title:
Solving the Shortest Vector Problem in Lattices Faster Using Quantum
  Search

abstract:
  By applying Grover's quantum search algorithm to the lattice algorithms of
Micciancio and Voulgaris, Nguyen and Vidick, Wang et al., and Pujol and
Stehl\'{e}, we obtain improved asymptotic quantum results for solving the
shortest vector problem. With quantum computers we can provably find a shortest
vector in time $2^{1.799n + o(n)}$, improving upon the classical time
complexity of $2^{2.465n + o(n)}$ of Pujol and Stehl\'{e} and the $2^{2n +
o(n)}$ of Micciancio and Voulgaris, while heuristically we expect to find a
shortest vector in time $2^{0.312n + o(n)}$, improving upon the classical time
complexity of $2^{0.384n + o(n)}$ of Wang et al. These quantum complexities
will be an important guide for the selection of parameters for post-quantum
cryptosystems based on the hardness of the shortest vector problem.


title: Light field integration in SUGRA theories

abstract:
  We revisit the integration of fields in N=1 Supergravity with the requirement
that the effective theory has a reliable two-derivative supersymmetric
description. In particular we study, in a supersymmetric manifest way, the
situation where the fields that are mapped out have masses comparable to the
Supersymmetry breaking scale and masses of the remaining fields.
  We find that as long as one stands in regions of the field configuration
space where the analytic continuation to superspace of the F-flatness
conditions be reliable equations of motion for the fields that are being mapped
out, and provided their solutions are stable regardless the dynamics of the
remaining fields, such a two-derivative description is a reliable truncation of
the full effective theory.
  The study is mainly focused to models with two chiral sectors, H and L,
described by a Kaehler invariant function with schematic dependencies of the
form G=G_H(H,\bar H)+G_L(L,\bar L), which leads to a nearly decoupled theory
that allows the previous requirements to be easily satisfied in a consistent
way. Interestingly enough for the matters of our study this kind of models
present an scenario that is as safe as the one presented in sequestered models.
  It is also possible to allow gauge symmetries as long as these appear also
factorized in hidden and visible sectors. Then, the integration of the hidden
vector superfields is compulsory and proceeds reliably through the D-flatness
condition analytically continued to superspace.


title: Experimental Null test of a Mach Effect Thruster

abstract:
  The Mach Effect Thruster (MET) is a device which utilizes fluctuations in the
rest masses of accelerating objects (capacitor stacks, in which internal energy
changes take place) to produce a steady linear thrust. The theory has been
given in detail elsewhere [1, 2] and references therein, so here we discuss
only an experiment. We show how to obtain thrust using a heavy reaction mass at
one end of our capacitor stack and a lighter end cap on the other. Then we show
how this thrust can be eliminated by having two heavy masses at either end of
the stack with a central mounting bracket. We show the same capacitor stack
being used as a thruster and then eliminate the thrust by arranging equal brass
masses on either end, so that essentially the capacitor stack is trying to push
in both directions at once. This arrangement in theory would only allow for a
small oscillation but no net thrust. We find the thrust does indeed disappear
in the experiment, as predicted. The device (in thruster mode) could in
principle be used for propulsion [1, 2]. Experimental apparatus based on a very
sensitive thrust balance is briefly described. The experimental protocol
employed to search for expected Mach effects is laid out, and the results of
this experimental investigation are described.


title: Automated Design of Two-Layer Fat-Tree Networks

abstract:
  This paper presents an algorithm to automatically design two-level fat-tree
networks, such as ones widely used in large-scale data centres and cluster
supercomputers. The two levels may each use a different type of switches from
design database to achieve an optimal network structure. Links between layers
can run in bundles to simplify cabling. Several sample network designs are
examined and their technical and economic characteristics are discussed.
  The characteristic feature of our approach is that real life equipment prices
and values of technical characteristics are used. This allows to select an
optimal combination of hardware to build the network (including semi-populated
configurations of modular switches) and accurately estimate the cost of this
network. We also show how technical characteristics of the network can be
derived from its per-port metrics and suggest heuristics for equipment
placement.
  The algorithm is useful as a part of a bigger design procedure that selects
optimal hardware of cluster supercomputer as a whole. Therefore the article is
focused on the use of fat-trees for high-performance computing, although the
results are valid for any type of data centres.


title: Automated Design of Torus Networks

abstract:
  This paper presents an algorithm to automatically design networks with torus
topologies, such as ones widely used in large-scale supercomputers. The
characteristic feature of our approach is that real life equipment prices and
values of technical characteristics are used. As a result, we also have the
opportunity to compare costs of torus and fat-tree networks.
  The algorithm is useful as a part of a bigger design procedure that selects
optimal hardware of cluster supercomputer as a whole.


title: Thermal properties of graphene: Fundamentals and applications

abstract:
  Graphene is a two-dimensional (2D) material with over 100-fold anisotropy of
heat flow between the in-plane and out-of-plane directions. High in-plane
thermal conductivity is due to covalent sp2 bonding between carbon atoms,
whereas out-of-plane heat flow is limited by weak van der Waals coupling.
Herein, we review the thermal properties of graphene, including its specific
heat and thermal conductivity (from diffusive to ballistic limits) and the
influence of substrates, defects, and other atomic modifications. We also
highlight practical applications in which the thermal properties of graphene
play a role. For instance, graphene transistors and interconnects benefit from
the high in-plane thermal conductivity, up to a certain channel length.
However, weak thermal coupling with substrates implies that interfaces and
contacts remain significant dissipation bottlenecks. Heat flow in graphene or
graphene composites could also be tunable through a variety of means, including
phonon scattering by substrates, edges or interfaces. Ultimately, the unusual
thermal properties of graphene stem from its 2D nature, forming a rich
playground for new discoveries of heat flow physics and potentially leading to
novel thermal management applications.


title: The TAOS Project: Results From Seven Years of Survey Data

abstract:
  The Taiwanese-American Occultation Survey (TAOS) aims to detect serendipitous
occultations of stars by small (about 1 km diameter) objects in the Kuiper Belt
and beyond. Such events are very rare (<0.001 events per star per year) and
short in duration (about 200 ms), so many stars must be monitored at a high
readout cadence. TAOS monitors typically around 500 stars simultaneously at a 5
Hz readout cadence with four telescopes located at Lulin Observatory in central
Taiwan. In this paper, we report the results of the search for small Kuiper
Belt Objects (KBOs) in seven years of data. No occultation events were found,
resulting in a 95% c.l. upper limit on the slope of the faint end of the KBO
size distribution of q = 3.34 to 3.82, depending on the surface density at the
break in the size distribution at a diameter of about 90 km.


title:
Precision measurement of charged pion and kaon differential cross
  sections in electron-positron annihilation at Q = 10.52 GeV

abstract:
  Measurements of inclusive differential cross sections for charged pion and
kaon production in electron-positron annihilation have been carried out at a
center-of-mass energy of Q = 10.52 GeV. The measurements were performed with
the Belle detector at the KEKB electron-positron collider using a data sample
containing 113 million e+e- -> qqbar events, where q={u,d,s,c}. We present
charge-integrated differential cross sections d\sigma_h+-/dz for h+- = pi+-,
K+- as a function of the relative hadron energy z = 2*E_h / sqrt{s} from 0.2 to
0.98. The combined statistical and systematic uncertainties for pi+- (K+-) are
4% (4%) at z ~ 0.6 and 15% (24%) at z ~ 0.9. The cross sections are the first
measurements of the z-dependence of pion and kaon production for z > 0.7 as
well as the first precision cross section measurements at a center-of-mass
energy far below the Z^0 resonance used by the experiments at LEP and SLC.


title: Search for a Scalar Axion-like Particle at 34 GHz

abstract:
  Light axion-like particles (ALPs) that couple to two photons are allowed in a
number of proposed extensions to the Standard Model of elementary particles. Of
particular interest from a theoretical and observational standpoint is the
energy regime near 0.1 meV. We present results from a pilot experiment to
search for a signal from a 0.14 meV scalar ALP by way of its coupling to two
photons. Using a copper resonant cavity cooled to four degrees Kelvin while
immersed in a seven Tesla magnetic field, and coupled to a low noise cryogenic
amplifier and room temperature receiver, we exclude an ALP-driven excess of 34
GHz photons with g$>10^{-8}$/GeV with 5$\sigma$ confidence. We discuss the
ramifications of this initial measurement as well as planned modifications to
the experiment for increased sensitivity.


title: A High Efficiency Architecture for Cascaded Raman Fiber Lasers

abstract:
  We demonstrate a new high efficiency architecture for cascaded Raman fiber
lasers based on a single pass cascaded amplifier configuration. Conversion is
seeded at all intermediate Stokes wavelengths using a multi-wavelength seed
source. A lower power Raman laser based on the conventional cascaded Raman
resonator architecture provides a convenient seed source providing all the
necessary wavelengths simultaneously. In this work we demonstrate a 1480nm
laser pumped by an 1117nm Yb-doped fiber laser with maximum output power of
204W and conversion efficiency of 65% (quantum-limited efficiency is ~75%). We
believe both the output power and conversion efficiency (relative to
quantum-limited efficiency) are the highest reported for cascaded Raman fiber
lasers.


title:
Magnetic order in the repulsive Fermi-Hubbard model in three-dimensions
  and the crossover to two-dimensions

abstract:
  Systems of fermions described by the three-dimensional (3D) repulsive Hubbard
model on a cubic lattice have recently attracted considerable attention due to
their possible experimental realization via cold atoms in an optical lattice.
Because analytical and numerical results are limited away from half-filling, we
study the ground state of the doped system from weak to intermediate
interaction strengths within the generalized Hartree-Fock approximation. The
exact solution to the self-consistent-field equations in the thermodynamic
limit is obtained and the ground state is shown to exhibit antiferromagnetic
order and incommensurate spin-density waves (SDW). At low interaction
strengths, the SDW has unidirectional character with a leading wave-vector
along the $<100>$-direction, and the system is metallic. As the interaction
increases, the system undergoes a simultaneous structural and
metal-to-insulator transition to a unidirectional SDW state along the
$<111>$-direction, with a different wavelength. We systematically determine the
real- and momentum-space properties of these states. The crossover from 3D to
two-dimensions (2D) is then studied by varying the inter-plane hopping
amplitude, which can be experimentally realized by tuning the distance between
a stack of square-lattice layers. Detailed comparisons are made between the
exact numerical results and predictions from the pairing model, a variational
{\em ansatz} based on the pairing of spins in the vicinity of the Fermi
surface. Most of the numerical results can be understood quantitatively from
the ansatz, which provides a simple picture for the nature of the SDW states.


title: A short proof of the bounded geodesic image theorem

abstract:
  We give a combinatorial proof, using the hyperbolicity of the curve graphs,
of the bounded geodesic image theorem of Masur and Minsky. Recently it has been
shown that curve graphs are uniformly hyperbolic, thus a universal bound can be
given for the diameter of the geodesic image. We also generalize the theorem
for projections to markings of the whole surface.


title:
Review of recent highlights in lattice calculations at finite
  temperature and finite density

abstract:
  I review some recent lattice results on studying chiral and deconfinement
transition in QCD at finite temperature and density, as well as properties of
strongly interacting matter at high temperatures. I discuss lattice results on
the equation of state, fluctuations of conserved charges, chromo-electric
screening as well as the determination of the chiral transition temperature.


title:
The importance of nonlinear fluid response in joint density-functional
  theory studies of battery systems

abstract:
  Delivering the full benefits of first principles calculations to battery
materials demands the development of accurate and computationally-efficient
electronic structure methods that incorporate the effects of the electrolyte
environment and electrode potential. Realistic electrochemical interfaces
containing polar surfaces are beyond the regime of validity of existing
continuum solvation theories developed for molecules, due to the presence of
significantly stronger electric fields. We present an ab initio theory of the
nonlinear dielectric and ionic response of solvent environments within the
framework of joint density-functional theory, with precisely the same
optimizable parameters as conventional polarizable continuum models. We
demonstrate that the resulting nonlinear theory agrees with the standard linear
models for organic molecules and metallic surfaces under typical operating
conditions. However, we find that the saturation effects in the rotational
response of polar solvent molecules, inherent to our nonlinear theory, are
crucial for a qualitatively correct description of the ionic surfaces typical
of the solid electrolyte interface.


title:
Blahut-Arimoto Algorithm and Code Design for Action-Dependent Source
  Coding Problems

abstract:
  The source coding problem with action-dependent side information at the
decoder has recently been introduced to model data acquisition in
resource-constrained systems. In this paper, an efficient algorithm for
numerical computation of the rate-distortion-cost function for this problem is
proposed, and a convergence proof is provided. Moreover, a two-stage code
design based on multiplexing is put forth, whereby the first stage encodes the
actions and the second stage is composed of an array of classical Wyner-Ziv
codes, one for each action. Specific coding/decoding strategies are designed
based on LDGM codes and message passing. Through numerical examples, the
proposed code design is shown to achieve performance close to the lower bound
dictated by the rate-distortion-cost function.


title:
Reuse, Temporal Dynamics, Interest Sharing, and Collaboration in Social
  Tagging Systems

abstract:
  User-generated content is shaping the dynamics of the World Wide Web. Indeed,
an increasingly large number of systems provide mechanisms to support the
growing demand for content creation, sharing, and management. Tagging systems
are a particular class of these systems where users share and collaboratively
annotate content such as photos and URLs. This collaborative behavior and the
pool of user-generated metadata create opportunities to improve existing
systems and to design new mechanisms. However, to realize this potential, it is
necessary to understand the usage characteristics of current systems. This work
addresses this issue characterizing three tagging systems (CiteULike, Connotea
and del.icio.us) while focusing on three aspects: i) the patterns of
information (tags and items) production; ii) the temporal dynamics of users'
tag vocabularies; and, iii) the social aspects of tagging systems.


title: An Ultraviolet Investigation of Activity on Exoplanet Host Stars

abstract:
  Using the far-UV (FUV) and near-UV (NUV) photometry from the NASA Galaxy
Evolution Explorer (GALEX), we searched for evidence of increased stellar
activity due to tidal and/or magnetic star-planet interactions (SPI) in the 272
of known FGK planetary hosts observed by GALEX. With the increased sensitivity
of GALEX, we are able probe systems with lower activity levels and at larger
distances than what has been done to date with X-ray satellites. We compared
samples of stars with close-in planets (a < 0.1 AU) to those with far-out
planets (a > 0.5 AU) and looked for correlations of excess activity with other
system parameters. This statistical investigation found no clear correlations
with a, M_p, nor M_p/a, in contrast to some X-ray and Ca II studies. However,
there is tentative evidence (at a level of 1.8-\sigma) that stars with
RV-detected close-in planets are more FUV-active than stars with far-out
planets, in agreement with several published X-ray and Ca II results. The case
is strengthened to a level of significance of 2.3-\sigma\ when transit-detected
close-in planets are included. This is most likely because the RV-selected
sample of stars is significantly less active than the field population of
comparable stars, while the transit-selected sample is similarly active. Given
the factor of 2-3 scatter in fractional FUV luminosity for a given stellar
effective temperature, it is necessary to conduct a time-resolved study of the
planet hosts in order to better characterize their UV variability and generate
a firmer statistical result.


title: Continuous Measurement and Stochastic Methods in Quantum Optical Systems

abstract:
  This dissertation studies the statistics and modeling of a quantum system
probed by a coherent laser field. We focus on an ensemble of qubits
dispersively coupled to a traveling wave light field. The first research topic
explores the quantum measurement statistics of a quasi-monochromatic laser
probe. We identify the shortest timescale that successive measurements
approximately commute. Our model predicts that for a probe in the near
infrared, noncommuting measurement effects are apparent for subpicosecond
times.
  The second dissertation topic attempts to find an approximation to a
conditional master equation, which maps identical product states to identical
product states. Through a technique known as projection filtering, we find such
a equation for an ensemble of qubits experiencing a diffusive measurement of a
collective angular momentum projection, and global rotations. We then test the
quality of the approximation through numerical simulations. In the presence of
strong randomized rotations, the approximation reproduces the exact expectation
values to within 95%.
  The final topic applies the projection filter to the problem of state
reconstruction. We find an initial state estimate based on a single continuous
measurement of an identically prepared atomic ensemble. Given the ability to
make a continuous collective measurement and simultaneously applying time
varying controls, it is possible to find an accurate estimate given based upon
a single measurement realization. Here we explore the fundamental limits of
this protocol by studying an idealized model for pure qubits, which is limited
only by measurement backaction. Using the exact dynamics to produce simulated
measurements, we then numerically search for a maximum likelihood estimate
based on the approximate expression. Our estimation technique nearly achieves
an average fidelity bound set by an optimum POVM.


title: Stability of Relative Equilibria in the Planar N-Vortex Problem

abstract:
  We study the linear and nonlinear stability of relative equilibria in the
planar N-vortex problem, adapting the approach of Moeckel from the
corresponding problem in celestial mechanics. After establishing some general
theory, a topological approach is taken to show that for the case of positive
circulations, a relative equilibrium is linearly stable if and only if it is a
nondegenerate minimum of the Hamiltonian restricted to a level surface of the
angular impulse (moment of inertia). Using a criterion of Dirichlet's, this
implies that any linearly stable relative equilibrium with positive vorticities
is also nonlinearly stable. Two symmetric families, the rhombus and the
isosceles trapezoid, are analyzed in detail, with stable solutions found in
each case.


title:
The Case for Cross-Layer Optimizations in Storage: A Workflow-Optimized
  Storage System

abstract:
  This paper proposes using file system custom metadata as a bidirectional
communication channel between applications and the storage system. This channel
can be used to pass hints that enable cross-layer optimizations, an option
hindered today by the ossified file-system interface. We study this approach in
context of storage system support for large-scale workflow execution systems:
Our workflow optimized storage system (WOSS), exploits application hints to
provide per-file optimized operations, and exposes data location to enable
location-aware scheduling.
  This paper argues that an incremental adoption path for adopting cross-layer
optimizations in storage systems exists, presents the system architecture for a
workflow-optimized storage system and its integration with a workflow runtime
engine, and evaluates the proposed approach using synthetic as well as real
applications workloads.


title:
On the Number of Interference Alignment Solutions for the K-User MIMO
  Channel with Constant Coefficients

abstract:
  In this paper, we study the number of different interference alignment (IA)
solutions in a K-user multiple-input multiple-output (MIMO) interference
channel, when the alignment is performed via beamforming and no symbol
extensions are allowed. We focus on the case where the number of IA equations
matches the number of variables. In this situation, the number of IA solutions
is finite and constant for any channel realization out of a zero-measure set
and, as we prove in the paper, it is given by an integral formula that can be
numerically approximated using Monte Carlo integration methods. More precisely,
the number of alignment solutions is the scaled average of the determinant of a
certain Hermitian matrix related to the geometry of the problem. Interestingly,
while the value of this determinant at an arbitrary point can be used to check
the feasibility of the IA problem, its average (properly scaled) gives the
number of solutions. For single-beam systems the asymptotic growth rate of the
number of solutions is analyzed and some connections with classical
combinatorial problems are presented. Nonetheless, our results can be applied
to arbitrary interference MIMO networks, with any number of users, antennas and
streams per user.


title:
The Infrared Absorption Band and Vibronic Structure of the
  Nitrogen-Vacancy Center in Diamond

abstract:
  Negatively-charged nitrogen-vacancy (NV$^-$) color centers in diamond have
generated much interest for use in quantum technology. Despite the progress
made in developing their applications, many questions about the basic
properties of NV$^-$ centers remain unresolved. Understanding these properties
can validate theoretical models of NV$^-$, improve their use in applications,
and support their development into competitive quantum devices. In particular,
knowledge of the phonon modes of the $^1A_1$ electronic state is key for
understanding the optical pumping process. Using pump-probe spectroscopy, we
measured the phonon sideband of the ${^1}E\rightarrow{^1}A_1$ electronic
transition in the NV$^-$ center. From this we calculated the
${^1}E\rightarrow{^1}A_1$ one-phonon absorption spectrum and found it to differ
from that of the ${^3}E\rightarrow{^3}A_2$ transition, a result which is not
anticipated by previous group-theoretical models of the NV$^-$ electronic
states. We identified a high-energy 169 meV localized phonon mode of the
$^1A_1$ level.


title:
Approximate Sum-Capacity of K-user Cognitive Interference Channels with
  Cumulative Message Sharing

abstract:
  This paper considers the K user cognitive interference channel with one
primary and K-1 secondary/cognitive transmitters with a cumulative message
sharing structure, i.e cognitive transmitter $i\in [2:K]$ knows non-causally
all messages of the users with index less than i. We propose a computable outer
bound valid for any memoryless channel. We first evaluate the sum-rate outer
bound for the high- SNR linear deterministic approximation of the Gaussian
noise channel. This is shown to be capacity for the 3-user channel with
arbitrary channel gains and the sum-capacity for the symmetric K-user channel.
Interestingly. for the K user channel having only the K th cognitive know all
the other messages is sufficient to achieve capacity i.e cognition at
transmitter 2 to K-1 is not needed. Next the sum capacity of the symmetric
Gaussian noise channel is characterized to within a constant additive and
multiplicative gap. The proposed achievable scheme for the additive gap is
based on Dirty paper coding and can be thought of as a MIMO-broadcast scheme
where only one encoding order is possible due to the message sharing structure.
As opposed to other multiuser interference channel models, a single scheme
suffices for both the weak and strong interference regimes. With this scheme
the generalized degrees of freedom (gDOF) is shown to be a function of K, in
contrast to the non cognitive case and the broadcast channel case.
Interestingly, it is show that as the number of users grows to infinity the
gDoF of the K-user cognitive interference channel with cumulative message
sharing tends to the gDoF of a broadcast channel with a K-antenna transmitter
and K single-antenna receivers. The analytical additive additive and
multiplicative gaps are a function of the number of users. Numerical
evaluations of inner and outer bounds show that the actual gap is less than the
analytical one.


title: Sample Complexity of Bayesian Optimal Dictionary Learning

abstract:
  We consider a learning problem of identifying a dictionary matrix D (M times
N dimension) from a sample set of M dimensional vectors Y = N^{-1/2} DX, where
X is a sparse matrix (N times P dimension) in which the density of non-zero
entries is 0<rho< 1. In particular, we focus on the minimum sample size P_c
(sample complexity) necessary for perfectly identifying D of the optimal
learning scheme when D and X are independently generated from certain
distributions. By using the replica method of statistical mechanics, we show
that P_c=O(N) holds as long as alpha = M/N >rho is satisfied in the limit of N
to infinity. Our analysis also implies that the posterior distribution given Y
is condensed only at the correct dictionary D when the compression rate alpha
is greater than a certain critical value alpha_M(rho). This suggests that
belief propagation may allow us to learn D with a low computational complexity
using O(N) samples.

categories: cs.LG cond-mat.dis-nn cond-mat.stat-mech cs.IT math.IT


title: Atomic radiative corrections without QED: role of the zero-point field

abstract:
  We derive the atomic radiative corrections predicted by QED using an
alternative approach that offers the advantage of physical clarity and
transparency. The element that gives rise to these corrections is the
fluctuating zero-point radiation field (ZPF) of average energy (hbar \omega)/2
per mode, which - in contrast with QED - is taken here as a primordial real
entity in permanent interaction with matter and responsible for its
quantization. After briefly recalling how quantum mechanics itself emerges as a
result of the balance between the ZPF and radiation reaction, the most
important higher-order effects of the radiative terms on the atom are studied.
The nonrelativistic QED formulas for the lifetimes and the Lamb shift, as well
as the corrections to the latter due to external factors that modify the vacuum
field, are thus obtained in a self-consistent approach and without the need to
resort to second quantization to the present order of approximation.


title: Causal Theories: A Categorical Perspective on Bayesian Networks

abstract:
  In this dissertation we develop a new formal graphical framework for causal
reasoning. Starting with a review of monoidal categories and their associated
graphical languages, we then revisit probability theory from a categorical
perspective and introduce Bayesian networks, an existing structure for
describing causal relationships. Motivated by these, we propose a new algebraic
structure, which we term a causal theory. These take the form of a symmetric
monoidal category, with the objects representing variables and morphisms ways
of deducing information about one variable from another. A major advantage of
reasoning with these structures is that the resulting graphical representations
of morphisms match well with intuitions for flows of information between these
variables. These categories can then be modelled in other categories, providing
concrete interpretations for the variables and morphisms. In particular, we
shall see that models in the category of measurable spaces and stochastic maps
provide a slight generalisation of Bayesian networks, and naturally form a
category themselves. We conclude with a discussion of this category,
classifying the morphisms and discussing some basic universal constructions.
  ERRATA: (i) Pages 41-42: Objects of a causal theory are words, not
collections, in $V$, and we include swaps as generating morphisms, subject to
the identities defining a symmetric monoidal category. (ii) Page 46: A causal
model is a strong symmetric monoidal functor.


title: Heat Equation on the Cone and the Spectrum of the Spherical Laplacian

abstract:
  Spectrum of the Laplacian on spherical domains is analyzed from the point of
view of the heat equation on the cone. The series solution to the heat equation
on the cone is known to lead to a study of the Laplacian eigenvalue problem on
domains on the sphere in higher dimensions. It is found that the solution leads
naturally to a spectral function, a `generating function' for the eigenvalues
and multiplicities of the Laplacian, expressible in closed form for certain
domains on the sphere. Analytical properties of the spectral function suggest a
simple scaling procedure for estimating the eigenvalues. Comparison of the
first eigenvalue estimate with the available theoretical and numerical results
for some specific domains shows remarkable agreement.


title:
Stimulated Raman scattering cascade spanning the wavelength range of 523
  to 1750~nm using a graded-index multimode optical fiber

abstract:
  We report on the generation of a Raman cascade spanning the wavelength range
of 523 to 1750 nm wavelength range, in a standard telecommunication
graded-index multimode optical fiber. Despite the highly multimode nature of
the pump, the Raman peaks are generated in specific modes of the fiber,
confirming substantial beam cleanup during the stimulated Raman scattering
process.


title: Shock Dynamics In Relativistic Jets

abstract:
  We present a formalism of the dynamics of internal shocks in relativistic
jets where the source has a time-dependent injection velocity and mass-loss
rate. The variation of the injection velocity produces a two-shock wave
structure, the working surface, that moves along the jet. This new formalism
takes into account the fact that momentum conservation is not valid for
relativistic flows where the relativistic mass lost by radiation must be taken
into account, in contrast to the classic regime. We find analytic solutions for
the working surface velocity and radiated energy for the particular case of a
step function variability of the injection parameters. We model two cases: a
pulse of fast material and a pulse of slow material (with respect to the mean
flow). Applying these models to gamma ray burst light curves, one can determine
the ratio of the Lorentz factors gamma_2 / gamma_1 and the ratio of the
mass-loss rates dot{m_2} / dot{m_1} of the upstream and downstream flows. As an
example, we apply this model to the sources GRB 080413B and GRB 070318 and find
the values of these ratios. Assuming a Lorentz factor gamma_1=100, we further
estimate jet mass-loss rates between dot{m_1} ~ 10^{-5}-1 Msun.yr^{-1}. We also
calculate the fraction of the injected mass lost by radiation. For GRB 070318
this fraction is ~7%. In contrast, for GRB 080413B this fraction is larger than
50%; in this case radiation losses clearly affect the dynamics of the internal
shocks.


title:
Phase Errors in Diffraction-Limited Imaging: Contrast Limits for Sparse
  Aperture Masking

abstract:
  Bispectrum phase, closure phase and their generalisation to kernel-phase are
all independent of pupil-plane phase errors to first-order. This property, when
used with Sparse Aperture Masking (SAM) behind adaptive optics, has been used
recently in high-contrast observations at or inside the formal diffraction
limit of large telescopes. Finding the limitations to these techniques requires
an understanding of spatial and temporal third-order phase effects, as well as
effects such as time-variable dispersion when coupled with the non-zero
bandwidths in real observations. In this paper, formulae describing many of
these errors are developed, so that a comparison can be made to fundamental
noise processes of photon- and background-noise. I show that the current
generation of aperture-masking observations of young solar-type stars, taken
carefully in excellent observing conditions, are consistent with being limited
by temporal phase noise and photon noise. This has relevance for plans to
combine pupil-remapping with spatial filtering. Finally, I describe calibration
strategies for kernel-phase, including the optimised calibrator weighting as
used for LkCa 15, and the restricted kernel-phase POISE technique that avoids
explicit dependence on calibrators.


title: Optimal Sequential Joint Detection and Estimation

abstract:
  This paper has been withdrawn by the authors. Please see arXiv:1302.6058. We
consider the sequential joint detection and estimation problem. Minimizing the
average stopping time subject to a combination of detection and estimation
constraints we obtain the optimal triplet of stopping time, detector and
estimator. In the joint detection and estimation problem the primary goal is to
detect and estimate together, as opposed to the conventional testing of
composite hypotheses where the primary goal is to detect only. For the first
time in the literature we develop optimal solution to the sequential joint
detection and estimation problem. In the sequential version of the problem,
different from the fixed sample size version, optimal stopping time is also
sought, complicating the solution considerably.


title: Critical behavior of the PT-symmetric $i\phi^3$ quantum field theory

abstract:
  It was shown recently that a PT-symmetric $i\phi^3$ quantum field theory in
$6-\epsilon$ dimensions possesses a nontrivial fixed point. The critical
behavior of this theory around the fixed point is examined and it is shown that
the corresponding phase transition is related to the existence of a nontrivial
solution of the gap equation. The theory is studied first in the mean-field
approximation and the critical exponents are calculated. Then, it is examined
beyond the mean-field approximation by using renormalization-group techniques,
and the critical exponents for $6-\epsilon$ dimensions are calculated to order
$\epsilon$. It is shown that because of its stability the PT-symmetric
$i\phi^3$ theory has a higher predictive power than the conventional $\phi^3$
theory. A comparison of the $i\phi^3$ model with the Lee-Yang model is given.


title: Additive systems and a theorem of de Bruijn

abstract:
  This paper gives a complete proof of a theorem of de Bruijn that classifies
additive systems for the nonnegative integers, that is, families $\mca =
(A_i)_{i\in I}$ of sets of nonnegative integers, each set containing 0, such
that every nonnegative integer can be written uniquely in the form $\sum_{i\in
I} a_i$ with $a_i \in A_i$ for all $i$ and $a_i \neq 0$ for only finitely many
$i$. All indecomposable additive systems are determined.


title:
On the achievable region for interference networks with point-to-point
  codes

abstract:
  This paper studies evaluation of the capacity region for interference
networks with point-to-point (p2p) capacity-achieving codes. Such capacity
region has recently been characterized as union of several sub-regions each of
which has distinctive operational characteristics. Detailed evaluation of this
region, therefore, can be accomplished in a very simple manner by acknowledging
such characteristics, which, in turn, provides an insight for a simple
implementation scenario. Completely generalized message assignment which is
also practically relevant is considered in this paper, and it is shown to
provide strictly larger achievable rates than what traditional message
assignment does when a receiver with joint decoding capability is used.


title: Embedding loop quantum cosmology without piecewise linearity

abstract:
  An important goal is to understand better the relation between full loop
quantum gravity (LQG) and the simplified, reduced theory known as loop quantum
cosmology (LQC), {\em directly at the quantum level}. Such a firmer
understanding would increase confidence in the reduced theory as a tool for
formulating predictions of the full theory, as well as permitting lessons from
the reduced theory to guide further development in the full theory. The present
paper constructs an embedding of the usual state space of LQC into that of
standard LQG, that is, LQG based on \textit{piecewise analytic paths}. The
embedding is well-defined even prior to solving the diffeomorphism constraint,
at no point is a graph fixed, and at no point is the piecewise linear category
used. This motivates for the first time a definition of operators in LQC
corresponding to holonomies along non-piecewise-linear paths, without changing
the usual kinematics of LQC in any way. The new embedding intertwines all
operators corresponding to such holonomies, and all elements in its image
satisfy an operator equation which classically implies homogeneity and
isotropy. The construction is made possible by a recent result proven by
Fleischhack.


title:
Quantitative quantum ergodicity and the nodal domains of Maass-Hecke
  cusp forms

abstract:
  We prove a quantitative statement of the quantum ergodicity for Hecke--Maass
cusp forms on the modular surface. As an application of our result, along a
density $1$ subsequence of even Hecke--Maass cusp forms, we obtain a sharp
lower bound for the $L^2$-norm of the restriction to a fixed compact geodesic
segment of $\eta=\{iy~:~y>0\} \subset \mathbb{H}$. We also obtain an upper
bound of $O_\epsilon\left(t_\phi^{3/8+\epsilon}\right)$ for the $L^\infty$ norm
along a density $1$ subsequence of Hecke--Maass cusp forms; for such forms,
this is an improvement over the upper bound of
$O_\epsilon\left(t_\phi^{5/12+\epsilon}\right)$ given by Iwaniec and Sarnak.
  In a recent work of Ghosh, Reznikov, and Sarnak, the authors proved for all
even Hecke--Maass forms that the number of nodal domains, which intersect a
geodesic segment of $\eta$, grows faster than $t_\phi^{1/12-\epsilon}$ for any
$\epsilon>0$, under the assumption that the Lindel{\"o}f Hypothesis is true and
that the geodesic segment is long enough. Upon removing a density zero subset
of even Hecke--Maass forms, we prove without making any assumptions that the
number of nodal domains grows faster than $t_\phi^{1/8-\epsilon}$ for any
$\epsilon>0$.


title: Adiabaticity and color mixing in tetraquark spectroscopy

abstract:
  We revisit the role of color mixing in the quark-model calculation of
tetraquark states, and compare simple pairwise potentials to more elaborate
string models with three- and four-body forces. We attempt to disentangle the
improved dynamics of confinement from the approximations made in the treatment
of the internal color degrees of freedom.


title: Compactification of spacetime in SU($\infty$) Yang-Mills theory

abstract:
  The compactification on a torus in $SU(\infty)$ Yang-Mills theory is
considered. A special form of the configuration of a gauge field on a torus is
examined. The vacuum energy and free energy in the presence of fermions coupled
with this background in the theory are derived and possible symmetry breaking
is investigated.


title: Knot Logic and Topological Quantum Computing with Majorana Fermions

abstract:
  This paper is an introduction to relationships between quantum topology and
quantum computing. We take a foundational approach, showing how knots are
related not just to braiding and quantum operators, but to quantum set
theoretical foundations and algebras of fermions. We show how the operation of
negation in logic, seen as both a value and an operator, can generate the
fusion algebra for a Majorana fermion, a particle that is its own anti-particle
and interacts with itself either to annihilate itself or to produce itself. We
call negation in this mode the mark, as it operates on itself to change from
marked to unmarked states. The mark viewed recursively as a simplest discrete
dynamical system naturally generates the fermion algebra, the quaternions and
the braid group representations related to Majorana fermions. The paper begins
with these fundmentals. They provide a conceptual key to many of the models
that appear later in the paper. In particular, the Fibonacci model for
topological quantum computing is seen to be based on the fusion rules for a
Majorana fermion and these in turn are the interaction rules for the mark seen
as a logical particle. It requires a shift in viewpoint to see that the
operator of negation can also be seen as a logical value. The quaternions
emerge naturally from the reentering mark. All these models have their roots in
unitary representations of the Artin braid group to the quaternions.


title:
Hole-lattice Coupling and Photo-induced Insulator-Metal Transition in
  VO$_2$

abstract:
  Photo-induced insulator-metal transition in VO$_2$ and the related transient
and multi-timescale structural dynamics upon photoexcitation are explained
within a unified framework. Holes created by photoexcitation weaken the V-V
bonds and eventually break V-V dimers in the M$_1$ phase of VO$_2$ when the
laser fluence reaches a critical value. The breaking of the V-V bonds in turn
leads to an immediate electronic phase transition from an insulating to a
metallic state while the crystal lattice remains monoclinic in shape. The
coupling between excited electrons and the 6.0 THz phonon mode is found to be
responsible for the observed zig-zag motion of V atoms upon photoexcitation and
is consistent with coherent phonon experiments.


title:
Moduli of holomorphic functions and logarithmically convex radial
  weights

abstract:
  Let $H(D)$ denote the space of holomorphic functions on the unit disk $D$. We
characterize those radial weights $w$ on $D$, for which there exist functions
$f, g \in H(D)$ such that the sum $|f| + |g|$ is equivalent to $w$. Also, we
obtain similar results in several complex variables for circular, strictly
convex domains with smooth boundary.


title:
The Aharonov-Bohm effect in spectral asymptotics of the magnetic
  Schr\"odinger operator

abstract:
  We show that in the absence of a magnetic field the spectrum of the magnetic
Schr\"odinger operator in an annulus depends on the cosine of the flux
associated with the magnetic potential. This result follows from an analysis of
a singularity in the wave trace for this Schr\"odinger operator, and hence
shows that even in the absence of a magnetic field the magnetic potential can
change the asymptotics of the Schr\"odinger spectrum, i.e. the Aharonov-Bohm
effect takes place. We also study the Aharonov-Bohm effect for the magnetic
Schr\"odinger operator on a torus.


title:
Electronic Structure and magnetism in Ir based double-perovskite
  Sr$_2$CeIrO$_6$

abstract:
  The electronic structure and magnetism of Sr$_2$CeIrO$_6$, an Ir-based double
perovskite system has been investigated using first-principles calculations. We
found that a strong spin-orbit coupling dictate the electronic and magnetic
properties of this system. A small value of $U$ along with SOC could open up a
gap at the Fermi level, offering the possibility of novel J$_{eff}$ = 1/2 Mott
quantum state. Our calculations reveal that the magnetic ground state is
antiferromagnetic in agreement with the magnetization data and provide the
value of spin and orbital moment for this system which is in agreement with the
other isostructural Ir-based compound.


title:
Optimistic limits of Kashaev invariants and complex volumes of
  hyperbolic links

abstract:
  Yokota suggested an optimistic limit method of the Kashaev invariants of
hyperbolic knots and showed it determines the complex volumes of the knots. His
method is very effective and gives almost combinatorial method of calculating
the complex volumes. However, to describe the triangulation of the knot
complement, he restricted his method to knot diagrams with certain conditions.
Although these restrictions are general enough for any hyperbolic knots, we
have to select a good diagram of the knot to apply his theory.
  In this article, we suggest more combinatorial way to calculate the complex
volumes of hyperbolic links using the modified optimistic limit method. This
new method works for any link diagrams, and it is more intuitive, easy to
handle and has natural geometric meaning.


title: Role of uniform horizontal magnetic field on convective flow

abstract:
  The effect of uniform magnetic field applied along a fixed horizontal
direction in Rayleigh-B\'enard convection in low-Prandtl-number fluids has been
studied using a low dimensional model. The model shows the onset of convection
(primary instability) in the form of two dimensional stationary rolls in the
absence of magnetic field, when the Rayleigh number $R$ is raised above a
critical value $R_c$. The flow becomes three dimensional at slightly higher
values of Rayleigh number via wavy instability. These wavy rolls become chaotic
for slightly higher values of $R$ in low-Prandtl-number ($P_r$) fluids. A
uniform magnetic field along horizontal plane strongly affects all kinds of
convective flows observed at higher values of $R$ in its absence. As the
magnetic field is raised above certain value, it orients the convective rolls
in its own direction. Although the horizontal magnetic field does not change
the threshold for the primary instability, it affects the threshold for
secondary (wavy) instability. It inhibits the onset of wavy instability. The
critical Rayleigh number $R_o (Q,P_r)$ at the onset of wavy instability, which
depends on Chandrasekhar's number $Q$ and $P_r$, increases monotonically with
$Q$ for a fixed value of $P_r$. The dimensionless number $R_o (Q, P_r)/(R_c Q
P_r)$ scales with $Q$ as $Q^{-1}$. A stronger magnetic field suppresses chaos
and makes the flow two dimensional with roll pattern aligned along its
direction.


title:
Constraining the cometary flux through the asteroid belt during the late
  heavy bombardment

abstract:
  In the Nice model, the late heavy bombardment (LHB) is related to an orbital
instability of giant planets which causes a fast dynamical dispersion of a
transneptunian cometary disk. We study effects produced by these hypothetical
cometary projectiles on main-belt asteroids. In particular, we want to check
whether the observed collisional families provide a lower or an upper limit for
the cometary flux during the LHB.
  We present an updated list of observed asteroid families as identified in the
space of synthetic proper elements by the hierarchical clustering method,
colour data, albedo data and dynamical considerations and we estimate their
physical parameters. We selected 12 families which may be related to the LHB
according to their dynamical ages. We then used collisional models and N-body
orbital simulations to gain insight into the long-term dynamical evolution of
synthetic LHB families over 4 Gyr. We account for the mutual collisions, the
physical disruptions of comets, the Yarkovsky/YORP drift, chaotic diffusion, or
possible perturbations by the giant-planet migration.
  Assuming a "standard" size-frequency distribution of primordial comets, we
predict the number of families with parent-body sizes D_PB >= 200 km which
seems consistent with observations. However, more than 100 asteroid families
with D_PB >= 100 km should be created at the same time which are not observed.
This discrepancy can be nevertheless explained by the following processes: i)
asteroid families are efficiently destroyed by comminution (via collisional
cascade), ii) disruptions of comets below some critical perihelion distance (q
<~ 1.5 AU) are common.
  Given the freedom in the cometary-disruption law, we cannot provide stringent
limits on the cometary flux, but we can conclude that the observed distribution
of asteroid families does not contradict with a cometary LHB.


title: On the associated sequences of special polynomials

abstract:
  In this paper, we investigate some properties of the associated sequence of
Daehee and Changhee polynomials. Finally, we give some interesting identities
of associated sequence involving some special polynomials.


title: Relaxor behavior and morphotropic phase boundary in a simple model

abstract:
  A simple model to reproduce strong enhancement of dielectric response near
the morphotropic phase boundary (MPB) is proposed. This model consists of
long-range dipole-dipole interaction and compositional chemical disorder
incorporated by the variation in lengths of dipole moments. By applying Monte
Carlo simulation, we show that there appears a ferroelectric boundary phase
between two types of antiferroelectric phases at an optimal strength of
randomness. In the boundary phase, ferroelectric domain becomes remarkably
large and flexible to external electric fields, leading to huge dielectric
response. This observation indicates that huge dielectric response near the MPB
originates from {\it local} polarization rotation under suppressed anisotropy
by phase competition.


title: The skew energy of random oriented graphs

abstract:
  Given a graph $G$, let $G^\sigma$ be an oriented graph of $G$ with the
orientation $\sigma$ and skew-adjacency matrix $S(G^\sigma)$. The skew energy
of the oriented graph $G^\sigma$, denoted by $\mathcal{E}_S(G^\sigma)$, is
defined as the sum of the absolute values of all the eigenvalues of
$S(G^\sigma)$. In this paper, we study the skew energy of random oriented
graphs and formulate an exact estimate of the skew energy for almost all
oriented graphs by generalizing Wigner's semicircle law. Moreover, we consider
the skew energy of random regular oriented graphs $G_{n,d}^\sigma$, and get an
exact estimate of the skew energy for almost all regular oriented graphs.


title:
Hydrodynamic and field-theoretic approaches of light localization in
  open media

abstract:
  Many complex systems exhibit hydrodynamic (or macroscopic) behavior at large
scales characterized by few variables such as the particle number density,
temperature and pressure obeying a set of hydrodynamic (or macroscopic)
equations. Does the hydrodynamic description exist also for waves in complex
open media? This is a long-standing fundamental problem in studies on wave
localization. Practically, if it does exist, owing to its simplicity
macroscopic equations can be mastered far more easily than sophisticated
microscopic theories of wave localization especially for experimentalists. The
purposes of the present paper are two-fold. On the one hand, it is devoted to a
review of substantial recent progress in this subject. We show that in random
open media the wave energy density obeys a highly unconventional macroscopic
diffusion equation at scales much larger than the elastic mean free path. The
diffusion coefficient is inhomogeneous in space; most strikingly, as a function
of the distance to the interface, it displays novel single parameter scaling
which captures the impact of rare high-transmission states that dominate
long-time transport of localized waves. We review aspects of this novel
macroscopic diffusive phenomenon. On the other hand, it is devoted to a review
of the supersymmetric field theory of light localization in open media. In
particular, we review its application in establishing a microscopic theory of
the aforementioned unconventional diffusive phenomenon.

categories: cond-mat.dis-nn cond-mat.mes-hall cond-mat.stat-mech physics.optics


title: On Read's type operators on Hilbert spaces

abstract:
  Using Read's construction of operators without non-trivial invariant
subspaces/subsets on $\ell_{1}$ or $c_{0}$, we construct examples of operators
on a Hilbert space whose set of hypercyclic vectors is "large" in various
senses. We give an example of an operator such that the closure of every orbit
is a closed subspace, and then, answering a question of D. Preiss, an example
of an operator such that the set of its non-hypercyclic vectors is Gauss null.
This operator has the property that it is orbit-unicellular, i.e. the family of
the closures of its orbits is totally ordered. We also exhibit an example of an
operator on a Hilbert space which is not orbit-reflexive.


title: Chiral soliton model at finite temperature and density

abstract:
  In mean field approximation, we study a chiral soliton of the linear sigma
model with two flavors at finite temperature and density. The stable soliton
solutions are calculated with some appropriate boundary conditions. Energy and
radius of the soliton are determined in a hot medium of constituent quarks. It
is found that for $T<T_c$, the energy of the soliton $E^*$ is less than the
energy of three constituent quarks $3M_q$, but with the increasing of
temperature, the difference between $E^*$ and $3M_q$ becomes smaller and
smaller, once $T>T_c$, there is a sharp delocalization phase transition from
hadron matter to quark matter coincident with the restoration of chiral
symmetry. In the transition region, the thermodynamic properties show large
discontinuities which is an indication for a first-order phase transition.


title: Pilot-Data: An Abstraction for Distributed Data

abstract:
  Scientific problems that depend on processing large amounts of data require
overcoming challenges in multiple areas: managing large-scale data
distribution, controlling co-placement and scheduling of data with compute
resources, and storing, transferring, and managing large volumes of data.
Although there exist multiple approaches to addressing each of these
challenges, an integrative approach is missing; furthermore, extending existing
functionality or enabling interoperable capabilities remains difficult at best.
We propose the concept of Pilot-Data to address the fundamental challenges of
co-placement and scheduling of data and compute in heterogeneous and
distributed environments with interoperability and extensibility as first-order
concerns. Pilot-Data is an extension of the Pilot-Job abstraction for
supporting the management of data in conjunction with compute tasks. Pilot-Data
separates logical data units from physical storage, thereby providing the basis
for efficient compute/data placement and scheduling. In this paper, we discuss
the design and implementation of the Pilot-Data prototype, demonstrate its use
by data-intensive applications on multiple production distributed
cyberinfrastructure and illustrate the advantages arising from flexible
execution modes enabled by Pilot-Data. Our experiments utilize an
implementation of Pilot-Data in conjunction with a scalable Pilot-Job (BigJob)
to establish the application performance that can be enabled by the use of
Pilot-Data. We demonstrate how the concept of Pilot-Data also provides the
basis upon which to build tools and support capabilities like affinity which in
turn can be used for advanced data-compute co-placement and scheduling.


title:
Regularity of optimal maps on the sphere: the quadratic cost and the
  reflector antenna

abstract:
  Building on the results of Ma, Trudinger and Wang \cite{MTW}, and of the
author \cite{L5}, we study two problems of optimal transportation on the
sphere: the first corresponds to the cost function $d^2(x,y)$, where
$d(\cdot,\cdot)$ is the Riemannian distance of the round sphere; the second
corresponds to the cost function $-\log|x-y|$, it is known as the reflector
antenna problem. We show that in both cases, the {\em cost-sectional curvature}
is uniformly positive, and establish the geometrical properties so that the
results of \cite{L5} and \cite{MTW} can apply: global smooth solutions exist
for arbitrary smooth positive data and optimal maps are H\"older continuous
under weak assumptions on the data.


title:
Numerical homotopy continuation for control and online identification of
  nonlinear systems: the survey of selected results

abstract:
  The article gives an overview of the parameter numerical continuation
methodology applied to setpoint control and parameter identification of
nonlinear systems. The control problems for affine systems as well as general
(nonaffine) nonlinear systems are considered. Online parameter identification
is also presented in two versions: with linear and nonlinear nonconvex
parameterization. Simulation results for illustrative examples are shown.


title:
Generalizing Bounds on the Minimum Distance of Cyclic Codes Using Cyclic
  Product Codes

abstract:
  Two generalizations of the Hartmann--Tzeng (HT) bound on the minimum distance
of q-ary cyclic codes are proposed. The first one is proven by embedding the
given cyclic code into a cyclic product code. Furthermore, we show that unique
decoding up to this bound is always possible and outline a quadratic-time
syndrome-based error decoding algorithm. The second bound is stronger and the
proof is more involved.
  Our technique of embedding the code into a cyclic product code can be applied
to other bounds, too and therefore generalizes them.


title: A degree theory approach for the shooting method

abstract:
  The classical shooting-method is about finding a suitable initial shooting
positions to shoot to the desired target. The new approach formulated here,
with the introduction and the analysis of the `target map' as its core,
naturally connects the classical shooting-method to the simple and beautiful
topological degree theory.
  We apply the new approach, to a motivating example, to derive the existence
of global positive solutions of the Hardy-Littlewood-Sobolev (also known as
Lane-Emden) type system: [{{aligned}
  &(-\triangle)^ku(x) = v^p(x), \,\, u(x)>0 \quad\text{in}\quad\mathbb{R}^n,
  & (-\triangle)^k v(x) =u^q(x), \,\, v(x)>0 \quad\text{in}\quad\mathbb{R}^n,
p, q>0,
  {aligned}.] in the critical and supercritical cases
$\frac{1}{p+1}+\frac{1}{q+1}\leq\frac{n-2k}{n}$. Here we derive the existence
with the computation of the topological degree of a suitably defined target
map. This and some other results presented in this article completely solved
several long-standing open problems about the existence or non-existence of
positive entire solutions.


title: Homology equivalences of manifolds and zero-in-the-spectrum examples

abstract:
  Working with group homomorphisms, a construction of manifolds is introduced
to preserve homology groups. The construction gives as special cases Qullien's
plus construction with handles obtained by Hausmann, the existence of one-sided
$h$-cobordism of Guilbault and Tinsley, the existence of homology spheres and
higher-dimensional knots proved by Karvaire. We also use it to get
counter-examples to the zero-in-the-spectrum conjecture found by
Farber-Weinberger, and by Higson-Roe-Schick.


title: A Note on Fractional Evolutionary Equations

abstract:
  A class of linear evolutionary equations with material laws involving
fractional time-derivatives is considered. The main result is well-posedness
and causality for this problem class. The approach is illustrated with two
examples: a fractional Fokker-Planck type equation and a class of visco-elastic
materials described via fractional derivatives. In conclusion the possibility
of imposing initial conditions is discussed.


title: Sharp criteria of Liouville type for some nonlinear systems

abstract:
  In this paper, we establish the sharp criteria for the nonexistence of
positive solutions to the Hardy-Littlewood-Sobolev (HLS) type system of
nonlinear equations and the corresponding nonlinear differential systems of
Lane-Emden type equations. These nonexistence results, known as Liouville type
theorems, are fundamental in PDE theory and applications. A special iteration
scheme, a new shooting method and some Pohozaev type identities in integral
form as well as in differential form are created. Combining these new
techniques with some observations and some critical asymptotic analysis, we
establish the sharp criteria of Liouville type for our systems of nonlinear
equations. Similar results are also derived for the system of Wolff type
integral equations and the system of $\gamma$-Laplace equations. A dichotomy
description in terms of existence and nonexistence for solutions with finite
energy is also obtained.


title:
Multi-Trial Guruswami--Sudan Decoding for Generalised Reed--Solomon
  Codes

abstract:
  An iterated refinement procedure for the Guruswami--Sudan list decoding
algorithm for Generalised Reed--Solomon codes based on Alekhnovich's module
minimisation is proposed. The method is parametrisable and allows variants of
the usual list decoding approach. In particular, finding the list of
\emph{closest} codewords within an intermediate radius can be performed with
improved average-case complexity while retaining the worst-case complexity.


title:
Convergence to the Equilibrium in a Lotka-Volterra Ode Competition
  System with Mutations

abstract:
  In this paper we are investigating the long time behaviour of the solution of
a mutation competition model of Lotka-Volterra's type. Our main motivation
comes from the analysis of the Lotka-Volterra's competition system with
mutation which simulates the demo-genetic dynamics of diverse virus in their
host : $$ \frac{dv_{i}(t)}{dt}=v_i\[r_i-\frac{1}{K}\Psi_i(v)\]+\sum_{j=1}^{N}
\mu_{ij}(v_j-v_i). $$ In a first part we analyse the case where the competition
terms $\Psi_i$ are independent of the virus type $i$. In this situation and
under some rather general assumptions on the functions $\Psi_i$, the
coefficients $r_i$ and the mutation matrix $\mu_{ij}$ we prove the existence of
a unique positive globally stable stationary solution i.e. the solution
attracts the trajectory initiated from any nonnegative initial datum. Moreover
the unique steady state $\bar v$ is strictly positive in the sense that $\bar
v_i>0$ for all $i$. These results are in sharp contrast with the behaviour of
Lotka-Volterra without mutation term where it is known that multiple non
negative stationary solutions exist and an exclusion principle occurs (i.e For
all $i\neq i_0, \bar v_{i}=0$ and $\bar v_{i_0}>0$). Then we explore a typical
example that has been proposed to explain some experimental data. For such
particular models we characterise the speed of convergence to the equilibrium.
In a second part, under some additional assumption, we prove the existence of a
positive steady state for the full system and we analyse the long term
dynamics. The proofs mainly rely on the construction of a relative entropy
which plays the role of a Lyapunov functional.


title: On the rough-paths approach to non-commutative stochastic calculus

abstract:
  We study different possibilities to apply the principles of rough paths
theory in a non-commutative probability setting. First, we extend previous
results obtained by Capitaine, Donati-Martin and Victoir in Lyons' original
formulation of rough paths theory. Then we settle the bases of an alternative
non-commutative integration procedure, in the spirit of Gubinelli's controlled
paths theory, and which allows us to revisit the constructions of Biane and
Speicher in the free Brownian case. New approximation results are also derived
from the strategy.


title: On an analogue of Schwarz's reflection principle

abstract:
  We consider the Bergman space on the complex plane. We prove an analogue of
Schwarz's reflection principle for unbounded quasidisks.


title: The exact number of r-regular elements in finite exceptional groups

abstract:
  We calculate the precise number of r-regular elements in the finite
exceptional groups. As a corollary we find that the proportion of r-regular
elements is at least 3577/18432 and for all \epsilon>0, there are infinitely
finite simple exceptional groups such that the proportion of r-regular elements
is less than $3577/18432+\epsilon$ for some prime r.


title:
Multiple Plasmoid Ejections and Associated Hard X-ray Bursts in the 2000
  November 24 Flare

abstract:
  The Soft X-ray Telescope (SXT) on board Yohkoh revealed that the ejection of
X-ray emitting plasmoid is sometimes observed in a solar flare. It was found
that the ejected plasmoid is strongly accelerated during a peak in the hard
X-ray emission of the flare. In this paper we present an examination of the
GOES X 2.3 class flare that occurred at 14.51 UT on 2000 November 24. In the
SXT images we found multiple plasmoid ejections with velocities in the range of
250-1500 km/s, which showed blob-like or loop-like structures. Furthermore, we
also found that each plasmoid ejection is associated with an impulsive burst of
hard X-ray emission. Although some correlation between plasmoid ejection and
hard X-ray emission has been discussed previously, our observation shows
similar behavior for multiple plasmoid ejection such that each plasmoid
ejection occurs during the strong energy release of the solar flare. As a
result of temperature-emission measure analysis of such plasmoids, it was
revealed that the apparent velocities and kinetic energies of the plasmoid
ejections show a correlation with the peak intensities in the hard X-ray
emissions.


title:
Fermi Acceleration in Plasmoids interacting with Fast Shocks of
  Reconnection via Fractal Reconnection

abstract:
  We propose the particle acceleration model coupled with multiple plasmoid
ejections in a solar flare. Unsteady reconnection produces plasmoids in a
current sheet and ejects them out to the fast shocks, where particles in a
plasmoid are reflected upstream the shock front by magnetic mirror effect. As
the plasmoid passes through the shock front, the reflection distance becomes
shorter and shorter driving Fermi acceleration, until it becomes proton Larmor
radius. The fractal distribution of plasmoids may also have a role in naturally
explaining the power-law spectrum in nonthermal emissions.


title: DAMA/LIBRA results and perspectives

abstract:
  The DAMA/LIBRA experiment, running at the Gran Sasso National Laboratory of
the I.N.F.N. in Italy, has a sensitive mass of about 250 kg highly radiopure
NaI(Tl). It is mainly devoted to the investigation of Dark Matter (DM)
particles in the Galactic halo by exploiting the model independent DM annual
modulation signature. The present DAMA/LIBRA experiment and the former DAMA/NaI
one (the first generation experiment having an exposed mass of about 100 kg)
have released so far results corresponding to a total exposure of 1.17 ton yr
over 13 annual cycles. They provide a model independent evidence of the
presence of DM particles in the galactic halo at 8.9 sigma C.L.. A short
summary of the obtained results is presented and future perspectives of the
experiment mentioned.


title:
The Power-Law Distribution of Flare Kernels and Fractal Current Sheets
  in a Solar Flare

abstract:
  We report a detailed examination of the fine structure inside flare ribbons
and the temporal evolution of this fine structure during the X2.5 solar flare
that occurred on 2004 November 10. We examine elementary bursts of the C IV
(1550{\AA}) emission lines seen as local transient brightenings inside the
flare ribbons in the ultraviolet (1600{\AA}) images taken with Transition
Region and Coronal Explorer, and we call them C IV kernels. This flare was also
observed in Ha with the Sartorius 18 cm Refractor telescope at Kwasan
observatory, Kyoto University, and in hard X-rays (HXR) with Reuven Ramaty High
Energy Solar Spectroscopic Imager. Many C IV kernels, whose sizes were
comparable to or less than 2", were found to brighten successively during the
evolution of the flare ribbon. The majority of them were well correlated with
the Ha kernels in both space and time, while some of them were associated with
the HXR emission. These kernels were thought to be caused by the precipitation
of nonthermal particles at the footpoints of the reconnecting flare loops. The
time profiles of the C IV kernels showed intermittent bursts, whose peak
intensity, duration, and time interval were well described by power-law
distribution functions. This result is interpreted as evidence for
"self-organized criticality" in avalanching behavior in a single flare event,
or for fractal current sheets in the impulsive reconnection region.


title: Deformation of vortex patches by boundaries

abstract:
  The deformation of two-dimensional vortex patches in the vicinity of fluid
boundaries is investigated. The presence of a boundary causes an initially
circular patch of uniform vorticity to deform. Sufficiently far away from the
boundary, the deformed shape is well approximated by an ellipse. This leading
order elliptical deformation is investigated via the elliptic moment model of
Melander, Zabusky & Styczek [M. V. Melander, N. J. Zabusky & A. S. Styczek, J.
Fluid. Mech., 167, 95 (1986)]. When the boundary is straight, the centre of the
elliptic patch remains at a constant distance from the boundary, and the motion
is integrable. Furthermore, since the straining flow acting on the patch is
constant in time, the problem is that of an elliptic vortex patch in constant
strain, which was analysed by Kida [S. Kida, J. Phys. Soc. Japan, 50, 3517
(1981)]. For more complicated boundary shapes, such as a square corner, the
motion is no longer integrable. Instead, there is an adiabatic invariant for
the motion. This adiabatic invariant arises due to the separation in times
scales between the relatively rapid time scale associated with the rotation of
the patch and the slower time scale associated with the self-advection of the
patch along the boundary. The interaction of a vortex patch with a circular
island is also considered. Without a background flow, conservation of angular
impulse implies that the motion is again integrable. The addition of an
irrotational flow past the island can drive the patch towards the boundary,
leading to the possibility of large deformations and breakup.


title:
Semileptonic decays $B \to D^{(*)} l\nu$ in the perturbative QCD
  factorization approach

abstract:
  In this paper, we study the $B \to D^{(*)} l^- \bar{\nu}_{\rm l}$
semileptonic decays and calculate the branching ratios ${\cal B}(B \to D^{(*)}
l^- \bar{\nu}_{\rm l})$ and the ratios $R(D^{(*)})$ and $R_{\rm D}^{\rm
l,\tau}$ by employing the perturbative QCD (pQCD) factorization approach. We
find that (a) for $R(D)$ and $R(D^*)$ ratios, the pQCD predictions are
$R(D)=0.430^{+0.021}_{-0.026}$, $R(D^*)=0.301 \pm 0.013$ and agree well with
BaBar's measurements of $R(D^{(*)})$; (b) for the newly defined $R_{\rm D}^{\rm
l}$ and $R_{\rm D}^{\rm \tau}$ ratios, the pQCD predictions are $R_{\rm D}^{\rm
l} = 0.450^{+0.064}_{-0.051}$ and $R_{\rm D}^{\rm \tau}
=0.642^{+0.081}_{-0.070}$, which may be more sensitive to the QCD dynamics of
the considered semileptonic decays than $R(D^{(*)})$ and should be tested by
experimental measurements.


title: Analysis of one assumption of the Navier-Stokes equations

abstract:
  This article analyses the assumptions regarding the influence of pressure
forces during the calculation of the motion of a Newtonian fluid. The purpose
of the analysis is to determine the reasonableness of the assumptions and their
impact on the results of the analytical calculation. The connections between
equations, causes of discrepancies in exact solutions of the Navier-Stokes
equations at low Reynolds numbers and the emergence of unstable solutions using
computer programs are also addressed. The necessity to complement the
well-known equations of motion in mechanical stress requires other equations
are substantive. It is shown that there are three methods of solving such a
problem and the requirements for the unknown equations are described. Keywords:
Navier-Stokes, approximate equation, closing equations, holonomic system.


title: Monitoring the formation of oxide apertures in micropillar cavities

abstract:
  An imaging technique is presented that enables monitoring of the wet thermal
oxidation of a thin AlAs layer embedded between two distributed Bragg reflector
(DBR) mirrors in a micropillar. After oxidation we confirm by white light
reflection spectroscopy that high quality optical modes confined to a small
volume have been formed. The combination of these two optical techniques
provides a reliable and efficient way of producing oxide apertured micropillar
cavities for which the wet thermal oxidation is a critical fabrication step.


title:
One-dimensional energy spectra in three-dimensional incompressible
  homogeneous isotropic turbulence

abstract:
  The paper investigates the detailed features of one-dimensional energy
spectra in three-dimensional isotropic turbulence, based on the exact solution
of Karman-Howarth equation. Particular interest will be paid on the degree to
which spectral scaling can lead the spectral data to be collapsed. The theory
appears to be consistent with the wealth of experimental data (G.Comte-Bellot
and S. Corrsin, 1971) at least in low Taylor microscale Reynolds number.

categories: physics.flu-dyn cond-mat.stat-mech math-ph math.MP nlin.SI


title:
A Bohl-Bohr-Kadets type theorem characterizing Banach spaces not
  containing c0

abstract:
  We prove that a separable Banach space $E$ does not contain a copy of the
space $\co$ of null-sequences if and only if for every doubly power-bounded
operator $T$ on $E$ and for every vector $x\in E$ the relative compactness of
the sets $\{T^{n+m}x-T^nx: n\in \NN\}$ (for some/all $m\in\NN$, $m\geq 1$) and
$\{T^nx:n\in \NN\}$ are equivalent. With the help of the Jacobs--de
Leeuw--Glicksberg decomposition of strongly compact semigroups the case of (not
necessarily invertible) power-bounded operators is also handled.


title: Constants of cyclotomic derivations

abstract:
  Let $k[X]=k[x_0,...,x_{n-1}]$ and $k[Y]=k[y_0,...,y_{n-1}]$ be the polynomial
rings in $n\geqslant 3$ variables over a field $k$ of characteristic zero
containing the $n$-th roots of unity. Let $d$ be the cyclotomic derivation of
$k[X]$, and let $\Delta$ be the factorisable derivation of $k[Y]$ associated
with $d$, that is, $d(x_j)=x_{j+1}$ and $\Delta(y_j)=y_j(y_{j+1}-y_j)$ for all
$j\in\mathbb Z_n$. We describe polynomial constants and rational constants of
these derivations. We prove, among others, that the field of constants of $d$
is a field of rational functions over $k$ in $n-\f(n)$ variables, and that the
ring of constants of $d$ is a polynomial ring if and only if $n$ is a power of
a prime. Moreover, we show that the ring of constants of $\Delta$ is always
equal to $k[v]$, where $v$ is the product $y_0... y_{n-1}$, and we describe the
field of constants of $\Delta$ in two cases: when $n$ is power of a prime, and
when $n=p q$.


title:
Option pricing with linear market impact and non-linear Black and
  Scholes equations

abstract:
  We consider a model of linear market impact, and address the problem of
replicating a contingent claim in this framework. We derive a non-linear
Black-Scholes Equation that provides an exact replication strategy.
  This equation is fully non-linear and singular, but we show that it is well
posed, and we prove existence of smooth solutions for a large class of final
payoffs, both for constant and local volatility. To obtain regularity of the
solutions, we develop an original method based on Legendre transforms.
  The close connections with the problem of hedging with it gamma constraints
studied by Cheridito, Soner and Touzi and with the problem of hedging under it
liquidity costs are discussed.
  We also derive a modified Black-Scholes formula valid for asymptotically
small impact parameter, and finally provide numerical simulations as an
illustration.


title:
A Model of Four Generation Fermions and Cold Dark Matter and
  Matter-Antimatter Asymmetry

abstract:
  I suggest a practical particle model as an extension to the standard model.
The model has a TeV scale $U(1)_{B-L}$ symmetry and it contains the fourth
generation fermions with the TeV scale masses, in which including a cold dark
matter neutrino. The model can completely account for the fermion flavor
puzzles, the cold dark matter, and the matter-antimatter asymmetry through the
leptogenesis. In particular, it is quite feasible and promising to test the
model in future experiments.


title: Elastic properties and phase stability of AgBr under pressure

abstract:
  Ab initio calculations have been used to derive the elastic constants,
equation of state and free energy of NaCl-, KOH-, and CsCl-type structures of
AgBr. The elastic constants have been derived by the stress-strain relation.
The shear elastic constants $C_{44}$ has proven to be exceptionally soft. We
have found that at temperature T=0 the phase transition from the low pressure
NaCl-type to the high-pressure CsCl-type structure goes over a monoclinic
KOH-type structure. The free energy comparison indicates that the monoclinic
phase ranges from 8 to 35 GPa.


title:
Information Loss due to Finite Block Length in a Gaussian Line Network:
  An Improved Bound

abstract:
  A bound on the maximum information transmission rate through a cascade of
Gaussian links is presented. The network model consists of a source node
attempting to send a message drawn from a finite alphabet to a sink, through a
cascade of Additive White Gaussian Noise links each having an input power
constraint. Intermediate nodes are allowed to perform arbitrary
encoding/decoding operations, but the block length and the encoding rate are
fixed. The bound presented in this paper is fundamental and depends only on the
design parameters namely, the network size, block length, transmission rate,
and signal-to-noise ratio.


title:
Tight is better: Performance Improvement of the Compressive Classifier
  Using Equi-Norm Tight Frames

abstract:
  Detecting or classifying already known sparse signals contaminated by
Gaussian noise from compressive measurements is different from reconstructing
sparse signals, as its objective is to minimize the error probability which
describes performance of the detectors or classifiers. This paper is concerned
about the performance improvement of a commonly used Compressive Classifier. We
prove that when the arbitrary sensing matrices used to get the Compressive
Measurements are transformed into Equi-Norm Tight Frames, i.e. the matrices
that are row-orthogonal, The Compressive Classifier achieves better
performance. Although there are other proofs that among all Equi-Norm Tight
Frames the Equiangular tight Frames (ETFs) bring best worst-case performance,
the existence and construction of ETFs on some dimensions is still an open
problem. As the construction of Equi-Norm Tight Frames from any arbitrary
matrices is very easy and practical compared with ETF matrices, the result of
this paper can also provide a practical method to design an improved sensing
matrix for Compressive Classification. We can conclude that: Tight is Better!


title:
Rigidity of area-minimizing free boundary surfaces in mean convex
  three-manifolds

abstract:
  We prove a local splitting theorem for three-manifolds with mean convex
boundary and scalar curvature bounded from below that contain certain locally
area-minimizing free boundary surfaces. Our methods are based on those of
Micallef and Moraru. We use this local result to establish a global rigidity
theorem for area-minimizing free boundary disks. In the negative scalar
curvature case, this global result implies a rigidity theorem for solutions of
the Plateau problem with length-minimizing boundary.


title:
On Soliton Collisions between Localizations in Complex Elementary
  Cellular Automata: Rules 54 and 110 and Beyond

abstract:
  In this paper we present a single-soliton two-component cellular automata
(CA) model of waves as mobile self-localizations, also known as: particles,
waves, or gliders; and its version with memory. The model is based on coding
sets of strings where each chain represents a unique mobile self-localization.
We will discuss briefly the original soliton models in CA proposed with {\it
filter automata}, followed by solutions in elementary CA (ECA) domain with the
famous universal ECA {\it Rule 110}, and reporting a number of new solitonic
collisions in ECA {\it Rule 54}. A mobile self-localization in this study is
equivalent a single soliton because the collisions of these mobile
self-localizations studied in this paper satisfies the property of solitonic
collisions. We also present a specific ECA with memory (ECAM), the ECAM Rule
$\phi_{R9maj:4}$, that displays single-soliton solutions from any initial
codification (including random initial conditions) for a kind of mobile
self-localization because such automaton is able to adjust any initial
condition to soliton structures.


title: Inconsistencies from a Running Cosmological Constant

abstract:
  We examine the general issue of whether a scale dependent cosmological
constant can be consistent with general covariance, a problem that arises
naturally in the treatment of quantum gravitation where coupling constants
generally run as a consequence of renormalization group effects. The issue is
approached from several points of view, which include the manifestly covariant
functional integral formulation, covariant continuum perturbation theory about
two dimensions, the lattice formulation of gravity, and the non-local effective
action and effective field equation methods. In all cases we find that the
cosmological constant cannot run with scale, unless general covariance is
explicitly broken by the regularization procedure. Our results are expected to
have some bearing on current quantum gravity calculations, but more generally
should apply to phenomenological approaches to the cosmological vacuum energy
problem.


title: Problems of Inheritance at Java Inner Class

abstract:
  Single inheritance has been widely accepted in the current programming
practice to avoid the complication that incurred by multiple inheritance.
Single inheritance enhances the reusability of codes and eliminates the
confusion of identical methods that possibly defined in two superclasses.
However, the mechanism of inner class in Java potentially reintroduces the
problems encountered by multiple inheritance. When the depth of Java inner
class is increased, the problem becomes severe. This paper aims at exposing the
problems of inheritance at the Java inner class. In addition, a measure is
proposed to evaluate the potential problem of inheritance for Java inner class


title: Canonical basis, KLR-algebras and parity sheaves

abstract:
  We give a construction of a basis of the positive part of the Drinfeld-Jimbo
quantum enveloping algebra associated with a Dynkin quiver in terms of parity
sheaves.


title: Developing Parallel Dependency Graph In Improving Game Balancing

abstract:
  The dependency graph is a data architecture that models all the dependencies
between the different types of assets in the game. It depicts the
dependency-based relationships between the assets of a game. For example, a
player must construct an arsenal before he can build weapons. It is vital that
the dependency graph of a game is designed logically to ensure a logical
sequence of game play. However, a mere logical dependency graph is not
sufficient in sustaining the players' enduring interests in a game, which
brings the problem of game balancing into picture. The issue of game balancing
arises when the players do not feel the chances of winning the game over their
AI opponents who are more skillful in the game play. At the current state of
research, the architecture of dependency graph is monolithic for the players.
The sequence of asset possession is always foreseeable because there is only a
single dependency graph. Game balancing is impossible when the assets of AI
players are overwhelmingly outnumbering that of human players. This paper
proposes a parallel architecture of dependency graph for the AI players and
human players. Instead of having a single dependency graph, a parallel
architecture is proposed where the dependency graph of AI player is adjustable
with that of human player using a support dependency as a game balancing
mechanism. This paper exhibits that the parallel dependency graph helps to
improve game balancing.


title: A Secure Submission System for Online Whistleblowing Platforms

abstract:
  Whistleblower laws protect individuals who inform the public or an authority
about governmental or corporate misconduct. Despite these laws, whistleblowers
frequently risk reprisals and sites such as WikiLeaks emerged to provide a
level of anonymity to these individuals. However, as countries increase their
level of network surveillance and Internet protocol data retention, the mere
act of using anonymizing software such as Tor, or accessing a whistleblowing
website through an SSL channel might be incriminating enough to lead to
investigations and repercussions. As an alternative submission system we
propose an online advertising network called AdLeaks. AdLeaks leverages the
ubiquity of unsolicited online advertising to provide complete sender
unobservability when submitting disclosures. AdLeaks ads compute a random
function in a browser and submit the outcome to the AdLeaks infrastructure.
Such a whistleblower's browser replaces the output with encrypted information
so that the transmission is indistinguishable from that of a regular browser.
Its back-end design assures that AdLeaks must process only a fraction of the
resulting traffic in order to receive disclosures with high probability. We
describe the design of AdLeaks and evaluate its performance through analysis
and experimentation.


title: Electromagnetically induced transparency with degenerate atomic levels

abstract:
  For the coherently driven \Lambda-type three-level systems the general
ready-to-calculate expression for the susceptibility tensor at the frequency of
the weak probe field is obtained for the arbitrary polarization of the strong
coupling laser field and arbitrary values of the angular momenta of resonant
atomic levels. The dependence of the relative difference in the group
velocities of the two polarization components of the probe field on the
polarization of the coupling field is studied.


title: Neural Networks Built from Unreliable Components

abstract:
  Recent advances in associative memory design through strutured pattern sets
and graph-based inference algorithms have allowed the reliable learning and
retrieval of an exponential number of patterns. Both these and classical
associative memories, however, have assumed internally noiseless computational
nodes. This paper considers the setting when internal computations are also
noisy. Even if all components are noisy, the final error probability in recall
can often be made exceedingly small, as we characterize. There is a threshold
phenomenon. We also show how to optimize inference algorithm parameters when
knowing statistical properties of internal noise.


title:
Stochastic resonance driven by quantum shot noise in superradiant Raman
  scattering

abstract:
  We discuss the effects of noise on the timing and strength of superradiant
Raman scattering from a small dense sample of atoms. We demonstrate a genuine
quantum stochastic resonance effect, where the atomic response is largest for
an appropriate quantum noise level. The peak scattering intensity per atom
assumes its maximum for a specific non-zero value of quantum noise given by the
square root of the number of atoms.


title: The class Bp for weighted generalized Fourier transform inequalities

abstract:
  In the present paper, we prove for the Dunkl transform which generalizes the
Fourier transform, weighted inequalities when the weights belong to the well
known class Bp. As application, we obtain for power weights Pitt's inequality.


title: Singular values of Gaussian matrices and permanent estimators

abstract:
  We present estimates on the small singular values of a class of matrices with
independent Gaussian entries and inhomogeneous variance profile, satisfying a
broad-connectedness condition. Using these estimates and concentration of
measure for the spectrum of Gaussian matrices with independent entries, we
prove that for a large class of graphs satisfying an appropriate expansion
property, the Barvinok--Godsil-Gutman estimator for the permanent achieves
sub-exponential errors with high probability.


title: One-loop Euclidean Einstein-Weyl gravity in de Sitter universe

abstract:
  By making use of the background field method, the one-loop quantization for
Euclidean Einstein-Weyl quadratic gravity model on the de Sitter universe is
investigated. Using generalized zeta function regularization, the on-shell and
off-shell one-loop effective actions are explicitly obtained and one-loop
renormalizability, as well as the corresponding one-loop renormalization group
equations, are discussed. The so called critical gravity is also considered.


title: Nonparametric Clustering of Mixed Data Using Modified Chi-square Tests

abstract:
  We propose a non-parametric method to cluster mixed data containing both
continuous and discrete random variables. The product space of continuous and
categorical sample spaces is approximated locally by analyzing neighborhoods
with cluster patterns. Detection of cluster patterns on the product space is
determined by using a modified Chi-square test. The proposed method does not
impose a global distance function which could be difficult to specify in
practice. Results from simulation studies have shown that our proposed methods
out-performed the benchmark method, AutoClass, for various settings.


title: Analytical approximations for spiral waves

abstract:
  We propose a non-perturbative attempt to solve the kinematic equations for
spiral waves in excitable media. From the eikonal equation for the wave front
we derive an implicit analytical relation between rotation frequency $\Omega$
and core radius $R_{0}$. For free, rigidly rotating spiral waves our analytical
prediction is in good agreement with numerical solutions of the linear eikonal
equation not only for very large but also for intermediate and small values of
the core radius. An equivalent $\Omega\left(R_{+}\right)$ dependence improves
the result by Keener and Tyson for spiral waves pinned to a circular defect
with radius $R_{+}$ with Neumann boundaries at the periphery. Simultaneously,
analytical approximations for the shape of free and pinned spirals are given.
We discuss the reasons why the ansatz fails to correctly describe the result
for the dependence of the rotation frequency on the excitability of the medium.

categories: nlin.PS nlin.AO physics.bio-ph physics.chem-ph


title: State-Dependent Z Channel

abstract:
  In this paper we study the Z channel with side information non-causally
available at the encoders. We use Marton encoding along with Gelfand-Pinsker
random binning scheme and Chong-Motani-Garg-El Gamal (CMGE) jointly decoding to
find an achievable rate region. We will see that our achievable rate region
gives the achievable rate of the multiple access channel with side information
and also degraded broadcast channel with side information. We will also derive
an inner bound and an outer bound on the capacity region of the state-dependent
degraded discrete memoryless Z channel and also will observe that our outer
bound meets the inner bound for the rates corresponding to the second
transmitter. Also, by assuming the high signal to noise ratio and strong
interference regime, and using the lattice strategies, we derive an achievable
rate region for the Gaussian degraded Z channel with additive interference
non-causally available at both of the encoders. Our method is based on lattice
transmission scheme, jointly decoding at the first decoder and successive
decoding at the second decoder. Using such coding scheme we remove the effect
of the interference completely.


title: Crystal nucleation and near-epitaxial growth in nacre

abstract:
  Nacre is a layered, iridescent lining found inside many mollusk shells, with
a unique brick-and-mortar periodic structure at the sub-micron scale, and
remarkable resistance to fracture. Despite extensive studies, it remains
unclear how nacre forms. Here we present 20-nm, 2{\deg}-resolution
Polarization-dependent Imaging Contrast (PIC) images of shells from 15 mollusk
shell species, mapping nacre tablets and their orientation patterns, showing
where new crystal orientations appear and how they propagate across organic
sheets as nacre grows. In all shells we found stacks of co-oriented aragonite
(CaCO3) tablets arranged into vertical columns or staggered diagonally. Only
near the nacre-prismatic boundary are disordered crystals nucleated, as
spherulitic aragonite. Overgrowing nacre tablet crystals are most frequently
co-oriented with the underlying spherulitic aragonite or with another tablet,
connected by mineral bridges. Therefore aragonite crystal growth in nacre is
epitaxial or near-epitaxial, with abrupt or gradual changes in orientation,
with c-axes within 20{\deg}. Based on these data, we propose that there is one
mineral bridge per tablet, and that "bridge-tilting" is a possible mechanism to
introduce small, gradual or abrupt changes in the orientation of crystals
within a stack of tablets as nacre grows.


title: Interaction between Vortices in CFL Phase

abstract:
  We try to calculate the interaction between vortices in the color-flavor
locked (CFL) phase of Quantum Chromodynamics (QCD). The most fundamental
strings in high density color superconductivity are the non-abelian semi-super
fluid strings. Using Abrikosov ansatz, one can show that the interaction
between these vortices has a universal repulsion form when they are far from
each other. The Ginzburg-Landau (GL) Lagrangian of CFL phase may be compared
with the Lagrangian of Quantum Electrodynamics (QED) with three condensation
states. The behavior of vortices of multi-component superconductivity, within
the framework of GL theory was done for two condensation states ($\rm{MgB_2}$
superconductors) by variational method. The interaction between these vortices
is attractive when they are far from each other and repulsive when they get
close. We attempt to obtain the interaction between these vortices in such
substances using numerical variational method for three condensation states
(Fe-based superconductors). The ultimate aim of the research is to apply these
calculations to the vortices in the color-flavor locked phase of QCD to be able
to study the interaction between them.


title: Orbital Magnetization as a Local Property

abstract:
  The modern expressions for polarization $\P$ and orbital magnetization $\M$
are $\k$-space integrals. But a genuine bulk property should also be
expressible in $\r$-space, as unambiguous function of the ground-state density
matrix, "nearsighted" in insulators, independently of the boundary
conditions---either periodic or open. While $\P$---owing to its "quantum"
indeterminacy---is {\it not} a bulk property in this sense, $\M$ is. We provide
its $\r$-space expression for any insulator, even with nonzero Chern invariant.
Simulations on a model Hamiltonian validate our theory.


title:
Suppression of the radiative decay of atomic coherence in squeezed
  vacuum

abstract:
  Quantum fluctuations of the electromagnetic vacuum are responsible for
physical effects such as the Casimir force and the radiative decay of atoms,
and set fundamental limits on the sensitivity of measurements. Entanglement
between photons can produce correlations that result in a reduction of these
fluctuations below the vacuum level allowing measurements that surpass the
standard quantum limit in sensitivity. Here we demonstrate that the radiative
decay rate of an atom that is coupled to quadrature squeezed electromagnetic
vacuum can be reduced below its natural linewidth. We observe a two-fold
reduction of the transverse radiative decay rate of a superconducting
artificial atom coupled to continuum squeezed vacuum generated by a Josephson
parametric amplifier, allowing the transverse coherence time T_2 to exceed the
vacuum decay limit of 2T_1. We demonstrate that the measured radiative decay
dynamics can be used to tomographically reconstruct the Wigner distribution of
the the itinerant squeezed state. Our results are the first confirmation of a
canonical prediction of quantum optics and open the door to new studies of the
quantum light-matter interaction.

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


title: LA-LDA: A Limited Attention Topic Model for Social Recommendation

abstract:
  Social media users have finite attention which limits the number of incoming
messages from friends they can process. Moreover, they pay more attention to
opinions and recommendations of some friends more than others. In this paper,
we propose LA-LDA, a latent topic model which incorporates limited,
non-uniformly divided attention in the diffusion process by which opinions and
information spread on the social network. We show that our proposed model is
able to learn more accurate user models from users' social network and item
adoption behavior than models which do not take limited attention into account.
We analyze voting on news items on the social news aggregator Digg and show
that our proposed model is better able to predict held out votes than
alternative models. Our study demonstrates that psycho-socially motivated
models have better ability to describe and predict observed behavior than
models which only consider topics.