title: Quantum Quenches in Free Field Theory: Universal Scaling at Any Rate

abstract:
  Quantum quenches display universal scaling in several regimes. For quenches
which start from a gapped phase and cross a critical point, with a rate slow
compared to the initial gap, many systems obey Kibble-Zurek scaling. More
recently, a different scaling behaviour has been shown to occur when the quench
rate is fast compared to all other physical scales, but still slow compared to
the UV cutoff. We investigate the passage from fast to slow quenches in scalar
and fermionic free field theories with time dependent masses for which the
dynamics can be solved exactly for all quench rates. We find that renormalized
one point functions smoothly cross over between the regimes.


title:
Modifications of Wald's score tests on large dimensional covariance
  matrices structure

abstract:
  This paper considers testing the covariance matrices structure based on
Wald's score test in large dimensional setting. The hypothesis $H_0: \Sigma
=\Sigma_0 $ for a given matrix $\Sigma_0$, which covers the identity hypothesis
test and sphericity hypothesis test as the special cases, is reviewed by the
generalized CLT (Central Limit Theorem) for the linear spectral statistics of
large dimensional sample covariance matrices from Jiang(2015) . The proposed
tests can be applicable for large dimensional non-Gaussian variables in a wider
range. Furthermore, the simulation study is provided to compare the proposed
tests with other large dimensional covariance matrix tests for evaluation of
their performances. As seen from the simulation results, our proposed tests are
feasible for large dimensional data without restriction of population
distribution and provide the accurate and steady empirical sizes, which are
almost around the nominal size.


title: Improved Cryptanalysis of Rank Metric Schemes Based on Gabidulin Codes

abstract:
  We prove that any variant of the GPT cryptosystem which uses a right column
scrambler over the extension field as advocated by the works of Gabidulin et
al. with the goal to resist to Overbeck's structural attack are actually still
vulnerable to that attack. We show that by applying the Frobenius operator
appropriately on the public key, it is possible to build a Gabidulin code
having the same dimension as the original secret Gabidulin code but with a
lower length. In particular, the code obtained by this way correct less errors
than the secret one but its error correction capabilities are beyond the number
of errors added by a sender, and consequently an attacker is able to decrypt
any ciphertext with this degraded Gabidulin code. We also considered the case
where an isometric transformation is applied in conjunction with a right column
scrambler which has its entries in the extension field. We proved that this
protection is useless both in terms of performance and security. Consequently,
our results show that all the existing techniques aiming to hide the inherent
algebraic structure of Gabidulin codes have failed.


title:
Sediment Micromechanics in Sheet Flows Induced by Asymmetric Waves: A
  CFD-DEM Study

abstract:
  Understanding the sediment transport in oscillatory flows is essential to the
investigation of the overall sediment budget for coastal regions. This overall
budget is crucial for the prediction of the morphological change of coastline
in engineering applications. Since the sediment transport in oscillatory flows
is dense particle-laden flow, appropriate modeling of the particle interaction
is critical. Although traditional two-fluid approaches have been applied to the
study of sediment transport in oscillatory flows, the approaches do not resolve
the interaction of the particles. Particle-resolved modeling of sediment
transport in oscillatory flows and the study of micromechanics of sediment
particles are still lacking. In this work, a parallel CFD-DEM solver that can
resolve the inter-particle collision is applied to study the granular
micromechanics of sediment particles in oscillatory flows. The results obtained
from the CFD-DEM solver are validated by using the experimental data of coarse
and medium sands. The comparison with experimental results suggests that the
flow velocity, the sediment flux and the net sediment transport rate predicted
by are satisfactory. Moreover, the micromechanic quantities of the sediment bed
are presented in detail, including Voronoi concentration, coordination number,
and particle interaction force. It is demonstrated that variation of these
micromechanic quantities at different phases in the oscillatory cycle is
significant, which is due to different responses of the sediment bed. To
investigate the structural properties of the sediment bed, the correlation of
the Voronoi volume fraction and coordination number are compared to the results
from the fluidized bed simulations. The consistency in the comparison indicates
the structural micromechanics of sediment transport and fluidized bed are
similar despite the differences in flow patterns.


title:
The Refined Shock Velocity of the X-Ray Filaments in the RCW 86
  Northeast Rim

abstract:
  A precise measurement of shock velocities is crucial for constraining the
mechanism and efficiency of cosmic-ray (CR) acceleration at supernova remnant
(SNR) shock fronts. The northeastern rim of the SNR RCW 86 is thought to be a
particularly efficient CR acceleration site, owing to the recent result in
which an extremely high shock velocity of ~6000 km/s was claimed (Helder et al.
2009). Here we revisit the same SNR rim with the Chandra X-ray Observatory, 11
years after the first observation. This longer baseline than previously
available allows us to determine a more accurate proper motion of the
nonthermal X-ray filament, revealing a much lower velocity of 3000 \pm 340 km/s
(and even slower at a brighter region). Although the value has dropped to a
half of that from the previous X-ray measurement, it is still higher than the
mean velocity of the H-alpha filaments in this region (~1200 km/s). This
discrepancy implies that the filaments bright in nonthermal X-rays and H-alpha
emission trace different velocity components, and thus a CR pressure
constrained by combining the X-ray kinematics and the H-alpha spectroscopy can
easily be overestimated. We also measure the proper motion of the thermal X-ray
filament immediately to the south of the nonthermal one. The inferred velocity
(720 \pm 360 km/s) is significantly lower than that of the nonthermal filament,
suggesting the presence of denser ambient material, possibly a wall formed by a
wind from the progenitor, which has drastically slowed down the shock.


title:
Updated Results of a Solid-State Sensor Irradiation Study for ILC
  Extreme Forward Calorimetry

abstract:
  Detectors proposed for the International Linear Collider (ILC) incorporate a
tungsten sampling calorimeter (`BeamCal') intended to reconstruct showers of
electrons, positrons and photons that emerge from the interaction point of the
collider with angles between 5 and 50 milliradians. For the innermost radius of
this calorimeter, radiation doses at shower max are expected to reach 100 Mrad
per year, primarily due to minimum-ionizing electrons and positrons that arise
in the induced electromagnetic showers of e+e- `beamstrahlung' pairs produced
in the ILC beam-beam interaction. However, radiation damage to calorimeter
sensors may be dominated by hadrons induced by nuclear interactions of shower
photons, which are much more likely to contribute to the non-ionizing energy
loss that has been observed to damage sensors exposed to hadronic radiation. We
report here on the results of SLAC Experiment T-506, for which several
different types of silicon diode and gallium-arsenide sensors were exposed to
doses of radiation induced by showering electrons of energy 3.5-13.3 GeV. By
embedding the sensor under irradiation within a tungsten radiator, the exposure
incorporated hadronic species that would potentially contribute to the
degradation of a sensor mounted in a precision sampling calorimeter. Depending
on sensor technology, efficient charge collection was observed for doses as
large as 270 Mrad.


title:
Quantum topological Hall effect and noncoplanar antiferromagnetism in
  K$_{0.5}$RhO$_2$

abstract:
  Quantum anomalous Hall (QAH) phase is a two-dimensional bulk ferromagnetic
insulator with a nonzero Chern number in presence of spin-orbit coupling (SOC)
but absence of applied magnetic fields. Associated metallic chiral edge states
host dissipationless current transport in electronic devices. This intriguing
QAH phase has recently been observed in magnetic impurity-doped topological
insulators, {\it albeit}, at extremely low temperatures. Based on
first-principles density functional calculations, here we predict that layered
rhodium oxide K$_{0.5}$RhO$_2$ in noncoplanar chiral antiferromagnetic state is
an unconventional three-dimensional QAH insulator with a large band gap and a
Neel temperature of a few tens Kelvins. Furthermore, this unconventional QAH
phase is revealed to be the exotic quantum topological Hall effect caused by
nonzero scalar spin chirality due to the topological spin structure in the
system and without the need of net magnetization and SOC.


title:
Water-phospholipid interactions at the interface of lipid membranes:
  comparison of different force fields

abstract:
  Water-phospholipid interactions at the lipid bilayer/water interfaces are of
essential importance for the dynamics, stability and function of biological
membrane, and are also strongly associated with numerous biological processes
at the interfaces of lipid bilayers. Various force fields, such as the
united-atom Berger force field, its two improved versions by Kukol and by
Poger, and the all-atom Slipid force field developed recently, can be applied
to simulating the structures of lipid bilayer, with their structural
predictions in good agreement with experimental data. In this work, we show
that despite the similarity in structural predictions of lipid bilayers, there
are observable differences in formation of hydrogen bonds and the interaction
energy profiles between water and phospholipid groups at the lipid
bilayer/water interfaces, when four force fields for
dipalmitoylphosphatidylcholine (DPPC) phospholipids are employed in molecular
dynamics simulations. In particular, the Slipid force field yields more
hydrogen bonds between water and phospholipids and more symmetrical interaction
energy distributions for the two carboxylic groups on their respective acyl
tails, compared to the Berger and its two improved force fields. These
differences are mainly attributed to the different interfacial water
distributions and ability to form hydrogen bonds between interfacial water and
oxygen atoms of the DPPC lipids using different force fields. These results
would be helpful in understanding the behaviors of water as well as its
interaction with phospholipids at the lipid bilayer/water interfaces, and
provide a guide for making the appropriate choice on the force field in
simulations of lipid bilayers.


title:
Self-consistent van der Waals density functional study of benzene
  adsorption on Si(100)

abstract:
  The adsorption of benzene on the Si(100) surface is studied theoretically
using the self-consistent van der Waals density functional (vdW-DF) method. The
adsorption energies of two competing adsorption structures, butterfly (BF) and
tight-bridge (TB) structures, are calculated with several vdW-DFs at saturation
coverage. Our results show that recently proposed vdW-DFs with high accuracy
all prefer TB to BF, in accord with more accurate calculations based on exact
exchange and correlation within the random phase approximation. Detailed
analyses reveal the important roles played by the molecule-surface interaction
and molecular deformation upon adsorption, and we suggest that their precise
description is prerequisite for accurate prediction of the most stable
adsorption structure of organic molecules on semiconductor surfaces.


title:
Significance Driven Hybrid 8T-6T SRAM for Energy-Efficient Synaptic
  Storage in Artificial Neural Networks

abstract:
  Multilayered artificial neural networks (ANN) have found widespread utility
in classification and recognition applications. The scale and complexity of
such networks together with the inadequacies of general purpose computing
platforms have led to a significant interest in the development of efficient
hardware implementations. In this work, we focus on designing energy efficient
on-chip storage for the synaptic weights. In order to minimize the power
consumption of typical digital CMOS implementations of such large-scale
networks, the digital neurons could be operated reliably at scaled voltages by
reducing the clock frequency. On the contrary, the on-chip synaptic storage
designed using a conventional 6T SRAM is susceptible to bitcell failures at
reduced voltages. However, the intrinsic error resiliency of NNs to small
synaptic weight perturbations enables us to scale the operating voltage of the
6TSRAM. Our analysis on a widely used digit recognition dataset indicates that
the voltage can be scaled by 200mV from the nominal operating voltage (950mV)
for practically no loss (less than 0.5%) in accuracy (22nm predictive
technology). Scaling beyond that causes substantial performance degradation
owing to increased probability of failures in the MSBs of the synaptic weights.
We, therefore propose a significance driven hybrid 8T-6T SRAM, wherein the
sensitive MSBs are stored in 8T bitcells that are robust at scaled voltages due
to decoupled read and write paths. In an effort to further minimize the area
penalty, we present a synaptic-sensitivity driven hybrid memory architecture
consisting of multiple 8T-6T SRAM banks. Our circuit to system-level simulation
framework shows that the proposed synaptic-sensitivity driven architecture
provides a 30.91% reduction in the memory access power with a 10.41% area
overhead, for less than 1% loss in the classification accuracy.


title:
Multiplier-less Artificial Neurons Exploiting Error Resiliency for
  Energy-Efficient Neural Computing

abstract:
  Large-scale artificial neural networks have shown significant promise in
addressing a wide range of classification and recognition applications.
However, their large computational requirements stretch the capabilities of
computing platforms. The fundamental components of these neural networks are
the neurons and its synapses. The core of a digital hardware neuron consists of
multiplier, accumulator and activation function. Multipliers consume most of
the processing energy in the digital neurons, and thereby in the hardware
implementations of artificial neural networks. We propose an approximate
multiplier that utilizes the notion of computation sharing and exploits error
resilience of neural network applications to achieve improved energy
consumption. We also propose Multiplier-less Artificial Neuron (MAN) for even
larger improvement in energy consumption and adapt the training process to
ensure minimal degradation in accuracy. We evaluated the proposed design on 5
recognition applications. The results show, 35% and 60% reduction in energy
consumption, for neuron sizes of 8 bits and 12 bits, respectively, with a
maximum of ~2.83% loss in network accuracy, compared to a conventional neuron
implementation. We also achieve 37% and 62% reduction in area for a neuron size
of 8 bits and 12 bits, respectively, under iso-speed conditions.


title:
Convergence properties of Gibbs samplers for Bayesian probit regression
  with proper priors

abstract:
  The Bayesian probit regression model (Albert and Chib (1993)) is popular and
widely used for binary regression. While the improper flat prior for the
regression coefficients is an appropriate choice in the absence of any prior
information, a proper normal prior is desirable when prior information is
available or in modern high dimensional settings where the number of
coefficients ($p$) is greater than the sample size ($n$). For both choices of
priors, the resulting posterior density is intractable and a Data Dugmentation
(DA) Markov chain is used to generate approximate samples from the posterior
distribution. Establishing geometric ergodicity for this DA Markov chain is
important as it provides theoretical guarantees for constructing standard
errors for Markov chain based estimates of posterior quantities. In this paper,
we first show that in case of proper normal priors, the DA Markov chain is
geometrically ergodic *for all* choices of the design matrix $X$, $n$ and $p$
(unlike the improper prior case, where $n \geq p$ and another condition on $X$
are required for posterior propriety itself). We also derive sufficient
conditions under which the DA Markov chain is trace-class, i.e., the
eigenvalues of the corresponding operator are summable. In particular, this
allows us to conclude that the Haar PX-DA sandwich algorithm (obtained by
inserting an inexpensive extra step in between the two steps of the DA
algorithm) is strictly better than the DA algorithm in an appropriate sense.


title:
Temperature-dependent dielectric function of bulk SrTiO$_3$: Urbach
  tail, band edges, and excitonic effects

abstract:
  We report the temperature-dependent complex dielectric function of pristine
bulk SrTiO$_3$ between 4.2 and 300 K within the energy range of 0.6-6.5 eV
determined by spectroscopic ellipsometry. Fundamental indirect and direct
band-gap energies have been extracted and are discussed with regard to existing
state-of-the-art theoretical calculations. Furthermore, the dielectric function
around the fundamental direct gap is analyzed by considering excitonic states.
The excitonic effects, including the Coulomb enhancement of the continuum, are
characterized using an extension of the Elliott's formula considering both the
real and imaginary parts of the dielectric function. The Urbach tail below the
indirect edge shows an unconventional temperature-dependent behavior correlated
to the microstructural changes near the structural phase transition around 105
K from the low-temperature tetragonal phase to the cubic phase. The
temperature-dependent characterization reveals that the fundamental indirect
edge as well as the Urbach tail are affected conspicuously by the structural
phase transition while the fundamental direct edge is not. Moreover, the
indirect edge follows Varshni's rule only in the cubic phase and the direct
edge exhibits an anomalous linear increase with increasing temperature.


title:
Observation of magnetoelectric effects in a S=1/2 frustrated spin chain
  magnet SrCuTe2O6

abstract:
  The magnetoelectric (ME) effects are investigated in a cubic compound
SrCuTe2O6, in which uniform Cu2+ (S=1/2) spin chains with considerable spin
frustration exhibit a concomitant antiferromagnetic transition and dielectric
constant peak at TN=5.5 K. Pyroelectric Jp(T) and magnetoelectric current
JME(H) measurements in the presence of a bias electric field are used to reveal
that SrCuTe2O6 shows clear variations of Jp(T) across TN at constant magnetic
fields. Furthermore, isothermal measurements of JME(H) also develop clear peaks
at finite magnetic fields, of which traces are consistent with the spin-flop
transitions observed in the magnetization studies. As a result, the anomalies
observed in Jp(T) and JME(H) curves well match with the field-temperature phase
diagram constructed from magnetization and dielectric constant measurements,
demonstrating that SrCuTe2O6 is a new magnetoelectric compound with S=1/2 spin
chains.


title:
Subnatural-linewidth biphotons from a Doppler-broadened hot atomic vapor
  cell

abstract:
  We report the efficient generation of subnatural-linewidth (< 6 MHz, for Rb
D1/D2 lines) biphotons from a Doppler-broadened (530 MHz) hot atomic vapor
cell. We use on-resonance spontaneous four-wave mixing in a hot paraffin-coated
87Rb vapor cell at 63 C to produce time-frequency entangled photon pairs with
controllable bandwidth (1.9 - 3.2 MHz) and coherence time (47 - 94 ns). Our
backward phase-matching scheme with optical pumping is the key to minimize the
generation of uncorrelated photons from resonance fluorescence. The result
paves the way toward miniature narrowband biphoton source based on atomic cells


title: Clifford algebra and the projective model of Hyperbolic spaces

abstract:
  I apply the algebraic framework developed in [1] to study geometry of
hyperbolic spaces in 1, 2, and 3 dimensions. The background material on
projectivised Clifford algebras and their application to Cayley-Klein
geometries is described in [2].


title: Online Tree Caching

abstract:
  We initiate the study of a natural and practically relevant new variant of
online caching where the to-be-cached items can have dependencies. We assume
that the universe is a tree T and items are tree nodes; we require that if a
node v is cached then the whole subtree T(v) rooted at v is cached as well.
This theoretical problem finds an immediate application in the context of
forwarding table optimization in IP routing and software-defined networks.
  We present an elegant online deterministic algorithm TC for this problem, and
rigorously prove that its competitive ratio is O(height(T) *
k_ALG/(k_ALG-k_OPT+1)), where k_ALG and k_OPT denote the cache sizes of an
online and the optimal offline algorithm, respectively. The result is optimal
up to a factor of O(height(T)).


title: Minimal subshifts of arbitrary mean topological dimension

abstract:
  Let $G$ be a countable infinite amenable group and $P$ be a polyhedron. We
give a construction of minimal subshifts of $P^G$ with arbitrarily mean
topological dimension less than $\dim P$.


title: On Equivalence and Uniformisation Problems for Finite Transducers

abstract:
  Transductions are binary relations of finite words. For rational
transductions, i.e., transductions defined by finite transducers, the
inclusion, equivalence and sequential uniformisation problems are known to be
undecidable. In this paper, we investigate stronger variants of inclusion,
equivalence and sequential uniformisation, based on a general notion of
transducer resynchronisation, and show their decidability. We also investigate
the classes of finite-valued rational transductions and deterministic rational
transductions, which are known to have a decidable equivalence problem. We show
that sequential uniformisation is also decidable for them.


title: Pseudo-local Theories: A Functional Class Proposal

abstract:
  In this article, using the language of jet space, we propose a functional
class space for pseudo-local functionals. We test this functional class
proposal in a number of examples ranging from string-field-theory to AdS/CFT
dualities. Implications of the locality proposal at the quartic order are also
discussed.


title:
Opportunistic Jamming for Enhancing Security: Stochastic Geometry
  Modeling and Analysis

abstract:
  This correspondence studies the secrecy communication of the single-input
single-output multi-eavesdropper (SISOME) channel with multiple single-antenna
jammers, where the jammers and eavesdroppers are distributed according to the
independent two-dimensional homogeneous Poisson point process (PPP). For
enhancing the physical layer security, we propose an opportunistic multiple
jammer selection scheme, where the jammers whose channel gains to the
legitimate receiver less than a threshold, are selected to transmit independent
and identically distributed (\emph{i.i.d.}) Gaussian jamming signals to
confound the eavesdroppers. We characterize the secrecy throughput achieved by
our proposed jammer selection scheme, and show that the secrecy throughput is a
quasi-concave function of the selection threshold.


title:
Gene expression noise is affected differentially by feedback in burst
  frequency and burst size

abstract:
  Inside individual cells, expression of genes is stochastic across organisms
ranging from bacterial to human cells. A ubiquitous feature of stochastic
expression is burst-like synthesis of gene products, which drives considerable
intercellular variability in protein levels across an isogenic cell population.
One common mechanism by which cells control such stochasticity is negative
feedback regulation, where a protein inhibits its own synthesis. For a single
gene that is expressed in bursts, negative feedback can affect the burst
frequency or the burst size. In order to compare these feedback types, we study
a piecewise deterministic model for gene expression of a self-regulating gene.
Mathematically tractable steady-state protein distributions are derived and
used to compare the noise suppression abilities of the two feedbacks. Results
show that in the low noise regime, both feedbacks are similar in term of their
noise buffering abilities. Intriguingly, feedback in burst size outperforms the
feedback in burst frequency in the high noise regime. Finally, we discuss
various regulatory strategies by which cells implement feedback to control
burst sizes of expressed proteins at the level of single cells.


title:
Extracting the differential phase in dual atom interferometers by
  modulating magnetic fields

abstract:
  We present a new scheme for measuring the differential phase in dual atom
interferometers. The magnetic field is modulated in one interferometer, and the
differential phase can be extracted without measuring the amplitude of the
magnetic field by combining the ellipse and linear fitting methods. The gravity
gradient measurements are discussed based on dual atom interferometers.
Numerical simulation shows that the systematic error of the differential phase
measurement is largely decreased when the duration of the magnetic field is
symmetrically modulated. This combined fitting scheme has a high accuracy for
measuring an arbitrary differential phase in dual atom interferometers.


title: Bulk quartic vertices from boundary four-point correlators

abstract:
  We present arguments which suggest that the bulk higher-spin gravity duals of
weakly-coupled conformal field theories obey some refined notion of locality.
In particular, we discuss the Mellin amplitude programme in this context. We
focus on the $O(N)$ vector model and minimal higher-spin gravity as a
paradigmatic example of such holographic dual pairs. We restrict ourselves to
three- and four-point functions of scalar primary operators, but the
qualitative conclusions are expected to hold for the generic case.


title: Towards Neural Knowledge DNA

abstract:
  In this paper, we propose the Neural Knowledge DNA, a framework that tailors
the ideas underlying the success of neural networks to the scope of knowledge
representation. Knowledge representation is a fundamental field that dedicate
to representing information about the world in a form that computer systems can
utilize to solve complex tasks. The proposed Neural Knowledge DNA is designed
to support discovering, storing, reusing, improving, and sharing knowledge
among machines and organisation. It is constructed in a similar fashion of how
DNA formed: built up by four essential elements. As the DNA produces
phenotypes, the Neural Knowledge DNA carries information and knowledge via its
four essential elements, namely, Networks, Experiences, States, and Actions.


title:
Solitons in an extended nonlinear Schr\"odinger equation with
  third-order dispersion and pseudo-Raman effect

abstract:
  Dynamics of solitons is considered in an extended nonlinear Schr\"odinger
equation, including a pseudo-stimulated-Raman-scattering (pseudo-SRS) term
(scattering on damping low-frequency waves, third-order dispersion (TOD) and
inhomogeneity of the spatial second-order dispersion (SOD). It is shown that
wave-number downshift by the pseudo-SRS may be compensated by upshift provided
by spatially increasing SOD with taking into account TOD. The equilibrium state
is stable for positive parameter of TOD and unstable for negative one. The
analytical solutions are verified by comparison with numerical results


title:
Geometric pressure in real and complex 1-dimensional dynamics via trees
  of preimages and via spanning sets

abstract:
  We consider $f:\hat I\to \R$ being a $C^3$ (or $C^2$ with bounded distortion)
real-valued multimodal map with non-flat critical points, defined on $\hat I$
being the union of closed intervals, and its restriction to the maximal forward
invariant subset $K\subset I$. We assume that $f|_K$ is topologically
transitive. We call this setting the (generalized multimodal) real case. We
consider also $f:\C\to \C$ a rational map on the Riemann sphere and its
restriction to $K=J(f)$ being Julia set (the complex case). We consider
topological pressure $P_{\spanning}(t)$ for the potential function
$\varphi_t=-t\log |f'|$ for $t>0$ and iteration of $f$ defined in a standard
way using $(n,\e)$-spanning sets. Despite of $\phi_t=\infty$ at critical points
of $f$, this definition makes sense (unlike the standard definition using
$(n,\e)$-separated sets) and we prove that $P_{\spanning}(t)$ is equal to other
pressure quantities, called for this potential {\it geometric pressure}, in the
real case under mild additional assumptions, and in the complex case provided
there is at most one critical point with forward trajectory accumulating in
$J(f)$. $P_{\spanning}(t)$ is proved to be finite for general rational maps,
but it may occur infinite in the real case. We also prove that geometric tree
pressure in the real case is the same for trees rooted at all `safe' points, in
particular at all points except the set of Hausdorff dimension 0.


title:
Graph clustering, variational image segmentation methods and Hough
  transform scale detection for object measurement in images

abstract:
  We consider the problem of scale detection in images where a region of
interest is present together with a measurement tool (e.g. a ruler). For the
segmentation part, we focus on the graph based method by Flenner and Bertozzi
which reinterprets classical continuous Ginzburg-Landau minimisation models in
a totally discrete framework. To overcome the numerical difficulties due to the
large size of the images considered we use matrix completion and splitting
techniques. The scale on the measurement tool is detected via a Hough transform
based algorithm. The method is then applied to some measurement tasks arising
in real-world applications such as zoology, medicine and archaeology.


title:
Superresolution of Noisy Remotely Sensed Images Through Directional
  Representations

abstract:
  We develop an algorithm for single-image superresolution of remotely sensed
data, based on the discrete shearlet transform. The shearlet transform extracts
directional features of signals, and is known to provide near-optimally sparse
representations for a broad class of images. This often leads to superior
performance in edge detection and image representation when compared to
isotropic frames. We justify the use of shearlets mathematically, before
presenting a denoising single-image superresolution algorithm that combines the
shearlet transform with sparse mixing estimators (SME). Our algorithm is
compared with a variety of single-image superresolution methods, including
wavelet SME superresolution. Our numerical results demonstrate competitive
performance in terms of PSNR and SSIM.


title: Box model for channels of human migration

abstract:
  We discuss a mathematical model of migration channel based on the truncated
Waring distribution. The truncated Waring distribution is obtained for a more
general model of motion of substance through a channel containing finite number
of boxes. The model is applied then for case of migrants moving through a
channel consisting of finite number of countries or cities. The number of
migrants in the channel strongly depends on the number of migrants that enter
the channel through the country of entrance. It is shown that if the final
destination country is very popular then large percentage of migrants may
concentrate there.


title: On asymorphisms of groups

abstract:
  Let $G$, $H$ be groups and $\kappa$ be a cardinal. A bijection $f:G\to H$ is
caled on asymorphism if, for any $X\in[G]^{<\kappa}$, $Y\in[H]^{<\kappa}$,
there exist $X'\in[G]^{<\kappa}$, $Y'\in[H]^{<\kappa}$ such that for all $x\in
G$ and $y\in H$, we have $f(Xx)\subseteq Y'f(x)$, $f^{-1}(Yy)\subseteq
X'f^{-1}(y)$. For a set $S$, $[S]^{<\kappa}$ denotes the set $\{S'\subseteq S:
|S'|<\kappa\}$.
  Let $\kappa$ and $\gamma$ be cardinals such that $\aleph_0<\kappa\le\gamma$.
We prove that any two Abelian groups of cardinality $\gamma$ are
$\kappa$-asymorphic, but the free group of rank $\gamma$ is not
$\kappa$-asymorphic to an Abelian group provided that either $\kappa<\gamma$ or
$\kappa=\gamma$ and $\kappa$ is a singular cardinal. It is known [7] that if
$\gamma = \kappa$ and $\kappa$ is regular then any two groups of cardinality
$\kappa$ are $\kappa$-asymorphic.


title:
Hadron shower decomposition in the highly granular CALICE analogue
  hadron calorimeter

abstract:
  The spatial development of hadronic showers in the CALICE scintillator-steel
analogue hadron calorimeter is studied using test beam data collected at CERN
and FNAL for single positive pions and protons with initial momenta in the
range from 10 to 80 GeV/c. Both longitudinal and radial development of hadron
showers are parametrised with two-component functions. The parametrisation is
fit to test beam data and simulations using the QGSP_BERT and FTFP_BERT physics
lists from Geant4 version 9.6. The parameters extracted from data and simulated
samples are compared for the two types of hadrons. The response to pions and
the ratio of the non-electromagnetic to the electromagnetic calorimeter
response, h/e, are estimated using the extrapolation and decomposition of the
longitudinal profiles.


title: On automatic subsets of the Gaussian integers

abstract:
  Suppose that $a$ and $b$ are multiplicatively independent Gaussian integers,
that are both of modulus~$\geq \sqrt 5$. We prove that there exist a $X\subset
\mathbb Z[i]$ which is $a$-automatic but not $b$-automatic. This settles a
problem of Allouche, Cateland, Gilbert, Peitgen, Shallit, and Skordev.


title:
Fractional and Complex Pseudo-Splines and the Construction of Parseval
  Frames

abstract:
  Pseudo-splines of integer order $(m,\ell)$ were introduced by Daubechies,
Han, Ron, and Shen as a family which allows interpolation between the classical
B-splines and the Daubechies' scaling functions. The purpose of this paper is
to generalize the pseudo-splines to fractional and complex orders $(z, \ell)$
with $\alpha:=\re z > 1$. This allows increased flexibility in regard to
smoothness: instead of working with a discrete family of functions from $C^m$,
$m\in \N_0$, one uses a \emph{continuous} family of functions belonging to the
H\"older spaces $C^{\alpha-1}$. The presence of the imaginary part of $z$
allows for direct utilization in complex transform techniques for signal and
image analyses. We also show that in analogue to the integer case, the
generalized pseudo-splines lead to constructions of Parseval wavelet frames via
the unitary extension principle.


title: Content-based Video Indexing and Retrieval Using Corr-LDA

abstract:
  Existing video indexing and retrieval methods on popular web-based multimedia
sharing websites are based on user-provided sparse tagging. This paper proposes
a very specific way of searching for video clips, based on the content of the
video. We present our work on Content-based Video Indexing and Retrieval using
the Correspondence-Latent Dirichlet Allocation (corr-LDA) probabilistic
framework. This is a model that provides for auto-annotation of videos in a
database with textual descriptors, and brings the added benefit of utilizing
the semantic relations between the content of the video and text. We use the
concept-level matching provided by corr-LDA to build correspondences between
text and multimedia, with the objective of retrieving content with increased
accuracy. In our experiments, we employ only the audio components of the
individual recordings and compare our results with an SVM-based approach.


title:
Photometric brown-dwarf classification. II. A homogeneous sample of 1361
  L and T dwarfs brighter than J = 17.5 with accurate spectral types

abstract:
  We present a homogeneous sample of 1361 L and T dwarfs brighter than J = 17.5
(of which 998 are new), from an effective area of 3070 deg2, classified by the
photo-type method to an accuracy of one spectral sub-type using izYJHKW1W2
photometry from SDSS+UKIDSS+WISE. Other than a small bias in the early L types,
the sample is shown to be effectively complete to the magnitude limit, for all
spectral types L0 to T8. The nature of the bias is an incompleteness estimated
at 3% because peculiar blue L dwarfs of type L4 and earlier are classified late
M. There is a corresponding overcompleteness because peculiar red (likely
young) late M dwarfs are classified early L. Contamination of the sample is
confirmed to be small: so far spectroscopy has been obtained for 19 sources in
the catalogue and all are confirmed to be ultracool dwarfs. We provide
coordinates and izYJHKW1W2 photometry of all sources. We identify an apparent
discontinuity, $\Delta$m $\sim$ 0.4 mag., in the Y-K colour between spectral
types L7 and L8. We present near-infrared spectra of nine sources identified by
photo-type as peculiar, including a new low-gravity source ULAS
J005505.68+013436.0, with spectroscopic classification L2{$\gamma$}. We provide
revised izYJHKW1W2 template colours for late M dwarfs, types M7 to M9.


title: Simple inhomogeneous cosmological (toy) models

abstract:
  Based on the Lema\^itre-Tolman-Bondi (LTB) metric we consider two flat
inhomogeneous big-bang models. We aim at clarifying, as far as possible
analytically, basic features of the dynamics of the simplest inhomogeneous
models and to point out the potential usefulness of exact inhomogeneous
solutions as generalizations of the homogeneous configurations of the
cosmological standard model. We discuss explicitly partial successes but also
potential pitfalls of these simplest models. Although primarily seen as toy
models, the relevant free parameters are fixed by best-fit values using the
Joint Light-curve Analysis (JLA)-sample data. On the basis of a likelihood
analysis we find that a local hump with an extension of almost 2 Gpc provides a
better description of the observations than a local void for which we obtain a
best-fit scale of about 30 Mpc. Future redshift-drift measurements are
discussed as a promising tool to discriminate between inhomogeneous
configurations and the $\Lambda$CDM model.


title:
Harish-Chandra invariants and the centre of the reduced enveloping
  algebra

abstract:
  In this article we consider the centre of the reduced enveloping algebra of
the Lie algebra of a reductive algebraic group in very good characteristic p >
2. The Harish-Chandra centre maps to the centre of each reduced enveloping
algebra and, using a combination of induction and deformation arguments, we
describe precisely for which p-characters this map is surjective: it is if and
only if the chosen character is regular. This provides the converse to a
theorem of Mirkovi\'{c} and Rumynin.


title: Spin structures of flat manifolds of diagonal type

abstract:
  For each integer $d$ at least two, we construct non-spin closed oriented flat
manifolds with holonomy group $\mathbb Z_2^d$ and with the property that all of
their finite proper covers have a spin structure. Moreover, all such covers
have trivial Stiefel-Whitney classes.


title: Quantum noise limit for force sensitivity of linear detectors

abstract:
  We prove that the force sensitivity of the conventional optomechanical
detector associated with the optical quadrature measurement of the output beam
is lower bounded by the so-called ultimate quantum limit (UQL), i.e., the
absolute value of the imaginary part of the inverse mechanical susceptibility.
Through the linear response theory, we find that the force sensitivity of any
linear detector is lower bounded by a generalized UQL, which might beat the
usual UQL by properly tailoring the detector-oscillator interaction. We believe
that our results open a new direction for improving the performance of
high-sensitivity detection schemes.


title:
Explicit Forms of Cluster Variables on Double Bruhat Cells G^{u,e} of
  type B

abstract:
  Let $G$ be a simply connected simple algebraic group over $\mathbb{C}$ of
type $B_r$, $B$ and $B_-$ be its two opposite Borel subgroups, and $W$ be the
associated Weyl group. For $u$, $v\in W$, it is known that the coordinate ring
${\mathbb C}[G^{u,v}]$ of the double Bruhat cell $G^{u,v}=BuB\cap B_-vB_-$ is
isomorphic to an upper cluster algebra
$\overline{\mathcal{A}}(\textbf{i})_{{\mathbb C}}$ and the generalized minors
$\Delta(k;\textbf{i})$ are the cluster variables of ${\mathbb
C}[G^{u,v}]$[A.Berenstein, S.Fomin, A.Zelevinsky, Duke Math. J. 126 (2005),
1-52, arxiv:math.RT/0305434]. Recently, it is also shown that ${\mathbb
C}[G^{u,v}]$ have structure of cluster algebra [K. R. Goodearl, M. T. Yakimov,
arxiv:1602.00498 (2016)]. In the case $v=e$, we shall describe the generalized
minor $\Delta(k;\textbf{i})$ explicitly.


title: Refined Schur Method for Robust Pole Assignment with Repeated Poles

abstract:
  Schur-type methods in \cite{Chu2} and \cite{GCQX} solve the robust pole
assignment problem by employing the departure from normality of the closed-loop
system matrix as the measure of robustness. They work well generally when all
poles to be assigned are simple. However, when some poles are close or even
repeated, the eigenvalues of the computed closed-loop system matrix might be
inaccurate. In this paper, we present a refined Schur method, which is able to
deal with the case when some or all of the poles to be assigned are repeated.
More importantly, the refined Schur method can still be applied when
\verb|place| \cite{KNV} and \verb|robpole| \cite{Tits} fail to output a
solution when the multiplicity of some repeated poles is greater than the input
freedom.


title: Quantum billiards with branes on product of Einstein spaces

abstract:
  We consider a gravitational model in dimension D with several forms, l scalar
fields and a Lambda-term. We study cosmological-type block-diagonal metrics
defined on a product of an 1-dimensional interval and n oriented Einstein
spaces. As an electromagnetic composite brane ansatz is adopted and certain
restrictions on the branes are imposed the conformally covariant Wheeler-DeWitt
(WDW) equation for the model is studied. Under certain restrictions, asymptotic
solutions to the WDW equation are found in the limit of the formation of the
billiard walls. These solutions reduce the problem to the so-called quantum
billiard in (n + l - 1)-dimensional hyperbolic space. Several examples of
quantum billiards in the model with electric and magnetic branes, e.g.
corresponding to hyperbolic Kac-Moody algebras, are considered. In the case n=2
we find a set of basis asymptotic solutions to the WDW equation and derive
asymptotic solutions for the metric in the classical case.


title: Maximum-a-posteriori estimation with Bayesian confidence regions

abstract:
  Solutions to inverse problems that are ill-conditioned or ill-posed may have
significant intrinsic uncertainty. Unfortunately, analysing and quantifying
this uncertainty is very challenging, particularly in high-dimensional
problems. As a result, while most modern mathematical imaging methods produce
impressive point estimation results, they are generally unable to quantify the
uncertainty in the solutions delivered. This paper presents a new general
methodology for approximating Bayesian high-posterior-density credibility
regions in inverse problems that are convex and potentially very
high-dimensional. The approximations are derived by using recent concentration
of measure results related to information theory for log-concave random
vectors. A remarkable property of the approximations is that they can be
computed very efficiently, even in large-scale problems, by using standard
convex optimisation techniques. In particular, they are available as a
by-product in problems solved by maximum-a-posteriori estimation. The
approximations also have favourable theoretical properties, namely they
outer-bound the true high-posterior-density credibility regions, and they are
stable with respect to model dimension. The proposed methodology is illustrated
on two high-dimensional imaging inverse problems related to tomographic
reconstruction and sparse deconvolution, where the approximations are used to
perform Bayesian hypothesis tests and explore the uncertainty about the
solutions, and where proximal Markov chain Monte Carlo algorithms are used as
benchmark to compute exact credible regions and measure the approximation
error.


title: A Case for Time Slotted Channel Hopping for ICN in the IoT

abstract:
  Recent proposals to simplify the operation of the IoT include the use of
Information Centric Networking (ICN) paradigms. While this is promising,
several challenges remain. In this paper, our core contributions (a) leverage
ICN communication patterns to dynamically optimize the use of TSCH (Time
Slotted Channel Hopping), a wireless link layer technology increasingly popular
in the IoT, and (b) make IoT-style routing adaptive to names, resources, and
traffic patterns throughout the network--both without cross-layering. Through a
series of experiments on the FIT IoT-LAB interconnecting typical IoT hardware,
we find that our approach is fully robust against wireless interference, and
almost halves the energy consumed for transmission when compared to CSMA. Most
importantly, our adaptive scheduling prevents the time-slotted MAC layer from
sacrificing throughput and delay.


title: On the Waring-Goldbach problem for seventh and higher powers

abstract:
  We apply recent progress on Vinogradov's mean value theorem to improve bounds
for the function $H(k)$ in the Waring-Goldbach problem. We obtain new results
for all exponents $k \ge 7$, and in particular establish that for large $k$ one
has \[H(k)\le (4k-2)\log k-(2\log 2-1)k-3.\]


title: Fourier transforms of polytopes, solid angle sums, and discrete volume

abstract:
  Given a real closed polytope $P$, we first describe the Fourier transform of
its indicator function by using iterations of Stokes' theorem. We then use the
ensuing Fourier transform formulations, together with the Poisson summation
formula, to give a new algorithm to count fractionally-weighted lattice points
inside the one-parameter family of all real dilates of $P$. The combinatorics
of the face poset of $P$ plays a central role in the description of the Fourier
transform of $P$. We also obtain a closed form for the codimension-1
coefficient that appears in an expansion of this sum in powers of the real
dilation parameter $t$. This closed form generalizes some known results about
the Macdonald solid-angle polynomial, which is the analogous expression
traditionally obtained by requiring that $t$ assumes only integer values.
Although most of the present methodology applies to all real polytopes, a
particularly nice application is to the study of all real dilates of integer
(and rational) polytopes.


title: Avalanche-like metamagnetic transition in (LaNd)CaMnO manganites

abstract:
  We investigate the behavior of ultrasharp metamagnetic transitions in
La(5/8-y)Nd(y)Ca(3/8)MnO(3) manganites. These compounds change from a low
temperature ferromagnetic metallic state at low Nd doping to a charge-ordered
antiferromagnetic insulator for high Nd content. At an intermediate doping a
phase-separated state is established. At low temperatures (2 K), we observe an
avalanche-like field-induced metamagnetic transition, when the entire compound
changes abruptly from one phase to the other. We investigate the signatures of
this ultrasharp transition using magnetization and specific heat measurements.
We observe a first order transition in the specific heat associated with
discontinuous jumps in the magnetization. A strong increase of the sample
temperature is simultaneously observed. The results are interpret in terms of
latent heat release from the field induced enhancement of the ferromagnetic
fraction, triggering the avalanche process.


title: Fast Gibbs sampling for high-dimensional Bayesian inversion

abstract:
  Solving ill-posed inverse problems by Bayesian inference has recently
attracted considerable attention. Compared to deterministic approaches, the
probabilistic representation of the solution by the posterior distribution can
be exploited to explore and quantify its uncertainties. In applications where
the inverse solution is subject to further analysis procedures, this can be a
significant advantage. Alongside theoretical progress, various new
computational techniques allow to sample very high dimensional posterior
distributions: In [Lucka2012], a Markov chain Monte Carlo (MCMC) posterior
sampler was developed for linear inverse problems with $\ell_1$-type priors. In
this article, we extend this single component Gibbs-type sampler to a wide
range of priors used in Bayesian inversion, such as general $\ell_p^q$ priors
with additional hard constraints. Besides a fast computation of the
conditional, single component densities in an explicit, parameterized form, a
fast, robust and exact sampling from these one-dimensional densities is key to
obtain an efficient algorithm. We demonstrate that a generalization of slice
sampling can utilize their specific structure for this task and illustrate the
performance of the resulting slice-within-Gibbs samplers by different computed
examples. These new samplers allow us to perform sample-based Bayesian
inference in high-dimensional scenarios with certain priors for the first time,
including the inversion of computed tomography (CT) data with the popular
isotropic total variation (TV) prior.


title:
Coherent transfer of singlet-triplet qubit states in an architecture of
  triple quantum dots

abstract:
  We propose two schemes to coherently transfer arbitrary quantum states of the
two-electron singlet-triplet qubit across a chain of 3 quantum dots. The
schemes are based on electrical control over the detuning energy of the quantum
dots. The first is a pulse-gated scheme, requiring dc pulses and engineering of
inter- and intra-dot Coulomb energies. The second scheme is based on the
adiabatic theorem, requiring time-dependent control of the detuning energy
through avoided crossings at a rate that the system remains in the ground
state. We simulate the transfer fidelity using typical experimental parameters
for silicon quantum dots. Our results give state transfer fidelities between
$94.3\% < \mathcal{F} < 99.5\%$ at sub-ns gate times for the pulse-gated scheme
and between $75.4\% < \mathcal{F} < 99.0 \%$ at tens of ns for the adiabatic
scheme. Taking into account dephasing from charge noise, we obtain state
transfer fidelities between $94.0\% < \mathcal{F} < 99.2\%$ for the pulse-gated
scheme and between $64.9\% < \mathcal{F} < 93.6\%$ for the adiabatic scheme.


title: Coupled magnetic and elastic properties in LaPr(CaSr)MnO manganites

abstract:
  We investigate a series of manganese oxides, the
La0.225Pr0.4(Ca1-xSrx)0.375MnO3 system. The x = 0 sample is a prototype
compound for the study of phase separation in manganites, where ferromagnetic
and charge ordered antiferromagnetic phases coexist. Replacing Ca2+ by Sr2+
gradually turns the system into a homogeneous ferromagnet. Our results show
that the material structure plays a major role in the observed magnetic
properties. On cooling, at temperatures below 100 K, a strong contraction of
the lattice is followed by an increase in the magnetization. This is observed
both through thermal expansion and magnetostriction measurements, providing
distinct evidence of magneto-elastic coupling in these phase separated
compounds.


title: Comparison of the spatial and the angular clustering of X-ray AGN

abstract:
  The angular correlation function is a powerful tool for deriving the
clustering properties of AGN and hence the mass of the corresponding dark
matter halos in which they reside. However, studies based on the application of
the angular correlation function on X-ray samples, yield results apparently
inconsistent with those based on the direct estimation of the spatial
correlation function. The goal of the present paper is to attempt to
investigate this issue by analysing a well defined sample. To this end we use
the hard-band (2-10 keV) X-ray selected sources of the Chandra AEGIS fields,
chosen because of the availability of accurately derived flux sensitivity maps.
In particular we use the 186 hard-band sources with spectroscopic redshifts in
the range z=0.3-1.3, a range selected in order to contain the bulk of the AGN
while minimizing the contribution of unknown clustering and luminosity
evolution from very high redshifts. Using the projected spatial
auto-correlation function, we derive a clustering comoving length of 5.4+-1.0
Mpc (for gamma=1.8), consistent with results in the literature. We further
derive the angular correlation function and the corresponding spatial
clustering length using the Limber's inversion equation and a novel
parametrization of the clustering evolution model that also takes into account
the bias evolution of the host dark matter halo. The Limber's inverted spatial
comoving clustering length of 5.5+-1.2 Mpc at a median redshift of z~0.75,
matches the directly measured one, from the spatial correlation function
analysis, but for a significant non-linear contribution to the growing mode of
perturbations, estimated independently from literature results of x_0 at
different redshifts. Therefore, using this sample of X-ray AGN and our
clustering evolution parametrization we have found an excellent consistency
between the angular and spatial clustering analysis.


title: Anti-dark matter: a hidden face of mirror world

abstract:
  B and L violating interactions of ordinary particles with their twin
particles from hypothetical mirror world can co-generate baryon asymmetries in
both worlds in comparable amounts, $\Omega'_B/\Omega_B \sim 5$ or so. On the
other hand, the same interactions induce the oscillation phenomena between the
neutral particles of two sectors which convert e.g. mirror neutrons into our
antineutrons. These oscillations are environment dependent and can have
fascinating physical consequences.

categories: astro-ph.CO astro-ph.GA astro-ph.HE hep-ph


title:
Atom assisted cavity cooling of a micromechanical oscillator in the
  unresolved sideband regime

abstract:
  The ground state cooling of a mechanical oscillator in an optomechanical
cavity containing an ensemble of identical two-level ground-state atoms is
studied in the highly unresolved-sideband regime. The system exhibits
electromagnetically-induced transparency-like quantum interference effect. The
mutual interaction with the cavity optical field gives rise to an indirect
coupling between the atomic and mechanical modes. In presence of this
interaction, the noise spectrum gets modified and leads to asymmetric cooling
and heating rates. Using the quantum master equation, time evolution of the
average phonon number is studied and it is observed that the average phonon
occupancy in the mechanical resonator exhibits ground-state cooling.


title:
Enhanced terahertz transmission through a periodic array of tapered
  rectangular apertures

abstract:
  We numerically analyse extraordinary terahertz transmission properties of an
array of rectangular shaped apertures perforated periodically on a thin metal
film. The apertures are tapered at different angles to achieve higher field
concentration at the tapered end. The periodic sub-wavelength scale apertures
ensure plasmonic behaviour giving rise to the enhanced transmission of a
specific frequency mode decided by the periodicity. We compare results of
transmission with the rectangular shaped apertures of same parameters and
observe a significant increase in the transmission for the tapered case. We
have compared results of our numerical simulations with theory and have found
them consistent.


title:
A stabilized finite element method for the two-field and three-field
  Stokes eigenvalue problems

abstract:
  In this paper, the stabilized finite element approximation of the Stokes
eigenvalue problems is considered for both the two-field
(displacement-pressure) and the three-field (stress-displacement-pressure)
formulations. The method presented is based on a subgrid scale concept, and
depends on the approximation of the unresolvable scales of the continuous
solution. In general, subgrid scale techniques consist in the addition of a
residual based term to the basic Galerkin formulation. The application of a
standard residual based stabilization method to a linear eigenvalue problem
leads to a quadratic eigenvalue problem in discrete form which is physically
inconvenient. As a distinguished feature of the present study, we take the
space of the unresolved subscales orthogonal to the finite element space, which
promises a remedy to the above mentioned complication. In essence, we put
forward that only if the orthogonal projection is used, the residual is
simplified and the use of term by term stabilization is allowed. Thus, we do
not need to put the whole residual in the formulation, and the linear
eigenproblem form is recovered properly. We prove that the method applied is
convergent, and present the error estimates for the eigenvalues and the
eigenfunctions. We report several numerical tests in order to illustrate that
the theoretical results are validated.


title: Measurement back-action in stacked graphene quantum dots

abstract:
  We present an electronic transport experiment in graphene where both
classical and quantum mechanical charge detector back-action on a quantum dot
are investigated. The device consists of two stacked graphene quantum dots
separated by a thin layer of boron nitride. This device is fabricated by van
der Waals stacking and is equipped with separate source and drain contacts to
both dots. By applying a finite bias to one quantum dot, a current is induced
in the other unbiased dot. We present an explanation of the observed
measurement-induced current based on strong capacitive coupling and energy
dependent tunneling barriers, breaking the spatial symmetry in the unbiased
system. This is a special feature of graphene-based quantum devices. The
experimental observation of transport in classically forbidden regimes is
understood by considering higher order quantum mechanical back-action
mechanisms.


title: Full reconstruction of a 14-qubit state within four hours

abstract:
  Full quantum state tomography (FQST) plays a unique role in the estimation of
the state of a quantum system without \emph{a priori} knowledge or assumptions.
Unfortunately, since FQST requires informationally (over)complete measurements,
both the number of measurement bases and the computational complexity of data
processing suffer an exponential growth with the size of the quantum system. A
14-qubit entangled state has already been experimentally prepared in an ion
trap, and the data processing capability for FQST of a 14-qubit state seems to
be far away from practical applications. In this paper, the computational
capability of FQST is pushed forward to reconstruct a 14-qubit state with a run
time of only 3.35 hours using the linear regression estimation (LRE) algorithm,
even when informationally overcomplete Pauli measurements are employed. The
computational complexity of the LRE algorithm is first reduced from
$O(10^{19})$ to $O(10^{15})$ for a 14-qubit state, by dropping all the zero
elements, and its computational efficiency is further sped up by fully
exploiting the parallelism of the LRE algorithm with parallel Graphic
Processing Unit (GPU) programming. Our result can play an important role in
quantum information technologies with large quantum systems.


title: Solar wind magnetic turbulence: Inferences from spectral shape

abstract:
  Some differences between theoretical, numerical and observational
determinations of spectral slopes of solar wind turbulence are interpreted in
the thermodynamical sense. Confirmations of turbulent Kolmogorov slopes in
solar wind magnetic turbulence and magnetohydrodynamic simulations exhibit tiny
differences. These are used to infer about entropy generation in the turbulent
cascade and to infer about the anomalous turbulent collision frequency in the
dissipative range as well as the average energy input in solar wind turbulence.
Anomalous turbulent collision frequencies are obtained of the order of v < 200
Hz. The corresponding stationary solar wind magnetic energy input into magnetic
turbulence in the Kolmogorov inertial range is obtained to be of the order of
50 eV/s. Its thermal fate is discussed.


title: Exotic Brane Junctions from F-theory

abstract:
  Applying string dualities to F-theory, we obtain various $[p,q]$-branes whose
constituents are standard branes of codimension two and exotic branes. We
construct junctions of the exotic five-branes and their Hanany-Witten
transitions associated with those in F-theory. In this procedure, we understand
the monodromy of the single $5^2_2$-brane. We also find the objects which are
sensitive to the branch cut of the $5^2_2$-brane. Considering the web of branes
in the presence of multiple exotic five-branes analogous to the web of
five-branes with multiple seven-branes, we obtain novel brane constructions for
$SU(2)$ gauge theories with $n$ flavors and their superconformal limit with
enhanced $E_{n+1}$ symmetry in five, four, and three dimensions. Hence,
adapting the techniques of the seven-branes to the exotic branes, we will be
able to construct F-theories in diverse dimensions.


title:
Disappearance of stretch-induced wrinkles of thin sheets: a study of
  orthotropic films

abstract:
  A recent paper (Healey et al., J. Nonlin. Sci., 2013, 23:777-805.) predicted
the disappearance of the stretch-induced wrinkled pattern of thin, clamped,
elastic sheets by numerical simulation of the F\"oppl-von K\'arm\'an equations
extended to the finite in-plane strain regime. It has also been revealed that
for some aspect ratios of the rectangular domain wrinkles do not occur at all
regardless of the applied extension. To verify these predictions we carried out
experiments on thin 20 micrometer thick adhesive covered), previously
prestressed elastomer sheets with different aspect ratios under displacement
controlled pull tests. On one hand the the adjustment of the material
properties during prestressing is highly advantageous as in targeted strain
regime the film becomes substantially linearly elastic (which is far not the
case without prestress). On the other hand a significant, non-ignorable
orthotropy develops during this first extension. To enable quantitative
comparisons we abandoned the assumption about material isotropy inherent in the
original model and derived the governing equations for an orthotropic medium.
In this way we found good agreement between numerical simulations and
experimental data.
  Analysis of the negativity of the second Piola-Kirchhoff stress tensor
revealed that the critical stretch for a bifurcation point at which the
wrinkles disappear must be finite for any aspect ratio. On the contrary there
is no such a bound for the aspect ratio as a bifurcation parameter. Physically
this manifests as complicated wrinkled patterns with more than one highly
wrinkled zones on the surface in case of elongated rectangles. These
arrangements have been found both numerically and experimentally. These
findings also support the new, finite strain model, since the F\"oppl-von
K\'arm\'an equations based on infinitesimal strains do not exhibit such a
behavior.


title: An Approximation Problem in Multiplicatively Invariant Spaces

abstract:
  Let $\mathcal{H}$ be Hilbert space and $(\Omega,\mu)$ a $\sigma$-finite
measure space. Multiplicatively invariant (MI) spaces are closed subspaces of $
L^2(\Omega, \mathcal{H})$ that are invariant under point-wise multiplication by
functions in a fix subset of $L^{\infty}(\Omega).$ Given a finite set of data
$\mathcal{F}\subseteq L^2(\Omega, \mathcal{H}),$ in this paper we prove the
existence and construct an MI space $M$ that best fits $\mathcal{F}$, in the
least squares sense. MI spaces are related to shift invariant (SI) spaces via a
fiberization map, which allows us to solve an approximation problem for SI
spaces in the context of locally compact abelian groups. On the other hand, we
introduce the notion of decomposable MI spaces (MI spaces that can be
decomposed into an orthogonal sum of MI subspaces) and solve the approximation
problem for the class of these spaces. Since SI spaces having extra invariance
are in one-to-one relation to decomposable MI spaces, we also solve our
approximation problem for this class of SI spaces. Finally we prove that
translation invariant spaces are in correspondence with totally decomposable MI
spaces.


title:
A New Robust Frequency Domain Echo Canceller With Closed-Loop Learning
  Rate Adaptation

abstract:
  One of the main difficulties in echo cancellation is the fact that the
learning rate needs to vary according to conditions such as double-talk and
echo path change. Several methods have been proposed to vary the learning. In
this paper we propose a new closed-loop method where the learning rate is
proportional to a misalignment parameter, which is in turn estimated based on a
gradient adaptive approach. The method is presented in the context of a
multidelay block frequency domain (MDF) echo canceller. We demonstrate that the
proposed algorithm outperforms current popular double-talk detection techniques
by up to 6 dB.


title: Scalable Bayesian Rule Lists

abstract:
  We present an algorithm for building probabilistic rule lists that is two
orders of magnitude faster than previous work. Rule list algorithms are
competitors for decision tree algorithms. They are associative classifiers, in
that they are built from pre-mined association rules. They have a logical
structure that is a sequence of IF-THEN rules, identical to a decision list or
one-sided decision tree. Instead of using greedy splitting and pruning like
decision tree algorithms, we fully optimize over rule lists, striking a
practical balance between accuracy, interpretability, and computational speed.
The algorithm presented here uses a mixture of theoretical bounds (tight enough
to have practical implications as a screening or bounding procedure),
computational reuse, and highly tuned language libraries to achieve
computational efficiency. Currently, for many practical problems, this method
achieves better accuracy and sparsity than decision trees; further, in many
cases, the computational time is practical and often less than that of decision
trees. The result is a probabilistic classifier (which estimates P(y = 1|x) for
each x) that optimizes the posterior of a Bayesian hierarchical model over rule
lists.


title: Conformal dimension on boundary of right-angled hyperbolic buildings

abstract:
  In this note, we use some combinatorial modulus on the boundary of a
right-angled hyperbolic building to control its conformal dimension. The lower
bound obtained is optimal in the case of Fuchsian buildings.


title:
Volume constrained minimizers of the fractional perimeter with a
  potential energy

abstract:
  We consider volume-constrained minimizers of the fractional perimeter with
the addition of a potential energy in the form of a volume inte- gral. Such
minimizers are solutions of the prescribed fractional curvature problem. We
prove existence and regularity of minimizers under suitable assumptions on the
potential energy, which cover the periodic case. In the small volume regime we
show that minimizers are close to balls, with a quantitative estimate.


title:
CLT for linear eigenvalue statistics for a tensor product version of
  sample covariance matrices

abstract:
  For $k,m,n\in \mathbb{N}$, we consider $n^k\times n^k$ random matrices of the
form $$ \mathcal{M}_{n,m,k}(\mathbf{y})=\sum_{\alpha=1}^m\tau_\alpha
{Y_\alpha}Y_\alpha^T,\quad
Y_\alpha=\mathbf{y}_\alpha^{(1)}\otimes...\otimes\mathbf{y}_\alpha^{(k)}, $$
where $\tau _{\alpha }$, $\alpha\in[m]$, are real numbers and
$\mathbf{y}_\alpha^{(j)}$, $\alpha\in[m]$, $j\in[k]$, are i.i.d. copies of a
normalized isotropic random vector $\mathbf{y}\in \mathbb{R}^n$. For every
fixed $k\ge 1$, if the Normalized Counting Measures of $\{\tau _{\alpha
}\}_{\alpha}$ converge weakly as $m,n\rightarrow \infty$, $m/n^k\rightarrow
c\in \lbrack 0,\infty )$ and $\mathbf{y}$ is a good vector in the sense of
Definition 1.1, then the Normalized Counting Measures of eigenvalues of
$\mathcal{M}_{n,m,k}(\mathbf{y})$ converge weakly in probability to a
non-random limit found in [15]. For $k=2$, we define a subclass of good vectors
$\mathbf{y}$ for which the centered linear eigenvalue statistics
$n^{-1/2}\text{Tr} \,\varphi(\mathcal{M}_{n,m,2}(\mathbf{y}))^\circ$ converge
in distribution to a Gaussian random variable, i.e., the Central Limit Theorem
is valid.


title: A Super-Resolution Framework for Tensor Decomposition

abstract:
  This work considers a super-resolution framework for overcomplete tensor
decomposition. Specifically, we view tensor decomposition as a super-resolution
problem of recovering a sum of Dirac measures on the sphere and solve it by
minimizing a continuous analog of the $\ell_1$ norm on the space of measures.
The optimal value of this optimization defines the tensor nuclear norm. Similar
to the separation condition in the super-resolution problem, by explicitly
constructing a dual certificate, we develop incoherence conditions of the
tensor factors so that they form the unique optimal solution of the continuous
analog of $\ell_1$ norm minimization. Remarkably, the derived incoherence
conditions are satisfied with high probability by random tensor factors
uniformly distributed on the sphere, implying global identifiability of random
tensor factors.


title: Compressive Sampling Based UWB TOA Estimator

abstract:
  This paper proposes two compressive sampling based time of arrival (TOA)
estimation algorithms using a sub-Nyquist rate receiver. We also describe a
novel compressive sampling dictionary design for the compact representation of
the received UWB signal. One of the proposed algorithm exploits the a-priori
information with regard to the channel and range of the target. The performance
of the algorithms are compared against the maximum likelihood (ML) based
receiver using IEEE 802.15.4a CM1 line of sight (LOS) UWB channel model. The
proposed algorithm yields performance similar to the ML TOA estimation at high
SNRs. However, the computational complexity and the sampling rate requirements
are lesser compared to the ML estimator. Simulation results show that the
proposed algorithms can match ML estimator performance with only 1/4-th the
sampling rate at 25 dB SNR. We analyze the performance of the algorithm with
respect to practical constraints like size of the holographic dictionary and
sampling rates. We also propose a new algorithm which can exploit the a-priori
information regarding the UWB channel and the geographical constraints on the
target that may be available at the receiver. This algorithm can substantially
boost the performance compared to the algorithm without a-priori information at
low SNRs.


title:
Pressure-driven Superconductivity in Transition-metal Pentatelluride
  HfTe5

abstract:
  Layered transition-metal tellurides have attracted considerable attention
because of their rich physics; for example, tungsten ditelluride WTe2 exhibits
extremely large magnetoresistance; the tritelluride ZrTe3 shows a charge
density wave transition at low temperature; and the pentatelluride ZrTe5
displays an enigmatic resistivity anomaly and large thermoelectric power.
Recently some transition-metal tellurides are predicted to be quantum spin Hall
insulators (e.g. ZrTe5 and HfTe5) or Weyl semimetals (e.g. WTe2 and MoTe2) and
were subjected to intensive investigations. Here, we report on the discovery of
superconductivity in hafnium pentatelluride HfTe5 under high pressure. We
observe two structural phase transitions and metallization with
superconductivity developing at around 5 GPa. A maximal critical temperature of
4.8 K is attained at a pressure of 20 GPa, and superconductivity persists up to
the maximum pressure in our study (42 GPa). Theoretical calculations indicate
that the superconductivity develops mainly in the Te atom layers at medium
pressure and in the Te atom chains at high pressure.


title:
Blow-up solutions for $L^2$-supercritical gKdV equations with exactly
  $k$ blow-up points

abstract:
  In this paper we consider the slightly $L^2$-supercritical gKdV equations
$\partial_t u+(u_{xx}+u|u|^{p-1})_x=0$, with the nonlinearity
$5<p<5+\varepsilon$ and $0<\varepsilon\ll 1$ . In the previous work of the
author we know that there exists an stable self-similar blow-up dynamics for
slightly $L^2$-supercritical gKdV equations. Such solution can be viewed as
solutions with single blow-up point. In this paper we will prove the existence
of solutions with multiple blow-up points, and give a description of the
formation of the singularity near the blow-up time.


title: Riccati equations and optimal control of well-posed linear systems

abstract:
  We generalize the classical theory on algebraic Riccati equations and
optimization to infinite-dimensional well-posed linear systems, thus completing
the work of George Weiss, Olof Staffans and others. We show that the optimal
control is given by the stabilizing solution of an integral Riccati equation.
If the input operator is not maximally unbounded, then this integral Riccati
equation is equivalent to the algebraic Riccati equation.
  Using the integral Riccati equation, we show that for (nonsingular)
minimization problems the optimal state-feedback loop is always well-posed. In
particular, the optimal state-feedback operator is admissible also for the
original semigroup, not only for the closed-loop semigroup (as has been known
in some cases); moreover, both settings are well-posed with respect to an
external input. This leads to the positive solution of several central,
previously open questions on exponential, output and dynamic (aka. "internal")
stabilization and on coprime factorization of transfer functions.
  Our theory covers all quadratic (possibly indefinite) cost functions, but the
optimal state feedback need not be well-posed (admissible) unless the cost
function is uniformly positive or the system is sufficiently regular.


abstract:
  Adaptive Horizon Model Predictive Control (AHMPC) is a scheme for varying as
needed the horizon length of Model Predictive Control (MPC). Its goal is to
achieve stabilization with horizons as small as possible so that MPC can be
used on faster or more complicated dynamic processes. Beside the standard
requirements of MPC including a terminal cost that is a control Lyapunov
function, AHMPC requires a terminal feedback that turns the control Lyapunov
function into a standard Lyapunov function in some domain around the operating
point. But this domain need not be known explicitly. MPC does not compute
off-line the optimal cost and the optimal feedback over a large domain instead
it computes these quantities on-line when and where they are needed. AHMPC does
not compute off-line the domain on which the terminal cost is a control
Lyapunov function instead it computes on-line when a state is in this domain.


title: On the Hardness of SAT with Community Structure

abstract:
  Recent attempts to explain the effectiveness of Boolean satisfiability (SAT)
solvers based on conflict-driven clause learning (CDCL) on large industrial
benchmarks have focused on the concept of community structure. Specifically,
industrial benchmarks have been empirically found to have good community
structure, and experiments seem to show a correlation between such structure
and the efficiency of CDCL. However, in this paper we establish hardness
results suggesting that community structure is not sufficient to explain the
success of CDCL in practice. First, we formally characterize a property shared
by a wide class of metrics capturing community structure, including
"modularity". Next, we show that the SAT instances with good community
structure according to any metric with this property are still NP-hard.
Finally, we study a class of random instances generated from the
"pseudo-industrial" community attachment model of Gir\'aldez-Cru and Levy. We
prove that, with high probability, instances from this model that have
relatively few communities but are still highly modular require exponentially
long resolution proofs and so are hard for CDCL. We also present experimental
evidence that our result continues to hold for instances with many more
communities. This indicates that actual industrial instances easily solved by
CDCL may have some other relevant structure not captured by the community
attachment model.


title:
Self-referenced characterization of space-time couplings in near
  single-cycle laser pulses

abstract:
  We report on the characterization of space-time couplings in high energy
sub-2-cycle 770nm laser pulses using a self-referencing single-shot method.
Using spatially-encoded arrangement filter-based spectral phase interferometry
for direct electric field reconstruction (SEA-F-SPIDER) we characterize
few-cycle pulses with a wave-front rotation of 2.8x?10^11 rev/sec (1.38 mrad
per half-cycle) and pulses with pulse front tilts ranging from to -0.33 fs/um
to -3.03 fs/um.


title: Kaluza-Klein gluons at 100 TeV: NLO corrections

abstract:
  We explore the reach of a 100 TeV proton collider to discover KK gluons in a
warped extra dimension. These particles are templates for color adjoint vectors
that couple dominantly to the top quark. We examine their production rate at
NLO in the six-flavor m-ACOT scheme for a variety of reference models defining
their coupling to quarks, largely inspired by the RS model of a warped extra
dimension. In agreement with previous calculations aimed at lower energy
machines, we find that the NLO corrections are typically negative, resulting in
a $K$-factor of around 0.7 (depending on the model) and with a residual scale
dependence on the order of $\pm 20\%$, greater than the variation from the
scale exhibited by the na\"{i}ve LO estimate.


title: On the dimension of the locus of determinantal hypersurfaces

abstract:
  The characteristic polynomial of an $r$-tuple $(A_1,..., A_r)$ of $n \times
n$ matrices is the determinant $\det(x_0 I + x_1 A_1 + ... + x_r A_r)$. We show
that if $r$ is at least 3 and $A = (A_1,..., A_r)$ is an $r$-tuple of matrices
in general position, then up to conjugacy there are only finitely many
$r$-tuples of matrices with the same characteristic polynomial as $A$.
Equivalently, the locus of determinantal hypersurfaces of degree $n$ in $P^r$
is irreducible of dimension $(r-1)n^2 + 1$.


title: Central spectral gaps of the almost Mathieu operator

abstract:
  We consider the spectrum of the almost Mathieu operator $H_\alpha$ with
frequency $\alpha$ and in the case of the critical coupling. Let an irrational
$\alpha$ be such that $|\alpha-p_n/q_n|<c q_n^{-\varkappa}$, where $p_n/q_n$,
$n=1,2,\dots$ are the convergents to $\alpha$, and $c$, $\varkappa$ are
positive absolute constants, $\varkappa<56$. Assuming certain conditions on the
parity of the coefficients of the continued fraction of $\alpha$, we show that
the central gaps of $H_{p_n/q_n}$, $n=1,2,\dots$, are inherited as spectral
gaps of $H_\alpha$ of length at least $c'q_n^{-\varkappa/2}$, $c'>0$.


title: Associated Primes and Syzygies of Linked Modules

abstract:
  Motivated by the notion of geometrically linked ideals, we show that over a
Gorenstein local ring $R$, if a Cohen-Macaulay $R$-module $M$ of grade $g$ is
linked to an $R$-module $N$ by a Gorenstein ideal $c$, such that $Ass_R(M)\cap
Ass_R(N)=\emptyset$, then $M\otimes_RN$ is isomorphic to direct sum of copies
of $R/a$, where $a$ is a Gorenstein ideal of $R$ of grade $g+1$. We give a
criterion for the depth of a local ring $(R,m,k)$ in terms of the homological
dimensions of the modules linked to the syzygies of the residue field $k$. As a
result we characterize a local ring $(R,m,k)$ in terms of the homological
dimensions of the modules linked to the syzygies of $k$.


title:
Jacobi Polynomials, Bernstein-type Inequalities and Dispersion Estimates
  for the Discrete Laguerre Operator

abstract:
  The present paper is about Bernstein-type estimates for Jacobi polynomials
and their applications to various branches in mathematics. This is an old topic
but we want to add a new wrinkle by establishing some intriguing connections
with dispersive estimates for a certain class of Schr\"odinger equations whose
Hamiltonian is given by the generalized Laguerre operator. More precisely, we
show that dispersive estimates for the Schr\"odinger equation associated with
the generalized Laguerre operator are connected with Bernstein-type
inequalities for Jacobi polynomials. We use known uniform estimates for Jacobi
polynomials to establish some new dispersive estimates. In turn, the optimal
dispersive decay estimates lead to new Bernstein-type inequalities.


title: What is an ideal a zero-class of?

abstract:
  We characterise, in pointed regular categories, the ideals as the
zero-classes of surjective relations. Moreover, we study a variation of the
"Smith is Huq" condition: two surjective left split relations commute as soon
as their zero-classes commute.


title: The Colored Jones Polynomial of Singular Knots

abstract:
  We generalize the colored Jones polynomial to $4$-valent graphs. This
generalization is given as a sequence of invariants in which the first term is
a one variable specialization of the Kauffman-Vogel polynomial. We use the
invariant we construct to give a sequence of singular braid group
representations.


title:
Localization of Simultaneous Moving Sound Sources for Mobile Robot Using
  a Frequency-Domain Steered Beamformer Approach

abstract:
  Mobile robots in real-life settings would benefit from being able to localize
sound sources. Such a capability can nicely complement vision to help localize
a person or an interesting event in the environment, and also to provide
enhanced processing for other capabilities such as speech recognition. In this
paper we present a robust sound source localization method in three-dimensional
space using an array of 8 microphones. The method is based on a
frequency-domain implementation of a steered beamformer along with a
probabilistic post-processor. Results show that a mobile robot can localize in
real time multiple moving sources of different types over a range of 5 meters
with a response time of 200 ms.


title:
Efficiency at maximum power of thermochemical engines with
  near-independent particles

abstract:
  Two-reservoir thermochemical engines are established in by using
near-independent particles (including Maxwell-Boltzmann, Fermi-Dirac, and
Bose-Einstein particles) as the working substance. Particle and heat fluxes can
be formed based on the temperature and chemical potential gradients between two
different reservoirs. A rectangular-type energy filter with width $\Gamma$ is
introduced for each engine to weaken the coupling between the particle and heat
fluxes. The efficiency at maximum power of each particle system decreases
monotonously from an upper bound $\eta^+$ to a lower bound $\eta^-$ when
$\Gamma$ increases from 0 to $\infty$. It is found that the $\eta^+$ values for
all three systems are bounded by $\eta_{\mathrm{C}}/2 \leq \eta^+ \leq
\eta_{\mathrm{C}}/(2-\eta_{\mathrm{C}})$ due to strong coupling, where
$\eta_{\mathrm{C}}$ is the Carnot efficiency. For the Bose-Einstein system, it
is found that the upper bound is approximated by the Curzon-Ahlborn efficiency:
$\eta_{\mathrm{CA}}=1-\sqrt{1-\eta _{\mathrm{C}}}$. When
$\Gamma\rightarrow\infty$, the intrinsic maximum powers are proportional to the
square of the temperature difference of two reservoirs for all three systems,
and the corresponding lower bounds of efficiency at maximum power can be
simplified in the same form of
$\eta^{-}=\eta_{\mathrm{C}}/[1+a_0(2-\eta_{\mathrm{C}})]$.


title: The Second Neighborhood Conjecture for Oriented Graphs Missing Combs

abstract:
  Seymour's Second Neighborhood Conjecture asserts that every oriented graph
has a vertex whose first out-neighborhood is at most as large as its second
out-neighborhood. Combs are the graphs having no induced $C_4$,
$\overline{C_4}$, $C_5$, chair or $\overline{chair}$. We characterize combs
using dependency digraphs. We characterize the graphs having no induced $C_4$,
$\overline{C_4}$, chair or $\overline{chair}$ using dependency digraphs. Then
we prove that every oriented graph missing a comb satisfies this conjecture. We
then deduce that every oriented comb and every oriented threshold graph
satisfies Seymour's conjecture.


title: Dynamics of the Zeraoulia-Sprott map revisited

abstract:
  In the paper "Some Open Problems in Chaos Theory and Dynamics" by Zeraoulia
and Sprott, the two-dimensional map (x,y) -> (-ax(1+y^2)^{-1}, x+by) was
considered and the problem of analytical study of the boundedness of its
attractors was formulated. In the present paper, the boundedness of its
attractors is studied, the corresponding analytical estimation of absorbing set
is obtained, and thus an answer to the problem is given.


title:
Perceptually-Motivated Nonlinear Channel Decorrelation For Stereo
  Acoustic Echo Cancellation

abstract:
  Acoustic echo cancellation with stereo signals is generally an
under-determined problem because of the high coherence between the left and
right channels. In this paper, we present a novel method of significantly
reducing inter-channel coherence without affecting the audio quality. Our work
takes into account psychoacoustic masking and binaural auditory cues. The
proposed non-linear processing combines a shaped comb-allpass (SCAL) filter
with the injection of psychoacoustically masked noise. We show that the
proposed method performs significantly better than other known methods for
reducing inter-channel coherence.


title: Replication of Li-Yorke Chaos Near a Homoclinic Orbit

abstract:
  We prove the presence of chaos near a homoclinic orbit in the modified
Li-Yorke sense [10] by implementing chaotic perturbations. A Duffing oscillator
is considered to show the effectiveness of our technique, and simulations that
support the theoretical results are depicted. Ott-Grebogi-Yorke and Pyragas
control methods are used to stabilize almost periodic motions.


title: Embedding Right-Angled Artin Groups into Brin-Thompson Groups

abstract:
  We prove that every finitely-generated right-angled Artin group can be
embedded into some Brin-Thompson group $nV$. It follows that many other groups
can be embedded into some $nV$ (e.g., any finite extension of any of Haglund
and Wise's special groups), and that various decision problems involving
subgroups of $nV$ are unsolvable.


title: Computing ultra-precise eigenvalues of the Laplacian within polygons

abstract:
  The main difficulty in solving the Helmholtz equation within polygons is due
to non-analytic vertices. By using a method nearly identical to that used by
Fox, Henrici, and Moler in their 1967 paper; it is demonstrated that such
eigenvalue calculations can be extended to unprecedented precision, very often
to well over a hundred digits, and sometimes to over a thousand digits.
  A curious observation is that as one increases the number of terms in the
eigenfunction expansion, the approximate eigenvalue may be made to alternate
above and below the exact eigenvalue. This alternation provides a new method to
bound eigenvalues, by inspection.
  Symmetry must be exploited to simplify the geometry, reduce the number of
non-analytic vertices and disentangle degeneracies. The symmetry-reduced
polygons considered here have at most one non-analytic vertex from which all
edges can be seen. Dirichlet, Neumann, and periodic-type edge conditions, are
independently imposed on each polygon edge.
  The full shapes include the regular polygons and some with re-entrant angles
(cut-square, L-shape, 5-point star). Thousand-digit results are obtained for
the lowest Dirichlet eigenvalue of the L-shape, and regular pentagon and
hexagon.


title:
Bounded Geometry and Characterization of Some Transcendental Entire and
  Meromorphic Maps

abstract:
  We define two classes of topological infinite degree covering maps modeled on
two families of transcendental holomorphic maps. The first, which we call
exponential maps of type $(p,q)$, are branched covers and is modeled on
transcendental entire maps of the form $P e^{Q}$, where $P$ and $Q$ are
polynomials of degrees $p$ and $q$. The second is the class of universal
covering maps from the plane to the sphere with two removed points modeled on
transcendental meromorphic maps with two asymptotic values. The problem we
address is to give a combinatorial characterization of the holomorphic maps
contained in these classes whose post-singular sets are finite. The main
results in this paper are that a post-singularly finite topological exponential
map of type $(0,1)$ or a certain post-singularly finite topological exponential
map of type $(p,1)$ or a post-singularly finite universal covering map from the
plane to the sphere with two points removed is combinatorially equivalent to a
holomorphic same type map if and only if this map has bounded geometry.


title: S-folds and 4d N=3 superconformal field theories

abstract:
  S-folds are generalizations of orientifolds in type IIB string theory, such
that the geometric identifications are accompanied by non-trivial S-duality
transformations. They were recently used by Garcia-Etxebarria and Regalado to
provide the first construction of four dimensional N=3 superconformal theories.
In this note, we classify the different variants of these N=3 preserving
S-folds, distinguished by an analog of discrete torsion, using both a direct
analysis of the different torsion classes and the compactification of the
S-folds to three dimensional M-theory backgrounds. Upon adding D3-branes, these
variants lead to different classes of N=3 superconformal field theories. We
also analyze the holographic duals of these theories, and in particular clarify
the role of discrete gauge and global symmetries in holography.


title:
Taylor's modularity conjecture and related problems for idempotent
  varieties

abstract:
  We provide a partial result on Taylor's modularity conjecture, and several
related problems. Namely, we show that the interpretability join of two
idempotent varieties that are not congruence modular is not congruence modular
either, and we prove an analogue for idempotent varieties with a cube term.
Also, similar results are proved for linear varieties and the properties of
congruence modularity, having a cube term, congruence $n$-permutability for a
fixed $n$, and satisfying a non-trivial congruence identity.


title:
Nonlinear separate spin evolution in degenerate electron-positron-ion
  plasmas

abstract:
  The non-linear evolution of spin-electron acoustic, positron-acoustic, and
spin-electron-positron acoustic waves is considered. It is demonstrated that
weakly nonlinear dynamics of each wave leads to the soliton formation.
Altogether, we report on existence of three different solitons. The
spin-electron acoustic soliton known for electron-ion plasmas is described for
electron-positron-ion plasmas for the first time. The existence of the
spin-electron-positron acoustic soliton is reported for the first time. The
positron-acoustic soliton and the spin-electron-positron acoustic soliton arise
as the areas of a positive electric potential. The spin-electron acoustic
soliton behaves as the area of a negative electric potential at the relatively
small positron imbalance $n_{0p}/n_{0e}=0.1$ and as the area of a positive
electric potential at the relatively large positron imbalance
$n_{0p}/n_{0e}=0.5$.


title: No Evidence for [O III] Variability in Mrk 142

abstract:
  Using archival data from the 2008 Lick AGN Monitoring Project, Zhang & Feng
(2016) claimed to find evidence for flux variations in the narrow [O III]
emission of the Seyfert 1 galaxy Mrk 142 over a two-month time span. If
correct, this would imply a surprisingly compact size for the narrow-line
region. We show that the claimed [O III] variations are merely the result of
random errors in the overall flux calibration of the spectra. The data do not
provide any support for the hypothesis that the [O III] flux was variable
during the 2008 monitoring period.


title: Mass and decay constant of the newly observed exotic $X(5568)$ state

abstract:
  The mass and decay constant of the $X(5568)$ state newly observed by D0
Collaboration are computed within the two-point sum rule method using the
diquark-antidiquark interpolating current. In calculations, the vacuum
condensates up to eight dimensions are taken into account. The obtained result
for the mass of the $X(5568)$ state is in a nice agreement with the
experimental data.


title: On assessing the accuracy of defect free energy computations

abstract:
  We develop a rigorous error analysis for coarse-graining of defect-formation
free energy. For a one-dimensional constrained atomistic system, we establish
the thermodynamic limit of the defect-formation free energy and obtain
explicitly the rate of convergence. We then construct a sequence of
coarse-grained energies with the same rate but significantly reduced
computational cost. We illustrate our analytical results through explicit
computations for the case of harmonic potentials and through numerical
simulations.


title:
Relationship Between the Uncompensated Price-Elasticity and the
  Income-Elasticity of Demand Under Conditions of Additive Preferences

abstract:
  Income- and price-elasticity of demand quantify the responsiveness of markets
to changes in income, and in prices, respectively. Under the assumptions of
utility maximization and preference-independence (additive preferences),
mathematical relationships between income-elasticity values and uncompensated
own and cross price-elasticity of demand are here derived for bundle of goods,
using the differential approach to demand analysis. Key parameters are: the
elasticity of the marginal utility of income, and the average budget-share. The
proposed method can be applied to forecast the direct and indirect impact of
price changes, and of financial instruments of policy using available estimates
of the income elasticity of demand.


title: Quantum Lock-in Force Sensing using Optical Clock Doppler Velocimetry

abstract:
  Force sensors are at the heart of different technologies such as atomic force
microscopy or inertial sensing \cite{RMPforce2003, Rugar2004, YazdiIEEE}. These
sensors often rely on the measurement of the displacement amplitude of
mechanical oscillators under applied force. Examples for such mechanical
oscillators include micro-fabricated cantilevers \cite{YazdiIEEE}, carbon
nanotubes \cite{NanotubeForce} as well as single trapped ions \cite{Bollinger,
Udem} . The best sensitivity is typically achieved when the force is
alternating at the mechanical resonance frequency of the oscillator thus
increasing its response by the mechanical quality factor. The measurement of
low-frequency forces, that are below resonance, is a more difficult task as the
resulting oscillation amplitudes are significantly lower. Here we use a single
trapped $^{88}Sr^{+}$ ion as a force sensor. The ion is trapped in a linear
harmonic trap, and is electrically driven at a frequency much lower than the
trap resonance frequency. To be able to measure the small amplitude of motion
we combine two powerful techniques. The force magnitude is determined by the
measured periodic Doppler shift of an atomic optical clock transition and the
Quantum Lock-in technique is used to coherently accumulate the phases acquired
during different force half-cycles. We demonstrate force detection both when
the oscillating force is phase-synchronized with the quantum lock-in sequence
and when it is asynchronous and report frequency force detection sensitivity as
low as $5.3\times10^{-19}\frac{\mathrm{N}}{\sqrt{\mathrm{Hz}}}$ .


title: The Ambiguity of Simplicity

abstract:
  A system's apparent simplicity depends on whether it is represented
classically or quantally. This is not so surprising, as classical and quantum
physics are descriptive frameworks built on different assumptions that capture,
emphasize, and express different properties and mechanisms. What is surprising
is that, as we demonstrate, simplicity is ambiguous: the relative simplicity
between two systems can change sign when moving between classical and quantum
descriptions. Thus, notions of absolute physical simplicity---minimal structure
or memory---at best form a partial, not a total, order. This suggests that
appeals to principles of physical simplicity, via Ockham's Razor or to the
"elegance" of competing theories, may be fundamentally subjective, perhaps even
beyond the purview of physics itself. It also raises challenging questions in
model selection between classical and quantum descriptions. Fortunately,
experiments are now beginning to probe measures of simplicity, creating the
potential to directly test for ambiguity.

categories: quant-ph cond-mat.stat-mech cs.IT math.IT