structures,
called photonic crystals (PCs), has begun with the pioneer works of
Yablonovitch and John as one can efficiently control the propagation of the
electromagnetic (EM) waves in the same manner with semiconductors that affect
the electron conduction. One of the main peculiar properties of PCs is that
they have photonic band gap in the transmission spectrum similar to electronic
band gap and hence, they are able to prevent the light to propagate in certain
frequency regions irrespective of the propagation direction in space. Inside
the band gaps, neither optical modes nor spontaneous emissions exist. Breaking
the rotational and mirror symmetries of PC unit cells provides rich dispersive
features such as tilted self-collimation, and wavelength de-multiplexing
effects. Another important issue in PC designs is that it is feasible to design
graded index medium if the parameters of the two dimensional PCs is
intentionally rearranged. That type of configuration is known as Graded index
photonic crystals (GRIN PCs). The implementations of GRIN via periodic
structures provide great flexibilities in terms of designing different index
gradient and photonic integrated circuit components such as couplers, lenses,
and mode order converters. It is crucial to deliver optical signal without any
loss for the long distances where light diffraction plays an important role.
Hence, dealing with the alternative solution to light diffraction phenomena
using 2D axicon shape annular type photonic structure is another topic of this
thesis. In addition to conventional photonic all dielectric structures, we have
proposed gain-loss modulated parity-time (PT-) symmetric photonic structures to
obtain strong asymmetric light transmission close to the crystallographic
resonances or, equivalently, close to high-symmetry points.


title: Networks of plants: how to measure similarity in vegetable species

abstract:
  Despite the common misconception of nearly static organisms, plants do
interact continuously with the environment and with each other. It is fair to
assume that during their evolution they developed particular features to
overcome problems and to exploit possibilities from environment. In this paper
we introduce various quantitative measures based on recent advancements in
complex network theory that allow to measure the effective similarities of
various species. By using this approach on the similarity in fruit-typology
ecological traits we obtain a clear plant classification in a way similar to
traditional taxonomic classification. This result is not trivial, since a
similar analysis done on the basis of diaspore morphological properties do not
provide any clear parameter to classify plants species. Complex network theory
can then be used in order to determine which feature amongst many can be used
to distinguish scope and possibly evolution of plants. Future uses of this
approach range from functional classification to quantitative determination of
plant communities in nature.


title: Character Values of the Sidelnikov-Lempel-Cohn-Eastman Sequences

abstract:
  Binary sequences with good autocorrelation properties and large linear
complexity are useful in stream cipher cryptography. The
Sidelnikov-Lempel-Cohn-Eastman (SLCE) sequences have nearly optimal
autocorrelation. However, the problem of determining the linear complexity of
the SLCE sequences is still open. Our approach is to exploit the fact that
character values associated with the SLCE sequences can be expressed in terms
of a certain type of Jacobi sum. By making use of known evaluations of Gauss
and Jacobi sums in the "pure" and "small index" cases, we are able to obtain
new insight into the linear complexity of the SLCE sequences.


title: Distortion-Resistant Hashing for rapid search of similar DNA subsequence

abstract:
  One of the basic tasks in bioinformatics is localizing a short subsequence
$S$, read while sequencing, in a long reference sequence $R$, like the human
geneome. A natural rapid approach would be finding a hash value for $S$ and
compare it with a prepared database of hash values for each of length $|S|$
subsequences of $R$. The problem with such approach is that it would only spot
a perfect match, while in reality there are lots of small changes:
substitutions, deletions and insertions.
  This issue could be repaired if having a hash function designed to tolerate
some small distortion accordingly to an alignment metric (like
Needleman-Wunch): designed to make that two similar sequences should most
likely give the same hash value. This paper discusses construction of
Distortion-Resistant Hashing (DRH) to generate such fingerprints for rapid
search of similar subsequences. The proposed approach is based on the rate
distortion theory: in a nearly uniform subset of length $|S|$ sequences, the
hash value represents the closest sequence to $S$. This gives some control of
the distance of collisions: sequences having the same hash value.


title: Depth stability of edge ideals

abstract:
  Let $G$ be a connected finite simple graph and let $I_G$ be the edge ideal of
$G$. The smallest number $k$ for which $\depth S/I_G^k$ stabilizes is denoted
by $\dstab(I_G)$. We show that $\dstab(I_G)<\ell(I_G)$ where $\ell(I_G)$
denotes the analytic spread of $I$. For trees we give a stronger upper bound
for $\dstab(I_G)$. We also show for any two integers $1\leq a<b$ there exists a
tree for which $\dstab(I_G)=a$ and $\ell(I_G)=b$.


title: JSClassFinder: A Tool to Detect Class-like Structures in JavaScript

abstract:
  With the increasing usage of JavaScript in web applications, there is a great
demand to write JavaScript code that is reliable and maintainable. To achieve
these goals, classes can be emulated in the current JavaScript standard
version. In this paper, we propose a reengineering tool to identify such
class-like structures and to create an object-oriented model based on
JavaScript source code. The tool has a parser that loads the AST (Abstract
Syntax Tree) of a JavaScript application to model its structure. It is also
integrated with the Moose platform to provide powerful visualization, e.g., UML
diagram and Distribution Maps, and well-known metric values for software
analysis. We also provide some examples with real JavaScript applications to
evaluate the tool.


title:
The Solar Internetwork. II. Magnetic Flux Appearance and Disappearance
  Rates

abstract:
  Small-scale internetwork magnetic fields are important ingredients of the
quiet Sun. In this paper we analyze how they appear and disappear on the solar
surface. Using high resolution Hinode magnetograms, we follow the evolution of
individual magnetic elements in the interior of two supergranular cells at the
disk center. From up to 38 hr of continuous measurements, we show that magnetic
flux appears in internetwork regions at a rate of $120\pm3$ Mx cm$^{-2}$
day$^{-1}$ ($3.7 \pm 0.4 \times 10^{24}$ Mx day$^{-1}$ over the entire solar
surface). Flux disappears from the internetwork at a rate of $125 \pm 6$ Mx
cm$^{-2}$ day$^{-1}$ ($3.9\pm 0.5 \times 10^{24}$ Mx day$^{-1}$) through fading
of magnetic elements, cancellation between opposite-polarity features, and
interactions with network patches, which converts internetwork elements into
network features. Most of the flux is lost through fading and interactions with
the network, at nearly the same rate of about 50 Mx cm$^{-2}$ day$^{-1}$. Our
results demonstrate that the sources and sinks of internetwork magnetic flux
are well balanced. Using the instantaneous flux appearance and disappearance
rates, we successfully reproduce the time evolution of the total unsigned flux
in the two supergranular cells.


title:
On the recovery of ISW fluctuations using large-scale structure tracers
  and CMB temperature and polarization anisotropies

abstract:
  In this work we present a method to extract the signal induced by the
integrated Sachs-Wolfe (ISW) effect in the cosmic microwave background (CMB).
It makes use of the Linear Covariance-Based filter introduced by Barreiro et
al., and combines CMB data with any number of large-scale structure (LSS)
surveys and lensing information. It also exploits CMB polarization to reduce
cosmic variance. The performance of the method has been thoroughly tested with
simulations taking into account the impact of non-ideal conditions such as
incomplete sky coverage or the presence of noise. In particular, three galaxy
surveys are simulated, whose redshift distributions peak at low ($z \simeq
0.3$), intermediate ($z \simeq 0.6$) and high redshift ($z \simeq 0.9$). The
contribution of each of the considered data sets as well as the effect of a
mask and noise in the reconstructed ISW map is studied in detail. When
combining all the considered data sets (CMB temperature and polarization, the
three galaxy surveys and the lensing map), the proposed filter successfully
reconstructs a map of the weak ISW signal, finding a perfect correlation with
the input signal for the ideal case and around 80 per cent, on average, in the
presence of noise and incomplete sky coverage. We find that including CMB
polarization improves the correlation between input and reconstruction although
only at a small level. Nonetheless, given the weakness of the ISW signal, even
modest improvements can be of importance. In particular, in realistic
situations, in which less information is available from the LSS tracers, the
effect of including polarisation is larger. For instance, for the case in which
the ISW signal is recovered from CMB plus only one survey, and taking into
account the presence of noise and incomplete sky coverage, the improvement in
the correlation coefficient can be as large as 10 per cent.


title: Evaluating Surrogate Marker Information using Censored Data

abstract:
  Given the long follow-up periods that are often required for treatment or
intervention studies, the potential to use surrogate markers to decrease the
required follow-up time is a very attractive goal. However, previous studies
have shown that using inadequate markers or making inappropriate assumptions
about the relationship between the primary outcome and surrogate marker can
lead to inaccurate conclusions regarding the treatment effect. Currently
available methods for identifying and validating surrogate markers tend to rely
on restrictive model assumptions and/or focus on uncensored outcomes. The
ability to use such methods in practice when the primary outcome of interest is
a time-to-event outcome is difficult due to censoring and missing surrogate
information among those who experience the primary outcome before surrogate
marker measurement. In this paper, we propose a novel definition of the
proportion of treatment effect explained by surrogate information collected up
to a specified time in the setting of a time-to-event primary outcome. Our
proposed approach accommodates a setting where individuals may experience the
primary outcome before the surrogate marker is measured. We propose a robust
nonparametric procedure to estimate the defined quantity using censored data
and use a perturbation-resampling procedure for variance estimation. Simulation
studies demonstrate that the proposed procedures perform well in finite
samples. We illustrate the proposed procedures by investigating two potential
surrogate markers for diabetes using data from the Diabetes Prevention Program.


title: Lower bounds for uncentered maximal functions in any dimension

abstract:
  In this paper we address the following question: given $ p\in (1,\infty)$, $n
\geq 1$, does there exists a constant $A(p,n)>1$ such that $\| M
f\|_{L^{p}}\geq A(n,p) \| f\|_{L^{p}}$ for any nonnegative $f \in
L^{p}(\mathbb{R}^{n})$, where $Mf$ is a maximal function operator defined over
the family of shifts and dilates of a centrally symmetric convex body. The
inequality fails in general for the centered maximal function operator, but
nevertheless we give an affirmative answer to the question for the uncentered
maximal function operator and the almost centered maximal function operator. In
addition, we also present the Bellman function approach of Melas, Nikolidakis
and Stavropoulos to maximal function operators defined over various types of
families of sets, and in case of parallelepipeds we will show that
$A(n,p)=\left(\frac{p}{p-1}\right)^{1/p}$.


title:
Emulation of Fabry-Perot and Bragg resonators with temporal optical
  solitons

abstract:
  The scattering of weak dispersive waves (DW) on several equally spaced
temporal solitons is studied. It is shown by systematic numerical simulations
that the reflection of the DWs from the soliton trains strongly depends on the
distance between the solitons. The dependence of the reflection and
transmission coefficients on the inter-soliton distance and the frequency of
the incident waves is studied in detail, revealing fascinating quasi-periodic
behavior. The analogy between the observed nonlinear phenomena in temporal
domain and usual Fabry-Perot and Bragg resonators is discussed.


title:
Toward Deeper Understanding of Neural Networks: The Power of
  Initialization and a Dual View on Expressivity

abstract:
  We develop a general duality between neural networks and compositional
kernels, striving towards a better understanding of deep learning. We show that
initial representations generated by common random initializations are
sufficiently rich to express all functions in the dual kernel space. Hence,
though the training objective is hard to optimize in the worst case, the
initial weights form a good starting point for optimization. Our dual view also
reveals a pragmatic and aesthetic perspective of neural networks and
underscores their expressive power.


title:
Efficient temperature-dependent Green's function methods for realistic
  systems: using cubic spline interpolation to approximate Matsubara Green's
  functions

abstract:
  The popular, stable, robust and computationally inexpensive cubic spline
interpolation algorithm is adopted and used for finite temperature Green's
function calculations of realistic systems. We demonstrate that with
appropriate modifications the temperature dependence can be preserved while the
Green's function grid size can be reduced by about two orders of magnitude by
replacing the standard Matsubara frequency grid with a sparser grid and a set
of interpolation coefficients. We benchmarked the accuracy of our algorithm as
a function of a single parameter sensitive to the shape of the Green's
function. Through numerous examples, we confirmed that our algorithm can be
utilized in a systematically improvable, controlled, and black-box manner and
highly accurate one- and two-body energies and one-particle density matrices
can be obtained using only around 5% of the original grid points. Additionally,
we established that to improve accuracy by an order of magnitude, the number of
grid points needs to be doubled, whereas for the Matsubara frequency grid an
order of magnitude more grid points must be used. This suggests that realistic
calculations with large basis sets that were previously out of reach because
they required enormous grid sizes may now become feasible.


title: An algorithm for the weighted metric dimension of two-dimensional grids

abstract:
  A two-dimensional grid consists of vertices of the form (i,j) for 1 \leq i
\leq m and 1 \leq j \leq n, for fixed m,n > 1. Two vertices are adjacent if the
\ell_1 distance between their vectors is equal to 1. A landmark set is a subset
of vertices L \subseteq V, such that for any distinct pair of vertices u,v \in
V, there exists a vertex of L whose distances to u and v are not equal. We
design an efficient algorithm for finding a minimum landmark set with respect
to total cost in a grid graph with non-negative costs defined on the vertices.


title:
An Iterative Linearised Solution to the Sinusoidal Parameter Estimation
  Problem

abstract:
  Signal processing applications use sinusoidal modelling for speech synthesis,
speech coding, and audio coding. Estimation of the model parameters involves
non-linear optimisation methods, which can be very costly for real-time
applications. We propose a low-complexity iterative method that starts from
initial frequency estimates and converges rapidly. We show that for N sinusoids
in a frame of length L, the proposed method has a complexity of O(LN), which is
significantly less than the matching pursuits method. Furthermore, the proposed
method is shown to be more accurate than the matching pursuits and
time-frequency reassignment methods in our experiments.


title:
Development of A Scalable Platform for Large-scale Reservoir Simulations
  on Parallel computers

abstract:
  This paper presents our work on designing a parallel platform for large-scale
reservoir simulations. Detailed components, such as grid and linear solver, and
data structures are introduced, which can serve as a guide to parallel
reservoir simulations and other parallel applications. The main objective of
platform is to support implementation of various parallel reservoir simulators
on distributed-memory parallel systems, where MPI (Message Passing Interface)
is employed for communications among computation nodes. It provides structured
grid due to its simplicity and cell-centered data is applied for each cell. The
platform has a distributed matrix and vector module and a map module. The
matrix and vector module is the base of our parallel linear systems. The map
connects grid and linear system modules, which defines various mappings between
grid and linear systems. Commonly-used Krylov subspace linear solvers are
implemented, including the restarted GMRES method and the BiCGSTAB method. It
also has an interface to a parallel algebraic multigrid solver, BoomerAMG from
HYPRE. Parallel general-purpose preconditioners and special preconditioners for
reservoir simulations are also developed. Various data structures are designed,
such as grid, cell, data, linear solver and preconditioner, and some key
default parameters are presented in this paper. The numerical experiments show
that our platform has excellent scalability and it can simulate giant reservoir
models with hundreds of millions of grid cells using thousands of CPU cores.


title: Dark Radiation and Inflationary Freedom

abstract:
  We perform a cosmological analysis in which we allow the primordial power
spectrum of scalar perturbations to assume a shape that is different with
respect to the usual power-law, arising from the simplest models of
cosmological inflation. We parametrize the primordial power spectrum with a
piecewise monotone cubic Hermite function and we use it to investigate how the
constraints on the various cosmological parameters change: we find that the
obtained limits are relaxed with respect to the power-law case, if CMB
polarization data are not included. Moreover, the cosmological analyses provide
us some indications about the shape of the reconstructed primordial power
spectrum, where we notice possible features around
$k\simeq0.002\,\mathrm{Mpc}^{-1}$ and $k\simeq0.0035\,\mathrm{Mpc}^{-1}$. If
confirmed in future analyses involving enhanced experimental data, these
features suggests that the simplest cosmological inflation models may be
incomplete.


title:
The magnetized galactic wind and synchrotron halo of the starburst dwarf
  galaxy IC10

abstract:
  We aim to explore whether strong magnetic fields can be effectively generated
in low-mass dwarf galaxies and, if so, whether such fields can be affected by
galactic outflows and spread out into the intergalactic medium (IGM). We
performed a radio continuum polarimetry study of IC10, the nearest starbursting
dwarf galaxy, using a combination of multifrequency interferometric (VLA) and
single-dish (Effelsberg) observations. VLA observations at 1.43 GHz reveal an
extensive and almost spherical radio halo of IC10 in total intensity, extending
twice more than the infrared-emitting galactic disk. The halo is magnetized
with a magnetic field strength of 7 microG in the outermost parts. Locally, the
magnetic field reaches about 29 microG in HII complexes, becomes more ordered,
and weakens to 22 microG in the synchrotron superbubble and to 7-10 microG
within HI holes. At the higher frequency of 4.86 GHz, we found a large-scale
magnetic field structure of X-shaped morphology, similar to that observed in
several edge-on spiral galaxies. The X-shaped magnetic structure can be caused
by the galactic wind, advecting magnetic fields injected into the interstellar
medium by stellar winds and supernova explosions. The radio continuum scale
heights at 1.43 GHz indicate the bulk speed of cosmic-ray electrons outflowing
from HII complexes of about 60 km/s, exceeding the escape velocity of 40 km/s.
Hence, the magnetized galactic wind in IC10 inflates the extensive radio halo
visible at 1.43 GHz and can seed the IGM with both random and ordered magnetic
fields. These are signatures of intense material feedback onto the IGM,
expected to be prevalent in the protogalaxies of the early Universe.


title:
Integral Field Spectroscopy of the circumnuclear region of the Radio
  Galaxy Pictor A

abstract:
  We present optical integral field spectroscopy of the inner $2.5 \times 3.4$
kpc$^2$ of the broad-line radio galaxy Pictor A, at a spatial resolution of
$\approx 400$ pc. Line emission is observed over the whole field-of-view, being
strongest at the nucleus and in an elongated linear feature (ELF) crossing the
nucleus from the south-west to the north-east along PA $\sim 70^\circ$.
Although the broad double-peaked H$\alpha$ line and the [OI]6300/H$\alpha$ and
[SII]6717+31/H$\alpha$ ratios are typical of AGNs, the [NII]6584/H$\alpha$
ratio (0.15 - 0.25) is unusually low. We suggest that this is due to the
unusually low metallicity of the gas. Centroid velocity maps show mostly
blueshifts to the south and redshifts to the north of the nucleus, but the
velocity field is not well fitted by a rotation model. Velocity dispersions are
low (< 100 km s$^{-1}$) along the ELF, ruling out a jet-cloud interaction as
the origin of this structure. The ELF shows both blueshifts and redshifts in
channel maps, suggesting that it is close to the plane of the sky. The ELF is
evidently photoionized by the AGN, but its kinematics and inferred low
metallicity suggest that this structure may have originated in a past merger
event with another galaxy. We suggest that the gas acquired in this interaction
may be feeding the ELF.


title:
One-dimensional Coulomb-like problem in general case of deformed space
  with minimal length

abstract:
  We present a definition of the two-sided inverse of position operator in
general case of deformed Heisenberg algebra leading to minimal length. Energy
spectrum and eigenfunctions in momentum space for 1D Coulomb-like potential in
deformed space are found exactly. We analyse the energy spectrum for different
partial cases of deformation function and find that correction due to the
deformation highly depends on type of the deformation function.


title:
Estimating the turning point location in shifted exponential model of
  time series

abstract:
  We consider the distribution of the turning point location of time series
modeled as the sum of deterministic trend plus random noise. If the variables
are modeled by shifted exponentials, whose location parameters define the
trend, we provide a formula for computing the distribution of the turning point
location and consequently to estimate a confidence interval for the location.
We test this formula in simulated data series having a trend with asymmetric
minimum, investigating the coverage rate as a function of a bandwidth
parameter. The method is applied to estimate the confidence interval of the
minimum location of the time series of RT intervals extracted from the
electrocardiogram recorded during the exercise test. We discuss the connection
with stochastic ordering.


title:
Trend extraction in functional data of R and T waves amplitudes of
  exercise electrocardiogram

abstract:
  The R and T waves amplitudes of the electrocardiogram recorded during the
exercise test undergo strong modifications in response to stress. We analyze
the time series of these amplitudes in a group of normal subjects in the
framework of functional data, performing reduction of dimensionality, smoothing
and principal component analysis. These methods show that the R and T
amplitudes have opposite responses to stress, consisting respectively in a bump
and a dip at the early recovery stage. We test these features computing a
confidence band for the trend of the population mean and analyzing the zero
crossing of its derivative.
  Our findings support the existence of a relationship between R and T wave
amplitudes and respectively diastolic and systolic ventricular volumes.


title:
Efficient approaches for escaping higher order saddle points in
  non-convex optimization

abstract:
  Local search heuristics for non-convex optimizations are popular in applied
machine learning. However, in general it is hard to guarantee that such
algorithms even converge to a local minimum, due to the existence of
complicated saddle point structures in high dimensions. Many functions have
degenerate saddle points such that the first and second order derivatives
cannot distinguish them with local optima. In this paper we use higher order
derivatives to escape these saddle points: we design the first efficient
algorithm guaranteed to converge to a third order local optimum (while existing
techniques are at most second order). We also show that it is NP-hard to extend
this further to finding fourth order local optima.


title: On the Complexity of Weighted Greedy Matchings

abstract:
  Motivated by the fact that in several cases a matching in a graph is stable
if and only if it is produced by a greedy algorithm, we study the problem of
computing a maximum weight greedy matching on weighted graphs, termed
GreedyMatching. In wide contrast to the maximum weight matching problem, for
which many efficient algorithms are known, we prove that GreedyMatching is
strongly NP-hard and APX-complete, and thus it does not admit a PTAS unless
P=NP, even on graphs with maximum degree at most 3 and with at most three
different integer edge weights. Furthermore we prove that GreedyMatching is
strongly NP-hard if the input graph is in addition bipartite. Moreover we
consider two natural parameters of the problem, for which we establish a sharp
threshold behavior between NP-hardness and tractability. On the positive side,
we present a randomized approximation algorithm (RGMA) for GreedyMatching on a
special class of weighted graphs, called bush graphs. We highlight an
unexpected connection between RGMA and the approximation of maximum cardinality
matching in unweighted graphs via randomized greedy algorithms. We show that,
if the approximation ratio of RGMA is $\rho$, then for every $\epsilon>0$ the
randomized MRG algorithm of [Aronson et al., Rand. Struct. Alg. 1995] gives a
$(\rho-\epsilon)$-approximation for the maximum cardinality matching. We
conjecture that a tight bound for $\rho$ is $\frac{2}{3}$; we prove our
conjecture true for two subclasses of bush graphs. Proving a tight bound for
the approximation ratio of MRG on unweighted graphs (and thus also proving a
tight value for $\rho$) is a long-standing open problem [Poloczek and Szegedy;
FOCS 2012]. This unexpected relation of our RGMA algorithm with the MRG
algorithm may provide new insights for solving this problem.


title:
Bose-Einstein condensation of positronium: modification of the s-wave
  scattering length below the critical temperature

abstract:
  The production of a Bose-Einstein condensate made of positronium may be
feasible in the near future. Below the condensation temperature, the
positronium collision process is modified by the presence of the condensate.
This makes the theoretical description of the positronium kinetics at low
temperature challenging. Based on the quasi-particle Bogoliubov theory, we
describe the many-body particle-particle collision in a simple manner. We find
that, in a good approximation, the full positronium-positronium interaction can
be described by an effective scattering length. Our results are general and
apply to different species of bosons. The correction to the bare scattering
length is expressed in terms of a single dimensionless parameter that
completely characterizes the condensate.


title:
A reanalysis of radioisotope measurements of the $^9$Be$(\gamma,n)^8$Be
  cross-section

abstract:
  The $^9$Be$(\gamma,n)^8$Be reaction is enhanced by a near threshold $1/2^+$
state. Contradictions between existing measurements of this reaction
cross-section affect calculations of astrophysical r-process yields, dark
matter detector calibrations, and the theory of the nuclear structure of
$^9$Be. Select well-documented radioisotope $^9$Be$(\gamma,n)$ source yield
measurements have been reanalyzed, providing a set of high-accuracy
independently measured cross sections. A Breit-Wigner fit of these corrected
measurements yields $E_R=1738.8\pm1.9$ keV, $\Gamma_\gamma=0.771\pm0.021$ eV,
and $\Gamma_n=268\pm15$ keV for the $1/2^+$ state. A virtual $1/2^+$ state is
excluded with 99.3\% confidence.


title: Observation of Nondegenerate Two-Photon Gain in GaAs

abstract:
  Two-photon lasers require materials with large two-photon gain (2PG)
coefficients and low linear and nonlinear losses. Our previous demonstration of
large enhancement of two-photon absorption in semiconductors for very different
photon energies translates directly into enhancement of 2PG. We experimentally
demonstrate nondegenerate 2PG in optically excited bulk GaAs via femtosecond
pump-probe measurements. 2PG is isolated from other pump induced effects
through the difference between measurements performed with parallel and
perpendicular polarizations of pump and probe. An enhancement in the 2PG
coefficient of nearly two orders-of-magnitude is reported. The results point a
possible way toward two-photon semiconductor lasers.


title:
Expensive control of long-time averages using sum of squares and its
  application to a laminar wake flow

abstract:
  The paper presents a nonlinear state-feedback control design approach for
long-time average cost control, where the control effort is assumed to be
expensive. The approach is based on sum-of-squares and semi-definite
programming techniques. It is applicable to dynamical systems whose right-hand
side is a polynomial function in the state variables and the controls. The key
idea, first described but not implemented in (Chernyshenko et al., Phil. Trans.
R. Soc. A, 372, 2014), is that the difficult problem of optimizing a cost
function involving long-time averages is replaced by an optimization of the
upper bound of the same average. As such, controller design requires the
simultaneous optimization of both the control law and a tunable function,
similar to a Lyapunov function. The present paper introduces a method resolving
the well-known inherent non-convexity of this kind of optimization. The method
is based on the formal assumption that the control is expensive, from which it
follows that the optimal control is small. The resulting asymptotic
optimization problems are convex. The derivation of all the polynomial
coefficients in the controller is given in terms of the solvability conditions
of state-dependent linear and bilinear inequalities. The proposed approach is
applied to the problem of designing a full-information feedback controller that
mitigates vortex shedding in the wake of a circular cylinder in the laminar
regime via rotary oscillations. Control results on a reduced-order model of the
actuated wake and in direct numerical simulation are reported.


title:
Breaking the Logarithmic Barrier for Truthful Combinatorial Auctions
  with Submodular Bidders

abstract:
  We study a central problem in Algorithmic Mechanism Design: constructing
truthful mechanisms for welfare maximization in combinatorial auctions with
submodular bidders. Dobzinski, Nisan, and Schapira provided the first mechanism
that guarantees a non-trivial approximation ratio of $O(\log^2 m)$ [STOC'06],
where $m$ is the number of items. This was subsequently improved to $O(\log
m\log \log m)$ [Dobzinski, APPROX'07] and then to $O(\log m)$ [Krysta and
Vocking, ICALP'12].
  In this paper we develop the first mechanism that breaks the logarithmic
barrier. Specifically, the mechanism provides an approximation ratio of
$O(\sqrt {\log m})$. Similarly to previous constructions, our mechanism uses
polynomially many value and demand queries, and in fact provides the same
approximation ratio for the larger class of XOS (a.k.a. fractionally
subadditive) valuations.
  We also develop a computationally efficient implementation of the mechanism
for combinatorial auctions with budget additive bidders. Although in general
computing a demand query is NP-hard for budget additive valuations, we observe
that the specific form of demand queries that our mechanism uses can be
efficiently computed when bidders are budget additive.


title:
The VIPERS Multi-Lambda Survey. I. UV and NIR Observations, multi-color
  catalogues and photometric redshifts

abstract:
  We present observations collected in the CFHTLS-VIPERS region in the
ultraviolet (UV) with the GALEX satellite (far and near UV channels) and the
near infrared with the CFHT/WIRCam camera ($K_s$-band) over an area of 22 and
27 deg$^2$, respectively. The depth of the photometry was optimized to measure
the physical properties (e.g., SFR, stellar masses) of all the galaxies in the
VIPERS spectroscopic survey. The large volume explored by VIPERS will enable a
unique investigation of the relationship between the galaxy properties and
their environment (density field and cosmic web) at high redshift (0.5 < z <
1.2). In this paper, we present the observations, the data reductions and the
build-up of the multi-color catalogues. The CFHTLS-T0007 (gri-{\chi}^2) images
are used as reference to detect and measure the $K_s$-band photometry, while
the T0007 u-selected sources are used as priors to perform the GALEX photometry
based on a dedicated software (EMphot). Our final sample reaches $NUV_{AB}$~25
(at 5{\sigma}) and $K_{AB}$~22 (at 3{\sigma}). The large spectroscopic sample
(~51,000 spectroscopic redshifts) allows us to highlight the robustness of our
star/galaxy separation, and the reliability of our photometric redshifts with a
typical accuracy $\sigma_z \le$ 0.04 and a catastrophic failure rate {\eta} <
2% down to i~23. We present various tests on the $K_s$ band completeness and
photometric redshift accuracy by comparing with existing, overlapping deep
photometric catalogues. Finally, we discuss the BzK sample of passive and
active galaxies at high redshift and the evolution of galaxy morphology in the
(NUV-r) vs (r-K_s) diagram at low redshift (z < 0.25) thanks to the high image
quality of the CFHTLS. The images, catalogues and photometric redshifts for 1.5
million sources (down to $NUV \le$ 25 or $K_s \le$ 22) are released and
available at this URL: http://cesam.lam.fr/vipers-mls/


title:
Local Rademacher Complexity-based Learning Guarantees for Multi-Task
  Learning

abstract:
  We show a Talagrand-type concentration inequality for Multi-Task Learning
(MTL), using which we establish sharp excess risk bounds for MTL in terms of
distribution- and data-dependent versions of the Local Rademacher Complexity
(LRC). We also give a new bound on the LRC for norm regularized as well as
strongly convex hypothesis classes, which applies not only to MTL but also to
the standard i.i.d. setting. Combining both results, one can now easily derive
fast-rate bounds on the excess risk for many prominent MTL methods,
including---as we demonstrate---Schatten-norm, group-norm, and
graph-regularized MTL. The derived bounds reflect a relationship akeen to a
conservation law of asymptotic convergence rates. This very relationship allows
for trading off slower rates w.r.t. the number of tasks for faster rates with
respect to the number of available samples per task, when compared to the rates
obtained via a traditional, global Rademacher analysis.


title:
The VIPERS Multi-Lambda Survey. II. Diving with massive galaxies in 22
  square degrees since z = 1.5

abstract:
  We investigate the evolution of the galaxy stellar mass function (SMF) and
stellar mass density from redshift z=0.2 to z=1.5 of a $K_{AB}$<22-selected
sample with highly reliable photometric redshifts and over an unprecedentedly
large area. Our study is based on NIR observations carried out with WIRCam at
CFHT over the footprint of the VIPERS spectroscopic survey and benefits from
the high quality optical photometry from the CFHTLS and UV observations with
the GALEX satellite. The accuracy of our photometric redshifts is $\sigma_z$ <
0.03 and 0.05 for the bright ($i_{AB}$<22.5) and faint ($i_{AB}$>22.5) samples,
respectively. The SMF is measured with ~760,000 galaxies down to $K_s$=22 and
over an effective area of ~22.4 deg$^2$, the latter of which drastically
reduces the statistical uncertainties (i.e. Poissonian error & cosmic
variance). We point out the importance of a careful control of the photometric
calibration, whose impact becomes quickly dominant when statistical
uncertainties are reduced, which will be a major issue for future generation of
cosmological surveys with, e.g. EUCLID or LSST. By exploring the rest-frame
(NUV-r) vs (r-$K_s$) color-color diagram separating star-forming and quiescent
galaxies, (1) we find that the density of very massive log($M_*/ M_{\odot}$) >
11.5 galaxies is largely dominated by quiescent galaxies and increases by a
factor 2 from z~1 to z~0.2, which allows for additional mass assembly via dry
mergers, (2) we confirm a scenario where star formation activity is impeded
above a stellar mass log($M^*_{SF} / M_{\odot}$) = 10.64$\pm$0.01, a value that
is found to be very stable at 0.2 < z < 1.5, (3) we discuss the existence of a
main quenching channel that is followed by massive star-forming galaxies, and
finally (4) we characterise another quenching mechanism required to explain the
clear excess of low-mass quiescent galaxies observed at low redshift.


title:
The very low-mass stellar content of the young supermassive Galactic
  star cluster Westerlund 1

abstract:
  We present deep near-infrared HST/WFC3 observations of the young supermassive
Galactic star cluster Westerlund 1 and an adjacent control field. The depth of
the data is sufficient to derive the mass function for the cluster as a
function of radius down to 0.15 M$_\odot$ in the outer parts of the cluster. We
identify for the first time a flattening in the mass function (in logarithmic
units) at a mass range that is consistent with that of the field and nearby
embedded clusters. Through log-normal functional fits to the mass functions we
find the nominal peak mass to be comparable to that of the field and nearby
embedded star clusters. The width of a log-normal fit appears slightly narrow
compared to the width of the field IMF, closer to the values found for globular
clusters. The subsolar content within the cluster does not appear to be mass
segregated in contrast to the findings for the supersolar content. The total
mass of Westerlund 1 is estimated to be 44-57 $\times 10^3$ M$_\odot$ where the
main uncertainty is the choice of the isochrone age and the higher mass slope.
Comparing the photometric mass with the dynamically determined mass, Westerlund
1 is sufficiently massive to remain bound and could potentially evolve into a
low-mass globular cluster.


title: Schubert polynomials and degeneracy locus formulas

abstract:
  In our previous work arXiv:1305.3543, we employed the approach to Schubert
polynomials by Fomin, Stanley, and Kirillov to obtain simple, uniform proofs
that the double Schubert polynomials of Lascoux and Schutzenberger and Ikeda,
Mihalcea, and Naruse represent degeneracy loci for the classical groups in the
sense of Fulton. Using this as our starting point, and purely combinatorial
methods, we obtain a new proof of the general formulas of arXiv:0908.3628,
which represent the degeneracy loci coming from any isotropic partial flag
variety. Along the way, we also find several new formulas and elucidate the
connections between some earlier ones.


title: Weighted Unsupervised Learning for 3D Object Detection

abstract:
  This paper introduces a novel weighted unsupervised learning for object
detection using an RGB-D camera. This technique is feasible for detecting the
moving objects in the noisy environments that are captured by an RGB-D camera.
The main contribution of this paper is a real-time algorithm for detecting each
object using weighted clustering as a separate cluster. In a preprocessing
step, the algorithm calculates the pose 3D position X, Y, Z and RGB color of
each data point and then it calculates each data point's normal vector using
the point's neighbor. After preprocessing, our algorithm calculates k-weights
for each data point; each weight indicates membership. Resulting in clustered
objects of the scene.


title:
Multiscale Modeling of the effect of Pressure on the Interfacial Tension
  and other Cohesion Parameters in Binary Mixtures

abstract:
  We study and predict the interfacial tension, solubility parameters and
Flory-Huggins parameters of binary mixtures as functions of pressure and
temperature, using multiscale numerical simulation. A mesoscopic approach is
proposed for simulating the pressure dependence of the interfacial tension for
binary mixtures, at different temperatures, using classical Dissipative
Particle Dynamics (DPD). The thermodynamic properties of real systems are
reproduced via the parametrization of the repulsive interaction parameters as
functions of pressure and temperature via Molecular Dynamics simulations. Using
this methodology, we calculate and analyze the cohesive density energy and the
solubility parameters of different species obtaining excellent agreement with
reported experimental behavior. The pressure- and temperature-dependent
Flory-Huggins and repulsive DPD interaction parameters for binary mixtures are
also obtained and validated against experimental data. This multiscale
methodology offers the benefit of being applicable for any species and under
difficult or non-feasible experimental conditions, at a relatively low
computational cost.


title:
Connectivity, toughness, spanning trees of bounded degree, and the
  spectrum of regular graphs

abstract:
  In this paper, we present some new results describing connections between the
spectrum of a regular graph and its generalized connectivity, toughness, and
the existence of spanning trees with bounded degree.


title: A Newly-Discovered Radio Halo in Merging Cluster MACS J2243.3-0935

abstract:
  We report the discovery of a radio halo in the massive merging cluster
MACSJ2243.3-0935, as well as a new radio relic candidate, using the Giant
Meterwave Radio Telescope and the KAT-7 telescope. The radio halo is coincident
with the cluster X-ray emission and has a largest linear scale of approximately
0.9 Mpc. We measure a flux density of $10.0\pm 2.0$ mJy at 610 MHz for the
radio halo. We discuss equipartition estimates of the cluster magnetic field
and constrain the value to be of the order of 1 $\mu$G. The relic candidate is
detected at the cluster virial radius where a filament meets the cluster. The
relic candidate has a flux density of $5.2\pm 0.8$ mJy at 610 MHz. We discuss
possible origins of the relic candidate emission and conclude that the
candidate is consistent with an infall relic.


title: On the uncomputability of the spectral gap

abstract:
  This paper reviews the 1994 proof that the spectral gap of Hamiltonian
quantum systems capable of universal computation is uncomputable.


title: Encoding Data for HTM Systems

abstract:
  Hierarchical Temporal Memory (HTM) is a biologically inspired machine
intelligence technology that mimics the architecture and processes of the
neocortex. In this white paper we describe how to encode data as Sparse
Distributed Representations (SDRs) for use in HTM systems. We explain several
existing encoders, which are available through the open source project called
NuPIC, and we discuss requirements for creating encoders for new types of data.


title: Colouring and Covering Nowhere Dense Graphs

abstract:
  It was shown by Grohe et al. that nowhere dense classes of graphs admit
sparse neighbourhood covers of small degree. We show that a monotone graph
class admits sparse neighbourhood covers if and only if it is nowhere dense.
The existence of such covers for nowhere dense classes is established through
bounds on so-called weak colouring numbers.
  The core results of this paper are various lower and upper bounds on the weak
colouring numbers and other, closely related generalised colouring numbers. We
prove tight bounds for these numbers on graphs of bounded tree width. We
clarify and tighten the relation between the expansion (in the sense of
"bounded expansion" as defined by Nesetril and Ossona de Mendez) and the
various generalised colouring numbers. These upper bounds are complemented by
new, stronger exponential lower bounds on the generalised colouring numbers.
Finally, we show that computing weak r-colouring numbers is NP-complete for all
r>2.


title: A multiscale approach for spatially inhomogeneous disease dynamics

abstract:
  In this paper we introduce an agent-based epidemiological model that
generalizes the classical SIR model by Kermack and McKendrick. We further
provide a multiscale approach to the derivation of a macroscopic counterpart
via the mean-field limit. The chain of equations acquired via the multiscale
approach are investigated, analytically as well as numerically. The outcome of
these results provide strong evidence of the models' robustness and justifies
their applicability in describing disease dynamics, in particularly when
mobility is involved.


title:
Reachability in Networks of Register Protocols under Stochastic
  Schedulers

abstract:
  We study the almost-sure reachability problem in a distributed system
obtained as the asynchronous composition of N copies (called processes) of the
same automaton (called protocol), that can communicate via a shared register
with finite domain. The automaton has two types of transitions:
write-transitions update the value of the register, while read-transitions move
to a new state depending on the content of the register. Non-determinism is
resolved by a stochastic scheduler. Given a protocol, we focus on almost-sure
reachability of a target state by one of the processes. The answer to this
problem naturally depends on the number N of processes. However, we prove that
our setting has a cut-off property: the answer to the almost-sure reachability
problem is constant when N is large enough; we then develop an EXPSPACE
algorithm deciding whether this constant answer is positive or negative.


title:
Existence results for degenerate $p(x)$-Laplace equations with
  Leray-Lions type operators

abstract:
  We show the various existence results for degenerate $p(x)$-Laplace equations
with Leray-Lions type operators. A suitable condition on degeneracy is
discussed and proofs are mainly based on direct methods and critical point
theories in Calculus of Variations. In particular, we investigate the various
situations of the growth rates between principal operators and nonlinearities.


title:
On discontinuity of information characteristics of quantum systems and
  channels

abstract:
  Quantitative analysis of discontinuity of basic characteristics of quantum
states and channels is presented.
  First we consider general estimates for discontinuity jump (loss) of the von
Neumann entropy for a given converging sequence of states. It is shown, in
particular, that for any sequence the loss of entropy is upper bounded by the
loss of mean energy (with the coefficient characterizing Hamiltonian of a
system).
  Then we prove that discontinuity jumps of several correlation and
entanglement measures in composite quantum systems are upper bounded by loss of
one of the marginal entropies (with a corresponding coefficient).
  We also analyse discontinuity of the output entropy of a quantum operation
and of basic information charateristics of a quantum channel with respect to
simultaneous variations of an input state and of a channel.


title:
RandomOut: Using a convolutional gradient norm to rescue convolutional
  filters

abstract:
  Filters in convolutional neural networks are sensitive to their
initialization. The random numbers used to initialize filters are a bias and
determine if you will "win" and converge to a satisfactory local minimum so we
call this The Filter Lottery. We observe that the 28x28 Inception-V3 model
without Batch Normalization fails to train 26% of the time when varying the
random seed alone. This is a problem that affects the trial and error process
of designing a network. Because random seeds have a large impact it makes it
hard to evaluate a network design without trying many different random starting
weights. This work aims to reduce the bias imposed by the initial weights so a
network converges more consistently. We propose to evaluate and replace
specific convolutional filters that have little impact on the prediction. We
use the gradient norm to evaluate the impact of a filter on error, and
re-initialize filters when the gradient norm of its weights falls below a
specific threshold. This consistently improves accuracy on the 28x28
Inception-V3 with a median increase of +3.3%. In effect our method RandomOut
increases the number of filters explored without increasing the size of the
network. We observe that the RandomOut method has more consistent
generalization performance, having a standard deviation of 1.3% instead of 2%
when varying random seeds, and does so faster and with fewer parameters.


title:
Kepler Eclipsing Binary Stars. VIII. Identification of False Positive
  Eclipsing Binaries and Re-extraction of New Light Curves

abstract:
  The Kepler Mission has provided unprecedented, nearly continuous photometric
data of $\sim$200,000 objects in the $\sim$105 deg$^{2}$ field of view from the
beginning of science operations in May of 2009 until the loss of the second
reaction wheel in May of 2013. The Kepler Eclipsing Binary Catalog contains
information including but not limited to ephemerides, stellar parameters and
analytical approximation fits for every known eclipsing binary system in the
Kepler Field of View. Using Target Pixel level data collected from Kepler in
conjunction with the Kepler Eclipsing Binary Catalog, we identify false
positives among eclipsing binaries, i.e. targets that are not eclipsing
binaries themselves, but are instead contaminated by eclipsing binary sources
nearby on the sky and show eclipsing binary signatures in their light curves.
We present methods for identifying these false positives and for extracting new
light curves for the true source of the observed binary signal. For each
source, we extract three separate light curves for each quarter of available
data by optimizing the signal-to-noise ratio, the relative percent eclipse
depth and the flux eclipse depth. We present 289 new eclipsing binaries in the
Kepler Field of View that were not targets for observation, and these have been
added to the Catalog. An online version of this Catalog with downloadable
content and visualization tools is maintained at
http://keplerEBs.villanova.edu.


title: The Intrinsic Matter Bispectrum in $\Lambda$CDM

abstract:
  We present a fully relativistic calculation of the matter bispectrum at
second order in cosmological perturbation theory assuming a Gaussian primordial
curvature perturbation. For the first time we perform a full numerical
integration of the bispectrum for both baryons and cold dark matter using the
second-order Einstein-Boltzmann code, SONG. We review previous analytical
results and provide an improved analytic approximation for the second-order
kernel in Poisson gauge which incorporates Newtonian nonlinear evolution,
relativistic initial conditions, the effect of radiation at early times and the
cosmological constant at late times. Our improved kernel provides a percent
level fit to the full numerical result at late times for most configurations,
including both equilateral shapes and the squeezed limit. We show that baryon
acoustic oscillations leave an imprint in the matter bispectrum, making a
significant impact on squeezed shapes.


title: Spread of entanglement for small subsystems in holographic CFTs

abstract:
  We develop an analytic perturbative expansion to study the propagation of
entanglement entropy for small subsystems after a global quench, in the context
of the AdS/CFT correspondence. Opposite to the large interval limit, in this
case the evolution of the system takes place at timescales that are shorter in
comparison to the local equilibration scale and thus, different physical
mechanisms govern the dynamics and subsequent thermalization. In particular, we
show that the heuristic picture in terms of a "entanglement tsunami" does not
apply in this regime. We find two crucial differences. First, that the
instantaneous rate of growth of the entanglement is not constrained by
causality, but rather its time average. And second, that the approach to
saturation is always continuous, regardless the shape of the entangling
surface. Our analytic expansion also enables us to verify some previous
numerical results, namely, that the saturation time is non-monotonic with
respect to the chemical potential. All of our results are pertinent to CFTs
with a classical gravity dual formulation.


title: Parametrisation in electrostatic DPD Dynamics and Applications

abstract:
  A brief overview of mesoscopic modelling via dissipative particle dynamics is
presented, with emphasis on the appropriate parametrisation and how to
calculate the relevant parameters for given realistic systems. The dependence
on concentration and temperature of the interaction parameters is also
considered, as well as some applications.


title:
Modular extensions of unitary braided fusion categories and 2+1D
  topological/SPT orders with symmetries

abstract:
  A finite bosonic or fermionic symmetry can be described uniquely by a
symmetric fusion category $\mathcal{E}$. In this work, we propose that 2+1D
topological/SPT orders with a fixed finite symmetry $\mathcal{E}$ are
classified, up to $E_8$ quantum Hall states, by the unitary modular tensor
categories $\mathcal{C}$ over $\mathcal{E}$ and the modular extensions of each
$\mathcal{C}$. In the case $\mathcal{C}=\mathcal{E}$, we prove that the set
$\mathcal{M}_{ext}(\mathcal{E})$ of all modular extensions of $\mathcal{E}$ has
a natural structure of a finite abelian group. We also prove that the set
$\mathcal{M}_{ext}(\mathcal{C})$ of all modular extensions of $\mathcal{C}$, if
not empty, is equipped with a natural $\mathcal{M}_{ext}(\mathcal{E})$-action
that is free and transitive. Namely, the set $\mathcal{M}_{ext}(\mathcal{C})$
is an $\mathcal{M}_{ext}(\mathcal{E})$-torsor. As special cases, we explain in
details how the group $\mathcal{M}_{ext}(\mathcal{E})$ recovers the well-known
group-cohomology classification of the 2+1D bosonic SPT orders and Kitaev's 16
fold ways. We also discuss briefly the behavior of the group
$\mathcal{M}_{ext}(\mathcal{E})$ under the symmetry-breaking processes and its
relation to Witt groups.


title: Convergence of graphs with intermediate density

abstract:
  We propose a notion of graph convergence that interpolates between the
Benjamini--Schramm convergence of bounded degree graphs and the dense graph
convergence developed by L\'aszl\'o Lov\'asz and his coauthors. We prove that
spectra of graphs, and also some important graph parameters such as numbers of
colorings or matchings, behave well in convergent graph sequences. Special
attention is given to graph sequences of large essential girth, for which
asymptotics of coloring numbers are explicitly calculated. We also treat
numbers of matchings in approximately regular graphs.
  We introduce tentative limit objects that we call graphonings because they
are common generalizations of graphons and graphings. Special forms of these,
called Hausdorff and Euclidean graphonings, involve geometric measure theory.
We construct Euclidean graphonings that provide limits of hypercubes and of
finite projective planes, and, more generally, of a wide class of regular
sequences of large essential girth. For any convergent sequence of large
essential girth, we construct weaker limit objects: an involution invariant
probability measure on the sub-Markov space of consistent measure sequences
(this is unique), or an acyclic reversible sub-Markov kernel on a probability
space (non-unique). We also pose some open problems.


title: Decoherence Free Neutron Interferometry

abstract:
  Perfect single-crystal neutron interferometers are adversely sensitive to
environmental disturbances, particularly mechanical vibrations. The sensitivity
to vibrations results from the slow velocity of thermal neutrons and the long
measurement time that are encountered in a typical experiment. Consequently, to
achieve a good interference solutions for reducing vibration other than those
normally used in optical experiments must be explored. Here we introduce a
geometry for a neutron interferometer that is less sensitive to low-frequency
vibrations. This design may be compared with both dynamical decoupling methods
and decoherence-free subspaces that are described in quantum information
processing. By removing the need for bulky vibration isolation setups, this
design will make it easier to adopt neutron interferometry to a wide range of
applications and increase its sensitivity.


title:
First search for a dark matter annual modulation signal with NaI(Tl) in
  the Southern Hemisphere by DM-Ice17

abstract:
  We present the first search for a dark matter annual modulation signal in the
Southern Hemisphere conducted with NaI(Tl) detectors, performed by the DM-Ice17
experiment. Nuclear recoils from dark matter interactions are expected to yield
an annually modulated signal independent of location within the Earth's
hemispheres. DM-Ice17, the first step in the DM-Ice experimental program,
consists of 17 kg of NaI(Tl) located at the South Pole under 2200 m.w.e.
overburden of Antarctic glacial ice. Taken over 3.6 years for a total exposure
of 60.8 kg yr, DM-Ice17 data are consistent with no modulation in the energy
range of 4-20 keV, providing the strongest limits on weakly interacting massive
particle dark matter from a direct detection experiment located in the Southern
Hemisphere. The successful deployment and stable long-term operation of
DM-Ice17 establishes the South Pole ice as a viable location for future dark
matter searches and in particular for a high-sensitivity NaI(Tl) dark matter
experiment to directly test the DAMA/LIBRA claim of the observation of dark
matter.

categories: physics.ins-det astro-ph.CO astro-ph.IM hep-ex


title: One-Counter Automata with Counter Observability

abstract:
  In a one-counter automaton (OCA), one can produce a letter from some finite
alphabet, increment and decrement the counter by one, or compare it with
constants up to some threshold. It is well-known that universality and language
inclusion for OCAs are undecidable. In this paper, we consider OCAs with
counter observability: Whenever the automaton produces a letter, it outputs the
current counter value along with it. Hence, its language is now a set of words
over an infinite alphabet. We show that universality and inclusion for that
model are PSPACE-complete, thus no harder than the corresponding problems for
finite automata. In fact, by establishing a link with visibly one-counter
automata, we show that OCAs with counter observability are effectively
determinizable and closed under all boolean operations.


title: Multi-resolution Compressive Sensing Reconstruction

abstract:
  We consider the problem of reconstructing an image from compressive
measurements using a multi-resolution grid. In this context, the reconstructed
image is divided into multiple regions, each one with a different resolution.
This problem arises in situations where the image to reconstruct contains a
certain region of interest (RoI) that is more important than the rest. Through
a theoretical analysis and simulation experiments we show that the
multi-resolution reconstruction provides a higher quality of the RoI compared
to the traditional single-resolution approach.


title:
Appearance and disappearance of quantum correlations in
  measurement-based feedback control of a mechanical oscillator

abstract:
  Quantum correlations between imprecision and back-action are a hallmark of
continuous linear measurements. Here we study how measurement-based feedback
can be used to improve the visibility of quantum correlations due to the
interaction of a laser field with a nano-optomechanical system. Back-action
imparted by the meter laser, due to radiation pressure quantum fluctuations,
gives rise to correlations between its phase and amplitude quadratures. These
quantum correlations are observed in the experiment both as squeezing of the
meter field fluctuations below the vacuum level in a homodyne measurement, and
as sideband asymmetry in a heterodyne measurement, demonstrating the common
origin of both phenomena. We show that quantum feedback, i.e. feedback that
suppresses measurement back-action, can be used to increase the visibility of
the sideband asymmetry ratio. In contrast, by operating the feedback loop in
the regime of noise squashing, where the in-loop photocurrent variance is
reduced below the vacuum level, the visibility of the sideband asymmetry is
reduced. This is due to feedback back-action arising from vacuum noise in the
homodyne detector. These experiments demonstrate the possibility, as well as
the fundamental limits of measurement-based feedback as a tool to manipulate
quantum correlations.


title: Conductivity bound from dirty black holes

abstract:
  We propose a lower bound of the dc electrical conductivity in strongly
disordered, strongly interacting quantum field theories using holography. We
study linear response of black holes with broken translational symmetry in
Einstein-Maxwell-dilaton theories of gravity. Using the generalized Stokes
equations at the horizon, we derive the lower bound of the electrical
conductivity for the dual two dimensional disordered field theory.


title:
The Interaction of Memory and Attention in Novel Word Generalization: A
  Computational Investigation

abstract:
  People exhibit a tendency to generalize a novel noun to the basic-level in a
hierarchical taxonomy -- a cognitively salient category such as "dog" -- with
the degree of generalization depending on the number and type of exemplars.
Recently, a change in the presentation timing of exemplars has also been shown
to have an effect, surprisingly reversing the prior observed pattern of
basic-level generalization. We explore the precise mechanisms that could lead
to such behavior by extending a computational model of word learning and word
generalization to integrate cognitive processes of memory and attention. Our
results show that the interaction of forgetting and attention to novelty, as
well as sensitivity to both type and token frequencies of exemplars, enables
the model to replicate the empirical results from different presentation
timings. Our results reinforce the need to incorporate general cognitive
processes within word learning models to better understand the range of
observed behaviors in vocabulary acquisition.


title: Atomic Properties of Lu$^+$

abstract:
  Singly ionised Lutetium has recently been suggested as a potential clock
candidate. Here we report a joint experimental and theoretical investigation of
\ce{Lu^+}. Measurements relevant to practical clock operation are made and
compared to atomic structure calculations. Calculations of scalar and tensor
polarizabilities for clock states over a range of wavelengths are also given.
These results will be useful for future work with this clock candidate.


title:
Classification of 2+1D topological orders and SPT orders for bosonic and
  fermionic systems with on-site symmetries

abstract:
  Gapped quantum liquids (GQL) include both topologically ordered states (with
long range entanglement) and symmetry protected topological (SPT) states (with
short range entanglement). In this paper, we propose a classification of 2+1D
GQL for both bosonic and fermionic systems: 2+1D bosonic/fermionic GQLs with
finite on-site symmetry are classified by non-degenerate unitary braided fusion
categories over a symmetric fusion category (SFC) $\cal E$, abbreviated as
$\text{UMTC}_{/\cal E}$, together with their modular extensions and total
chiral central charges. The SFC $\cal E$ is $\text{Rep}(G)$ for bosonic
symmetry $G$, or $\text{sRep}(G^f)$ for fermionic symmetry $G^f$. As a special
case of the above result, we find that the modular extensions of
$\text{Rep}(G)$ classify the 2+1D bosonic SPT states of symmetry $G$, while the
$c=0$ modular extensions of $\text{sRep}(G^f)$ classify the 2+1D fermionic SPT
states of symmetry $G^f$. Many fermionic SPT states are studied based on the
constructions from free-fermion models. But it is not clear if free-fermion
constructions can produce all fermionic SPT states. Our classification does not
have such a drawback. We show that, for interacting 2+1D fermionic systems,
there are exactly 16 superconducting phases with no symmetry and no fractional
excitations (up to $E_8$ bosonic quantum Hall states). Also, there are exactly
8 $Z_2\times Z_2^f$-SPT phases, 2 $Z_8^f$-SPT phases, and so on. Besides, we
show that two topological orders with identical bulk excitations and central
charge always differ by the stacking of the SPT states of the same symmetry.


title:
Probing the Higgs Sector of the Minimal Left-Right Symmetric Model at
  Future Hadron Colliders

abstract:
  If neutrino masses arise from a TeV-scale minimal Left-Right seesaw model,
the ensuing extended Higgs sector with neutral, singly and doubly-charged
scalars has a plethora of implications for new Higgs boson searches beyond the
Standard Model at future hadron colliders, such as the $\sqrt s=14$ TeV
High-Luminosity Large Hadron Collider (HL-LHC) and the proposed $\sqrt s=100$
TeV collider (FCC-hh or SPPC). In this article, we provide a glimpse of this
new physics in the Higgs sector. Our discussion focuses on the minimal
non-supersymmetric version of the Left-Right model with high-scale parity
breaking but TeV-scale $SU(2)_R$-breaking, a property desirable to suppress the
type-II seesaw contribution to neutrino masses. We analyze the masses and
couplings of the physical Higgs bosons in this model, and discuss their
dominant production and decay modes at hadron colliders. We identify the best
discovery channels for each of the non-SM Higgs bosons and estimate the
expected SM backgrounds in these channels to derive the sensitivity reaches for
the new Higgs sector at future hadron colliders under discussion. Following a
rather conservative approach, we estimate that the heavy Higgs sector can be
effectively probed up to 15 TeV at the $\sqrt s=100$ TeV machine. We also
discuss how the LR Higgs sector can be distinguished from other extended Higgs
sectors.


title: Open Whitney umbrellas are locally polynomially convex

abstract:
  It is proved that any smooth open Whitney umbrella in $\mathbb C^2$ is
locally polynomially convex near the singular point.


title:
Testing the Strong Equivalence Principle with spacecraft ranging towards
  the nearby Lagrangian points

abstract:
  General relativity is supported by great experimental evidence. Yet there is
a lot of interest in precisely setting its limits with on going and future
experiments. A question to answer is about the validity of the Strong
Equivalence Principle. Ground experiments and Lunar Laser Ranging have provided
the best upper limit on the Nordtvedt parameter $\sigma[\eta]=4.4\times
10^{-4}$. With the future planetary mission BepiColombo, this parameter will be
further improved by at least an order of magnitude. In this paper we envisage
yet another possible testing environment with spacecraft ranging towards the
nearby Sun-Earth collinear Lagrangian points. Neglecting errors in planetary
masses and ephemerides, we forecast $\sigma[\eta]=6.4\,(2.0)\times10^{-4}$ (5
yr integration time) via ranging towards $L_1$ in a realistic (optimistic)
scenario depending on current (future) range capabilities and knowledge of the
Earth's ephemerides. A combined measurement, $L_1$+$L_2$, gives instead
$4.8\,(1.7)\times10^{-4}$. In the optimistic scenario a single measurement of
one year would be enough to reach $\approx3\times10^{-4}$. All figures are
comparable with Lunar Laser Ranging, but worse than BepiColombo. Performances
could be much improved if data were integrated over time and over the number of
satellites flying around either of the two Lagrangian points. We point out that
some systematics (gravitational perturbations of other planets or figure
effects) are much more in control compared to other experiments. We do not
advocate a specific mission to constrain the Strong Equivalence Principle, but
we do suggest analysing ranging data of present and future spacecrafts flying
around $L_1$/$L_2$ (one key mission is, for instance, LISA Pathfinder). This
spacecraft ranging would be a new and complementary probe to constrain the
Strong Equivalence Principle in space.


title:
An Efficient, Sparsity-Preserving, Online Algorithm for Low-Rank
  Approximation

abstract:
  Low-rank matrix approximation is a fundamental tool in data analysis for
processing large datasets, reducing noise, and finding important signals. In
this work, we present a novel truncated LU factorization called
Spectrum-Revealing LU (SRLU) for effective low-rank matrix approximation, and
develop a fast algorithm to compute an SRLU factorization. We provide both
matrix and singular value approximation error bounds for the SRLU approximation
computed by our algorithm. Our analysis suggests that SRLU is competitive with
the best low-rank matrix approximation methods, deterministic or randomized, in
both computational complexity and approximation quality. Numeric experiments
illustrate that SRLU preserves sparsity, highlights important data features and
variables, can be efficiently updated, and calculates data approximations
nearly as accurately as possible. To the best of our knowledge this is the
first practical variant of the LU factorization for effective and efficient
low-rank matrix approximation.


title: Quantum Statistics and Spacetime Surgery

abstract:
  We apply the geometric-topology surgery theory on spacetime manifolds to
study the constraints of quantum statistics data in 2+1 and 3+1 spacetime
dimensions. First, we introduce the fusion data for worldline and worldsheet
operators capable creating anyon excitations of particles and strings,
well-defined in gapped states of matter with intrinsic topological orders.
Second, we introduce the braiding statistics data of particles and strings,
such as the geometric Berry matrices for particle-string Aharonov-Bohm and
multi-loop adiabatic braiding process, encoded by submanifold linkings, in the
closed spacetime 3-manifolds and 4-manifolds. Third, we derive new quantum
surgery constraints analogous to Verlinde formula associating fusion and
braiding statistics data via spacetime surgery, essential for defining the
theory of topological orders, and potentially correlated to bootstrap boundary
physics such as gapless modes, conformal field theories or quantum anomalies.

categories: cond-mat.str-el hep-th math-ph math.GT math.MP quant-ph


title: Accretion onto Some Well-Known Regular Black Holes

abstract:
  In this work, we discuss the accretion onto static spherical symmetric
regular black holes for specific choices of equation of state parameter. The
underlying regular black holes are charged regular black hole using Fermi-Dirac
Distribution, logistic distribution, nonlinear electrodynamics, respectively
and Kehagias-Sftesos asymptotically flat regular black hole. We obtain the
critical radius, critical speed and squared sound speed during the accretion
process near the regular black holes. We also study the behavior of radial
velocity, energy density and rate of change of mass for each regular black
holes.


title:
Looking for central tendencies in the conformational freedom of proteins
  using NMR measurements

abstract:
  We study the conformational freedom of a protein made by two rigid domains
connected by a flexible linker. The conformational freedom is represented as an
unknown probability distribution on the space of allowed states. A new
algorithm for the calculation of the Maximum Allowable Probability is proposed,
which can be extended to any type of measurements. In this paper we use Pseudo
Contact Shifts and Residual Dipolar Coupling. We reconstruct a single central
tendency in the distribution and discuss in depth the results.