title: Aspects of TMD evolution of azimuthal asymmetries

abstract:
  In this contribution TMD evolution of azimuthal asymmetries, in particular of
the Sivers and double Collins asymmetries, is addressed. A comparison of the
scale dependence is made between asymmetries described with TMD factorization
at low transverse momentum and those described with collinear factorization at
high transverse momentum. Finally, the advantages of Bessel weighting are
discussed: convergence of transverse momentum integrals, suppression of large
transverse momentum contributions, and well-defined lattice QCD evaluations of
Bessel-weighted TMDs including proper gauge links.


title:
Compressive Sampling for the Packet Loss Recovery in Audio Multimedia
  Streaming

abstract:
  The aim of this paper is to introduce a new schema, based on a Compressive
Sampling technique, for the recovery of lost data in multimedia streaming. The
audio streaming data are encapsuled in different packets by using an
interleaving technique. The Compressive Sampling technique is used to recover
audio information in case of lost packets. Experimental results are presented
on speech and musical audio signals to illustrate the performances and the
capabilities of the proposed methodology.


title: Non-self-adjoint graphs

abstract:
  On finite metric graphs we consider Laplace operators, subject to various
classes of non-self-adjoint boundary conditions imposed at graph vertices. We
investigate spectral properties, existence of a Riesz basis of projectors and
similarity transforms to self-adjoint Laplacians. Among other things, we
describe a simple way how to relate the similarity transforms between
Laplacians on certain graphs with elementary similarity transforms between
matrices defining the boundary conditions.


title:
Group classification and exact solutions of variable-coefficient
  generalized Burgers equations with linear damping

abstract:
  Admissible point transformations between Burgers equations with linear
damping and time-dependent coefficients are described and used in order to
exhaustively classify Lie symmetries of these equations. Optimal systems of
one- and two-dimensional subalgebras of the Lie invariance algebras obtained
are constructed. The corresponding Lie reductions to ODEs and to algebraic
equations are carried out. Exact solutions to particular equations are found.
Some generalized Burgers equations are linearized to the heat equation by
composing equivalence transformations with the Hopf-Cole transformation.


title: Floquet Weyl Semimetal Induced by Off-Resonant Light

abstract:
  We propose that a Floquet Weyl semimetal state can be induced in
three-dimensional topological insulators, either nonmagnetic or magnetic, by
the application of off-resonant light. The virtual photon processes play a
critical role in renormalizing the Dirac mass and so resulting in a topological
semimetal with vanishing gap at Weyl points. The present mechanism via
off-resonant light is quite different from that via on-resonant light, the
latter being recently suggested to give rise to a Floquet topological state in
ordinary band insulators.


title: LOFAR imaging capabilities and system sensitivity

abstract:
  This document describes the general astronomical capabilities of the LOw
Frequency ARray (LOFAR). The frequency range covered by LOFAR is split into two
bands denoted as low band (LB, 10 - 80 MHz) and high band (HB, 120 - 240 MHz).
LOFAR stations are spread over a 100 km sized region in the northern part of
the Netherlands. In addition to the Dutch stations there will be European
stations providing baselines between 200 km and 1000 km. Most of the results in
this document, however, are limited to the Dutch array. In section 2 the LBA
and HBA station configurations are reviewed. Section 3 reviews the imaging
capabilities as station Full Width Half Maximum, station Field of View, and
array resolution. In section 4 the system sensitivity is considered and thermal
noise levels in LOFAR images are given. Finally, in section 5 some cautionary
notes are collected. We advise you to read these notes carefully before using
the numbers that are presented in this report.


title:
Multirate Digital Signal Processing via Sampled-Data H-infinity
  Optimization

abstract:
  In this thesis, we present a new method for designing multirate signal
processing and digital communication systems via sampled-data H-infinity
control theory. The difference between our method and conventional ones is in
the signal spaces. Conventional designs are executed in the discrete-time
domain, while our design takes account of both the discrete-time and the
continuous-time signals. Namely, our method can take account of the
characteristic of the original analog signal and the influence of the A/D and
D/A conversion. While the conventional method often indicates that an ideal
digital low-pass filter is preferred, we show that the optimal solution need
not be an ideal low-pass when the original analog signal is not completely
band-limited. This fact can not be recognized only in the discrete-time domain.
Moreover, we consider quantization effects. We discuss the stability and the
performance of quantized sampled-data control systems. We justify H-infinity
control to reduce distortion caused by the quantizer. Then we apply it to
differential pulse code modulation. While the conventional Delta modulator is
not optimal and besides not stable, our modulator is stable and optimal with
respect to the H-infinity-norm. We also give an LMI (Linear Matrix Inequality)
solution to the optimal H-infinity approximation of IIR (Infinite Impulse
Response) filters via FIR (Finite Impulse Response) filters. A comparison with
the Nehari shuffle is made with a numerical example, and it is observed that
the LMI solution generally performs better. Another numerical study also
indicates that there is a trade-off between the pass-band and stop-band
approximation characteristics.


title:
Biased and greedy random walks on two-dimensional lattices with quenched
  randomness: the "greedy" ant within a disordered environment

abstract:
  The principle characteristics of biased greedy random walks (BGRWs) on
two-dimensional lattices with real-valued quenched disorder on the lattice
edges are studied. Here, the disorder allows for negative edge-weights. In
previous studies, considering the negative-weight percolation (NWP) problem,
this was shown to change the universality class of the existing, static
percolation transition. In the presented study, four different types of BGRWs
and an algorithm based on the ant colony optimization (ACO) heuristic were
considered. Regarding the BGRWs, the precise configurations of the lattice
walks constructed during the numerical simulations were influenced by two
parameters: a disorder parameter rho that controls the amount of negative edge
weights on the lattice and a bias strength B that governs the drift of the
walkers along a certain lattice direction. Here, the pivotal observable is the
probability that, after termination, a lattice walk exhibits a total negative
weight, which is here considered as percolating. The behavior of this
observable as function of rho for different bias strengths B is put under
scrutiny. Upon tuning rho, the probability to find such a feasible lattice walk
increases from zero to one. This is the key feature of the percolation
transition in the NWP model. Here, we address the question how well the
transition point rho_c, resulting from numerically exact and "static"
simulations in terms of the NWP model can be resolved using simple dynamic
algorithms that have only local information available, one of the basic
questions in the physics of glassy systems.


title:
Generation of tightly compressed solitons with a tunable frequency shift
  in Raman-free fibers

abstract:
  Optimization of the compression of input N-solitons into robust ultra-narrow
fundamental solitons, with a tunable up- or downshifted frequency, is proposed
in photonic crystal fibers (PCF) free of the Raman effect. Due to the absence
of the Raman self-frequency shift, these fundamental solitons continue
propagation maintaining the acquired frequency, once separated from the input
N-soliton's temporal slot. A universal optimal value of the relative strength
of the third-order-dispersion (TOD) is found, providing the strongest
compression of the fundamental soliton, is found. It depends only the order of
the injected N-soliton. The largest compression degree significantly exceeds
the analytical prediction supplied by the Satsuma-Yajima (SY) formula. The
mechanism behind this effect, which remains valid in the presence of the
self-steepening, is explained.


title:
The nature of LINER galaxies: Ubiquitous hot old stars and rare
  accreting black holes

abstract:
  Galaxies, which often contain ionised gas, sometimes also exhibit a so-called
low-ionisation nuclear emission line region (LINER). For 30 years this was
attributed to a central mass-accreting supermassive black hole (AGN) of low
luminosity, making LINER galaxies the largest AGN-sub-population, dominating in
numbers over higher luminosity Seyfert galaxies and quasars. This, however,
poses a serious problem. While the inferred energy balance is plausible, many
LINERs clearly do not contain any other independent signatures of an AGN. Using
integral field spectroscopic data from the CALIFA survey, we aim at comparing
the observed radial surface brightness profiles with what is expected from
illumination by an AGN. Essential for this analysis is a proper extraction of
emission-lines, especially weak lines such as the Balmer Hb line which is
superposed on an absorption trough. To accomplish this, we use the GANDALF code
which simultaneously fits the underlying stellar continuum and emission lines.
We show for 48 galaxies with LINER-like emission, that the radial emission-line
surface brightness profiles are inconsistent with ionisation by a central
point-source and hence cannot be due to an AGN alone. The most probable
explanation for the excess LINER-like emission is ionisation by evolved stars
during the short but very hot and energetic phase known as post-AGB. This leads
us to an entirely new interpretation. Post-AGB stars are ubiquitous and their
ionising effect should be potentially observable in every galaxy with gas
present and stars older than ~1 Gyr, unless a stronger radiation field from
young hot stars or an AGN outshines them. This means that galaxies with
LINER-like emission are in fact not a class defined by a property, but rather
by the absence of a property. It also explains why LINER emission is observed
mostly in massive galaxies with old stars and little star formation.


title: Measurement: still a problem in standard quantum theory

abstract:
  It is argued that recent claims by A. Hobson that standard quantum theory has
no measurement problem cannot be sustained. Moreover, it is pointed out that
taking the reduced density operator of a component system as an epistemic
(ignorance-based) mixture has long been known to be untenable based on direct
proof.


title: Adaptive matching pursuit for off-grid compressed sensing

abstract:
  Compressive sensing (CS) can effectively recover a signal when it is sparse
in some discrete atoms. However, in some applications, signals are sparse in a
continuous parameter space, e.g., frequency space, rather than discrete atoms.
Usually, we divide the continuous parameter into finite discrete grid points
and build a dictionary from these grid points. However, the actual targets may
not exactly lie on the grid points no matter how densely the parameter is
grided, which introduces mismatch between the predefined dictionary and the
actual one. In this article, a novel method, namely adaptive matching pursuit
with constrained total least squares (AMP-CTLS), is proposed to find actual
atoms even if they are not included in the initial dictionary. In AMP-CTLS, the
grid and the dictionary are adaptively updated to better agree with
measurements. The convergence of the algorithm is discussed, and numerical
experiments demonstrate the advantages of AMP-CTLS.


title:
Chaotic Characteristic of Discrete-time Linear Inclusion Dynamical
  Systems

abstract: In this paper, we study the fiber-chaos of switched linear dynamical systems.


title: Efficient estimation of eigenvalue counts in an interval

abstract:
  Estimating the number of eigenvalues located in a given interval of a large
sparse Hermitian matrix is an important problem in certain applications and it
is a prerequisite of eigensolvers based on a divide-and-conquer paradigm. Often
an exact count is not necessary and methods based on stochastic estimates can
be utilized to yield rough approximations. This paper examines a number of
techniques tailored to this specific task. It reviews standard approaches and
explores new ones based on polynomial and rational approximation filtering
combined with a stochastic procedure.


title:
Semiparametric Conditional Quantile Models for Financial Returns and
  Realized Volatility

abstract:
  This paper investigates how the conditional quantiles of future returns and
volatility of financial assets vary with various measures of ex-post variation
in asset prices as well as option-implied volatility. We work in the flexible
quantile regression framework and rely on recently developed model-free
measures of integrated variance, upside and downside semivariance, and jump
variation. Our results for the S&P 500 and WTI Crude Oil futures contracts show
that simple linear quantile regressions for returns and heterogenous quantile
autoregressions for realized volatility perform very well in capturing the
dynamics of the respective conditional distributions, both in absolute terms as
well as relative to a couple of well-established benchmark models. The models
can therefore serve as useful risk management tools for investors trading the
futures contracts themselves or various derivative contracts written on
realized volatility.


title:
Dynamic-Symmetry-Breaking Breathing and Spreading Transitions in
  Ferromagnetic Film Irradiated by Spherical Electromagnetic Wave

abstract:
  The dynamical responses of a ferromagnetic film to a propagating spherical
electromagnetic wave passing through it are studied by Monte Carlo simulation
of two dimensional Ising ferromagnet. For a fixed set of values of the
frequency and wavelength of the spherical EM wave, and depending on the values
of amplitude of the EM wave and temperature of the system, three different
modes are identified. The static pinned mode, the localised dynamical breathing
mode and extended dynamical spreading mode are observed. The nonequilibrium
dynamical-symmetry-breaking breathing and spreading phase transitions are also
observed and the transition temperatures are obtained as functions of the
amplitude of the magnetic field of EM wave. A comprehensive phase diagram is
drawn. The boundaries of breathing and spreading transitions merge eventually
at the equilibrium transition temperature for two dimensional Ising ferromagnet
as the value of the amplitude of the magnetic field becomes vanishingly small.


title:
Topological Kirchhoff Law and Bulk-Edge Correspondence for Valley-Chern
  and Spin-Valley-Chern Numbers

abstract:
  The valley-Chern and spin-valley-Chern numbers are the key concepts in
valleytronics. They are topological numbers in the Dirac theory but not in the
tight-binding model. We analyze the bulk-edge correspondence between the two
phases which have the same Chern and spin-Chern numbers but different
valley-Chern and spin-valley-Chern numbers. The edge state between them is
topologically trivial in the tight-binding model but is shown to be as robust
as the topological edge. We construct Y-junctions made of topological edges.
They satisfy the topological Kirchhoff law, where the topological charges are
conserved at the junction. We may interpret a Y-junction as a scattering
process of particles which have four topological numbers. It would be a
milestone of future topological electronics.


title: Laplace-Runge-Lenz vector for arbitrary spin

abstract:
  A countable set of superintegrable quantum mechanical systems is presented
which admit the dynamical symmetry with respect to algebra so(4). This algebra
is generated by the Laplace-Runge-Lenz vector generalized to the case of
arbitrary spin. The presented systems describe neutral particles with
non-trivial multipole momenta. Their spectra can be found algebraically like in
the case of Hydrogen atom. Solutions for the systems with spins 1/2 and 1 are
presented explicitly, solutions for spin 3/2 are expressed via solutions of an
ordinary differential equation of first order..


title: Birkhoff-von-Neumann Switches with Deflection-Compensated Mechanism

abstract:
  Despite the high throughput and low complexity achieved by input scheduling
based on Birkhoff-von-Neumann (BvN) decomposition; the performance of the BvN
switch becomes less predictable when the input traffic is bursty. In this
paper, we propose a deflection-compensated BvN (D-BvN) switch architecture to
enhance the quasi-static scheduling based on BvN decomposition. The D-BvN
switches provide capacity guarantee for virtual circuits (VCs) and deflect
bursty traffic when overflow occurs. The deflection scheme is devised to offset
the excessive buffer requirement of each VC when input traffic is bursty. The
design of our conditional deflection mechanism is based on the fact that it is
unlikely that the traffic input to VCs is all bursty at the same time; most
likely some starving VCs have spare capacities when some other VCs are in the
overflow state. The proposed algorithm makes full use of the spare capacities
of those starving VCs to deflect the overflow traffic to other inputs and
provide bandwidth for the deflected traffic to re-access the desired VC. Our
analysis and simulation show that this deflection-compensated mechanism can
support BvN switches to achieve close to 100% throughput of offered load even
with bursty input traffic, and reduces the average end-to-end delay and delay
jitter. Also, our result indicates that the packet out-of-sequence probability
due to deflection of overflow traffic is negligible, thus only a small
re-sequencing buffer is needed at each output port.


title: Microlensing towards the SMC: a new analysis of OGLE and EROS results

abstract:
  We present a new analysis of the results of the EROS-2, OGLE-II, and OGLE-III
microlensing campaigns towards the Small Magellanic Cloud (SMC). Through a
statistical analysis we address the issue of the \emph{nature} of the reported
microlensing candidate events, whether to be attributed to lenses belonging to
known population (the SMC luminous components or the Milky Way disc, to which
we broadly refer to as "self lensing") or to the would be population of dark
matter compact halo objects (MACHOs). To this purpose, we present profiles of
the optical depth and, comparing to the observed quantities, we carry out
analyses of the events position and duration. Finally, we evaluate and study
the microlensing rate. Overall, we consider five reported microlensing events
towards the SMC (one by EROS and four by OGLE). The analysis shows that in
terms of number of events the expected self lensing signal may indeed explain
the observed rate. However, the characteristics of the events, spatial
distribution and duration (and for one event, the projected velocity) rather
suggest a non-self lensing origin for a few of them. In particular we evaluate,
through a likelihood analysis, the resulting upper limit for the halo mass
fraction in form of MACHOs given the expected self-lensing and MACHO lensing
signal. At 95% CL, the tighter upper limit, about 10%, is found for MACHO mass
of $10^{-2} \mathrm{M}_\odot$, upper limit that reduces to above 20% for $0.5
\mathrm{M}_\odot$ MACHOs.


title:
The VLTI/MIDI survey of massive young stellar objects - Sounding the
  inner regions around intermediate- and high-mass young stars using
  mid-infrared interferometry

abstract:
  We aim to characterize the distribution and composition of circumstellar
material around young massive stars, and to investigate exactly which physical
structures in these objects are probed by long-baseline mid-infrared
interferometric observations. We used the two-telescope interferometric
instrument MIDI of the Very Large Telescope Interferometer of the European
Southern Observatory to observe a sample of 24 intermediate- and high-mass
young stellar objects in the N band (8-13 micron). We had successful fringe
detections for 20 objects, and present spectrally-resolved correlated fluxes
and visibility levels for projected baselines of up to 128 m. We fit the
visibilities with geometric models to derive the sizes of the emitting regions,
as well as the orientation and elongation of the circumstellar material.
Fourteen objects in the sample show the 10 micron silicate feature in
absorption in the total and correlated flux spectra. For 13 of these objects,
we were able to fit the correlated flux spectra with a simple absorption model,
allowing us to constrain the composition and absorptive properties of the
circumstellar material. Nearly all of the massive young stellar objects
observed show significant deviations from spherical symmetry at mid-infrared
wavelengths. In general, the mid-infrared emission can trace both disks and
outflows, and in many cases it may be difficult to disentangle these components
on the basis of interferometric data alone, because of the sparse spatial
frequency coverage normally provided by current long-baseline interferometers.
For the majority of the objects in this sample, the absorption occurs on
spatial scales larger than those probed by MIDI. Finally, the physical extent
of the mid-infrared emission around these sources is correlated with the total
luminosity, albeit with significant scatter.


title: Entanglement-assisted zero-error source-channel coding

abstract:
  We study the use of quantum entanglement in the zero-error source-channel
coding problem. Here, Alice and Bob are connected by a noisy classical one-way
channel, and are given correlated inputs from a random source. Their goal is
for Bob to learn Alice's input while using the channel as little as possible.
In the zero-error regime, the optimal rates of source codes and channel codes
are given by graph parameters known as the Witsenhausen rate and Shannon
capacity, respectively. The Lov\'asz theta number, a graph parameter defined by
a semidefinite program, gives the best efficiently-computable upper bound on
the Shannon capacity and it also upper bounds its entanglement-assisted
counterpart. At the same time it was recently shown that the Shannon capacity
can be increased if Alice and Bob may use entanglement.
  Here we partially extend these results to the source-coding problem and to
the more general source-channel coding problem. We prove a lower bound on the
rate of entanglement-assisted source-codes in terms Szegedy's number (a
strengthening of the theta number). This result implies that the theta number
lower bounds the entangled variant of the Witsenhausen rate. We also show that
entanglement can allow for an unbounded improvement of the asymptotic rate of
both classical source codes and classical source-channel codes. Our separation
results use low-degree polynomials due to Barrington, Beigel and Rudich,
Hadamard matrices due to Xia and Liu and a new application of remote state
preparation.


title:
Global Spectral Energy Distributions of the Large Magellanic Cloud with
  Interstellar Dust

abstract:
  The effects of dust on infrared emission vary among galaxies of different
morphological types. We investigated integrated spectral energy distributions
in infrared and submillimeter emissions from the Large Magellanic Cloud based
on the observations using the Herschel Space Observatory and near- to
mid-infrared observations from the Spitzer Space Telescope. We also used IRAS
and WMAP observations to constrain the SEDs. We explain the observations by
using dust models with different grain size distributions in the interstellar
medium of the LMC, noting that the LMC has undergone processes that are
different from those in the Milky Way. We determined a spectral index and a
normalization factor in the range of -3.5 to -3.45 with grain radii in the
range of 1 nm-300 nm for the silicate grain and 2 nm-1 um for the graphite
grain. The best fit to the observed SED was obtained with a spectral index of
-3.47. The grain size distribution is described using a power law but with a
break that is introduced below a_b, where a larger exponent is used. Changing
graphite grain size distribution significantly changed the SED pattern within
the observational uncertainties. Based on the SED fits to the observations from
submillimeter wavelengths to the infrared radiation in the LMC using GRASIL
(Silva et al. 1998), we obtained a reasonable set of parameter values in
chemical and geometric space together with the grain size distributions of a
modified MRN model with the LMC extinction curve.


title:
Almost critical local well-posedness for the space-time Monopole
  equation in Lorenz gauge

abstract:
  Recently, Candy and Bournaveas proved local well-posedness of the space-time
monopole equation in Lorenz gauge for initial data in $H^s $ with $s>\frac14$.
The equation is $L^2$-critical, and hence a $\frac14$ derivative gap is left
between their result and the scaling prediction. In this paper, we consider
initial data in the Fourier-Lebesgue space $\hat{H_p^s}$ for $1<p\le 2$ which
coincides with $H^s$ when $p=2$ but scales like lower regularity Sobolev spaces
for $1<p< 2$. In particular, we will see that as $p\rightarrow 1^+$, the
critical exponent $s^c_p\rightarrow 1^-$, in which case $\hat{\dot
H_{1+}^{1-}}$ is the critical space. We shall prove almost optimal local
well-posedness to the space-time monopole equation in Lorenz gauge with initial
data in the aforementioned spaces that correspond to $p$ close to 1.


title:
Schottky Collector Bipolar Transistor without Impurity Doped Emitter and
  Base: Design and Performance

abstract:
  In this paper, we report an alternative approach of implementing a Schottky
collector bipolar transistor without doping the ultrathin SOI film. Using
different metal work function electrodes, the electrons and holes are induced
in an intrinsic silicon film to create the n emitter and the p base regions,
respectively. Using two-dimensional device simulation, the performance of the
proposed device has been evaluated. Our results demonstrate that the charge
plasma based bipolar transistor with Schottky collector exhibits a high current
gain and a better cut-off frequency compared to its conventional counterpart.


title: On the chromatic number of random regular graphs

abstract:
  Let G(n,d) be the random d-regular graph on n vertices. For any integer k
exceeding a certain constant k_0 we identify a number d_{k-col} such that
G(n,d) is k-colorable w.h.p. if d<d_{k-col} and non-k-colorable w.h.p. if
d>d_{k-col}.


title:
Efficient hierarchical analysis of the stability of a network through
  dimensional reduction of its influence topology

abstract:
  The connection between network topology and stability remains unclear.
General approaches that clarify this relationship and allow for more efficient
stability analysis would be desirable. Inspired by chemical reaction networks,
I demonstrate the utility of expressing the governing equations of arbitrary
first-order dynamical systems (interaction networks) in terms of sums of real
functions (generalized reactions) multiplied by real scalars (generalized
stoichiometries). Specifically, I examine the mathematical notion of influence
topology, which is based on the reaction stoichiometries and the first
derivatives of the reactions with respect to each species at the steady state
solution(s). It is naturally represented as a signed directed bipartite graph
with arrows or blunt arrows connecting a species node to a reaction node
(positive/negative derivative) or a reaction node to a species node
(positive/negative stoichiometry). The set of all such graphs is denumerable. A
significant reduction in dimensionality is possible through stoichiometric
scaling, cycle compaction, and temporal scaling. All cycles in a network can be
read directly from the graph of its influence topology, enabling efficient and
intuitive computation of the principal minors (sums of products of
non-overlapping bipartite cycles) and the Hurwitz determinants (sums of
products of either the principal minors or the bipartite cycles) for testing
steady state stability. The stability of a given network is shown to have a
hierarchical dependence first on its influence topology and then, more
specifically, on algebraic conditions (exact functional form of the reactions).
The utility of this hierarchical approach to bifurcation analysis is
demonstrated on classical networks from control theory, biology, chemistry,
physics, and electronics.

categories: nlin.CD math-ph math.MP physics.bio-ph physics.chem-ph


title:
Effect of the Wood-Saxon nuclear distribution on the chiral magnetic
  field in Relativistic Heavy-ion Collisions

abstract:
  The formation of the QCD vacuum with nonzero winding number $Q_w$ during
relativistic heavy-ion collisions breaks the parity and charge-parity symmetry.
A new kind of field configuration can separate charge in the presence of a
background magnetic field-the "chiral magnetic effect". The strong magnetic
field and the QCD vacuum can both completely be produced in the noncentral
nuclear-nuclear collision. Basing on the theory of Kharzeev,Mclerran and
Warringa, we use the Wood-Saxon nucleon distribution to replace that of the
uniform distribution to improve the magnetic field calculation method of the
noncentral collision. The chiral magnetic field distribution at LHC(Large
Hadron Collider) energy regions are predicted. We also consider the
contributions to the magnetic field of the total charge given by the produced
quarks.


title: Twisted Automorphisms of Right Loops

abstract:
  In this paper we make an attempt to study right loops $(S, o)$ in which, for
each $y\in S$, the map $\sigma_y$ from the inner mapping group $G_S$ of $(S,
o)$ to itself given by $\sigma_y (h)(x) o\ h(y)= h(xoy)$, $x\in S, h\in G_S$ is
a homomorphism. The concept of twisted automorphisms of a right loop and also
the concept of twisted right gyrogroup appears naturally and it turns out that
the study is almost equivalent to the study of twisted automorphisms and a
twisted right gyrogroup. A representation theorem for twisted right gyrogroup
is established. We also study relationship between twisted gyrotransversals and
twisted subgroups (a concept which arose as a tool to study computational
complexity involving class NP).


title: Morphing Planar Graphs Drawings Efficiently

abstract:
  A morph between two straight-line planar drawings of the same graph is a
continuous transformation from the first to the second drawing such that
planarity is preserved at all times. Each step of the morph moves each vertex
at constant speed along a straight line. Although the existence of a morph
between any two drawings was established several decades ago, only recently it
has been proved that a polynomial number of steps suffices to morph any two
planar straight-line drawings. Namely, at SODA 2013, Alamdari et al.[1] proved
that any two planar straight-line drawings of a planar graph can be morphed in
O(n^4) steps, while O(n^2) steps suffice if we restrict to maximal planar
graphs.
  In this paper, we improve upon such results, by showing an algorithm to morph
any two planar straight-line drawings of a planar graph in O(n^2) steps;
further, we show that a morph with O(n) steps exists between any two planar
straight-line drawings of a series-parallel graph.


title: Regularized Reconstruction of a Surface from its Measured Gradient Field

abstract:
  This paper presents several new algorithms for the regularized reconstruction
of a surface from its measured gradient field. By taking a matrix-algebraic
approach, we establish general framework for the regularized reconstruction
problem based on the Sylvester Matrix Equation. Specifically, Spectral
Regularization via Generalized Fourier Series (e.g., Discrete Cosine Functions,
Gram Polynomials, Haar Functions, etc.), Tikhonov Regularization, Constrained
Regularization by imposing boundary conditions, and regularization via Weighted
Least Squares can all be solved expediently in the context of the Sylvester
Equation framework. State-of-the-art solutions to this problem are based on
sparse matrix methods, which are no better than $\mathcal{O}!(n^6)$ algorithms
for an $m\times n$ surface. In contrast, the newly proposed methods are based
on the global least squares cost function and are all $\mathcal{O}!(n^3)$
algorithms. In fact, the new algorithms have the same computational complexity
as an SVD of the same size. The new algorithms are several orders of magnitude
faster than the state-of-the-art; we therefore present, for the first time,
Monte-Carlo simulations demonstrating the statistical behaviour of the
algorithms when subject to various forms of noise. We establish methods that
yield the lower bound of their respective cost functions, and therefore
represent the "Gold-Standard" benchmark solutions for the various forms of
noise. The new methods are the first algorithms for regularized reconstruction
on the order of megapixels, which is essential to methods such as Photometric
Stereo.


title: Asymmetric Gaussian harmonic steering in second harmonic generation

abstract:
  Intracavity second harmonic generation is one of the simplest of the quantum
optical processes and is well within the expertise of most optical
laboratories. It is well understood and characterised, both theoretically and
experimentally. We show that it can be a source of continuous variable
asymmetric Gaussian harmonic steering with fields which have a coherent
excitation, hence combining the important effects of harmonic entanglement and
asymmetric steering in one easily controllable device, adjustable by the simple
means of tuning the cavity loss rates at the fundamental and harmonic
frequencies. We find that whether quantum steering is available via the
standard measurements of the Einstein-Podolsky-Rosen correlations can depend on
which quadrature measurements are inferred from output spectral measurements of
the fundamental and the harmonic. Altering the ratios of the cavity loss rates
can be used to tune the regions where symmetric steering is available, with the
results becoming asymmetric over all frequencies as the cavity damping at the
fundamental frequency becomes significantly greater than at the harmonic.
  This asymmetry and its functional dependence on frequency is a potential new
tool for experimental quantum information science, with possible utility for
quantum key distribution. Although we show the effect here for Gaussian
measurements of the quadratures, and cannot rule out a return of the steering
symmetry for some class of non-Gaussian measurements, we note here that the
system obeys Gaussian statistics in the operating regime investigated and
Gaussian inference is at least as accurate as any other method for calculating
the necessary correlations. Perhaps most importantly, this system is simpler
than any other methods we are aware of which have been used or proposed to
create asymmetric steering.


title: Expanding the Knowledge Horizon in Underwater Robot Swarms

abstract:
  In this paper we study the time delays affecting the diffusion of information
in an underwater heterogeneous robot swarm, considering a time-sensitive
environment. In many situations each member of the swarm must update its
knowledge about the environment as soon as possible, thus every effort to
expand the knowledge horizon is useful. Otherwise critical information may not
reach nodes far from the source causing dangerous misbehaviour of the swarm. We
consider two extreme situations. In the first scenario we have an unique
probabilistic delay distribution. In the second scenario, each agent is subject
to a different truncated gaussian distribution, meaning local conditions are
significantly different from link to link. We study how several swarm
topologies react to the two scenarios and how to allocate the more efficient
transmission resources in order to expand the horizon. Results show that
significant time savings under a gossip-like protocol are possible properly
allocating the resources. Moreover, methods to determine the fastest swarm
topologies and the most important nodes are suggested.


title: On distinguishability of hypotheses

abstract:
  We consider the problems of hypothesis testing on a probability measure of
independent sample, on solution of ill-posed problem, on deconvolution problem
and on Poisson mean measure. For all these setups necessary conditions and
sufficient conditions are given for distinguishability of sets of hypothesis.
In the case of hypothesis testing on a probability measure and on Poisson mean
measure the results are given in terms of weak topology and topology of weak
convergence on all Borel sets.
  The problem of discernibility of hypothesis is also studied. In other cases
the necessary and sufficient conditions of distinguishability are given if the
sets of hypotheses are bounded sets in $L_2$.


title:
Decomposable Specht modules for the Iwahori-Hecke algebra
  $\mathscr{H}_{\mathbb{F},-1}(\mathfrak{S}_n)$

abstract:
  Let $S_\lambda$ denote the Specht module defined by Dipper and James for the
Iwahori-Hecke algebra $\mathscr{H}_n$ of the symmetric group $\mathfrak{S}_n$.
When $e=2$ we determine the decomposability of all Specht modules corresponding
to hook partitions $(a,1^b)$. We do so by utilising the Brundan-Kleshchev
isomorphism between $\mathscr{H}$ and a Khovanov-Lauda-Rouquier algebra and
working with the relevant KLR algebra, using the set-up of
Kleshchev-Mathas-Ram. When $n$ is even, we easily arrive at the conclusion that
$S_\lambda$ is indecomposable. When $n$ is odd, we find an endomorphism of
$S_\lambda$ and use it to obtain a generalised eigenspace decomposition of
$S_\lambda$.


title:
Scalar sector properties of two-Higgs-doublet models with a global U(1)
  symmetry

abstract:
  We analyze the scalar sector properties of a general class of
two-Higgs-doublet models which has a global U(1) symmetry in the quartic terms.
We find constraints on the parameters of the potential from the considerations
of unitarity of scattering amplitudes, the global stability of the potential
and the $\rho$-parameter. We concentrate on the spectrum of the non-standard
scalar masses in the decoupling limit which is preferred by the Higgs data at
the LHC. We exhibit charged-Higgs induced contributions to the diphoton decay
width of the 125\,GeV Higgs boson and its correlation with the corresponding
$Z\gamma$ width.


title: Quantum Pieri rules for tautological subbundles

abstract:
  We give quantum Pieri rules for quantum cohomology of Grassmannians of
classical types, expressing the quantum product of Chern classes of the
tautological subbundles with general cohomology classes. We derive them by
showing the relevant genus zero, three-pointed Gromov-Witten invariants
coincide with certain classical intersection numbers.


title: Dust Properties of Clumpy Disc Galaxies at z~1.3 with Herschel-SPIRE

abstract:
  We present the far-infrared derived dust properties from Herschel SPIRE of
the WiggleZ kinematic sample of 13 star-forming galaxies at z~1.3, with
existing ancillary ~kpc resolution integral field spectroscopy. We detect 3
galaxies individually and place limits on the remainder by stacking. The
detected galaxies, two clumpy discs and one merger, have cold dust temperatures
of ~26 K and have infrared luminosities of ~1.2x10^12 solar luminosities,
determined by modified blackbody fitting. The two detected disc galaxies have
the largest H\alpha surface areas of the sample and have the reddest
ultraviolet to near-infrared spectral energy distributions. The likely source
of the infrared luminosity in these objects is dust heated by the interstellar
radiation field and young stellar emission from the clumps within the discs.
The source of infrared luminosity for the merger is likely a dust heated by a
starburst resulting from the merger. The WiggleZ detections are among the
coldest and lowest luminosity individual objects detected in the far-infrared
at z>1. When combining the kinematic data, we find that none of the compact
galaxies nor the 'dispersion dominated' galaxies of the WiggleZ kinematic
sample are detected, implying that they have warmer dust temperatures. The
compact objects show the highest H\alpha velocity dispersions in the sample, in
qualitative agreement with bulge formation models. These far-infrared results
strengthen the interpretation that the majority of galaxies in this sample
constitute different stages in clumpy disc formation as presented from
ancillary kinematic analysis.


title: Chirally motivated separable potential model for $\eta N$ amplitudes

abstract:
  We analyze the $\eta N$ interaction using a coupled channel separable
potential model that implements the chiral symmetry. The model predicts an
$\eta N$ stattering length $\Re a_{\eta N} \approx 0.7$ fm and in-medium
subthreshold attraction most likely sufficient to generate $\eta$-nuclear bound
states. The energy dependence of the $\eta N$ amplitude and pole content of the
model are discussed. An idea of the same origin of the baryon resonances
$N^{\star}(1535)$ and $N^{\star}(1650)$ is presented.


title: Crossover Behaviour In Driven Cascades

abstract:
  We propose a model which explains how power-law crossover behaviour can arise
in a system which is capable of experiencing cascading failure. In our model
the susceptibility of the system to cascades is described by a single number,
the propagation power, which measures the ease with which cascades propagate.
Physically, such a number could represent the density of unstable material in a
system, its internal connectivity, or the mean susceptibility of its component
parts to failure. We assume that the propagation power follows an upward
drifting Brownian motion between cascades, and drops discontinuously each time
a cascade occurs. Cascades are described by a continuous state branching
process with distributional properties determined by the value of the
propagation power when they occur. In common with many cascading models, pure
power law behaviour is exhibited at a critical level of propagation power, and
the mean cascade size diverges. This divergence constrains large systems to the
subcritical region. We show that as a result, crossover behaviour appears in
the cascade distribution when an average is performed over the distribution of
propagation power. We are able to analytically determine the exponents before
and after the crossover.

categories: nlin.AO cond-mat.stat-mech math-ph math.MP


title: Shocks Generate Crossover Behaviour In Lattice Avalanches

abstract:
  A spatial avalanche model is introduced, in which avalanches increase
stability in the regions where they occur. Instability is driven globally by a
driving process that contains shocks. The system is typically subcritical, but
the shocks occasionally lift it into a near or super critical state from which
it rapidly retreats due to large avalanches. These shocks leave behind a
signature -- a distinct power--law crossover in the avalanche size
distribution. The model is inspired by landslide field data, but the principles
may be applied to any system that experiences stabilizing failures, possesses a
critical point, and is subject to an ongoing process of destabilization which
includes occasional dramatic destabilizing events.


title: Dyson-Schwinger study of chiral density waves in QCD

abstract:
  The formation of inhomogeneous chiral condensates in QCD matter at nonzero
density and temperature is investigated for the first time with Dyson-Schwinger
equations. We consider two massless quark flavors in a so-called chiral density
wave, where scalar and pseudoscalar quark condensates vary sinusoidally along
one spatial dimension. We find that the inhomogeneous region covers the major
part of the spinodal region of the first-order phase transition which is
present when the analysis is restricted to homogeneous phases. The triple point
where the inhomogeneous phase meets the homogeneous phases with broken and
restored chiral symmetry, respectively, coincides, within numerical accuracy,
with the critical point of the homogeneous calculation. At zero temperature,
the inhomogeneous phase seems to extend to arbitrarily high chemical
potentials, as long as pairing effects are not taken into account.


title:
Tautological Sheaves: Stability, Moduli Spaces and Restrictions to
  Generalised Kummer Varieties

abstract:
  Results on stability of tautological sheaves on Hilbert schemes of points are
extended to higher dimensions and transferred to abelian surfaces and to the
restriction of tautological sheaves to generalised Kummer varieties. This
provides a big class of new examples of stable sheaves on higher dimensional
irreducible symplectic manifolds. Some aspects of deformations of tautological
sheaves are studied.


title: Number of fermion generations from a novel Grand Unified model

abstract:
  Electroweak interactions based on a gauge group $\rm SU(3)_L \times U(1)_X$,
coupled to the QCD gauge group $\rm SU(3)_c$, can predict the number of
generations to be multiples of three. We first try to unify these models within
SU(N) groups, using antisymmetric tensor representations only. After examining
why these attempts fail, we continue to search for an SU(N) GUT that can
explain the number of fermion generations. We show that such a model can be
found for $N=9$, with fermions in antisymmetric rank-1 and rank-3
representations only, and examine the constraints on various masses in the
model coming from the requirement of unification.


title:
Free motion around black holes with discs or rings: between
  integrability and chaos - III

abstract:
  We continue the study of time-like geodesic dynamics in exact static, axially
and reflection symmetric space-times describing the fields of a Schwarzschild
black hole surrounded by thin discs or rings. In the first paper of this
series, the rise (and decline) of geodesic chaos with ring/disc mass and
position and with test particle energy was revealed on Poincar\'e sections and
on time series of position or velocity and their power spectra. In the second
paper we compared these results with those obtained by two recurrence methods,
focusing on "sticky" orbits whose different parts show different degrees of
chaoticity. Here we complement the analysis by using several Lyapunov-type
coefficients which quantify the rate of orbital divergence. After comparing the
results with those obtained by the previous methods, we specifically consider a
system involving a black hole surrounded by a small thin disc or a large ring,
having in mind the configuration which probably occurs in galactic nuclei.
Within the range of parameters which roughly corresponds to our Galactic
center, we found that the black-hole accretion disc does not have a significant
gravitational effect on the dynamics of free motion at larger radii, while the
inner circumnuclear molecular ring (concentrated above 1 parsec radius) can
only induce some irregularity in motion of stars ("particles") on smaller radii
if its mass reaches 10 to 30% of the central black hole (which is the upper
estimate given in the literature), if it is sufficiently compact (which does
not hold but maybe for its inner rim) and if the stars can get to its close
vicinity. The outer dust ring between 60 and 100 parsecs appears to be less
important for the geodesic dynamics in its interior.


title:
Existence of Weak Conical K\"ahler-Einstein Metrics Along Smooth
  Hypersurfaces

abstract:
  The existence of \emph{weak conical K\"ahler-Einstein} metrics along smooth
hypersurfaces with angle between $0$ and $2\pi$ is obtained by studying a
smooth continuity method and a \emph{local Moser's iteration} technique. In the
case of negative and zero Ricci curvature, the $C^0$ estimate is unobstructed;
while in the case of positive Ricci curvature, the $C^0$ estimate obstructed by
the properness of the \emph{twisted K-Energy}. As soon as the $C^0$ estimate is
achieved, the local Moser iteration could improve the \emph{rough bound} on the
approximations to a \emph{uniform $C^2$ bound}, thus produce a \emph{weak
conical K\"ahler-Einstein} metric. The method used here do not depend on the
bound of any background conical K\"ahler metrics.


title: Toric ideals and diagonal 2-minors

abstract:
  Let $G$ be a simple graph on the vertex set $\{1,\ldots,n\}$ with $m$ edges.
An algebraic object attached to $G$ is the ideal $P_{G}$ generated by diagonal
2-minors of an $n \times n$ matrix of variables. In this paper we prove that if
$G$ is bipartite, then every initial ideal of $P_{G}$ is generated by
squarefree monomials of degree at most $\left \lfloor{\frac{m+n+1}{2}} \right
\rfloor$. Furthermore, we completely characterize all connected graphs $G$ for
which $P_{G}$ is the toric ideal associated to a finite simple graph. Finally
we compute in certain cases the universal Gr{\"o}bner basis of $P_{G}$.


title: The polarization properties of a tilted polarizer

abstract:
  Polarizers are key components in optical science and technology. Thus,
understanding the action of a polarizer beyond oversimplifying approximations
is crucial. In this work, we study the interaction of a polarizing interface
with an obliquely incident wave experimentally. To this end, a set of Mueller
matrices is acquired employing a novel procedure robust against experimental
imperfections. We connect our observation to a geometric model, useful to
predict the effect of polarizers on complex light fields.


title: Solution for an interaction quench in the Lieb-Liniger Bose gas

abstract:
  We study a quench protocol where the ground state of a free many-particle
bosonic theory in one dimension is let unitarily evolve in time under the
integrable Lieb-Liniger Hamiltonian of $\delta$-interacting repulsive bosons.
By using a recently-proposed variational method, we here obtain the exact
non-thermal steady-state of the system in the thermodynamic limit, and discuss
some of its main physical properties. Besides being a rare case of a
thermodynamically exact solution to a truly interacting quench situation, this
interestingly represents an example where a naive implementation of the
generalized Gibbs ensemble fails.


title:
Lepton Flavor Violating $\tau$ Decays in TeV Scale Type I See-Saw and
  Higgs Triplet Models

abstract:
  The lepton flavour violating (LFV) $\tau$ decays $\tau\to (e,\mu)\gamma$ and
$\tau\to 3\mu$ are investigated in the frameworks of the TeV scale type I
see-saw and Higgs Triplet (or type II see-saw) models. Predictions for the
rates of these processes are obtained. The implications of the existing
stringent experimental upper bounds on the $\mu\to e + \gamma$ and $\mu\to 3e$
decay branching ratios for the predictions of the $\tau\to (e,\mu)\gamma$ and
$\tau\to 3\mu$ decay rates are studied in detail. The possibilities to observe
the indicated LFV $\tau$ decays in present and future experiments are analysed.


title: Gravitational collapse in pure Lovelock gravity in higher dimensions

abstract:
  We study collapse of inhomogeneous dust and null dust (Vaidya radiation) in
pure Lovelock gravity in higher dimensions. Since pure Lovelock gravity is
kinematic in odd d=2N+1 dimension, hence pertinent dimension for the study is
even d=2N+2, where N is degree of Lovelock polynomial. It turns out that pure
Lovelock collapse favors naked singularity as against black hole for the
Einstein case in the same dimension while strength of singularity as measured
by divergence of Kretshmann scalar is interestingly the same in the two cases;
i.e. the corresponding scalars have the same fall off behavior.


title: Spin operator in the Dirac theory

abstract:
  We find all spin operators for a Dirac particle satisfying the following very
general conditions: (i) spin does not convert positive (negative) energy states
into negative (positive) energy states, (ii) spin is a pseudo-vector, and (iii)
eigenvalues of the projection of a spin operator on an arbitrary direction are
independent of this direction (isotropy condition). We show that there are four
such operators and all of them fulfill the standard su(2) Lie algebra
commutation relations. Nevertheless, only one of them has a proper
non-relativistic limit and acts in the same way on negative and positive energy
states. We show also that this operator is equivalent to the Newton-Wigner spin
operator and Foldy-Wouthuysen mean-spin operator. We also discuss another
operators proposed in the literature.


title: Testing atmospheric mixing sum rules at precision neutrino facilities

abstract:
  We study the prospects for testing classes of atmospheric mixing sum rules at
precision neutrino facilities. Such sum rules, which correlate the atmospheric
mixing angle theta23 with the recently measured reactor angle theta13 and the
cosine of the oscillation phase delta, are predicted by a variety of
semi-direct models based on discrete family symmetry, classified in terms of
finite von Dyck groups. We perform a detailed simulation of the performance of
the next generation of oscillation experiments, including the wide band
superbeam and low-energy neutrino factory proposals, and compare their
discriminating power for testing atmospheric mixing sum rules.


title: Dynamics of Desorption with Lateral Diffusion

abstract:
  The dynamics of desorption from a submonolayer of adsorbed atoms or ions are
significantly influenced by the absence or presence of lateral diffusion of the
adsorbed particles. When diffusion is present, the adsorbate configuration is
simultaneously changed by two distinct processes, proceeding in parallel:
adsorption/desorption, which changes the total adsorbate coverage, and lateral
diffusion, which is coverage conserving. Inspired by experimental results, we
here study the effects of these competing processes by kinetic Monte Carlo
simulations of a simple lattice-gas model. In order to untangle the various
effects, we perform large-scale simulations, in which we monitor coverage,
correlation length, and cluster-size distributions, as well as the behavior of
representative individual clusters, during desorption. For each initial
adsorbate configuration, we perform multiple, independent simulations, without
and with diffusion, respectively. We find that, compared to desorption without
diffusion, the coverage-conserving diffusion process produces two competing
effects: a retardation of the desorption rate, which is associated with a
coarsening of the adsorbate configuration, and an acceleration due to
desorption of monomers "evaporated" from the cluster perimeters. The balance
between these two effects is governed by the structure of the adsorbate layer
at the beginning of the desorption process. Deceleration and coarsening are
predominant for configurations dominated by monomers and small clusters, while
acceleration is predominant for configurations dominated by large clusters.


title:
Decentralized Charging of Plug-In Electric Vehicles with Distribution
  Feeder Overload Control

abstract:
  As the number of charging Plug-in Electric Vehicles (PEVs) increase, due to
the limited power capacity of the distribution feeders and the sensitivity of
the mid-way distribution transformers to the excessive load, it is crucial to
control the amount of power through each specific distribution feeder to avoid
system overloads that may lead to breakdowns. In this paper we develop, analyze
and evaluate charging algorithms for PEVs with feeder overload constraints in
the distribution grid. The algorithms we propose jointly minimize the variance
of the aggregate load and prevent overloading of the distribution feeders.


title: Quantifying Oxidation Rates of Carbon Monoxide on a Pt/C Electrode

abstract:
  The electrochemical oxidation of carbon monoxide adsorbed (COad) on
platinum-on-carbon electrodes was studied via a methodology in which
pre-adsorbed CO was partially oxidized by applying potentiostatic pulses for
certain durations. The residual COad was analyzed using stripping voltammetry
that involved the deconvolution of COad oxidation peaks of voltammograms to
quantify the weakly and strongly bound species of COad. The data obtained for
various potentials and temperatures were fit to a model based on a nucleation
and growth mechanism. The resulting fit produced potential- and
temperature-dependent rate parameters that provided insight into the oxidation
mechanism of the two COad species. Irrespective of the applied potential or
temperature, the concentration of weakly bound COad species decreased
exponentially with time. In contrast, the strongly bound COad species showed a
gradual transition of mechanisms, from progressive nucleation at relatively low
potentials to exponential decay at high potentials.


title: Evaporation of (quantum) black holes and energy conservation

abstract:
  We consider Hawking radiation as due to a tunneling process in a black hole
were quantum corrections, derived from Quantum Einstein Gravity, are taken into
account. The consequent derivation, satisfying conservation laws, leads to a
deviation from an exact thermal spectrum. The non-thermal radiation is shown to
carry information out of the black hole. Under the appropriate approximation, a
quantum corrected temperature is assigned to the black hole. The evolution of
the quantum black hole as it evaporates is then described by taking into
account the full implications of energy conservation as well as the
back-scattered radiation. It is shown that, as a critical mass of the order of
Planck's mass is reached, the evaporation process decelerates abruptly while
the black hole mass decays towards this critical mass.


title:
Conserved Charge Fluctuations in a Chiral Hadronic Model including
  Hadrons and Quarks

abstract:
  In this work the susceptibility coefficients of the strange and non-strange
quark number of second and fourth order are presented. The results at zero
baryonchemical potential are obtained using a well tested chiral effective
model including all known hadron degrees of freedom and additionally
incorporating quarks and gluons in a PNJL model approach. Quark number
susceptibilities are sensitive to the fundamental degrees of freedom in the
model and signal the shift from massive hadrons to light quarks at the
deconfinement transition by a sharp rise at the critical temperature.
Furthermore, all susceptibilities are found to be largely suppressed by
repulsive vector field interactions of the particles. In the hadronic sector
vector repulsion of baryon resonances restrains fluctuations to a region
determined in lattice QCD. However, in the quark sector above $T_c$ even small
vector field interactions of quarks quench all fluctuations almost completely.
For this reason, vector field interactions for quarks have to vanish in the
deconfinement limit.


title:
Solutions to a nonlinear Schr\"odinger equation with periodic potential
  and zero on the boundary of the spectrum

abstract:
  We study the following nonlinear Schr\"odinger equation $$-\Delta u + V(x) u
= g(x,u),$$ where V and g are periodic in x. We assume that 0 is a right
boundary point of the essential spectrum of $-\Delta+V$. The superlinear and
subcritical term g satisfies a Nehari type monotonicity condition. We employ a
Nehari manifold type technique in a strongly indefitnite setting and obtain the
existence of a ground state solution. Moreover we get infinitely many
geometrically distinct solutions provided that g is odd.


title: On Obstacle Numbers

abstract:
  The obstacle number is a new graph parameter introduced by Alpert, Koch, and
Laison (2010). Mukkamala etal (2012) show that there exist graphs with n
vertices having obstacle number in Omega(n/\log n). In this note, we up this
lower bound to Omega(n/(\log\log n)^2. Our proof makes use of an upper bound of
Mukkamala etal on the number of graphs having obstacle number at most h in such
a way that any subsequent improvements to their upper bound will improve our
lower bound.


title:
On the Optimal Rates of Convergence for Quadratures Derived from
  Chebyshev Points

abstract:
  In this paper, we study the optimal general convergence rates for quadratures
derived from Chebyshev points. By building on the aliasing errors on
integration of Chebyshev polynomials, together with the asymptotic formulae on
the coefficients of Chebyshev expansions, new and optimal convergence rates for
$n$-point Clenshaw-Curtis, Fej\'{e}r's first and second quadrature rules are
established for Jacobi weights or Jacobi weights multiplied by $\ln((x+1)/2)$.
The convergence orders are attainable for some functions of finite
regularities. In addition, by using refined estimates on aliasing errors on
integration of Chebyshev polynomials by Gauss-Legendre quadrature, an improved
convergence rate for Gauss-Legendre is given too.


title:
VISTA's view of the Sagittarius dwarf spheroidal galaxy and southern
  Galactic Bulge

abstract:
  We present the deepest near-infrared (ZJKs) photometry yet obtained of the
Sagittarius dwarf spheroidal (Sgr dSph), using VISTA to survey 11 square
degrees centred on its core. We list locations and ZJKs-band magnitudes for
over 2.9 million sources in the field. We discuss the isolation of the Sgr dSph
from the foreground and Galactic Bulge populations, identify the Sgr dSph's
horizontal branch in the near-infrared for the first time, and map the density
of the galaxy's stars. We present isochrones for the Sgr dSph and Bulge
populations. These are consistent with the previously-reported properties of
the Sgr dSph core: namely that it is dominated by a population between [Fe/H] ~
-1 dex and solar, with a significant [alpha/Fe] versus [Fe/H] gradient. While
strong contamination from the Galactic Bulge prevents accurate measurement of
the (Galactic) north side of the Sgr dSph, the dwarf galaxy can be
well-approximated by a roughly ovaloid projection of characteristic size 4 x 2
degrees, beyond which the projected stellar density is less than half that of
the region surrounding the core. The galaxy's major axis is perpendicular to
the Galactic Plane, as in previous studies. We find slight evidence to confirm
a metallicity gradient in the Sgr dSph and use isochrones to fit a distance of
24.3 +/- 2.3 kpc. We were unable to fully constrain the metallicity
distribution of the Sgr dSph due to the Bulge contamination and strong
correlation of [alpha/Fe] with metallicity, however we find that metal-poor
stars ([Fe/H] <~ --1) make up <~29 per cent of the Sgr dSph's upper-RGB
population. The Bulge population is best fit by a younger population with
[Fe/H] ~ 0 and [alpha/Fe] ~ 0 or slightly higher. We find no evidence for a
split, peanut- or X-shaped Bulge population in this line of sight (l = 5.6 +/-
~1 deg, b = -14.1 +/- ~3 deg).


title: Quasisymmetric geometry of the Julia sets of McMullen maps

abstract:
  We study the quasisymmetric geometry of the Julia sets of McMullen maps
$f_\lambda(z)=z^m+\lambda/z^\ell$, where $\ell$, $m\geq 2$ are integers
satisfying $1/\ell+1/m<1$ and $\lambda\in\mathbb{C}\setminus\{0\}$. If the free
critical points of $f_\lambda$ are escaped to the infinity, we prove that the
Julia set $J_\lambda$ of $f_\lambda$ is quasisymmetrically equivalent to either
a standard Cantor set, a standard Cantor set of circles or a round
Sierpi\'{n}ski carpet (which is also standard in some sense). If the free
critical points are not escaped, we give a sufficient condition on $\lambda$
such that $J_\lambda$ is a Sierpi\'{n}ski carpet and prove that most of them
are quasisymmetrically equivalent to some round carpets. In particular, there
exist infinitely renormalizable rational maps whose Julia sets are
quasisymmetrically equivalent to round carpets.


title: Foundation of Symbol Theory for Analytic Pseudodifferential Operators. I

abstract:
  A new symbol theory for pseudodifferential operators in the complex analytic
category is given. This theory provides a cohomological foundation of symbolic
calculus.


title:
An X-ray view of the very faint black hole X-ray transient Swift
  J1357.2-0933 during its 2011 outburst

abstract:
  We report on the X-ray spectral (using XMM-Newton data) and timing behavior
(using XMM-Newton and Rossi X-ray Timing Explorer [RXTE] data) of the very
faint X-ray transient and black hole system Swift J1357.2-0933 during its 2011
outburst. The XMM-Newton X-ray spectrum of this source can be adequately fitted
with a soft thermal component with a temperature of ~0.22 keV (using a disc
model) and a hard, non-thermal component with a photon index of ~1.6 when using
a simple power-law model. In addition, an edge at ~ 0.73 keV is needed likely
due to interstellar absorption. During the first RXTE observation we find a 6
mHz quasi-periodic oscillation (QPO) which is not present during any of the
later RXTE observations or during the XMM-Newton observation which was taken 3
days after the first RXTE observation. The nature of this QPO is not clear but
it could be related to a similar QPO seen in the black hole system H 1743-322
and to the so-called 1 Hz QPO seen in the dipping neutron-star X-ray binaries
(although this later identification is quite speculative). The observed QPO has
similar frequencies as the optical dips seen previously in this source during
its 2011 outburst but we cannot conclusively determine that they are due to the
same underlying physical mechanism. Besides the QPO, we detect strong
band-limited noise in the power-density spectra of the source (as calculated
from both the RXTE and the XMM-Newton data) with characteristic frequencies and
strengths very similar to other black hole X-ray transients when they are at
low X-ray luminosities. We discuss the spectral and timing properties of the
source in the context of the proposed very high inclination of this source. We
conclude that all the phenomena seen from the source cannot, as yet, be
straightforwardly explained neither by an edge-on configuration nor by any
other inclination configuration of the orbit.


title:
Four-Flavour Leading-Order Hadronic Contribution To The Muon Anomalous
  Magnetic Moment

abstract:
  We present a four-flavour lattice calculation of the leading-order hadronic
vacuum polarisation contribution to the anomalous magnetic moment of the muon,
$a_\mathrm{\mu}^{\rm hvp}$, arising from quark-connected Feynman graphs. It is
based on ensembles featuring $N_f=2+1+1$ dynamical twisted mass fermions
generated by the European Twisted Mass Collaboration (ETMC). Several light
quark masses are used in order to yield a controlled extrapolation to the
physical pion mass. We employ three lattice spacings to examine lattice
artefacts and several different volumes to check for finite-size effects.
Incorporating the complete first two generations of quarks allows for a direct
comparison with phenomenological determinations of $a_\mathrm{\mu}^{\rm hvp}$.
Our final result including an estimate of the systematic uncertainty
$$a_{\mathrm{\mu}}^{\rm hvp} = 6.74(21)(18) \cdot 10^{-8}$$ shows a good
overall agreement with these computations.


title: Localization under the effect of randomly distributed decoherence

abstract:
  Electron transport through disordered quasi one-dimensional quantum systems
is studied. Decoherence is taken into account by a spatial distribution of
virtual reservoirs, which represent local interactions of the conduction
electrons with their environment. We show that the decoherence distribution has
observable effects on the transport. If the decoherence reservoirs are
distributed randomly without spatial correlations, a minimal degree of
decoherence is necessary to obtain Ohmic conduction. Below this threshold the
system is localized and thus, a decoherence driven metal-insulator transition
is found. In contrast, for homogenously distributed decoherence, any finite
degree of decoherence is sufficient to destroy localization. Thus, the presence
or absence of localization in a disordered one-dimensional system may give
important insight about how the electron phase is randomized.


title:
Uniqueness of the thermodynamic limit for driven disordered elastic
  interfaces

abstract:
  We study the finite size fluctuations at the depinning transition for a
one-dimensional elastic interface of size $L$ displacing in a disordered medium
of transverse size $M=k L^\zeta$ with periodic boundary conditions, where
$\zeta$ is the depinning roughness exponent and $k$ is a finite aspect ratio
parameter. We focus on the crossover from the infinitely narrow ($k\to 0$) to
the infinitely wide ($k\to \infty$) medium. We find that at the thermodynamic
limit both the value of the critical force and the precise behavior of the
velocity-force characteristics are {\it unique} and $k$-independent. We also
show that the finite size fluctuations of the critical force (bias and
variance) as well as the global width of the interface cross over from a
power-law to a logarithm as a function of $k$. Our results are relevant for
understanding anisotropic size-effects in force-driven and velocity-driven
interfaces.


title:
Superdiffusion of energy in Hamiltonian systems perturbed by a
  conservative noise

abstract:
  We review some recent results on the anomalous diffusion of energy in systems
of 1D coupled oscillators and we revisit the role of momentum conservation.


title: New Physics signals from measurable polarization asymmetries at LHC

abstract:
  We propose a new type of Z polarization asymmetry in bottom-Z production at
LHC that should be realistically measurable and would provide the determination
of the so-called $A_b$ parameter, whose available measured value still appears
to be in disagreement with the Standard Model prediction. This polarization can
be measured independently of a possible existence of Supersymmetry. If
Supersymmetry is found, a second polarization, i.e. the top longitudinal
polarization in top-charged Higgs production, would neatly identify the $\tan
\beta$ parameter. In this case, the value of $A_b$ should be in agreement with
the Standard Model. If Supersymmetry does not exist, a residual disagreement of
$A_b$ from the Standard Model prediction would be a clean signal of New Physics
of "non Supersymmetric" origin.


title:
Broadband monitoring tracing the evolution of the jet and disk in the
  black hole candidate X-ray binary MAXI J1659-152

abstract:
  MAXI J1659-152 was discovered on 2010 September 25 as a new X-ray transient,
initially identified as a gamma-ray burst, but was later shown to be a new
X-ray binary with a black hole as the most likely compact object. Dips in the
X-ray light curves have revealed that MAXI J1659-152 is the shortest period
black hole candidate identified to date. Here we present the results of a large
observing campaign at radio, sub-millimeter, near-infrared (nIR), optical and
ultraviolet (UV) wavelengths. We have combined this very rich data set with the
available X-ray observations to compile a broadband picture of the evolution of
this outburst. We have performed broadband spectral modeling, demonstrating the
presence of a spectral break at radio frequencies and a relationship between
the radio spectrum and X-ray states. Also, we have determined physical
parameters of the accretion disk and put them into context with respect to the
other parameters of the binary system. Finally, we have investigated the
radio-X-ray and nIR/optical/UV-X-ray correlations up to ~3 years after the
outburst onset to examine the link between the jet and the accretion disk, and
found that there is no significant jet contribution to the nIR emission when
the source is in the soft or intermediate X-ray spectral state, consistent with
our detection of the jet break at radio frequencies during these states.


title:
Phase diagram and the strong-coupling fixed point in the disordered O(n)
  loop model

abstract:
  We numerically study the phase diagram and critical properties of the
two-dimensional disordered O(n) loop model by using the transfer matrix and the
worm Monte Carlo methods. The renormalization group flow is extracted from the
landscape of the effective central charge obtained by the transfer matrix
method based on the Zamolodchikov's C-theorem. We find a line of random fixed
points (FPs) for $n_c < n <1$, with $n_c \sim 0.5$, for which the central
charge and critical exponents agree well with the results of the $1-n$
perturbative expansion. Furthermore, for $n> n_c$, we find a line of
multicritical FPs at strong randomness. The FP at $n=1$ has $c=0.4612(4)$,
which suggests that it belongs to the universality class of the Nishimori point
in the $\pm J$ random-bond Ising model. For $n>2$, we find another critical
line that connects the hard-hexagon FP in the pure model to a finite-randomness
zero-temperature FP.

categories: cond-mat.dis-nn cond-mat.stat-mech hep-th math-ph math.MP


title: Contraction Formulas For Kirchhoff And Wiener Indices

abstract:
  We establish several contraction formulas for Kirchhoff index. We relate
Kirchhoff index with some other metrized graph invariants. By applying our
contraction formulas successively when the graph is a tree, we derive new
formulas for Wiener index and obtain some previously known Wiener index
formulas with new proofs.


title:
Ray-based analysis of the interference striation pattern in an
  underwater acoustic waveguide

abstract:
  In some underwater acoustic waveguides with specially selected sound speed
profiles striations or fringes of the interference pattern are determined by a
single parameter \beta\ called the waveguide (or Chuprov) invariant. In the
present paper it is shown that an analytical description of fringes may be
possible in a waveguide with an arbitrary sound speed profile. A simple
analytical expression is obtained for smooth lines formed by local maxima of
the interference pattern. This result is valid at long enough ranges. It is
derived proceeding from a known relation connecting the differences of ray
travel times and the action variables of ray paths.


title:
Dynamics of a two-dimensional quantum spin liquid: signatures of
  emergent Majorana fermions and fluxes

abstract:
  Topological states of matter present a wide variety of striking new
phenomena. Prominent among these is the fractionalisation of electrons into
unusual particles: Majorana fermions [1], Laughlin quasiparticles [2] or
magnetic monopoles [3]. Their detection, however, is fundamentally complicated
by the lack of any local order, such as, for example, the magnetisation in a
ferromagnet. While there are now several instances of candidate topological
spin liquids [4], their identification remains challenging [5]. Here, we
provide a complete and exact theoretical study of the dynamical structure
factor of a two-dimensional quantum spin liquid in gapless and gapped phases.
We show that there are direct signatures - qualitative and quantitative - of
the Majorana fermions and gauge fluxes emerging in Kitaev's honeycomb model.
These include counterintuitive manifestations of quantum number
fractionalisation, such as a neutron scattering response with a gap even in the
presence of gapless excitations, and a sharp component despite the
fractionalisation of electron spin. Our analysis identifies new varieties of
the venerable X-ray edge problem and explores connections to the physics of
quantum quenches.


title:
Scaling of Temperature Dependence of Charge Mobility in Molecular
  Holstein Chains

abstract:
  The temperature dependence of a charge mobility in a model DNA based on
Holstein Hamiltonian is calculated for 4 types of homogeneous sequences It has
turned out that upon rescaling all 4 types are quite similar. Two types of
rescaling, i.e. those for low and intermediate temperatures, are found. The
curves obtained are approximated on a logarithmic scale by cubic polynomials.
We believe that for model homogeneous biopolymers with parameters close to the
designed ones, one can assess the value of the charge mobility without carrying
out resource-intensive direct simulation, just by using a suitable
approximating function.


title:
SAR Image Despeckling Algorithms using Stochastic Distances and Nonlocal
  Means

abstract:
  This paper presents two approaches for filter design based on stochastic
distances for intensity speckle reduction. A window is defined around each
pixel, overlapping samples are compared and only those which pass a
goodness-of-fit test are used to compute the filtered value. The tests stem
from stochastic divergences within the Information Theory framework. The
technique is applied to intensity Synthetic Aperture Radar (SAR) data with
homogeneous regions using the Gamma model. The first approach uses a
Nagao-Matsuyama-type procedure for setting the overlapping samples, and the
second uses the nonlocal method. The proposals are compared with the Improved
Sigma filter and with anisotropic diffusion for speckled data (SRAD) using a
protocol based on Monte Carlo simulation. Among the criteria used to quantify
the quality of filters, we employ the equivalent number of looks, and line and
edge preservation. Moreover, we also assessed the filters by the Universal
Image Quality Index and by the Pearson correlation between edges. Applications
to real images are also discussed. The proposed methods show good results.

categories: cs.IT cs.CV cs.GR math.IT stat.AP stat.ML


title:
Spatial Inhomogeneity of the Superconducting Gap and Order Parameter in
  FeSe_{0.4}Te_{0.6}

abstract:
  We have performed a low temperature scanning tunneling microscopy and
spectroscopy study of the iron chalcogenide superconductor FeSe_{0.4}Te_{0.6}
with T_{C}~14 K. Spatially resolved measurements of the superconducting gap
reveal substantial inhomogeneity on a nanometer length scale. Analysis of the
structure of the gap seen in tunneling spectra by comparison with calculated
spectra for different superconducting order parameters (s-wave, d-wave, and
anisotropic s-wave) yields the best agreement for an order parameter with
anisotropic s-wave symmetry with an anisotropy of ~40%. The temperature
dependence of the superconducting gap observed in places with large and small
gap size indicates that it is indeed the superconducting transition temperature
which is inhomogeneous. The temperature dependence of the gap size is
substantially larger than would be expected from BCS theory. An analysis of the
local gap size in relation with the local chemical composition shows almost no
correlation with the local concentration of Se-/Te-atoms at the surface.


title:
Complementarity of Quantum Correlations in Cloning and Deleting of
  Quantum State

abstract:
  We quantify the amount of correlation generated between two different output
modes in the process of im- perfect cloning and deletion processes. We use
three different measures of correlations and study their role in determining
the fidelity of the cloning and deletion. We obtain a bound on the total
correlation generated in the successive process of cloning and deleting
operations. This displays a new kind of complementary relationship between the
quantum correlation required in generating a copy of a quantum state and the
amount of correlation required in bringing it back to the original state by
deleting and vice versa. Our result shows that better we clone (delete) a
state, more difficult it will be to bring the state back to its original form
by the process of deleting (cloning).


title: Maxima of the Q-index: graphs without long paths

abstract:
  This paper gives tight upper bound on the largest eigenvalue q(G) of the
signless Laplacian of graphs with no paths of given order. The main ingredient
of our proof is a stability result of its own interest, about graphs with large
minimum degree and with no long paths. This result extends previous work of Ali
and Staton.


title:
A new formulation of protein evolutionary models that account for
  structural constraints

abstract:
  Despite the importance of a thermodynamically stable structure with a
conserved fold for protein function, almost all evolutionary models neglect
site-site correlations that arise from physical interactions between
neighboring amino acid sites. This is mainly due to the difficulty in
formulating a computationally tractable model since rate matrices can no longer
be used. Here we introduce a general framework, based on factor graphs, for
constructing probabilistic models of protein evolution with site
interdependence. Conveniently, efficient approximate inference algorithms, like
Belief Propagation, can be used to calculate likelihoods for these models. We
fit an amino acid substitution model of this type that accounts for both
solvent accessibility and site-site correlations. Comparisons of the new model
with rate matrix models and a model accounting only for solvent accessibility
demonstrate that it better fits the sequence data. We also examine evolution
within a family of homohexameric enzymes and find that site-site correlations
between most contacting subunits contribute to a higher likelihood. In
addition, we show that the new substitution model has a similar mathematical
form to the one introduced in (Rodrigue et al. 2005), although with different
parameter interpretations and values. We also perform a statistical analysis of
the effects of amino acids at neighboring sites on substitution probabilities
and find a significant perturbation of most probabilities, further supporting
the significant role of site-site interactions in protein evolution and
motivating the development of new evolutionary models like the one described
here. Finally, we discuss possible extensions and applications of the new
substitution models.


title: Nonsingular Rainbow Universes

abstract:
  In this work, we study FRW cosmologies in the context of gravity rainbow. We
discuss the general conditions for having a nonsingular FRW cosmology in
gravity rainbow. We propose that gravity rainbow functions can be fixed using
two known modified dispersion relation (MDR), which have been proposed in
literature. The first MDR was introduced by Amelino-Camelia, et el. in [9] and
the second was introduced by Magueijo and Smolin in [24]. Studying these
FRW-like cosmologies, after fixing the gravity rainbow functions, leads to
nonsingular solutions which can be expressed in exact forms.


title:
White dwarf-main sequence binaries identified from the LAMOST pilot
  survey

abstract:
  We present a set of white dwarf-main sequence (WDMS) binaries identified
spectroscopically from the Large sky Area Multi-Object fiber Spectroscopic
Telescope (LAMOST, also called the Guo Shou Jing Telescope) pilot survey. We
develop a color selection criteria based on what is so far the largest and most
complete Sloan Digital Sky Survey (SDSS) DR7 WDMS binary catalog and identify
28 WDMS binaries within the LAMOST pilot survey. The primaries in our binary
sample are mostly DA white dwarfs except for one DB white dwarf. We derive the
stellar atmospheric parameters, masses, and radii for the two components of 10
of our binaries. We also provide cooling ages for the white dwarf primaries as
well as the spectral types for the companion stars of these 10 WDMS binaries.
These binaries tend to contain hot white dwarfs and early-type companions.
Through cross-identification, we note that nine binaries in our sample have
been published in the SDSS DR7 WDMS binary catalog. Nineteen spectroscopic WDMS
binaries identified by the LAMOST pilot survey are new. Using the 3$\sigma$
radial velocity variation as a criterion, we find two post-common-envelope
binary candidates from our WDMS binary sample.


title: Small cancellation in acylindrically hyperbolic groups

abstract:
  We generalize a version of small cancellation theory to the class of
acylindrically hyperbolic groups. This class contains many groups which admit
some natural action on a hyperbolic space, including non-elementary hyperbolic
and relatively hyperbolic groups, mapping class groups, and groups of outer
automorphisms of free groups. Several applications of this small cancellation
theory are given, including to Frattini subgroups and Kazhdan constants, the
construction of various \exotic"' quotients, and to approximating
acylindrically hyperbolic groups in the topology of marked group presentations.


title:
A decomposition technique for integrable functions with applications to
  the divergence problem

abstract:
  Let $\Omega\subset \mathbb{R}^n$ be a bounded domain that can be written as
$\Omega=\bigcup_{t} \Omega_t$, where $\{\Omega_t\}_{t\in\Gamma}$ is a countable
collection of domains with certain properties. In this work, we develop a
technique to decompose a function $f\in L^1(\Omega)$, with vanishing mean
value, into the sum of a collection of functions
$\{f_t-\tilde{f}_t\}_{t\in\Gamma}$ subordinated to $\{\Omega_t\}_{t\in\Gamma}$
such that $Supp\,(f_t-\tilde{f}_t)\subset\Omega_t$ and $\int
f_t-\tilde{f}_t=0$. As an application, we use this decomposition to prove the
existence of a solution in weighted Sobolev spaces of the divergence problem
$\di\uu=f$ and the well-posedness of the Stokes equations on H\"older-$\alpha$
domains and some other domains with an external cusp arbitrarily narrow. We
also consider arbitrary bounded domains. The weights used in each case depend
on the type of domain.


title:
Anisotropic flow of convex hypersurfaces by the square root of the
  scalar curvature

abstract:
  We show the existence of a smooth solution for the flow deformed by the
square root of the scalar curvature multiplied by a positive anisotropic factor
$\psi$ given a strictly convex initial hypersurface in Euclidean space suitably
pinched. We also prove the convergence of rescaled surfaces to a smooth limit
manifold which is a round sphere. In dimension two, it is shown that, with a
volume preserving rescaling, the limit profile satisfies a soliton equation.


title: Echo of the Quantum Bounce

abstract:
  We identify a signature of quantum gravitational effects that survives from
the early universe to the current era: Fluctuations of quantum fields as seen
by comoving observers are significantly influenced by the history of the early
universe. In particular we show how the existence (or not) of a quantum bounce
leaves a trace in the background quantum noise that is not damped and would be
non-negligible even nowadays. Furthermore, we estimate an upper bound for the
typical energy and length scales where quantum effects are relevant. We discuss
how this signature might be observed and therefore used to build falsifiability
tests of quantum gravity theories.


title: Frequency Multiplexed Magnetometry via Compressive Sensing

abstract:
  Quantum sensors based on single Nitrogen-Vacancy (NV) defects in diamond are
state-of-the-art tools for nano-scale magnetometry with precision scaling
inversely with total measurement time $\sigma_{B} \propto 1/T$ (Heisenberg
scaling) rather than as the inverse of the square root of $T$, with $\sigma_{B}
=1/\sqrt{T}$ the Shot-Noise limit. This scaling can be achieved by means of
phase estimation algorithms (PEAs) using adaptive or non-adaptive feedback, in
combination with single-shot readout techniques. Despite their accuracy, the
range of applicability of PEAs is limited to periodic signals involving single
frequencies with negligible temporal fluctuations. In this Letter, we propose
an alternative method for precision magnetometry in frequency multiplexed
signals via compressive sensing (CS) techniques. We show that CS can provide
for precision scaling approximately as $\sigma_{B} \approx 1/T$, both in the
case of single frequency and frequency multiplexed signals, as well as for a
5-fold increase in sensitivity over dynamic-range gain, in addition to reducing
the total number of resources required.


title: Coupled mode parametric resonance in a vibrating screen model

abstract:
  We consider a simple dynamic model of the vibrating screen operating in the
parametric resonance (PR) mode. This model was used in the course of designing
and setting of such a screen in LPMC. The PR-based screen compares favorably
with conventional types of such machines, where the transverse oscillations are
excited directly. It is characterized by larger values of the amplitude and by
insensitivity to damping in a rather wide range. The model represents an
initially strained system of two equal masses connected by a linearly elastic
string. Self-equilibrated, longitudinal, harmonic forces act on the masses.
Under certain conditions this results in transverse, finite-amplitude
oscillations of the string. The problem is reduced to a system of two ordinary
differential equations coupled by the geometric nonlinearity. Damping in both
the transverse and longitudinal oscillations is taken into account. Free and
forced oscillations of this mass-string system are examined analytically and
numerically. The energy exchange between the longitudinal and transverse modes
of free oscillations is demonstrated. An exact analytical solution is found for
the forced oscillations, where the coupling plays the role of a stabilizer. In
a more general case, the harmonic analysis is used with neglect of the higher
harmonics. Explicit expressions for all parameters of the steady nonlinear
oscillations are determined. The domains are found where the analytically
obtained steady oscillation regimes are stable. Over the frequency ranges,
where the steady oscillations exist, a perfect correspondence is found between
the amplitudes obtained analytically and numerically. Illustrations based on
the analytical and numerical simulations are presented.


title:
A Variational Formula for the Lyapunov Exponent of Brownian Motion in
  Stationary Ergodic Potential

abstract:
  We establish a variational formula for the exponential decay rate of the
Green function of Brownian motion evolving in a random stationary and ergodic
nonnegative potential. Such a variational formula is established by Schroeder
in 'Green's Functions for the Schr\"odinger Operator with Periodic Potential',
J. Funct. Anal. 77 (1988), for potentials on compact spaces and is generalised
in the present article to a non-compact setting. We show exponential decay of
the Green function implicitly. This formula for the Lyapunov exponent has
several direct implications. It allows to compare the influence of a random
potential to the influence of the averaged potential. It also leads to a
variational expression for the quenched free energy.


title: Seismic constraints on rotation of Sun-like star and mass of exoplanet

abstract:
  Rotation is thought to drive cyclic magnetic activity in the Sun and Sun-like
stars. Stellar dynamos, however, are poorly understood owing to the scarcity of
observations of rotation and magnetic fields in stars. Here, inferences are
drawn on the internal rotation of a distant Sun-like star by studying its
global modes of oscillation. We report asteroseismic constraints imposed on the
rotation rate and the inclination of the spin axis of the Sun-like star HD
52265, a principal target observed by the CoRoT satellite that is known to host
a planetary companion. These seismic inferences are remarkably consistent with
an independent spectroscopic observation (rotational line broadening) and with
the observed rotation period of star spots. Furthermore, asteroseismology
constrains the mass of exoplanet HD 52265b. Under the standard assumption that
the stellar spin axis and the axis of the planetary orbit coincide, the minimum
spectroscopic mass of the planet can be converted into a true mass of 1.85
(+0.52,-0.42) M_Jupiter, which implies that it is a planet, not a brown dwarf.


title: Hurwitz ball quotients

abstract:
  We consider the analogue of Hurwitz curves, smooth projective curves $C$ of
genus $g \ge 2$ that realize equality in the Hurwitz bound $|\mathrm{Aut}(C)|
\le 84 (g - 1)$, to smooth compact quotients $S$ of the unit ball in
$\mathbb{C}^2$. When $S$ is arithmetic, we show that $|\mathrm{Aut}(S)| \le 288
e(S)$, where $e(S)$ is the (topological) Euler characteristic, and in the case
of equality show that $S$ is a regular cover of a particular Deligne--Mostow
orbifold. We conjecture that this inequality holds independent of
arithmeticity, and note that work of Xiao makes progress on this conjecture and
implies the best-known lower bound for the volume of a complex hyperbolic
$2$-orbifold.


title:
Physical effects of gas envelopes with different extension on the
  collapse of a gas core

abstract:
  In this paper we study the gravitational collapse of a molecular hydrogen gas
cloud composed of a core plus a gas envelope surrounding the core. We
numerically simulate the collapse of four cloud models to take a glimpse to the
time evolution of several dynamic variables, such as the angular momentum and
the $aem$ ratio, as well as the ratios between the thermal and rotational
energies with respect to the potential gravitational energy, denoted as
$\alpha$ and $\beta$, respectively, among others. We re-take those models
introduced by Arreaga et.al (Astronomy and Astrophysics, {\bf Vol. 509},
(2010), pag. A96.) in the present paper in order to produce different outcomes
of the collapsing cloud characterized in terms of the aforementioned dynamical
variables. Such characterization was missing in the paper by Arreaga et.al
(Astronomy and Astrophysics, {\bf Vol. 509}, (2010), pag. A96.), and here we
show that the gas envelope extension effects on the collapsing core can be
quantitatively compared.


title:
Intrinsic Magnetism of Grain Boundaries in Two-dimensional Metal
  Dichalcogenides

abstract:
  Grain boundaries (GBs) are structural imperfections that typically degrade
the performance of materials. Here we show that dislocations and GBs in
two-dimensional (2D) metal dichalcogenides MX2 (M = Mo, W; X = S, Se) can
actually improve the material by giving it a qualitatively new physical
property: magnetism. The dislocations studied all have a substantial magnetic
moment of ~1 Bohr magneton. In contrast, dislocations in other well-studied 2D
materials are typically non-magnetic. GBs composed of pentagon-heptagon pairs
interact ferromagnetically and transition from semiconductor to half-metal or
metal as a function of tilt angle and/or doping level. When the tilt angle
exceeds 47{\deg} the structural energetics favor square-octagon pairs and the
GB becomes an antiferromagnetic semiconductor. These exceptional magnetic
properties arise from an interplay of dislocation-induced localized states,
doping, and locally unbalanced stoichiometry. Purposeful engineering of
topological GBs may be able to convert MX2 into a promising 2D magnetic
semiconductor.


title:
The resistance of 2D Topological insulator in the absence of the
  quantized transport

abstract:
  We report unconventional transport properties of HgTe wells with inverted
band structure: the resistance does not show insulating behavior even when it
is of the order of $10^2\times h/2e^{2}$. The system is expected to be a
two-dimensional topological insulator with a dominant edge state contribution.
The results are inconsistent with theoretical models developed within the
framework of the helical Luttinger liquid.


title: A high-throughput ab initio review of platinum-group alloy systems

abstract:
  We report a comprehensive study of the binary systems of the platinum group
metals with the transition metals, using high-throughput first-principles
calculations. These computations predict stability of new compounds in 38
binary systems where no compounds have been reported in the literature
experimentally, and a few dozen of as yet unreported compounds in additional
systems. Our calculations also identify stable structures at compound
compositions that have been previously reported without detailed structural
data and indicate that some experimentally reported compounds may actually be
unstable at low temperatures. With these results we construct enhanced
structure maps for the binary alloys of platinum group metals. These are much
more complete, systematic and predictive than those based on empirical results
alone.


title: The Structure of the Evolved Circumbinary Disk around V4046 Sgr

abstract:
  We present sensitive, sub-arcsecond resolution Submillimeter Array
observations of the protoplanetary disk around the nearby, pre-main sequence
spectroscopic binary V4046 Sgr. We report for the first time a large inner hole
(r=29 AU) spatially resolved in the 1.3 mm continuum emission and study the
structure of this disk using radiative transfer calculations to model the
spectral energy distribution (SED), continuum visibilities, and spectral line
emission of CO and its main isotopologues. Our modeling scheme demonstrates
that the majority of the dust mass is distributed in a narrow ring (centered at
37 AU with a FWHM of 16 AU) that is ~5 times more compact than the gas disk.
This structure implies that the dust-to-gas mass ratio has a strong spatial
variation, ranging from a value much larger than typical of the interstellar
medium (ISM) at the ring to much smaller than that of the ISM at larger disk
radii. We suggest that these basic structural features are potentially
observational signatures of the accumulation of solids at a local gas pressure
maximum. These models also require a substantial population of ~micron-sized
grains inside the central disk cavity. We suggest that this structure is likely
the result of dynamical interactions with a low-mass companion, although
photoevaporation may also play a secondary role.


title:
Employing real experiments and modern viewpoints in the teaching of
  modern physics

abstract:
  This is a report of a course on modern physics designed and taught to
undergraduate science and engineering students in the Spring of 2013. The
course, meant for freshmen, attempts to integrate statistical mechanics into
non-classical physics and introduces some novel teaching ideas such as the
field approach in contrast to typical wave and particle viewpoints
traditionally covered in usual textbooks. The various modern applications of
quantum theory in realizing practical devices are recounted in a way that is
amenable to beginners. Especially, we describe the inclusion of visually
appealing and carefully designed robust experiments inside the formal classroom
environment. This collection of applications and demonstrations serves as a
useful collection of teaching aids and can be easily transformed into active
learning exercises. The impact of this teaching strategy on student learning
and its role in exciting an interest in physics is assessed.