title:
Stripping of nitrogen-rich AGB ejecta from interacting dwarf irregular
  galaxies

abstract:
  Dwarf irregular galaxies (dIrrs) including the Magellanic Clouds in the local
Universe, in many cases, exhibit an unusually low N/O abundance ratio (log N/O
~ -1.5) in H II regions as compared with the solar value (~-0.9). This ratio is
broadly equivalent to the average level of extremely metal-poor stars in the
Galactic halo, suggesting that N released from asymptotic giant branch (AGB)
stars is missing in the present-day interstellar matter of these dIrrs. We find
evidence for past tidal interactions in the properties of individual dIrrs
exhibiting low N/O ratios, while a clear signature of interactions is unseen
for dIrrs with high N/O ratios. Accordingly, we propose that the ejecta of
massive AGB stars that correspond to a major production site of N can be
stripped from dIrrs that have undergone a strong interaction with a luminous
galaxy. The physical process of its stripping is made up of two stages: (i) the
ejecta of massive AGB stars in a dIrr are first merged with those of the
bursting prompt SNe Ia and pushed up together to the galaxy halo, and (ii)
subsequently through tidal interactions with a luminous galaxy, these ejecta
are stripped from a dwarf galaxy's potential well. Our new chemical evolution
models with stripping of AGB ejecta succeed in reproducing the observed low N/O
ratio. Furthermore, we perform N-body + hydrodynamical simulations to trace the
fate of AGB ejecta inside a dIrr orbiting the Milky Way, and confirm that a
tidal interaction is responsible for the efficient stripping of AGB ejecta from
dIrrs.


title: The weight part of Serre's conjecture for GL(2)

abstract:
  Let p > 2 be prime. We use purely local methods to determine the possible
reductions of certain two-dimensional crystalline representations, which we
call "pseudo-Barsotti-Tate representations", over arbitrary finite extensions
of the p-adics. As a consequence, we establish (under the usual Taylor-Wiles
hypothesis) the weight part of Serre's conjecture for GL(2) over arbitrary
totally real fields.


title: The State of Supersymmetry after Run I of the LHC

abstract:
  In these lectures I survey the state of supersymmetric extensions of the
Standard Model in light of data from the first run of the LHC. After assessing
pre-LHC expectations based on principles of naturalness and parsimony, I review
the landscape of direct and indirect search limits at the LHC, including the
implications of the observed Higgs mass and couplings. Finally, I survey
several broad classes of supersymmetric models that are consistent with current
data and enumerate the most promising search strategies and model-building
directions for the future.


title: Accidental Inflation from K\"ahler Uplifting

abstract:
  We analyze the possibility of realizing inflation with a subsequent dS vacuum
in the K\"ahler uplifting scenario. The inclusion of several quantum
corrections to the 4d effective action evades previous no-go theorems and
allows for construction of simple and successful models of string inflation.
The predictions of several benchmark models are in accord with current
observations, i.e., a red spectral index, negligible non-gaussianity, and
spectral distortions similar to the simplest models of inflation. A
particularly interesting subclass of models are "left-rolling" ones, where the
overall volume of the compactified dimensions shrinks during inflation. We call
this phenomenon "inflation by deflation" (IBD), where deflation refers to the
internal manifold. This subclass has the appealing features of being
insensitive to initial conditions, avoiding the overshooting problem, and
allowing for observable running $\alpha$ ~ 0.012 and enhanced tensor-to-scalar
ratio $r$ ~ $10^{-5}$. The latter results differ significantly from many string
inflation models.


title: Limits on New Physics from Black Holes

abstract:
  Black holes emit high energy particles which induce a finite density
potential for any scalar field $\phi$ coupling to the emitted quanta. Due to
energetic considerations, $\phi$ evolves locally to minimize the effective
masses of the outgoing states. In theories where $\phi$ resides at a metastable
minimum, this effect can drive $\phi$ over its potential barrier and
classically catalyze the decay of the vacuum. Because this is not a tunneling
process, the decay rate is not exponentially suppressed and a single black hole
in our past light cone may be sufficient to activate the decay. Moreover,
decaying black holes radiate at ever higher temperatures, so they eventually
probe the full spectrum of particles coupling to $\phi$. We present a detailed
analysis of vacuum decay catalyzed by a single particle, as well as by a black
hole. The former is possible provided large couplings or a weak potential
barrier. In contrast, the latter occurs much more easily and places new
stringent limits on theories with hierarchical spectra. Finally, we comment on
how these constraints apply to the standard model and its extensions, e.g.
metastable supersymmetry breaking.


title:
Analysis of multichannel measurements of rare processes with uncertain
  expected background and acceptance

abstract:
  A typical experiment in high energy physics is considered. The result of the
experiment is assumed to be a histogram consisting of bins or channels with
numbers of corresponding registered events. The expected background and
expected signal shape or acceptance are measured in separate auxiliary
experiments, or calculated by the Monte Carlo method with finite sample size,
and hence with finite precision. An especially complex situation occurs when
the expected background in some of the channels happens to be zero due to
either a fluctuation of the auxiliary measurement (or simulation) or because it
is truly zero. Different statistical methods give different confidence
intervals for the full signal rate and different significances of the
signal+background hypothesis versus the pure background hypothesis. Detailed
analysis and numerical tests are presented.


title: Tight and random nonorthogonal fusion frames

abstract:
  First we show that tight nonorthogonal fusion frames a relatively easy to com
by. In order to do this we need to establish a classification of how to to wire
a self adjoint operator as a product of (nonorthogonal) projection operators.
We also discuss the link between nonorthogonal fusion frames and positive
operator valued measures, we define and study a nonorthogonal fusion frame
potential, and we introduce the idea of random nonorthogonal fusion frames.


title: The Second Order Spectrum and Optimal Convergence

abstract:
  The method of second order relative spectra has been shown to reliably
approximate the discrete spectrum for a self-adjoint operator. We extend the
method to normal operators and find optimal convergence rates for eigenvalues
and eigenspaces. The convergence to eigenspaces is new, while the convergence
rate for eigenvalues improves on the previous estimate by an order of
magnitude.


title: Machines are benchmarked by code, not algorithms

abstract:
  This article highlights how small modifications to either the source code of
a benchmark program or the compilation options may impact its behavior on a
specific machine. It argues that for evaluating machines, benchmark providers
and users be careful to ensure reproducibility of results based on the machine
code actually running on the hardware and not just source code. The article
uses color to grayscale conversion of digital images as a running example.


title:
Decentralized Rigidity Maintenance Control with Range Measurements for
  Multi-Robot Systems

abstract:
  This work proposes a fully decentralized strategy for maintaining the
formation rigidity of a multi-robot system using only range measurements, while
still allowing the graph topology to change freely over time. In this
direction, a first contribution of this work is an extension of rigidity theory
to weighted frameworks and the rigidity eigenvalue, which when positive ensures
the infinitesimal rigidity of the framework. We then propose a distributed
algorithm for estimating a common relative position reference frame amongst a
team of robots with only range measurements in addition to one agent endowed
with the capability of measuring the bearing to two other agents. This first
estimation step is embedded into a subsequent distributed algorithm for
estimating the rigidity eigenvalue associated with the weighted framework. The
estimate of the rigidity eigenvalue is finally used to generate a local control
action for each agent that both maintains the rigidity property and enforces
additional con- straints such as collision avoidance and sensing/communication
range limits and occlusions. As an additional feature of our approach, the
communication and sensing links among the robots are also left free to change
over time while preserving rigidity of the whole framework. The proposed scheme
is then experimentally validated with a robotic testbed consisting of 6
quadrotor UAVs operating in a cluttered environment.


title: Plane curves containing a star configuration

abstract:
  Given a collection of $l$ general lines $\ell_1,\ldots,\ell_{l}$ in $\pr^2$,
the star configuration $\XX(l)$ is the set of points constructed from all
pairwise intersections of these lines. For each non-negative integer $d$, we
compute the dimension of the family of curves of degree $d$ that contain a star
configuration.


title:
Constraining Primordial Magnetic Fields by CMB Photon-Graviton
  Conversion

abstract:
  We revisit the method of using the photon-graviton conversion mechanism in
the presence of the external magnetic field to probe small-scale primordial
magnetic fields that may exist between the last scattering surface and present.
Specifically, we investigate impacts on the conversion efficiency due to the
presence of matter, including the plasma collective effect and the atomic
polarizability. In general, these effects tend to reduce the conversion
probability. Under this more realistic picture and based on the precision of
COBE's measurement of CMB (cosmic microwave background) blackbody spectrum, we
find an upper bound for the primordial magnetic field strength, B < 30G, at the
time of recombination. Although at present the bound based on the
photon-graviton conversion mechanism is not as tight as that obtained by the
direct use of CMB temperature anisotropy, it nevertheless provides an important
independent constraint on primordial magnetic fields and at epochs in addition
to the recombination. The bound can be significantly improved if the CMB
blackbody spectrum measurement becomes more precise in future experiments such
as PIXIE.


title:
Optical bistability in one dimensional doped photonic crystals with
  spontaneously generated coherence

abstract:
  We investigate optical bistability in a multilayer one-dimensional photonic
crystal where the central layer is doped with $\Lambda$-type three level atoms.
We take into account the influence of spontaneously generated coherence when
the lower atomic levels are sufficiently close to each other, in which case
Kerr-type nonlinear response of the atoms is enhanced. We calculate the
propagation of a probe beam in the defect mode window using numerical nonlinear
transfer matrix method. We find that Rabi frequency of a control field acting
on the defect layer and the detuning of the probe field from the atomic
resonance can be used to control the size and contrast of the hysteresis loop
and the threshold of the optical bistability. In particular we find that, at
the optimal spontaneously generated coherence, three orders of magnitude lower
threshold can be achieved relative to the case without the coherence.

categories: quant-ph cond-mat.mes-hall physics.atom-ph physics.optics


title: Balayage and Short time Fourier transform frames

abstract:
  Using his formulation of the potential theoretic notion of balayage and his
deep results about this idea, Beurling gave sufficient conditions for Fourier
frames in terms of balayage. The analysis makes use of spectral synthesis, due
to Wiener and Beurling, as well as properties of strict multiplicity, whose
origins go back to Riemann. In this setting and with this technology, we
formulate and prove non-uniform sampling formulas in the context of the short
time Fourier transform (STFT).


title:
Statistical Global Model of beta- Half-lives and r-Process
  Nucleosynthesis

abstract:
  Purpose: Our objective is to apply an improved statistical global model of
beta^- decay half-life systematics [1] generated by machine-learning techniques
to the prediction of beta half-lives relevant to r-process nuclei. The primary
aim of this application is to complement existing r-process-clock and
matter-flow studies, thereby providing additional theoretical support for the
planning of future activities of the world's network of rare-isotope
laboratories.
  Results: Results are presented for nuclides situated on the r-ladders at
N=50, 82, and 126 where abundances peak, as well as for nuclides that affect
abundances between peaks or may be relevant to r-processes under different
astrophysical scenarios. The half-lives of some of the targeted neutron-rich
nuclides have either been recently measured or will be accessible at
rare-isotope laboratories in the relatively near future. The results of our
large-scale data-driven half-life calculations (generated by a "theory-thin"
global statistical model) are compared to available experimental data,
including recent measurements on very neutron-rich nuclei along an r-process
path far from the valley of $\beta$ stability. Comparison is also made with
corresponding results from traditional global models derived by
semi-phenomenological "theory-thick" approaches.


title:
Periastron Advance in Spinning Black Hole Binaries: Gravitational
  Self-Force from Numerical Relativity

abstract:
  We study the general relativistic periastron advance in spinning black hole
binaries on quasi-circular orbits, with spins aligned or anti-aligned with the
orbital angular momentum, using numerical-relativity simulations, the
post-Newtonian approximation, and black hole perturbation theory. By imposing a
symmetry by exchange of the bodies' labels, we devise an improved version of
the perturbative result, and use it as the leading term of a new type of
expansion in powers of the symmetric mass ratio. This allows us to measure, for
the first time, the gravitational self-force effect on the periastron advance
of a non-spinning particle orbiting a Kerr black hole of mass M and spin S =
-0.5 M^2, down to separations of order 9M. Comparing the predictions of our
improved perturbative expansion with the exact results from numerical
simulations of equal-mass and equal-spin binaries, we find a remarkable
agreement over a wide range of spins and orbital separations.


title:
Bandwidth Aggregation Techniques in Heterogeneous Multi-homed Devices: A
  Survey

abstract:
  The widespread deployment of various networking technologies, coupled with
the exponential increase in end- user data demand, have led to the
proliferation of multi-homed, or multi-interface enabled, devices. These trends
drove researchers to investigate a wide spectrum of solutions, at different
layers of the protocol stack, that utilize available interfaces in such devices
by aggregating their bandwidth. In this survey paper, we provide an overview
and examine the evolution of bandwidth aggregation solutions over time. We
begin by describing the bandwidth aggregation problem. We investigate the
common features of proposed bandwidth aggregation systems and break them down
into two major categories: layer-dependent and layer-independent features.
Afterwards, we discuss the evolution trends in the literature and discuss some
open challenges requiring further research. We end the survey with a brief
presentation of related work in tangential research areas.


title:
Further Evidence of the Planetary Nature of HD 95086 b from Gemini/NICI
  H-band Data

abstract:
  We present our analysis of the Gemini/NICI H-band data of HD 95086, following
the discovery of the planet HD 95086 b in L'. The H-band data reach a contrast
of 12.7 mag relative to the host star at 5 sigma levels in the location of HD
95086 b, and no point source is found. Our non-detection and H-L' color limit
rules out the possibility that the object is a foreground L/T dwarf and that,
if it is bound to HD 95086, it is a genuine planetary mass object. We estimate
a new pre-main-sequence isochronal age for HD 95086 of 17+/-4 Myr, which is
commensurate with previous mean age estimates for the Lower Cen-Crux subgroup.
Adopting an age of 17 Myr, the color limit is inconsistent with the COND model,
marginally consistent with the BT-SETTL model, and consistent with the DUSTY
model.


title:
Periastron advance in spinning black hole binaries: comparing
  effective-one-body and Numerical Relativity

abstract:
  We compute the periastron advance using the effective-one-body formalism for
binary black holes moving on quasi-circular orbits and having spins collinear
with the orbital angular momentum. We compare the predictions with the
periastron advance recently computed in accurate numerical-relativity
simulations and find remarkable agreement for a wide range of spins and mass
ratios. These results do not use any numerical-relativity calibration of the
effective-one-body model, and stem from two key ingredients in the
effective-one-body Hamiltonian: (i) the mapping of the two-body dynamics of
spinning particles onto the dynamics of an effective spinning particle in a
(deformed) Kerr spacetime, fully symmetrized with respect to the two-body
masses and spins, and (ii) the resummation, in the test-particle limit, of all
post-Newtonian (PN) corrections linear in the spin of the particle. In fact,
even when only the leading spin PN corrections are included in the
effective-one-body spinning Hamiltonian but all the test-particle corrections
linear in the spin of the particle are resummed we find very good agreement
with the numerical results (within the numerical error for equal-mass binaries
and discrepancies of at most 1% for larger mass ratios). Furthermore, we
specialize to the extreme mass-ratio limit and derive, using the equations of
motion in the gravitational skeleton approach, analytical expressions for the
periastron advance, the meridional Lense-Thirring precession and spin
precession frequency in the case of a spinning particle on a nearly circular
equatorial orbit in Kerr spacetime, including also terms quadratic in the spin.


title: Torus orbits on homogeneous varieties and Kac polynomials of quivers

abstract:
  In this paper we prove that the counting polynomials of certain torus orbits
in products of partial flag varieties coincides with the Kac polynomials of
supernova quivers, which arise in the study of the moduli spaces of certain
irregular meromorphic connections on trivial bundles over the projective line.
We also prove that these polynomials can be expressed as a specialization of
Tutte polynomials of certain graphs providing a combinatorial proof of the
non-negativity of their coefficients.


title: Super Yang-Mills, division algebras and triality

abstract:
  We give a unified division algebraic description of (D=3, N=1,2,4,8), (D=4,
N=1,2,4), (D=6, N=1,2) and (D=10, N=1) super Yang-Mills theories. A given
(D=n+2, N) theory is completely specified by selecting a pair (A_n, A_{nN}) of
division algebras, A_n, A_{nN} = R, C, H, O, where the subscripts denote the
dimension of the algebras. We present a master Lagrangian, defined over
A_{nN}-valued fields, which encapsulates all cases. Each possibility is
obtained from the unique (O, O) (D=10, N=1) theory by a combination of
Cayley-Dickson halving, which amounts to dimensional reduction, and removing
points, lines and quadrangles of the Fano plane, which amounts to consistent
truncation. The so-called triality algebras associated with the division
algebras allow for a novel formula for the overall (spacetime plus internal)
symmetries of the on-shell degrees of freedom of the theories. We use imaginary
A_{nN}-valued auxiliary fields to close the non-maximal supersymmetry algebra
off-shell. The failure to close for maximally supersymmetric theories is
attributed directly to the non-associativity of the octonions.


title:
Causes and Consequences of genetic background effects illuminated by
  integrative genomic analysis

abstract:
  The phenotypic consequences of individual mutations are modulated by the wild
type genetic background in which they occur.Although such background dependence
is widely observed, we do not know whether general patterns across species and
traits exist, nor about the mechanisms underlying it. We also lack knowledge on
how mutations interact with genetic background to influence gene expression,
and how this in turn mediates mutant phenotypes. Furthermore, how genetic
background influences patterns of epistasis remains unclear. To investigate the
genetic basis and genomic consequences of genetic background dependence of the
scallopedE3 allele on the Drosophila melanogaster wing, we generated multiple
novel genome level datasets from a mapping by introgression experiment and a
tagged RNA gene expression dataset. In addition we used whole genome
re-sequencing of the parental lines two commonly used laboratory strains to
predict polymorphic transcription factor binding sites for SD. We integrated
these data with previously published genomic datasets from expression
microarrays and a modifier mutation screen. By searching for genes showing a
congruent signal across multiple datasets, we were able to identify a robust
set of candidate loci contributing to the background dependent effects of
mutations in sd. We also show that the majority of background-dependent
modifiers previously reported are caused by higher-order epistasis, not
quantitative non-complementation. These findings provide a useful foundation
for more detailed investigations of genetic background dependence in this
system, and this approach is likely to prove useful in exploring the genetic
basis of other traits as well.


title:
Two semi-automated computational approaches for spectroscopic analysis
  of stellar photospheres: detailed characterization at high resolution and
  abundance determination at medium resolution

abstract:
  We report on two distinct computational approaches to self-consistently
measure photospheric properties of large samples of stars. Both procedures
consist of a set of several semi-integrated tasks based on shell and Python
scripts, which efficiently run either our own codes or open source software
commonly adopted by the astronomical community. One approach aims to derive the
main stellar photospheric parameters and abundances of a few elements by
analysing high-resolution spectra from a given public library homogeneously
constructed. The other one is applied to recover the abundance of a single
element in stars with known photospheric parameters by using mid-resolution
spectra from another open homogeneous database and calibrating derived
abundances. Both semi-automated computational approaches provide homogeneity
and objectivity to every step of the process and represent a fast way to reach
partial and final results as well as to estimate measurement errors, making
possible to systematically evaluate and improve the distinct steps.


title:
Modern Ives-Stilwell Experiments At Storage Rings: Large Boosts Meet
  High Precision

abstract:
  We give a brief overview of time dilation tests using high-resolution laser
spectroscopy at heavy-ion storage rings. We reflect on the various methods used
to eliminate the first-order Doppler effect and on the pitfalls encountered,
and comment on possible extensions at future facilities providing relativistic
heavy ion beams at $\gamma \gg 1$.


title: On the slice-ribbon conjecture for pretzel knots

abstract:
  We give a necessary, and in some cases sufficient, condition for sliceness
inside the family of pretzel knots $P (p_1,...,p_n)$ with one $p_i$ even. The
three stranded case yields two interesting families of examples: the first
consists of knots for which the non-sliceness is detected by the Alexander
polynomial while several modern obstructions to sliceness vanish. The second
family has the property that the correction terms from Heegaard-Floer homology
of the double branched covers of these knots do not obstruct the existence of a
rational homology ball; however, the Casson-Gordon invariants show that the
double branched covers do not bound rational homology balls.


title:
Optimizing the performance of Lattice Gauge Theory simulations with
  Streaming SIMD extensions

abstract:
  Two factors, which affect simulation quality are the amount of computing
power and implementation. The Streaming SIMD (single instruction multiple data)
extensions (SSE) present a technique for influencing both by exploiting the
processor's parallel functionalism. In this paper, we show how SSE improves
performance of lattice gauge theory simulations. We identified two significant
trends through an analysis of data from various runs. The speed-ups were higher
for single precision than double precision floating point numbers. Notably,
though the use of SSE significantly improved simulation time, it did not
deliver the theoretical maximum. There are a number of reasons for this:
architectural constraints imposed by the FSB speed, the spatial and temporal
patterns of data retrieval, ratio of computational to non-computational
instructions, and the need to interleave miscellaneous instructions with
computational instructions. We present a model for analyzing the SSE
performance, which could help factor in the bottlenecks or weaknesses in the
implementation, the computing architecture, and the mapping of software to the
computing substrate while evaluating the improvement in efficiency. The model
or framework would be useful in evaluating the use of other computational
frameworks, and in predicting the benefits that can be derived from future
hardware or architectural improvements.


title:
Stress-Energy Tensor of the Quantized Massive Fields in
  Friedman-Robertson-Walker Spacetimes

abstract:
  The approximate stress-energy tensor of the quantized massive scalar, spinor
and vector fields in the spatially flat Friedman-Robertson-Walker universe is
constructed. It is shown that for the scalar fields with arbitrary curvature
coupling, $\xi,$ the stress-energy tensor calculated within the framework of
the Schwinger-DeWitt approach is identical to the analogous tensor constructed
in the adiabatic vacuum. Similarly, the Schwinger-DeWitt stress-energy tensor
for the fields of spin 1/2 and 1 coincides with the analogous result calculated
by the Zeldovich-Starobinsky method. The stress-energy tensor thus obtained are
subsequently used in the back reaction problem. It is shown that for pure
semiclassical Einstein field equations with the vanishing cosmological constant
and the source term consisting exclusively of its quantum part there are no
self-consistent exponential solutions driven by the spinor and vector fields. A
similar situation takes place for the scalar field if the coupling constant
belongs to the interval $\xi \gtrsim 0.1.$ For a positive cosmological constant
the expansion slows down for all considered types of massive fields except for
minimally coupled scalar field. The perturbative approach to the problem is
briefly discussed and possible generalizations of the stress-energy tensor are
indicated.


title: de Bruijn arrays for L-fillings

abstract:
  We use modular arithmetic to construct a de Bruijn array containing all
fillings of an L (a 2 x 2 array with the upper right corner removed) with
digits chosen from {0,...,k-1}.


title: Interaction effects in Aharonov-Bohm-Kondo Rings

abstract:
  We study the conductance through an Aharonov-Bohm ring, containing a quantum
dot in the Kondo regime in one arm, at finite temperature and arbitrary
electronic density. We develop a general method for this calculation based on
changing basis to the screening and non-screening channels. We show that an
unusual term appears in the conductance, involving the connected 4-point
Green's function of the conduction electrons. However, this term and terms
quadratic in the ${\rm T}$-matrix can be eliminated at sufficiently low
temperatures, leading to an expression for the conductance linear in the Kondo
T-matrix. Explicit results are given for temperatures high compared to the
Kondo temperature.


title: Non-additivity in laser-illuminated many-atom systems

abstract:
  We show that atoms subject to laser radiation may form a non-additive
many-body system on account of their long-range forces, when the atoms are
trapped in the vicinity of a fiber with a Bragg grating. When the laser
frequency is inside the grating's bandgap but very close to its edge, we find
that the range and strength of the laser-induced interaction becomes
substantially enhanced, due to the large density of states near the edge, while
the competing process of scattering to the fiber is inhibited. The dynamics of
the atomic positions in this system conforms to a prominent model of
statistical physics which exhibits slow relaxation. This suggests the
possibility of using laser-illuminated atoms to study the characteristics of
non-additive systems.

categories: quant-ph cond-mat.stat-mech physics.atom-ph physics.optics


title: Maximal mixing by incompressible fluid flows

abstract:
  We consider a model for mixing binary viscous fluids under an incompressible
flow. We proof the impossibility of perfect mixing in finite time for flows
with finite viscous dissipation. As measures of mixedness we consider a
Monge--Kantorovich--Rubinstein transportation distance and, more classically,
the $H^{-1}$ norm. We derive rigorous a priori lower bounds on these mixing
norms which show that mixing cannot proceed faster than exponentially in time.
The rate of the exponential decay is uniform in the initial data.


title: Exact Simulation of Wishart Multidimensional Stochastic Volatility Model

abstract:
  In this article, we propose an exact simulation method of the Wishart
multidimensional stochastic volatility (WMSV) model, which was recently
introduced by Da Fonseca et al. \cite{DGT08}. Our method is based onanalysis of
the conditional characteristic function of the log-price given volatility
level. In particular, we found an explicit expression for the conditional
characteristic function for the Heston model. We perform numerical experiments
to demonstrate the performance and accuracy of our method. As a result of
numerical experiments, it is shown that our new method is much faster and
reliable than Euler discretization method.


title:
Detection and Flux Density Measurements of the Millisecond Pulsar
  J2145-0750 below 100 MHz

abstract:
  We present flux density measurements and pulse profiles for the millisecond
pulsar PSR J2145-0750 spanning 37 to 81 MHz using data obtained from the first
station of the Long Wavelength Array. These measurements represent the lowest
frequency detection of pulsed emission from a millisecond pulsar to date. We
find that the pulse profile is similar to that observed at 102 MHz. We also
find that the flux density spectrum between ~40 MHz to 5 GHz is suggestive of a
break and may be better fit by a model that includes spectral curvature with a
rollover around 730 MHz rather than a single power law.


title:
Non-abelian Weyl Commutation Relations and the Series Product of Quantum
  Stochastic Evolutions

abstract:
  We show that the series product, which serves as an algebraic rule for
connecting state-based input/output systems, is intimately related to the
Heisenberg group and the canonical commutation relations. The series product
for quantum stochastic models then corresponds to a non-abelian generalization
of the Weyl commutation relation. We show that the series product gives the
general rule for combining the generators of quantum stochastic evolutions
using a Lie-Trotter product formula.


title: Spectral Aspects of the Skew-Shift Operator: A Numerical Perspective

abstract:
  In this paper we perform a numerical study of the spectra, eigenstates, and
Lyapunov exponents of the skew-shift counterpart to Harper's equation. This
study is motivated by various conjectures on the spectral theory of these
'pseudo-random' models, which are reviewed in detail in the initial sections of
the paper. The numerics carried out at different scales are within agreement
with the conjectures and show a striking difference compared with the spectral
features of the Almost Mathieu model. In particular our numerics establish a
small upper bound on the gaps in the spectrum (conjectured to be absent).


title:
On the prospects of ultra-high energy cosmic rays detection by high
  altitude antennas

abstract:
  Radio emission from Ultra-High Energy Cosmic Rays (UHECR) showers detected
after specular reflection off the Antarctic ice surface has been recently
demonstrated by the ANITA balloon-borne experiment. An antenna observing a
large area of ice or water from a mountaintop, a balloon or a satellite may be
competitive with more conventional techniques. We present an estimate of the
exposure of a high altitude antenna, which provides insight on the prospects of
this technique for UHECR detection. We find that a satellite antenna may reach
a significantly larger exposure than existing UHECR observatories, but an
experimental characterization of the radio reflected signal is required to
establish the potential of this approach. A balloon-borne or a mountaintop
antenna are found not to be competitive under any circumstances.


title:
On structure-preserving transformations of the Ito generator matrix for
  model reduction of quantum feedback networks

abstract:
  Two standard operations of model reduction for quantum feedback networks,
elimination of internal connections under the instantaneous feedback limit and
adiabatic elimination of fast degrees of freedom, are cast as
structure-preserving transformations of It\=o generator matrices. It is shown
that the order in which they are applied is inconsequential.


title: Approximate Constraint Satisfaction Requires Large LP Relaxations

abstract:
  We prove super-polynomial lower bounds on the size of linear programming
relaxations for approximation versions of constraint satisfaction problems. We
show that for these problems, polynomial-sized linear programs are exactly as
powerful as programs arising from a constant number of rounds of the
Sherali-Adams hierarchy.
  In particular, any polynomial-sized linear program for Max Cut has an
integrality gap of 1/2 and any such linear program for Max 3-Sat has an
integrality gap of 7/8.


title: On monoids, 2-firs, and semifirs

abstract:
  Several authors have studied the question of when the monoid ring DM of a
monoid M over a ring D is a right and/or left fir (free ideal ring), a semifir,
or a 2-fir (definitions recalled in section 1). It is known that for M
nontrivial, a necessary condition for any of these properties to hold is that D
be a division ring. Under that assumption, necessary and sufficient conditions
on M are known for DM to be a right or left fir, and various conditions on M
have been proved necessary or sufficient for DM to be a 2-fir or semifir.
  A sufficient condition for DM to be a semifir is that M be a direct limit of
monoids which are free products of free monoids and free groups. W.Dicks has
conjectured that this is also necessary. However F.Ced\'o has given an example
of a monoid M which is not such a direct limit, but satisfies the known
necessary conditions for DM to be a semifir. It is an open question whether for
this M, the rings DM are semifirs.
  We note some reformulations of the known necessary conditions for DM to be a
2-fir or a semifir, motivate Ced\'o's construction and a variant, and recover
Ced\'o's results for both constructions.
  Any homomorphism from a monoid M into \Z induces a \Z-grading on DM, and we
show that for the two monoids in question, the rings DM are "homogeneous
semifirs" with respect to all such nontrivial \Z-gradings; i.e., have (roughly)
the property that every finitely generated homogeneous one-sided ideal is free.
  If M is a monoid such that DM is an n-fir, and N a "well-behaved" submonoid
of M, we obtain results on DN. Using these, we show that for M a monoid such
that DM is a 2-fir, mutual commutativity is an equivalence relation on
nonidentity elements of M, and each equivalence class, together with the
identity element, is a directed union of infinite cyclic groups or infinite
cyclic monoids.
  Several open questions are noted.


title: Magnetism in Compact Ultra Dense Objects

abstract:
  This paper summarizes some of the recent results on magnetism in high dense
mediums, where the phenomenon of color superconductivity can be present, and
its possible implications for the astrophysics of compact objects. The
presentation will be organized through the answers to three fundamental
questions.


title:
Enhanced Precision Through Multiple Reads for LDPC Decoding in Flash
  Memories

abstract:
  Multiple reads of the same Flash memory cell with distinct word-line voltages
provide enhanced precision for LDPC decoding. In this paper, the word-line
voltages are optimized by maximizing the mutual information (MI) of the
quantized channel. The enhanced precision from a few additional reads allows
FER performance to approach that of full-precision soft information and enables
an LDPC code to significantly outperform a BCH code. A constant-ratio
constraint provides a significant simplification in the optimization with no
noticeable loss in performance. For a well-designed LDPC code, the quantization
that maximizes the mutual information also minimizes the frame error rate in
our simulations. However, for an example LDPC code with a high error floor
caused by small absorbing sets, the MMI quantization does not provide the
lowest frame error rate. The best quantization in this case introduces more
erasures than would be optimal for the channel MI in order to mitigate the
absorbing sets of the poorly designed code. The paper also identifies a
trade-off in LDPC code design when decoding is performed with multiple
precision levels; the best code at one level of precision will typically not be
the best code at a different level of precision.


title:
Detection and measurement of spin-dependent dynamics in random telegraph
  signals

abstract:
  A quantum point contact was used to observe single-electron fluctuations of a
quantum dot in a GaAs heterostructure. The resulting random telegraph signals
(RTS) contain statistical information about the electron spin state if the
tunneling dynamics are spin-dependent. We develop a statistical method to
extract information about spin-dependent dynamics from RTS and use it to
demonstrate that these dynamics can be studied in the thermal energy regime.
The tunneling rates of each spin state are independently measured in a finite
external magnetic field. We confirm previous findings of a decrease in overall
tunneling rates for the spin excited state compared to the ground state as an
external magnetic field is increased.


title:
The supercritical pile gamma-ray burst model: The GRB afterglow
  steep-decline-and-plateau phase

abstract:
  We present a process that accounts for the steep-decline-and-plateau phase of
the Swift-XRT light curves, vexing features of GRB phenomenology. This process
is an integral part of the "supercritical pile" GRB model, proposed a few years
ago to provide an account for the conversion of the GRB kinetic energy into
radiation with a spectral peak at $E_{\rm pk} \sim m_ec^2$. We compute the
evolution of the relativistic blast wave (RBW) Lorentz factor $\Gamma$ to show
that the radiation--reaction force due to the GRB emission can produce an
abrupt, small ($\sim 25%$) decrease in $\Gamma$ at a radius which is smaller
(depending on conditions) than the deceleration radius $R_D$. Because of this
reduction, the kinematic criticality criterion of the "supercritical pile" is
no longer fulfilled. Transfer of the proton energy into electrons ceases, and
the GRB enters abruptly the afterglow phase at a luminosity smaller by $\sim
m_p/m_e$ than that of the prompt emission. If the radius at which this
slow-down occurs is significantly smaller than $R_D$, the RBW internal energy
continues to drive the RBW expansion at a constant (new) $\Gamma$, and its
X-ray luminosity remains constant until $R_D$ is reached, at which point it
resumes its more conventional decay, thereby completing the "unexpected" XRT
light curve phase. If this transition occurs at $R \simeq R_D$, the steep
decline is followed by a flux decrease instead of a "plateau", consistent with
the conventional afterglow declines. Besides providing an account of these
peculiarities, the model suggests that the afterglow phase may in fact begin
before the RBW reaches $R \simeq R_D$, thus introducing novel insights into the
GRB phenomenology.


title:
Product-form solutions for integrated services packet networks and cloud
  computing systems

abstract:
  We iteratively derive the product-form solutions of stationary distributions
of priority multiclass queueing networks with multi-sever stations. The
networks are Markovian with exponential interarrival and service time
distributions. These solutions can be used to conduct performance analysis or
as comparison criteria for approximation and simulation studies of large scale
networks with multi-processor shared-memory switches and cloud computing
systems with parallel-server stations. Numerical comparisons with existing
Brownian approximating model are provided to indicate the effectiveness of our
algorithm.

categories: math.PR cs.IT cs.NI cs.PF math.IT math.OC


title:
The study of neutron activation yields in spallation reaction of 400
  MeV/u carbon on a thick lead target

abstract:
  The spallation-neutron yield was studied experimentally by bombarding a thick
lead target with 400 MeV/u carbon beam. The data were obtained with the
activation analysis method using foils of Au, Mn, Al, Fe and In. The yields of
produced isotopes were deduced by analyzing the measured {\gamma} spectra of
irradiated foils. According to the isotopes yields, the spatial and energy
distributions of the neutron field were discussed. The experimental results
were compared with Monte Carlo simulations performed by the GEANT4 + FLUKA
code.


title:
Large and symmetric: The Khukhro--Makarenko theorem on laws --- without
  laws

abstract:
  We prove a generalisation of the Khukhro--Makarenko theorem on large
characteristic subgroups with laws. This general fact implies new results on
groups, algebras, and even graphs and other structures. Concerning groups, we
obtain, e.g., a fact in a sense dual to the Khukhro--Makarenko theorem. A
graph-theoretic corollary is an analogue of this theorem in which planarity
plays the role of a multilinear identity. We answer also a question of
Makarenko and Shumyatsky.


title: Diagram automorphisms of quiver varieties

abstract:
  We show that the fixed-point subvariety of a Nakajima quiver variety under a
diagram automorphism is a disconnected union of quiver varieties for the
`split-quotient quiver' introduced by Reiten and Riedtmann. As a special case,
quiver varieties of type D arise as the connected components of fixed-point
subvarieties of diagram involutions of quiver varieties of type A. In the case
where the quiver varieties of type A correspond to small self-dual
representations, we show that the diagram involutions coincide with classical
involutions of two-row Slodowy varieties. It follows that certain quiver
varieties of type D are isomorphic to Slodowy varieties for orthogonal or
symplectic Lie algebras.


title: Once more on the derivation of the Dirac equation

abstract:
  A brief review of the different ways of the Dirac equation derivation is
given. The foundations of the relativistic canonical quantum mechanics of a
fermionic doublet are formulated. In our approach the Dirac equation is derived
from the main equation of relativistic canonical quantum mechanics. In the
formalism of relativistic canonical quantum mechanics the absence of necessity
to appeal for the conception of the negative mass of the antiparticle is shown.


title: Reified valuations and adic spectra

abstract:
  We revisit Huber's theory of continuous valuations, which give rise to the
adic spectra used in his theory of adic spaces. We instead consider valuations
which have been reified, i.e., whose value groups have been forced to contain
the real numbers. This yields reified adic spectra which provide a framework
for an analogue of Huber's theory compatible with Berkovich's construction of
nonarchimedean analytic spaces. As an example, we extend the theory of
perfectoid spaces to this setting.


title:
Measurement of $e^+ e^- \to \omega \pi^0$, $K^{\ast}(892)\bar{K}$ and
  $K_2^{\ast}(1430)\bar{K}$ at $\sqrt{s}$ near 10.6 GeV

abstract:
  Using data samples of 89 fb$^{-1}$, 703 fb$^{-1}$, and 121 fb$^{-1}$
collected with the Belle detector at the KEKB asymmetric-energy $e^+e^-$
collider at center-of-mass energies 10.52 GeV, 10.58 GeV, and 10.876 GeV,
respectively, we study the exclusive reactions $e^+e^- \to \omega\pi^0$,
$K^{\ast}(892)\bar{K}$, and $K_2^{\ast}(1430)\bar{K}$ (Charge-conjugate modes
are included implicitly). Significant signals of $\omega\pi^0$,
$K^{\ast}(892)^0\bar{K}^0$, and $K_2^{\ast}(1430)^-K^+$ are observed for the
first time at these energies, and the energy dependencies of the cross sections
are presented. On the other hand, no significant excesses for
$K^{\ast}(892)^-K^+$ and $K_2^{\ast}(1430)^0 \bar{K}^0$ are found, and we set
limits on the cross section ratios $R_{\rm VP} = \frac{\sigma_B(e^+e^-\to
K^{\ast}(892)^0\bar K^0)} {\sigma_B(e^+e^-\to K^{\ast}(892)^-K^+)}>$ 4.3, 20.0,
and 5.4, and $R_{\rm TP} = \frac{\sigma_B(e^+e^-\to K_2^{\ast}(1430)^0\bar
K^0)} {\sigma_B(e^+e^-\to K_2^{\ast}(1430)^-K^+)}<$ 1.1, 0.4, and 0.6, for
center-of-mass energies of 10.52 GeV, 10.58 GeV, and 10.876 GeV, respectively,
at the 90% C.L.


title: Robust Stability of Quantum Systems with Nonlinear Dynamic Uncertainties

abstract:
  This paper considers the problem of robust stability for a class of uncertain
nonlinear quantum systems subject to unknown perturbations in the system
Hamiltonian. The nominal system is a linear quantum system defined by a linear
vector of coupling operators and a quadratic Hamiltonian. This paper extends
previous results on the robust stability of nonlinear quantum systems to allow
for quantum systems with dynamic uncertainties. These dynamic uncertainties are
required to satisfy a certain quantum stochastic integral quadratic constraint.
The robust stability condition is given in terms of a strict bounded real
condition. This result is applied to the robust stability analysis of an
optical parametric amplifier.


title: On properness of the eigencurve

abstract:
  We prove that the Coleman-Mazur eigencurve is proper (over the weight space)
at a large class of points.


title: Coherent-Classical Estimation for Quantum Linear Systems

abstract:
  This paper introduces a problem of coherent-classical estimation for a class
of linear quantum systems. In this problem, the estimator is a mixed
quantum-classical system which produces a classical estimate of a system
variable. The coherent-classical estimator may also involve coherent feedback.
An example involving optical squeezers is given to illustrate the efficacy of
this idea.


title:
Modeling Bimodal Discrete Data Using Conway-Maxwell-Poisson Mixture
  Models

abstract:
  Bimodal truncated count distributions are frequently observed in aggregate
survey data and in user ratings when respondents are mixed in their opinion.
They also arise in censored count data, where the highest category might create
an additional mode. Modeling bimodal behavior in discrete data is useful for
various purposes, from comparing shapes of different samples (or survey
questions) to predicting future ratings by new raters. The Poisson distribution
is the most common distribution for fitting count data and can be modified to
achieve mixtures of truncated Poisson distributions. However, it is suitable
only for modeling equi-dispersed distributions and is limited in its ability to
capture bimodality. The Conway-Maxwell-Poisson (CMP) distribution is a
two-parameter generalization of the Poisson distribution that allows for over-
and under-dispersion. In this work, we propose a mixture of CMPs for capturing
a wide range of truncated discrete data, which can exhibit unimodal and bimodal
behavior. We present methods for estimating the parameters of a mixture of two
CMP distributions using an EM approach. Our approach introduces a special
two-step optimization within the M step to estimate multiple parameters. We
examine computational and theoretical issues. The methods are illustrated for
modeling ordered rating data as well as truncated count data, using simulated
and real examples.


title: Notes on the Universal Elliptic KZB Equation

abstract:
  The universal elliptic KZB equation is the integrable connection on the
pro-vector bundle over M_{1,2} whose fiber over the point corresponding to the
elliptic curve E and a non-zero point x of E is the unipotent completion of
\pi_1(E-{0},x). This was written down independently by Calaque, Enriquez and
Etingof (arXiv:math/0702670), and by Levin and Racinet (arXiv:math/0703237). It
generalizes the KZ-equation in genus 0. These notes are in four parts. The
first two parts provide a detailed exposition of this connection (following
Levin-Racinet); the third is a leisurely exploration of the connection in
which, for example, we compute the limit mixed Hodge structure on the unipotent
fundamental group of the Tate curve minus its identity. In the fourth part we
elaborate on ideas of Levin and Racinet and explicitly compute the connection
over the moduli space of elliptic curves with a non-zero abelian differential,
showing that it is defined over Q.


title:
Quantum Phases of the Shastry-Sutherland Kondo Lattice: Implications for
  the Global Phase Diagram of Heavy Fermion Metals

abstract:
  Considerable recent theoretical and experimental efforts have been devoted to
the study of quantum criticality and novel phases of antiferromagnetic
heavy-fermion metals. In particular, quantum phase transitions have been
discovered in the compound Yb$_2$Pt$_2$Pb. These developments have motivated us
to study the competition between the RKKY and Kondo interactions on the
Shastry-Sutherland lattice. We determine the zero-temperature phase diagram as
a function of magnetic frustration and Kondo coupling within a slave-fermion
approach. Pertinent phases include the Shastry-Sutherland valence bond solid
and heavy Fermi liquid. In the presence of antiferromagnetic order, our
zero-temperature phase diagram is remarkably similar to the global phase
diagram proposed earlier based on general grounds. We discuss the implications
of our results for the experiments on Yb$_2$Pt$_2$Pb and other geometrically
frustrated heavy fermion compounds.


title: Long-term memory in electricity prices: Czech market evidence

abstract:
  We analyze long-term memory properties of hourly prices of electricity in the
Czech Republic between 2009 and 2012. As the dynamics of the electricity prices
is dominated by cycles -- mainly intraday and daily -- we opt for the detrended
fluctuation analysis, which is well suited for such specific series. We find
that the electricity prices are non-stationary but strongly mean-reverting
which distinguishes them from other financial assets which are usually
characterized as unit root series. Such description is attributed to specific
features of electricity prices, mainly to non-storability. Additionally, we
argue that the rapid mean-reversion is due to the principles of electricity
spot prices. These properties are shown to be stable across all studied years.


title:
Asymmetry and non-random orientation of the inflight effective beam
  pattern in the WMAP Data

abstract:
  The anomaly against the Gaussianity in the WMAP data was alleged to be due to
insufficient handling of beam asymmetries. In this paper we investigate this
issue and develop a method to estimate the shape of the inflight effective
beam, particularly the asymmetry and azimuthal orientation. We divide the whole
map into square patches and exploit the information in the Fourier space. For
patches containing bright extra-galactic point sources, we can directly
estimate their shapes, from which the inflight effective beam manifests itself.
For those without, we estimate the pattern via perturbing the phases and
directly from the Fourier amplitudes. We show that the inflight effective beam
convolving the signal is indeed non-symmetric for most part of the sky, and
it's not randomly oriented. Around the ecliptic poles, however, the asymmetry
is smaller due to the averaging effect from different orientations of the beam
from the scan strategy. The effective beam with significant asymmetry is
combing with almost parallel fashion along the lines of Ecliptic longitude. In
the foreground-cleaned ILC map, however, the systematics caused by beam effect
is significantly lessened.


title: New Radial Abundance Gradients for NGC 628 and NGC 2403

abstract:
  Motived by recent ISM studies, we present high quality MMT and Gemini
spectroscopic observations of H II regions in the nearby spiral galaxies NGC
628 and NGC 2403 in order to measure their chemical abundance gradients. Using
long-slit and multi-object mask optical spectroscopy, we obtained measurements
of the temperature sensitive auroral lines [O III] {\lambda}4363 and/or [N II]
{\lambda}5755 at a strength of 4{\sigma} or greater in 11 H II regions in NGC
628 and 7 regions in NGC 2403. These observations allow us, for the first time,
to derive an oxygen abundance gradient in NGC 628 based solely on "direct"
oxygen abundances of H II regions: 12 + log(O/H) = (8.43+/-0.03) +
(-0.017+/-0.002) x Rg (dex/kpc), with a dispersion in log(O/H) of {\sigma} =
0.10 dex, from 14 regions with a radial coverage of ~2-19 kpc. This is a
significantly shallower slope than found by previous "strong-line" abundance
studies. In NGC 2403, we derive an oxygen abundance gradient of 12 + log(O/H) =
(8.48+/-0.04) + (-0.032+/-0.007) x Rg (dex/kpc), with a dispersion in log(O/H)
of {\sigma} = 0.07 dex, from 7 H II with a radial coverage of ~1-10 kpc.
  Additionally, we measure the N, S, Ne, and Ar abundances. We find the N/O
ratio decreases with increasing radius for the inner disk, but reaches a
plateau past R25 in NGC 628. NGC 2403 also has a negative N/O gradient with
radius, but we do not sample the outer disk of the galaxy past R25 and so do
not see evidence for a plateau. This bi-modal pattern measured for NGC 628
indicates dominant contributions from secondary nitrogen inside of the R25
transition and dominantly primary nitrogen farther out. As expected for
{\alpha}-process elements, S/O, Ne/O, and Ar/O are consistent with constant
values over a range in oxygen abundance.


title: Integral counts of pseudo-holomorphic curves

abstract:
  In \cite{FOinteger}, Fukaya and Ono outlined a way of counting
pseudo-holomorphic curves in a general compact symplectic manifold to obtain
integer valued invariants. This paper contains the details of Fukaya and Ono's
suggested construction for any compact symplectic manifold and a large class of
exploded manifolds.


title:
Relating Changes in Cometary Rotation to Activity: Current Status and
  Applications to Comet C/2012 S1 (ISON)

abstract:
  We introduce a parameter, X, to predict the changes in the rotational period
of a comet in terms of the rotational period itself, the nuclear radius, and
the orbital characteristics. We show that X should be a constant if the bulk
densities and shapes of nuclei are nearly identical and the activity patterns
are similar for all comets. For four nuclei for which rotational changes are
well documented, despite the nearly factor 30 variation observed among the
effective active fractions of these comets, X is constant to within a factor
two. We present an analysis for the sungrazing comet C/2012 S1 (ISON) to
explore what rotational changes it could undergo during the upcoming perihelion
passage where its perihelion distance will be ~2.7 solar radii. When close to
the sun, barring a catastrophic disruption of the nucleus, the activity of ISON
will be sufficiently strong to put the nucleus into a non-principal-axis
rotational state and observable changes to the rotational period should also
occur. Additional causes for rotational state changes near perihelion for ISON
are tidal torques caused by the sun and the significant mass loss due to a
number of mechanisms resulting in alterations to the moments of inertia of the
nucleus.


title: Observation of the decay $B_c \rightarrow J/\psi K^+ K^- \pi^+ $

abstract:
  The decay $B_c\rightarrow J/\psi K^+ K^- \pi^+$ is observed for the first
time, using proton-proton collisions collected with the LHCb detector
corresponding to an integrated luminosity of 3fb$^{-1}$. A signal yield of
$78\pm14$ decays is reported with a significance of 6.2 standard deviations.
The ratio of the branching fraction of $\B_c \rightarrow J/\psi K^+ K^- \pi^+$
decays to that of $B_c \rightarrow J/\psi \pi^+$ decays is measured to be
$0.53\pm 0.10\pm0.05$, where the first uncertainty is statistical and the
second is systematic.


title:
Remarks on generalized uncertainty principle induced from constraint
  system

abstract:
  The extended commutation relations for a generalized uncertainty principle
have been based on the assumption of the minimal length in position. Instead of
this assumption, we start with a constrained Hamiltonian system described by
the conventional Poisson algebra and then impose appropriate second class
constraints to this system. Consequently, we can show that the consistent Dirac
brackets for this system are nothing but the extended commutation relations
describing the generalized uncertainty principle.


title:
Multiparameter Monitoring and Fault Indication Using Inductive Power
  Transfer System

abstract:
  The paper aims at demonstrating communication capabilities of IPT. For this
data communication is performed between two modules using the concept of IPT.
IPT was deemed to be the best solution to the system houses a multi parameter
acquisition module such as temperature, speed, voltage, current and data
transfer from the motor. The receiver side is another microcontroller coupled
to an inductive coil that gets the data and displays in the LCD. A brief
background to IPT Inductive Power Transfer technology and its applications is
given and the design criteria for the paper are defined in detail. To be
accurate, IPT data communication helps to reduce unnecessary wire connections
and data is transmitted without any touch. Further the paper can be enhanced by
looking for fault analysis inside the motor. This can be done by analyzing
various parameters of the motor. A novel two-way IPT communication system was
designed, which worked on the concept of pulsing the system on and off to send
data serially. The paper involves transmission of data through inductive flux
without any contact between the two modules. Further as no frequency tunings or
any calibration is required between different modules a single system can be
used with multiple clients. This reduces a lot of hazards such as interference
with other modules and RF transmitters in the vicinity.


title:
The role of singular values in entanglement distillation and unambiguous
  state discrimination

abstract:
  Unambiguous (non-orthogonal) state discrimination (USD) has a fundamental
importance in quantum information and quantum cryptography. Various aspects of
two-state and multiple-state USD are studied here using singular value
decomposition (SVD) of the evolution operator that describes a given state
discriminating system. In particular, we relate the minimal angle between
states to the ratio of the minimal and maximal singular values. This is
supported by a simple geometrical picture in two-state USD. We apply our result
to study what states can undergo entanglement distillation in a given system.


title:
Study of Hadrons Using the Gaussian Functional Method in the O(4) Linear
  $\sigma$ Model

abstract:
  We study properties of hadrons in the O(4) linear $\sigma$ model, where we
take into account fluctuations of mesons around their mean field values using
the Gaussian functional (GF) method. In the GF method we calculate dressed
$\sigma$ and $\pi$ masses, where we include the effect of fluctuations of
mesons to find a better ground state wave function than the mean field
approximation. Then we solve the Bethe-Salpeter equations and calculate
physical $\sigma$ and $\pi$ masses. We recover the Nambu-Goldstone theorem for
the physical pion mass to be zero in the chiral limit. The $\sigma$ meson is a
strongly correlated meson-meson state, and has a 4 quark structure. We
calculate $\sigma$ and $\pi$ masses as functions of temperature for the two
cases of chiral limit and explicit chiral symmetry breaking. We get similar
behaviors for the $\sigma$ and $\pi$ masses as the case of the mean field
approximation, but the coupling constants are much larger than the values of
the case of the mean field approximation.


title: On W_2 lifting of Frobenius of Algebraic Surfaces

abstract:
  We completely decide which minimal algebraic surfaces in positive
characteristics allow a lifting of their Frobenius over the trucated witt rings
of lengh 2.


title: Additive decompositions of sets with restricted prime factors

abstract:
  We investigate sumset decompositions of quite general sets with restricted
prime factors. We manage to handle certain sets, such as the smooth numbers,
even though they have little sieve amenability, and conclude that these sets
cannot be written as a ternary sumset. This proves a conjecture by
S\'{a}rk\"ozy. We also clean up and sharpen existing results on sumset
decompositions of the prime numbers.


title:
Motivic functions, integrability, and uniform in p bounds for orbital
  integrals

abstract:
  This is a short announcement and summary of the results of arxiv:1111.7057,
arxiv.org:1111.4405, and Appendix B to arxiv:1208.1945. In particular, we
emphasize the exposition of the ideas related to model theory and motivic
integration, and simplify the definitions, to make these results easily
accessible to non-model theorists.


title: Probability distributions with binomial moments

abstract:
  We prove that if $p\geq 1$ and $-1\leq r\leq p-1$ then the binomial sequence
$\binom{np+r}{n}$, $n=0,1,...$, is positive definite and is the moment sequence
of a probability measure $\nu(p,r)$, whose support is contained in
$\left[0,p^p(p-1)^{1-p}\right]$. If $p>1$ is a rational number and $-1<r\leq
p-1$ then $\nu(p,r)$ is absolutely continuous and its density function
$V_{p,r}$ can be expressed in terms of the Meijer $G$-function. In particular
cases $V_{p,r}$ is an elementary function. We show that for $p>1$ the measures
$\nu(p,-1)$ and $\nu(p,0)$ are certain free convolution powers of the Bernoulli
distribution. Finally we prove that the binomial sequence $\binom{np+r}{n}$ is
positive definite if and only if either $p\geq 1$, $-1\leq r\leq p-1$ or $p\leq
0$, $p-1\leq r \leq 0$. The measures corresponding to the latter case are
reflections of the former ones.


title: Multiple Derived Lagrangian Intersections

abstract:
  We give a new way to produce examples of Lagrangians in shifted symplectic
derived stacks, based on multiple intersections. Specifically, we show that an
m-fold fiber product of Lagrangians in a shifted symplectic derived stack its
itself Lagrangian in a certain cyclic product of pairwise homotopy fiber
products of the Lagrangians.


title:
Cascade of minimizers for a nonlocal isoperimetric problem in thin
  domains

abstract:
  For $\Omega_\e=(0,\e)\times (0,1)$ a thin rectangle, we consider minimization
of the two-dimensional nonlocal isoperimetric problem given by \[ \inf_u
E^{\gamma}_{\Omega_\e}(u)\] where \[ E^{\gamma}_{\Omega_\e}(u):=
P_{\Omega_\e}(\{u(x)=1\})+\gamma\int_{\Omega_\e}\abs{\nabla{v}}^2\,dx \] and
the minimization is taken over competitors $u\in BV(\Omega_\e;\{\pm 1\})$
satisfying a mass constraint $\fint_{\Omega_\e}u=m$ for some $m\in (-1,1)$.
Here $P_{\Omega_\e}(\{u(x)=1\})$ denotes the perimeter of the set $\{u(x)=1\}$
in $\Omega_\e$, $\fint$ denotes the integral average and $v$ denotes the
solution to the Poisson problem \[ -\Delta
v=u-m\;\mbox{in}\;\Omega_\e,\quad\nabla v\cdot
n_{\partial\Omega_\e}=0\;\mbox{on}\;\partial\Omega_\e,\quad\int_{\Omega_\e}v=0.\]
We show that a striped pattern is the minimizer for $\e\ll 1$ with the number
of stripes growing like $\gamma^{1/3}$ as $\gamma\to\infty.$ We then present
generalizations of this result to higher dimensions.


title:
Survey of Context Information Fusion for Sensor Networks based
  Ubiquitous Systems

abstract:
  Sensor Networks produce a large amount of data. According to the needs this
data requires to be processed, delivered and accessed. This processed data when
made available with the physical device location, user preferences, time
constraints; generically called as context-awareness; is widely referred to as
the core function for ubiquitous systems. To our best knowledge there is lack
of analysis of context information fusion for ubiquitous sensor networks.
Adopting appropriate information fusion techniques can help in screening noisy
measurements, control data in the network and take necessary inferences that
can help in contextual computing. In this paper we try and explore different
context information fusion techniques by comparing a large number of solutions,
their methods, architectures and models.


title: Analysis of DevR regulated genes in Mycobacterium tuberculosis

abstract:
  The DevRS two component system of Mycobacterium tuberculosis is responsible
for its dormancy in host and becomes operative under hypoxic condition. It is
experimentally known that phosphorylated DevR controls the expression of
several downstream genes in a complex manner. In the present work we propose a
theoretical model to show role of binding sites in DevR mediated gene
expression. Individual and collective role of binding sites in regulating DevR
mediated gene expression has been shown via modeling. Objective of the present
work is two fold. First, to describe qualitatively the temporal dynamics of
wild type genes and their known mutants. Based on these results we propose that
DevR controlled gene expression follows a specific pattern which is efficient
in describing other DevR mediated gene expression. Second, to analyze behavior
of the system from information theoretical point of view. Using the tools of
information theory we have calculated molecular efficiency of the system and
have shown that it is close to the maximum limit of isothermal efficiency.


title:
Evolution and CNO yields of Z=10^-5 stars and possible effects on CEMP
  production

abstract:
  Our main goals are to get a deeper insight into the evolution and final fates
of intermediate-mass, extremely metal-poor (EMP) stars. We also aim to
investigate their C, N, and O yields. Using the Monash University Stellar
Evolution code we computed and analysed the evolution of stars of metallicity Z
= 10^-5 and masses between 4 and 9 M_sun, from their main sequence until the
late thermally pulsing (super) asymptotic giant branch, TP-(S)AGB phase. Our
model stars experience a strong C, N, and O envelope enrichment either due to
the second dredge-up, the dredge-out phenomenon, or the third dredge-up early
during the TP-(S)AGB phase. Their late evolution is therefore similar to that
of higher metallicity objects. When using a standard prescription for the mass
loss rates during the TP-(S)AGB phase, the computed stars lose most of their
envelopes before their cores reach the Chandrasekhar mass, so our standard
models do not predict the occurrence of SNI1/2 for Z = 10^-5 stars. However, we
find that the reduction of only one order of magnitude in the mass-loss rates,
which are particularly uncertain at this metallicity, would prevent the
complete ejection of the envelope, allowing the stars to either explode as an
SNI1/2 or become an electron-capture SN. Our calculations stop due to an
instability near the base of the convective envelope that hampers further
convergence and leaves remnant envelope masses between 0.25 M_sun for our 4
M_sun model and 1.5 M_sun for our 9 M_sun model. We present two sets of C, N,
and O yields derived from our full calculations and computed under two
different assumptions, namely, that the instability causes a practically
instant loss of the remnant envelope or that the stars recover and proceed with
further thermal pulses. Our results have implications for the early chemical
evolution of the Universe.


title:
Break-up phenomena of liquid metal thin film induced by high electric
  current

abstract:
  The room temperature liquid metal related electronics has been found
important in a wide variety of emerging areas over the past few years. However,
its failure features under high electrical current densities are not clear
until now. Here we show that a liquid metal thin film would break-up as the
applied current increases to a critical magnitude. The break-up phenomenon is
attributed to be caused by the so-called electromigration effect. This problem
could be one of the major hurdles that must be tackled with caution in the
research and application of future liquid metal film electronics.

categories: cond-mat.mtrl-sci cond-mat.other cond-mat.soft physics.flu-dyn physics.ins-det


title:
Segmentation procedure based on Fisher's exact test and its application
  to foreign exchange rates

abstract:
  This study proposes the segmentation procedure of univariate time series
based on Fisher's exact test. We show that an adequate change point can be
detected as the minimum value of p-value. It is shown that the proposed
procedure can detect change points for an artificial time series. We apply the
proposed method to find segments of the foreign exchange rates recursively. It
is also applied to randomly shuffled time series. It concludes that the
randomly shuffled data can be used as a level to determine the null hypothesis.


title: Graphs with $C_3_-free vertices are not universal fixers

abstract:
  A non-isolated vertex $x\in V(G)$ is called $C_{3}$-free if $x$ belongs to no
triangle of $G$. In \cite{BMW} Burger, Mynhardt and Weakley introduced the idea
of universal fixers. Let $G=(V,E)$ be a graph with $n$ vertices and $G'$ a copy
of $G$. For a bijective function $\pi:V(G)\mapsto V (G')$, we define the prism
$\pi G$ of $G$ as follows: $V(\pi G)=V(G)\cup V(G')$ and $E(\pi G)=E(G)\cup
E(G')\cup M_{\pi}$, where $M_{\pi}=\{u\pi (u): u\in V(G)\}$. Let $\gamma(G)$ be
the domination number of $G$. If $\gamma(\pi G)=\gamma(G)$ for any bijective
function $\pi$, then $G$ is called a universal fixer. In \cite{MX} it is
conjectured that the only universal fixer is the edgeless graph $\bar{K_n}$. In
this note, we prove that any graph $G$ with $C_3$-free vertices is not a
universal fixer graph.


title: Coding for Caches in the Plane

abstract:
  We consider wireless caches located in the plane according to general point
process and specialize the results for the homogeneous Poisson process. A large
data file is stored at the caches, which have limited storage capabilities.
Hence, they can only store parts of the data. Clients can contact the caches to
retrieve the data. We compare the expected cost of obtaining the complete data
under uncoded as well as coded data allocation strategies. It is shown that for
the general class of cost measures where the cost of retrieving data is
increasing with the distance between client and caches, coded allocation
outperforms uncoded allocation. The improvement offered by coding is quantified
for two more specific classes of performance measures. Finally, our results are
validated by computing the costs of the allocation strategies for the case that
caches coincide with currently deployed mobile base stations.


title: Rapidly rotating neutron stars in scalar-tensor theories of gravity

abstract:
  We present the field equations governing the equilibrium of rapidly rotating
neutron stars in scalar-tensor theories of gravity, as well as representative
numerical solutions. The conditions for the presence of a nontrivial scalar
field and the deviations from the general relativistic solutions are studied.
Two examples of scalar-tensor theories are examined - one case that is
equivalent to the Brans-Dicke theory and a second case, that is perturbatively
equivalent to Einstein's General Relativity in the weak field regime, but can
differ significantly for strong fields. Our numerical results show that rapidly
rotating neutron star models with a nontrivial scalar field exist in both cases
and that the effect of the scalar field is stronger for rapid rotation. If we
consider values of the coupling parameters in accordance with current
observations, only the second example of scalar-tensor theories has significant
influence on the neutron star structure. We show that scalarized, rapidly
rotating neutron stars exist for a larger range of the parameters than in the
static case, since a nontrivial scalar field is present even for values of the
coupling constant $\beta>-4.35$, and that these solutions are energetically
more favorable than the general relativistic ones. In addition, the deviations
of the rapidly rotating scalar-tensor neutron stars from the
general-relativistic solutions is significantly larger than in the static case.


title: Bose-Einstein Condensates with Cavity-Mediated Spin-Orbit Coupling

abstract:
  We propose a novel scheme to generate the spin-orbit coupling for a
condensate placed inside an optical cavity by using a standing wave and a
traveling wave. It is shown that the interplay of the laser lights and the
cavity gives rise to rich quantum phases. Our scheme also generates an
nontrivial lattice of the magnetic flux, which may facilitate the study of the
exotic quantum phases.


title:
On Throughput and Decoding Delay Performance of Instantly Decodable
  Network Coding

abstract:
  In this paper, a comprehensive study of packet-based instantly decodable
network coding (IDNC) for single-hop wireless broadcast is presented. The
optimal IDNC solution in terms of throughput is proposed and its packet
decoding delay performance is investigated. Lower and upper bounds on the
achievable throughput and decoding delay performance of IDNC are derived and
assessed through extensive simulations. Furthermore, the impact of receivers'
feedback frequency on the performance of IDNC is studied and optimal IDNC
solutions are proposed for scenarios where receivers' feedback is only
available after and IDNC round, composed of several coded transmissions.
However, since finding these IDNC optimal solutions is computational complex,
we further propose simple yet efficient heuristic IDNC algorithms. The impact
of system settings and parameters such as channel erasure probability, feedback
frequency, and the number of receivers is also investigated and simple
guidelines for practical implementations of IDNC are proposed.


title:
Search for and Characterization of Open Clusters Toward the Galactic
  Anti-center with Pan-STARRS1

abstract:
  We have used a star-count algorithm based the Panoramic Survey Telescope And
Rapid Response System 3$\pi$ survey data aim to identify and characterize
uncharted open clusters (OCs). With limiting magnitudes of about 22 mag in
\gps, \rps, \ips\ bands and about 20 mag in \zps\ and \yps\ bands, our data are
100 times more sensitive than currently available surveys. We analyzed a trial
region within $20\deg\times20\deg$ field toward the Galactic anticenter and
found 1660 density enhancement regions of which 79 (out of 129) are known OCs,
and 949 are OC candidates.


title:
Coherent prior distributions in univariate finite mixture and
  Markov-switching models

abstract:
  Finite mixture and Markov-switching models generalize and, therefore, nest
specifications featuring only one component. While specifying priors in the
two: the general (mixture) model and its special (single-component) case, it
may be desirable to ensure that the prior assumptions introduced into both
structures are coherent in the sense that the prior distribution in the nested
model amounts to the conditional prior in the mixture model under relevant
parametric restriction. The study provides the rudiments of setting coherent
priors in Bayesian univariate finite mixture and Markov-switching models. Once
some primary results are delivered, we derive specific conditions for coherence
in the case of three types of continuous priors commonly engaged in Bayesian
modeling: the normal, inverse gamma, and gamma distributions. Further, we study
the consequences of introducing additional constraints into the mixture model's
prior (such as the ones enforcing identifiability or some sort of regularity,
e.g. second-order stationarity) on the coherence conditions. Finally, the
methodology is illustrated through a discussion of setting coherent priors for
a class of Markov-switching AR(2) models.


title: Relativistic features and time delay of laser-induced tunnel-ionization

abstract:
  The electron dynamics in the classically forbidden region during relativistic
tunnel-ionization is investigated. The classical forbidden region in the
relativistic regime is identified by defining a gauge invariant total energy
operator. Introducing position dependent energy levels inside the tunneling
barrier, we demonstrate that the relativistic tunnel-ionization can be well
described by a one-dimensional intuitive picture. This picture predicts that,
in contrast to the well-known nonrelativistic regime, the ionized electron wave
packet arises with a momentum shift along the laser's propagation direction.
This is compatible with results from a strong field approximation calculation
where the binding potential is assumed to be zero-ranged. Further, the
tunneling time delay, stemming from Wigner's definition, is investigated for
model configurations of tunneling and compared with results obtained from the
exact propagator. By adapting Wigner's time delay definition to the ionization
process, the tunneling time is investigated in the deep-tunneling and in the
near-threshold-tunneling regimes. It is shown that while in the deep-tunneling
regime signatures of the tunneling time delay are not measurable at remote
distance, it is detectable, however, in the latter regime.


title:
Ultra-thin film and interface analysis of high-k dielectric materials
  employing Time-Of-Flight Medium Energy Ion Scattering (TOF-MEIS)

abstract:
  We explore the potential of Time-Of-Flight Medium Energy Ion Scattering
(TOFMEIS) for thin film analysis and analyze possible difficulties in
evaluation of experimental spectra. Issues regarding different combinations of
composition and stopping power as well as the influence of channeling are
discussed. As a model system high-k material stacks made from ultra-thin films
of HfO2 grown on a p-type Si (100) substrate with a 0.5 nm SiO2 interface layer
have been investigated. By comparison of experimental spectra and computer
simulations TOF-MEIS was employed to establish a depth profile of the films and
thus obtaining information on stoichiometry and film quality. Nominal film
thicknesses were in the range from 1.8 to 12.2 nm. As a supporting method
Rutherford-Backscattering spectrometry (RBS) was employed to obtain the areal
density of Hf atoms in the films.


title: Gamma-rays from Blazars and the Extragalactic Background Light

abstract:
  Recent observations of blazars at high energy (HE, 0.1-100 GeV) and very high
energy (VHE, >0.1 TeV) have provided important constraints on the intensity and
spectrum of the diffuse Extragalactic Background Light (EBL), shedding light on
its main origin. Several issues remain open, however, in particular in the mid-
and far-infrared bands and in the blazar emission at multi-TeV energies. This
review summarizes the observational and theoretical progress in the study of
the EBL with gamma-rays and the most promising future improvements, which are
mainly expected from spectra in the multi-TeV range.


title: Adiabatic passage in photon-echo quantum memories

abstract:
  Photon-echo based quantum memories use inhomogeneously broadened, optically
thick ensembles of absorbers to store a weak optical signal and employ various
protocols to rephase the atomic coherences for information retrieval. We study
the application of two consecutive, frequency-chirped control pulses for
coherence rephasing in an ensemble with a 'natural' inhomogeneous broadening.
Although propagation effects distort the two control pulses differently,
chirped pulses that drive adiabatic passage can rephase atomic coherences in an
optically thick storage medium. Combined with spatial phase mismatching
techniques to prevent primary echo emission, coherences can be rephased around
the ground state to achieve secondary echo emission with close to unit
efficiency. Potential advantages over similar schemes working with $\pi$-pulses
include greater potential signal fidelity, reduced noise due to spontaneous
emission and better capability for the storage of multiple memory channels.


title:
Using a complex system approach to address world challenges in Food and
  Agriculture

abstract:
  World food supply is crucial to the well-being of every human on the planet
in the basic sense that we need food to live. It also has a profound impact on
the world economy, international trade and global political stability.
Furthermore, consumption of certain types and amounts foods can affect health,
and the choice of livestock and plants for food production can impact
sustainable use of global resources. There are communities where insufficient
food causes nutritional deficiencies, and at the same time other communities
eating too much food leading to obesity and accompanying diseases. These
aspects reflect the utmost importance of agricultural production and conversion
of commodities to food products. Moreover, all factors contributing to the food
supply are interdependent, and they are an integrative part of the continuously
changing, adaptive and interdependent systems in the world around us. The
properties of such interdependent systems usually cannot be inferred from the
properties of its parts. In addressing current challenges, like the apparent
incongruences of obesity and hunger, we have to account for the complex
interdependencies among areas such as physics and sociology. This is possible
using the complex system approach. It encompasses an integrative multi-scale
and inter-disciplinary approach. Using a complex system approach that accounts
for the needs of stakeholders in the agriculture and food domain, and
determines which research programs will enable these stakeholders to better
anticipate emerging developments in the world around them, will enable them to
determine effective intervention strategies to simultaneously optimise and
safeguard their interests and the interests of the environment.


title:
Diffractionless image propagation and frequency conversion via four-wave
  mixing exploiting the thermal motion of atoms

abstract:
  A setup to frequency-convert an arbitrary image encoded in the spatial
profile of a probe field onto a signal field using four-wave mixing in a
thermal atom vapor is proposed. The atomic motion is exploited to cancel
diffraction of both signal and probe fields simultaneously. We show that an
incoherent probe field can be used to enhance the transverse momentum bandwidth
which can be propagated without diffraction, such that smaller structures with
higher spatial resolution can be transmitted. It furthermore compensate linear
absorption with non-linear gain, to improve the four-wave mixing performance
since the propagation dynamics of the various field intensities is favorably
modified.


title:
A model for high energy rho meson leptoproduction based on collinear
  factorization and dipole models

abstract:
  We present a phenomenological model for the helicity amplitudes T11 and T00
of the rho meson exclusive diffractive leptoproduction in the forward limit.
This model leads to a very good description of the polarized cross-sections
sigmaT and sigmaL when compared to HERA data. This model is based on the impact
factor representation of the helicity amplitudes. The gamma* -> rho impact
factor is computed within the light-cone collinear factorization scheme, the
impact parameter space representation allowing to factorize out the
dipole-target amplitude. Finally our description combines a model for the
dipole-target amplitude that includes the saturation effects with the results
for the impact factor where the twist 2 and twist 3 distribution amplitudes of
the rho meson are involved.


title: Local cohomology with support in generic determinantal ideals

abstract:
  For positive integers m >= n >= p, we compute the GL_m x GL_n-equivariant
description of the local cohomology modules of the polynomial ring S of
functions on the space of m x n matrices, with support in the ideal of p x p
minors. Our techniques allow us to explicitly compute all the modules
Ext_S(S/I_x,S), for x a partition and I_x the ideal generated by the
irreducible sub-representation of S indexed by x. In particular we determine
the regularity of the ideals I_x, and we deduce that the only ones admitting a
linear free resolution are the powers of the ideal of maximal minors of the
generic matrix, as well as the products between such powers and the maximal
ideal of S.


title: Actions of groups of diffeomorphisms on one-manifolds

abstract:
  Denote by $\DC(M)_0$ the identity component of the group of compactly
supported $C^\infty$ diffeomorphisms of a connected $C^\infty$ manifold $M$,
and by $\HR$ the group of the homeomorphisms of $\R$. We show that if $M$ is a
closed manifold which fibers over $S^m$ ($m\geq 2$), then any homomorphism from
$\DC(M)_0$ to $\HR$ is trivial.


title: Weak Differentiability of Solutions to SDEs With Semi-Monotone Drifts

abstract:
  In this work we prove Malliavin differentiability for the solution to an SDE
with locally Lipschitz and semi-monotone drift. To this end we construct a
sequence of SDEs with globally Lipschitz drifts. We show that the solutions of
these SDEs converge to the solution of the original SDE and the p-moments of
their Malliavin derivatives are uniformly bounded.


title:
Photon detection operator and complementarity between electric detector
  and magnetic detector

abstract:
  It had been a long standing problem that there is no consistent definition of
photon position operator nor photon number density in the context of quantum
theory. In this paper we derive the photon detection operator, which defines
location of photon absorption, by applying the theory of indirect measurement
to quantum electrodynamics. It is shown that the photon detection probability
depends on electric properties of a photon-absorbing atom, in particular, on
both electric and magnetic dipole moments of the atom. An experiment is
proposed, in which the complementarity of wave-particle nature of light will be
tested. It is also discussed that the complementarity is related to the
non-commutativity of the electric and the magnetic fields.


title:
Enhanced thermal stability of the toric code through coupling to a
  bosonic bath

abstract:
  We propose and study a model of a quantum memory that features
self-correcting properties and a lifetime growing arbitrarily with system size
at non-zero temperature. This is achieved by locally coupling a 2D L x L toric
code to a 3D bath of bosons hopping on a cubic lattice. When the stabilizer
operators of the toric code are coupled to the displacement operator of the
bosons, we solve the model exactly via a polaron transformation and show that
the energy penalty to create anyons grows linearly with L. When the stabilizer
operators of the toric code are coupled to the bosonic density operator, we use
perturbation theory to show that the energy penalty for anyons scales with
ln(L). For a given error model, these energy penalties lead to a lifetime of
the stored quantum information growing respectively exponentially and
polynomially with L. Furthermore, we show how to choose an appropriate coupling
scheme in order to hinder the hopping of anyons (and not only their creation)
with energy barriers that are of the same order as the anyon creation gaps. We
argue that a toric code coupled to a 3D Heisenberg ferromagnet realizes our
model in its low-energy sector. Finally, we discuss the delicate issue of the
stability of topological order in the presence of perturbations. While we do
not derive a rigorous proof of topological order, we present heuristic
arguments suggesting that topological order remains intact when perturbative
operators acting on the toric code spins are coupled to the bosonic
environment.


title: Quantitative convergence rates for sub-geometric Markov chains

abstract:
  We provide explicit expressions for the constants involved in the
characterisation of ergodicity of sub-geometric Markov chains. The constants
are determined in terms of those appearing in the assumed drift and one-step
minorisation conditions. The result is fundamental for the study of some
algorithms where uniform bounds for these constants are needed for a family of
Markov kernels. Our result accommodates also some classes of inhomogeneous
chains.


title:
Smooth density for the Solution of Scalar SDEs with Locally Lipschitz
  Coefficients under H\"ormander Condition

abstract:
  In this paper the existence of a smooth density is proved for the solution of
an SDE, with locally Lipschitz coefficients and semi-monotone drift, under
H\"ormander condition. We prove the nondegeneracy condition for the solution of
the SDE, from it an integration by parts formula would result in the Wiener
space. To this end we construct a sequence of SDEs with globally Lipschitz
coefficients whose solutions converge to the original one and use some Lyapunov
functions to show the uniformly boundedness of the p-moments of the solutions
and their Malliavin derivatives.


title: Information Transmission under Random Emission Constraints

abstract:
  We model the transmission of a message on the complete graph with n vertices
and limited resources. The vertices of the graph represent servers that may
broadcast the message at random. Each server has a random emission capital that
decreases at each emission. Quantities of interest are the number of servers
that receive the information before the capital of all the informed servers is
exhausted and the exhaustion time. We establish limit theorems (law of large
numbers, central limit theorem and large deviation principle), as n tends to
infinity, for the proportion of visited vertices before exhaustion and for the
total duration. The analysis relies on a construction of the transmission
procedure as a dynamical selection of successful nodes in a Galton-Watson tree
with respect to the success epochs of the coupon collector problem.


title: On the variational structure of breather solutions

abstract:
  In this paper we give a systematic and simple account that put in evidence
that many breather solutions of integrable equations satisfy suitable
variational elliptic equations, which also implies that the stability problem
reduces in some sense to $(i)$ the study of the spectrum of explicit linear
systems (\emph{spectral stability}), and $(ii)$ the understanding of how bad
directions (if any) can be controlled using low regularity conservation laws.
We exemplify this idea in the case of the modified Korteweg-de Vries (mKdV),
Gardner, and sine-Gordon (SG) equations. Then we perform numerical simulations
that confirm, at the level of the spectral problem, our previous rigorous
results, where we showed that mKdV breathers are $H^2$ and $H^1$ stable,
respectively. In a second step, we also discuss the Gardner and the Sine-Gordon
cases, where the spectral study of a fourth-order linear matrix system is the
key element to show stability. Using numerical methods, we confirm that all
spectral assumptions leading to the $H^2\times H^1$ stability of SG breathers
are numerically satisfied, even in the ultra-relativistic, singular regime. In
a second part, we study the periodic mKdV case, where a periodic breather is
known from the work of Kevrekidis et al. We rigorously show that these
breathers satisfy a suitable elliptic equation, and we also show numerical
spectral stability. However, we also identify the source of nonlinear
instability in the case described in Kevrekidis et al. Finally, we present a
new class of breather solution for mKdV, believed to exist from geometric
considerations, and which is periodic in time and space, but has nonzero mean,
unlike standard breathers.


title: Genuine Multipartite Entanglement in the $XY$ Model

abstract:
  We analyze the $XY$ model characterized by an anisotropy $\gamma$ in an
external magnetic field $h$ with respect to its genuine multipartite
entanglement content (in the thermodynamic and finite size case). Despite its
simplicity we show that the quantity -detecting genuine multipartite
entanglement through permutation operators and being a lower bound on measures-
witnesses the presence of genuine multipartite entanglement for nearly all
values of $\gamma$ and $h$. We further show that the phase transition and
scaling properties are fully characterized by this multipartite quantity.
Consequently, we provide a useful toolbox for other condensed matter systems,
where bipartite entanglement measures are known to fail.


title:
Temporal relation between quiet-Sun transverse fields and the strong
  flows detected by IMaX/SUNRISE

abstract:
  Localized strongly Doppler-shifted Stokes V signals were detected by
IMaX/SUNRISE. These signals are related to newly emerged magnetic loops that
are observed as linear polarization features. We aim to set constraints on the
physical nature and causes of these highly Doppler-shifted signals. In
particular, the temporal relation between the appearance of transverse fields
and the strong Doppler shifts is analyzed in some detail. We calculated the
time difference between the appearance of the strong flows and the linear
polarization. We also obtained the distances from the center of various
features to the nearest neutral lines and whether they overlap or not. These
distances were compared with those obtained from randomly distributed points on
observed magnetograms. Various cases of strong flows are described in some
detail. The linear polarization signals precede the appearance of the strong
flows by on average 84+-11 seconds. The strongly Doppler-shifted signals are
closer (0.19") to magnetic neutral lines than randomly distributed points
(0.5"). Eighty percent of the strongly Doppler-shifted signals are close to a
neutral line that is located between the emerging field and pre-existing
fields. That the remaining 20% do not show a close-by pre-existing field could
be explained by a lack of sensitivity or an unfavorable geometry of the
pre-existing field, for instance, a canopy-like structure. Transverse fields
occurred before the observation of the strong Doppler shifts. The process is
most naturally explained as the emergence of a granular-scale loop that first
gives rise to the linear polarization signals, interacts with pre-existing
fields (generating new neutral line configurations), and produces the observed
strong flows. This explanation is indicative of frequent small-scale
reconnection events in the quiet Sun.


title: Beyond Adiabatic Elimination: Systematic Expansions

abstract:
  We restate the adiabatic elimination approximation as the first term in a
singular perturbation expansion. We use the invariant manifold formalism for
singular perturbations in dynamical systems to identify systematic improvements
on adiabatic elimination, connecting with well established quantum mechanical
perturbation methods. We prove convergence of the expansions when energy scales
are well separated. We state and solve the problem of hermiticity of improved
effective hamiltonians.


title: Hidden Lorentz symmetry of the Horava - Lifshitz gravity

abstract:
  In this letter it is shown that the Horava-Lifshitz gravity theory admits
Lorentz symmetry preserving preferred global time foliation of the spacetime.


title: On the monodromy conjecture for non-degenerate hypersurfaces

abstract:
  The monodromy conjecture is an umbrella term for several conjectured
relationships between poles of zeta functions, monodromy eigenvalues and roots
of Bernstein-Sato polynomials in arithmetic geometry and singularity theory.
Even the weakest of these relations -- the Denef--Loeser conjecture on
topological zeta functions -- is open for surface singularities. We prove it
for a wide class of multidimensional singularities that are non-degenerate with
respect to their Newton polyhedra, including all such singularities of
functions of four variables. A crucial difference from the known case of three
variables is the existence of degenerate singularities arbitrarily close to a
non-degenerate one. Thus, even aiming at the study of non-degenerate
singularities, we have to go beyond this setting. We develop new tools to deal
with such multidimensional phenomena, and conjecture how the proof for
non-degenerate singularities of arbitrarily many variables might look like.


title: Biharmonic curves into quadrics

abstract:
  We develop an essentially algebraic method to study biharmonic curves into an
implicit surface. Although our method is rather general, it is especially
suitable to study curves into surfaces defined by a polynomial equation: in
particular, we use it to give a complete classification of biharmonic curves
into real quadrics of the 3-dimensional Euclidean space.