title: Semiclassical wave-packets emerging from interaction with an environment

abstract:
  We study the quantum evolution in dimension three of a system composed by a
test particle interacting with an environment made of $N$ harmonic oscillators.
At time zero the test particle is described by a spherical wave, i.e. a highly
correlated continuous superposition of states with well localized position and
momentum, and the oscillators are in the ground state. Under suitable
assumptions on the physical parameters characterizing the model, we give an
asymptotic expression of the solution of the Schr\"odinger equation of the
system with an explicit control of the error. The result shows that the
approximate expression of the wave function is the sum of two terms, orthogonal
in $L^2(\erre^{3(N+1)})$ and describing rather different situations. In the
first one all the oscillators remain in their ground state and the test
particle is described by the free evolution of a slightly deformed spherical
wave. The second one consists of a sum of $N$ terms where in each term there is
only one excited oscillator and the test particle is correspondingly described
by the free evolution of a wave packet, well concentrated in position and
momentum. Moreover the wave packet emerges from the excited oscillator with an
average momentum parallel to the line joining the oscillator with the center of
the initial spherical wave. Such wave packet represents a semiclassical state
for the test particle, propagating along the corresponding classical
trajectory. The main result of our analysis is to show how such a semiclassical
state can be produced, starting from the original spherical wave, as a result
of the interaction with the environment.


title: The quantization problem in Scherk-Schwarz compactifications

abstract:
  We re-examine the quantization of structure constants, or equivalently the
choice of lattice in the so-called flat group reductions, introduced originally
by Scherk and Schwarz. Depending on this choice, the vacuum either breaks
supersymmetry and lifts certain moduli, or preserves all supercharges and is
identical to the one obtained from the torus reduction. Nonetheless the
low-energy effective theory proposed originally by Scherk and Schwarz is a
gauged supergravity that describes supersymmetry breaking and moduli lifting
for all values of the structure constants. When the vacuum does not break
supersymmetry, such a description turns out to be an artifact of the consistent
truncation to left-invariant forms as illustrated for the example of ISO(2). We
furthermore discuss the construction of flat groups in d dimensions and find
that the Scherk--Schwarz algorithm is exhaustive. A classification of flat
groups up to six dimensions and a discussion of all possible lattices is
presented.


title:
Hidden beauty baryon states in the local hidden gauge approach with
  heavy quark spin symmetry

abstract:
  Using a coupled channel unitary approach, combining the heavy quark spin
symmetry and the dynamics of the local hidden gauge, we investigate the
meson-baryon interaction with hidden beauty and obtain several new states of
$N^*$ around 11 GeV. We consider the basis of states $\eta_b N$, $\Upsilon N$,
$B \Lambda_b$, $B \Sigma_b$, $B^* \Lambda_b$, $B^* \Sigma_b$, $B^* \Sigma_b^*$
and find four basic bound states which correspond to $B \Sigma_b$, $B
\Sigma_b^*$, $B^* \Sigma_b$ and $B^* \Sigma_b^*$, decaying mostly into $\eta_b
N$ and $\Upsilon N$ and with a binding energy about 50-130 MeV with respect to
the thresholds of the corresponding channel. All of them have isospin $I=1/2$,
and there are no bound states or resonances in $I=3/2$. The $B \Sigma_b$ state
appears in $J=1/2$, the $B \Sigma_b^*$ in $J=3/2$, the $B^* \Sigma_b$ appears
nearly degenerate in $J=1/2, ~3/2$ and the $B^* \Sigma_b^*$ appears nearly
degenerate in $J=1/2, ~3/2, ~5/2$. These states have a width from $6 \sim 45
\mev$ except for the one in $J=5/2$ which has zero width since it cannot decay
into any of the states of the basis chosen.


title: Monitoring Student Activity in Collaborative Software Development

abstract:
  This paper presents data analysis from a course on Software Engineering in an
effort to identify metrics and techniques that would allow instructor to act
proactively and identify patterns of low engagement and inefficient peer
collaboration. Over the last two terms, 106 students in their second year of
studies formed 20 groups and worked collaboratively to develop video games.
Throughout the lab, students have to use a variety of tools for managing and
developing their projects, such as software version control, static analysis
tools, wikis, mailing lists, etc. The students are also supported by weekly
meetings with teaching assistants and instructors regarding group progress,
code quality, and management issues. Through these meetings and their
interactions with the software tools, students leave a detailed trace of data
related to their individual engagement and their collaboration behavior in
their groups. The paper provides discussion on the different source of data
that can be monitored, and present preliminary results on how these data can be
used to analyze students' activity.


title:
Quantum Entanglement for Systems of Identical Bosons. Spin Squeezing and
  Other Entanglement Tests in Two Mode Systems

abstract:
  The concept of entangled quantum states is considered in the context of
systems of identical particles, based on the requirement that in order to
represent physical states both for the overall system and the sub-systems which
may be entangled, the density operators must satisfy the symmetrisation
principle and global and local super-selection rules that prohibit states in
which there are coherences between differing particle numbers. These
requirements and their justification are fully discussed. In the second
quantisation approach used, both the system and the sub-systems are modes (or
sets of modes) rather than particles, particles being associated with different
occupancies of the modes. The definition of entangled states is based on first
defining the non-entangled states - after specifying which modes constitute the
sub-systems. This paper mainly focuses on two mode entanglement for massive
bosons. Several inequalities involving variances and mean values of operators
involving mode annihilation, creation operators have been proposed as tests for
two mode entangled states, including the inequalities that define spin
squeezing. Spin squeezing criteria in two mode systems are examined, and spin
squeezing is best considered for principle spin operator components where the
covariance matrix is diagonal. It is shown that the presence of spin squeezing
in at least one of the spin components requires entanglement of the relevant
pair of modes. Several of the other proposed tests for entanglement, including
ones based on the sum of the variances for two spin components are considered.
All of the tests are still valid when the present concept of entanglement based
on the symmetrisation and super-selection rule criteria is applied, but further
tests have been obtained here. Sometimes the new tests are satisfied whilst
than those obtained in other papers are not.


title: Thermodynamics of black M-branes from SCFTs

abstract:
  We discuss thermodynamics of N M2-branes at strong coupling from the ABJM
theory by employing the Smilga-Wiseman method, which explains the black
Dp-brane thermodynamics from the maximally supersymmetric U(N) Yang-Mills
theories through a field theory analysis. As a result we obtain the free energy
of the ABJM theory ~N^{3/2}k^{1/2}T^3, which is consistent with the prediction
from eleven-dimensional supergravity. We also estimate the free energy of N
M5-branes by assuming some natural properties of the 6d superconformal field
theory. Remarkably we obtain the free energy ~N^3T^6, which is consistent again
with the supergravity prediction. This result might illuminate the low energy
field theory description of the multiple M5-branes.


title: Supersymmetry after the Higgs discovery and its LHC phenomenology

abstract:
  Under the minimal SUSY standard model (MSSM), the discrepancy in the muon g-2
suggests the SUSY particles are of order 100 GeV, which is also supported by
discussions on the little hierarchy problem. However, the LHC experiments have
found no scalar-quarks or gluinos in such mass range, and moreover, the Higgs
boson mass of 126 GeV requires, within the MSSM framework, the scalar-top mass
of order 1-10 TeV. This current status forces us to abandon the simplest
supersymmetry-breaking frameworks of the CMSSM and the GMSB scenarios.
  The V-MSSM is investigated in this dissertation, which is proposed as an
extension of the MSSM with a (10 + 10bar) pair of the SU(5) decuplets. In the
framework the Higgs mass is increased by effect from the extra matters, and
thus the 126 GeV is achieved with the scalar-top having a lighter mass. This
fact resurrects the CMSSM and the GMSB scenarios. This dissertation examines
the GMSB scenario under the V-MSSM; it is called V-GMSB scenario.
  It is shown that the V-GMSB has a potential to realize the 126 GeV mass of
the Higgs boson with holding the explanation of the muon magnetic moment
discrepancy, if the masses of the extra quarks are approximately less than 1.2
TeV. Constraints on the V-GMSB from the LHC experiments are discussed then; it
is concluded that the gluino mass must be approximately heavier than 1.1 TeV,
and that the extra quarks be heavier than 300-650 GeV depending on the decay
branches of them.
  LHC prospects are briefly discussed. As the extra quarks are expected to be
approximately less than 1.2 TeV, searches for the particles are of great
interest at the 14 TeV LHC; constraints from the supersymmetry search,
especially on the gluino mass, are expected to be much improved there.
Therefore, it is expected that the fate of the V-GMSB is adjudicated at the
court of the 14 TeV LHC.


title: Projective Tensor Products of $C^*$-algebras

abstract:
  For $C^*$-algebras $A$ and $B$, we study the bi-continuity of the canonical
embedding of $A^{**}\ot_{\gamma} B^{**}$ ($A^{**}\hat{\ot} B^{**}$) into $(A
\ot_{\gamma} B)^{**}$ (resp. $(A \hat{\ot} B)^{**}$), and its isomorphism.
Ideal structure of $A\hat{\ot} B$ has been obtained in case $A$ or $B$ has only
finitely many closed ideals.


title:
LOFT (Large Observatory For X-ray Timing): a candidate X-ray mission for
  the next decade

abstract:
  LOFT is one of the four medium mission candidates (M3), selected by ESA in
the framework of the Cosmic Vision Programme (2015-2025), for feasibility
study. If approved by ESA in 2014, its launch is foreseen in 2022-2024. LOFT is
being designed to observe X-ray sources with excellent temporal resolution and
very good spectral capability. Its main objectives are to directly probe the
motion of matter in the very close vicinity of black holes (Strong Field
Gravity), as well as to study the physics of ultra dense matter (Neutron
Stars). The payload includes a Large Area Detector (LAD) and a Wide Field
Monitor (WFM). The LAD is a collimated (< 1 degree field of view) experiment
operating in the energy range 2-30 keV, with a 10 m2 peak effective area and an
energy resolution of 260 eV at 6 keV. The WFM will operate in almost the same
energy range than the LAD, 2-50 keV, enabling simultaneous monitoring of a
few-steradian wide field of view, with an angular resolution of < 5 arcmin. In
addition to its main scientific objectives, LOFT will also do a complete plan
of observatory science, studying with unprecedented detail in the 2-80 keV
range several transient phenomena, like accreting white dwarfs in cataclysmic
variables, novae in outburst (internal and external shocks in the ejecta in
classical novae, and shocks with the wind of the companion in symbiotic
recurrent novae) and post-outburst novae (once accretion is re established).


title:
The Effective Number Density of Galaxies for Weak Lensing Measurements
  in the LSST Project

abstract:
  Future weak lensing surveys potentially hold the highest statistical power
for constraining cosmological parameters compared to other cosmological probes.
The statistical power of a weak lensing survey is determined by the sky
coverage, the inverse of the noise in shear measurements, and the galaxy number
density. The combination of the latter two factors is often expressed in terms
of $n_{\rm eff}$ -- the "effective number density of galaxies used for weak
lensing measurements". In this work, we estimate $n_{\rm eff}$ for the Large
Synoptic Survey Telescope (LSST) project, the most powerful ground-based
lensing survey planned for the next two decades. We investigate how the
following factors affect the resulting $n_{\rm eff}$ of the survey with
detailed simulations: (1) survey time, (2) shear measurement algorithm, (3)
algorithm for combining multiple exposures, (4) inclusion of data from multiple
filter bands, (5) redshift distribution of the galaxies, and (6) masking and
blending. For the first time, we quantify in a general weak lensing analysis
pipeline the sensitivity of $n_{\rm eff}$ to the above factors.
  We find that with current weak lensing algorithms, expected distributions of
observing parameters, and all lensing data ($r$- and $i$-band, covering 18,000
degree$^{2}$ of sky) for LSST, $n_{\rm eff} \approx37$ arcmin$^{-2}$ before
considering blending and masking, $n_{\rm eff} \approx31$ arcmin$^{-2}$ when
rejecting seriously blended galaxies and $n_{\rm eff} \approx26$ arcmin$^{-2}$
when considering an additional 15% loss of galaxies due to masking. With future
improvements in weak lensing algorithms, these values could be expected to
increase by up to 20%. Throughout the paper, we also stress the ways in which
$n_{\rm eff}$ depends on our ability to understand and control systematic
effects in the measurements.


title: The Effect of Growth On Equality in Models of the Economy

abstract:
  We investigate the relation between economic growth and equality in a
modified version of the agent-based asset exchange model (AEM). The modified
model is a driven system that for a range of parameter space is effectively
ergodic in the limit of an infinite system. We find that the belief that "a
rising tide lifts all boats" does not always apply, but the effect of growth on
the wealth distribution depends on the nature of the growth. In particular, we
find that the rate of growth, the way the growth is distributed, and the
percentage of wealth exchange determine the degree of equality. We find strong
numerical evidence that there is a phase transition in the modified model, and
for a part of parameter space the modified AEM acts like a geometric random
walk.


title:
Unformatted Digital Fiber-Optic Data Transmission for Radio Astronomy
  Front-Ends

abstract:
  We report on the development of a prototype integrated receiver front-end
that combines all conversions from RF to baseband, from analog to digital, and
from copper to fiber into one compact assembly, with the necessary gain and
stability suitable for radio astronomy applications. The emphasis in this
article is on a novel digital data link over optical fiber which requires no
formatting in the front-end, greatly reducing the complexity, bulk, and power
consumption of digital electronics inside the antenna, facilitating its
integration with the analog components, and minimizing the self-generated
radio-frequency interference (RFI) which could leak into the signal path.
Management of the serial data link is performed entirely in the back-end based
on the statistical properties of signals with a strong random noise component.
In this way, the full benefits of precision and stability afforded by
conventional digital data transmission are realized with far less overhead at
the focal plane of a radio telescope.


title:
Holonomy potential and confinement from a simple model of the gauge
  topology

abstract:
  We discuss an ensemble of topological solitons -- instanton-dyons and
antidyons - in SU(2) pure gauge theory at finite temperatures above and below
the deconfinement phase transition temperature. The main focus is on the
combined effect of this ensemble on the so called effective holonomy potential,
which drives the confinement/deconfinement phase transition. Using a simple
model with excluded volume and lattice data on caloron density we find that
repulsive part of the potential is robust enough to induce the phase transition
at the right temperature. Model's predictions -- the holonomy potential,
electric and magnetic screening masses as a function of T -- are in qualitative
agreement with the available lattice data. Further predictions are densities of
various dyon types as a function of temperature: while some lattice
measurements of them had been made, much more accurate data are needed to test
these predictions.


title:
Bose-Einstein condensation in the three-sphere and the infinite slab:
  analytical results

abstract:
  We study the finite size effects on Bose-Einstein condensation (BEC) of an
ideal non-relativistic Bose gas in the three-sphere (spatial section of the
Einstein universe) and in a partially finite box which is infinite in two of
the spatial directions (infinite slab). Using the framework of grand-canonical
statistics, we consider the number of particles, the condensate fraction and
the specific heat. After obtaining asymptotic expansions for large system size,
which are valid throughout the BEC regime, we describe analytically how the
thermodynamic limit behaviour is approached. In particular, in the critical
region of the BEC transition, we express the chemical potential and the
specific heat as simple explicit functions of the temperature, highlighting the
effects of finite size. These effects are seen to be different for the two
different geometries. We also consider the Bose gas in a one-dimensional box, a
system which does not possess BEC in the sense of a phase transition even in
the infinite volume limit.


title: Viscosity, wave damping and shock wave formation in cold hadronic matter

abstract:
  We study linear and nonlinear wave propagation in a dense and cold hadron gas
and also in a cold quark gluon plasma, taking viscosity into account and using
the Navier-Stokes equation. The equation of state of the hadronic phase is
derived from the nonlinear Walecka model in the mean field approximation. The
quark gluon plasma phase is described by the MIT equation of state. We show
that in a hadron gas viscosity strongly damps wave propagation and also hinders
shock wave formation. This marked difference between the two phases may have
phenomenological consequences and lead to new QGP signatures.


title: A Real Nullstellensatz for Matrices of Non-Commutative Polynomials

abstract:
  This article extends the classical Real Nullstellensatz to matrices of
polynomials in a free $\ast$-algebra $\RR\axs$ with $x=(x_1, \ldots, x_n)$.
This result is a generalization of a result of Cimpri\vc, Helton, McCullough,
and the author.
  In the free left $\RR\axs$-module $\RR^{1 \times \ell}\axs$ we introduce
notions of the (noncommutative) zero set of a left $\RR\axs$-submodule and of a
real left $\RR\axs$-submodule. We prove that every element from $\RR^{1 \times
\ell}\axs$ whose zero set contains the intersection of zero sets of elements
from a finite subset $S \subset \RR^{1 \times \ell}\axs$ belongs to the
smallest real left $\RR\axs$-submodule containing $S$. Using this, we derive a
nullstellensatz for matrices of polynomials in $\RR\axs$.
  The other main contribution of this article is an efficient, implementable
algorithm which for every finite subset $S \subset \RR^{1 \times \ell}\axs$
computes the smallest real left $\RR\axs$-submodule containing $S$. This
algorithm terminates in a finite number of steps. By taking advantage of the
rigid structure of $\RR\axs$, the algorithm presented here is an improvement
upon the previously known algorithm for $\RR\axs$.


title:
Observability Estimate and State Observation Problems for Stochastic
  Hyperbolic Equations

abstract:
  In this paper, we derive a boundary and an internal observability inequality
for stochastic hyperbolic equations with nonsmooth lower order terms. The
required inequalities are obtained by global Carleman estimate for stochastic
hyperbolic equations. By these inequalities, we study a state observation
problem for stochastic hyperbolic equations. As a consequence, we also
establish a unique continuation property for stochastic hyperbolic equations.


title: Pathways of large-scale magnetic couplings between solar coronal events

abstract:
  The high-cadence, comprehensive view of the solar corona by SDO/AIA shows
many events that are widely separated in space while occurring close together
in time. In some cases, sets of coronal events are evidently causally related,
while in many other instances indirect evidence can be found. We present case
studies to highlight a variety of coupling processes involved in coronal
events. We find that physical linkages between events do occur, but concur with
earlier studies that these couplings appear to be crucial to understanding the
initiation of major eruptive or explosive phenomena relatively infrequently. We
note that the post-eruption reconfiguration time scale of the large-scale
corona, estimated from the EUV afterglow, is on average longer than the mean
time between CMEs, so that many CMEs originate from a corona that is still
adjusting from a previous event. We argue that the coronal field is
intrinsically global: current systems build up over days to months, the
relaxation after eruptions continues over many hours, and evolving connections
easily span much of a hemisphere. This needs to be reflected in our modeling of
the connections from the solar surface into the heliosphere to properly model
the solar wind, its perturbations, and the generation and propagation of solar
energetic particles. However, the large-scale field cannot be constructed
reliably by currently available observational resources. We assess the
potential of high-quality observations from beyond Earth's perspective and
advanced global modeling to understand the couplings between coronal events in
the context of CMEs and solar energetic particle events.


title: Polarimetry in the hard X-ray domain with INTEGRAL SPI

abstract:
  We present recent improvements in polarization analysis with the INTEGRAL SPI
data. The SPI detector plane consists of 19 independent Ge crystals and can
operate as a polarimeter. The anisotropy characteristics of Compton diffusions
can provide information on the polarization parameters of the incident flux. By
including the physics of the polarized Compton process in the instrument
simulation, we are able to determine the instrument response for a linearly
polarized emission at any position angle. We compare the observed data with the
simulation sets by a minimum \chi^2 technique to determine the polarization
parameters of the source (angle and fraction). We have tested our analysis
procedure with Crab nebula observations and find a position angle similar to
those previously reported in the literature, with a comfortable significance.
Since the instrument response depends on the incident angle, each exposure in
the SPI data requires its own set of simulations, calculated for 18
polarization angles (from 0{\deg} to 170{\deg} in steps of 10{\deg}) and
unpolarized emission. The analysis of a large amount of observations for a
given source, required to obtain statistically significant results, represents
a large amount of computing time, but it is the only way to access this
complementary information in the hard X-ray regime. Indeed, major scientific
advances are expected from such studies since the observational results will
help to discriminate between the different models proposed for the high energy
emission of compact objects like X-ray binaries and active galactic nuclei or
gamma-ray bursts.


title: Concentric Maclaurin spheroid models of rotating liquid planets

abstract:
  I present exact expressions for the interior gravitational potential V of a
system of N concentric constant-density (Maclaurin) spheroids. I demonstrate an
iteration procedure to find a self-consistent solution for the shapes of the
interfaces between spheroids, and for the interior gravitational potential. The
external free-space potential, expressed as a multipole expansion, emerges as
part of the self-consistent solution. The procedure is both simpler and more
precise than perturbation methods. One can choose the distribution and mass
densities of the concentric spheroids so as to reproduce a prescribed barotrope
to a specified accuracy. I demonstrate the method's efficacy by comparing its
results with several published test cases.


title:
Theory of photo-injection of hot plasmonic carriers in
  metal-semiconductor nanostructures

abstract:
  We investigate theoretically the effect of injection of plasmonic carriers
from an optically-excited metal nanocrystal to a semiconductor contact or to
attached molecules. The distributions of optically-excited hot carriers are
dramatically different in metal nanocrystals with large and small sizes. In
large nanocrystals, most carriers have very small energies and the hot carrier
distribution resembles the case of a plasmon wave in bulk. In nanocrystals
smaller than 20nm, the carrier distribution extends to larger energies and
occupies the whole region E_{F}<E<omega. The physical reason for the above
behaviors is non-conservation of momentum in a nanocrystal. Because of the
above properties, nanocrystals of small sizes are most suitable for designing
of opto-electronic and photosynthetic devices based on injection of plasmonic
electrons and holes. The central parameter of the problem is
DeltaN=omega/q_{L}*v_{F}, where q_{L} is the momentum transfer and v_{F} is the
Fermi velocity. In gold nanocrystals, when DeltaN<7, the high-energy
hot-electron generation is efficient. For larger parameters DeltaN, the number
of high-energy electrons is greatly reduced. Another important factor is the
polarization of the exciting light. For efficient excitation of carriers with
high energies, the electric-field polarization vector should be perpendicular
to a prism-like nanoantenna (slab or platelet) with a small width ~ 10-20 nm.
We also show the relation between our theory for injection in plasmonic
nanocrystals and the Fowler theory of injection from a bulk metal. Along with a
prism geometry (or platelet geometry), we consider cubes. The results can be
applied to design both purely solid-state opto-electronic devices and systems
for photo-catalysis and solar conversion.


title:
Accessing quantum secrets via local operations and classical
  communication

abstract:
  Quantum secret-sharing and quantum error-correction schemes rely on
multipartite decoding protocols, yet the non-local operations involved are
challenging and sometimes infeasible. Here we construct a quantum
secret-sharing protocol with a reduced number of quantum communication channels
between the players. Our scheme is based on embedding a classical linear code
into a quantum error-correcting code. Our work paves the way towards the more
general problem of simplifying the decoding of quantum error-correcting codes.


title:
Fourier law from a chain of coupled anharmonic oscillators under energy
  conserving noise

abstract:
  We analyze the transport of heat along a chain of particles interacting
through anharmonic po- tentials consisting of quartic terms in addition to
harmonic quadratic terms and subject to heat reservoirs at its ends. Each
particle is also subject to an impulsive shot noise with exponentially
distributed waiting times whose effect is to change the sign of its velocity,
thus conserving the en- ergy of the chain. We show that the introduction of
this energy conserving stochastic noise leads to Fourier law. The behavior of
thels heat conductivity for small intensities of the shot noise and large
system sizes are found to obey a finite-size scaling relation. We also show
that the heat conductivity is not constant but is an increasing monotonic
function of temperature.


title:
A Novel Symmetric Key Cryptographic Technique at Bit Level Based on
  Spiral Matrix Concept

abstract:
  In this paper, we propose a session based bit level symmetric key
cryptographic technique and it is termed as Spiral Matrix Based Bit Orientation
Technique (SMBBOT). SMBBOT consider the input plain text as binary bit stream.
During encryption this stream is chopped into manageable sized blocks with
variable lengths. Bits of these blocks are taken from MSB to LSB to fit into a
square matrix of suitable order following the concept of Spiral matrix. This
square matrix splits into 2x2 sub-matrices. Bits are taken column-wise from all
2x2 sub-matrices to form the encrypted binary string. Cipher text is generated
from this encrypted binary string. Combination of values of block length and
no. of blocks of a session generates the session key for SMBBOT. For decryption
the cipher text is considered as binary bit string. Processing the session key
information, this binary string is broken down into predefined blocks. Bits of
these blocks are taken from MSB to LSB to fit column-wise into 2x2 square
matrices. Using these sub-matrices a single square matrix with suitable order
is formed. The decrypted binary string is formed after taking the bits from the
square matrix following the reverse concept of Spiral Matrix. The plain text is
regenerated from decrypted binary string. A comparison of SMBBOT with existing
and industrially accepted TDES and AES has been done.


title: Markov Random Fields, Markov Cocycles and The 3-colored Chessboard

abstract:
  The well-known Hammersley-Clifford theorem states (under certain conditions)
that any Markov random field is a Gibbs state for a nearest neighbor
interaction. In this paper we study Markov random fields for which the proof of
the Hammersley-Clifford theorem does not apply. Following Petersen and Schmidt
we utilize the formalism of cocycles for the homoclinic equivalence relation
and introduce "Markov cocycles", reparametrisations of Markov specifications.
The main part of this paper exploits this to deduce the conclusion of the
Hammersley-Clifford theorem for a family of Markov fields which are outside the
theorem's purview where the underlying graph is $\mathbb{Z}^d$. This family
includes all Markov random fields whose support is the d-dimensional "3-colored
chessboard". On the other extreme, we construct a family of shift-invariant
Markov random fields which are not given by any finite range shift-invariant
interaction.


title: Peaks of optical and X-ray afterglow light-curves

abstract:
  The peaks of 30 optical afterglows and 14 X-ray light-curves display a good
anticorrelation of the peak flux with the peak epoch: F_p ~ t_p^{-2.0} in the
optical, F_p ~ t_p^{-1.6} in the X-ray, the distributions of the peak epochs
being consistent with each other. We investigate the ability of two
forward-shock models for afterglow light-curve peaks -- an observer location
outside the initial jet aperture and the onset of the forward-shock
deceleration -- to account for those peak correlations. For both models, the
slope of the F_p - t_p relation depends only on the slope of the afterglow
spectrum. We find that only a conical jet seen off-aperture and interacting
with a wind-like medium can account for both the X-ray peak relation, given the
average X-ray spectral slope beta_x = 1.0, and for the larger slope of the
optical peak relation. However, any conclusion about the origin of the peak
flux - peak epoch correlation is, at best, tentative, because the current
sample of X-ray peaks is too small to allow a reliable measurement of the F_p -
t_p relation slope and because more than one mechanism and/or one afterglow
parameter may be driving that correlation.


title: Optimization of Clifford Circuits

abstract:
  We study optimal synthesis of Clifford circuits, and apply the results to
peep-hole optimization of quantum circuits. We report optimal circuits for all
Clifford operations with up to four inputs. We perform peep-hole optimization
of Clifford circuits with up to 40 inputs found in the literature, and
demonstrate the reduction in the number of gates by about 50%. We extend our
methods to the optimal synthesis of linear reversible circuits, partially
specified Clifford functions, and optimal Clifford circuits with five inputs up
to input/output permutation. The results find their application in randomized
benchmarking protocols, quantum error correction, and quantum circuit
optimization.


title: Overview of semi-sinusoidal stellar variability with the CoRoT satellite

abstract:
  To date, the CoRoT space mission has produced more than 124,471 light curves.
Classifying these curves in terms of unambiguous variability behavior is
mandatory for obtaining an unbiased statistical view on their controlling
root-causes. The present study provides an overview of semi-sinusoidal light
curves observed by the CoRoT exo-field CCDs. We selected a sample of 4,206
light curves presenting well-defined semi-sinusoidal signatures. The
variability periods were computed based on Lomb-Scargle periodograms, harmonic
fits, and visual inspection. Color-period diagrams for the present sample show
the trend of an increase of the variability periods as long as the stars
evolve. This evolutionary behavior is also noticed when comparing the period
distribution in the Galactic center and anti-center directions. These aspects
indicate a compatibility with stellar rotation, although more information is
needed to confirm their root-causes. Considering this possibility, we
identified a subset of three Sun-like candidates by their photometric period.
Finally, the variability period versus color diagram behavior was found to be
highly dependent on the reddening correction.


title:
The Trispectrum in the Effective Theory of Inflation with Galilean
  symmetry

abstract:
  We calculate the trispectrum of curvature perturbations for a model of
inflation endowed with Galilean symmetry at the level of the fluctuations
around an FRW background. Such a model has been shown to posses desirable
properties such as unitarity (up to a certain scale) and non-renormalization of
the leading operators, all of which point towards the reasonable assumption
that a full theory whose fluctuations reproduce the one here might exist as
well as be stable and predictive. The cubic curvature fluctuations of this
model produce quite distinct signatures at the level of the bispectrum. Our
analysis shows how this holds true at higher order in perturbations. We provide
a detailed study of the trispectrum shape-functions in different configurations
and a comparison with existent literature. Most notably, predictions markedly
differ from their P(X,\phi) counterpart in the so called equilateral
trispectrum configuration. The zoo of inflationary models characterized by
somewhat distinctive predictions for higher order correlators is already quite
populated; what makes this model more compelling resides in the above mentioned
stability properties.


title:
Hemispherical Asymmetry and Local non-Gaussianity: a Consistency
  Condition

abstract:
  In this paper we provide a consistency relation between the amplitude of the
hemispherical bipolar asymmetry, $A$, and the amplitude of the primordial
non-Gaussianity in the squeezed limit, $f_{NL}$, as $|A| \lesssim 10^{-1}
f_{NL}$. We demonstrate that this consistency condition is at work for any
model of inflation in which the curvature perturbations is sourced by a single
light field with the Bunch-Davies initial condition, irrespective of the number
of inflation fields which contribute to the background inflationary expansion.
As a non-trivial example, we show that observable hemispherical asymmetry can
be generated in single field non-attractor inflationary models. We also study
hemispherical asymmetry generated in the models of multiple fields inflation.
We show that $A$ is controlled by the weighted sum of non-Gaussianity
contribution from each field. In particular, we show that observable
hemispherical asymmetry can be generated in models where inhomogeneities are
generated from a light scalar field modulating the surface of end of inflation.


title: Increasing paths in regular trees

abstract:
  We consider a regular $n$-ary tree of height $h$, for which every vertex
except the root is labelled with an independent and identically distributed
continuous random variable. Taking motivation from a question in evolutionary
biology, we consider the number of simple paths from the root to a leaf along
vertices with increasing labels. We show that if $\alpha = n/h$ is fixed and
$\alpha > 1/e$, the probability there exists such a path converges to 1 as $h
\to \infty$. This complements a previously known result that the probability
converges to 0 if $\alpha \leq 1/e$.


title: Synchronization of two anharmonic nanomechanical oscillators

abstract:
  We investigate the synchronization of oscillators based on anharmonic
nanoelectromechanical resonators. Our experimental implementation allows
unprecedented observation and control of parameters governing the dynamics of
synchronization. We find close quantitative agreement between experimental data
and theory describing reactively coupled Duffing resonators with fully
saturated feedback gain. In the synchronized state we demonstrate a significant
reduction in the phase noise of the oscillators, which is key for sensor and
clock applications. Our work establishes that oscillator networks constructed
from nanomechanical resonators form an ideal laboratory to study
synchronization given their high-quality factors, small footprint, and ease of
co-integration with modern electronic signal processing technologies.


title: The Transient Gravitational-Wave Sky

abstract:
  Interferometric detectors will very soon give us an unprecedented view of the
gravitational-wave sky, and in particular of the explosive and transient
Universe. Now is the time to challenge our theoretical understanding of
short-duration gravitational-wave signatures from cataclysmic events, their
connection to more traditional electromagnetic and particle astrophysics, and
the data analysis techniques that will make the observations a reality. This
paper summarizes the state of the art, future science opportunities, and
current challenges in understanding gravitational-wave transients.


title:
Optimal Relay Selection for Physical-Layer Security in Cooperative
  Wireless Networks

abstract:
  In this paper, we explore the physical-layer security in cooperative wireless
networks with multiple relays where both amplify-and-forward (AF) and
decode-and-forward (DF) protocols are considered. We propose the AF and DF
based optimal relay selection (i.e., AFbORS and DFbORS) schemes to improve the
wireless security against eavesdropping attack. For the purpose of comparison,
we examine the traditional AFbORS and DFbORS schemes, denoted by T-AFbORS and
TDFbORS, respectively. We also investigate a so-called multiple relay combining
(MRC) framework and present the traditional AF and DF based MRC schemes, called
T-AFbMRC and TDFbMRC, where multiple relays participate in forwarding the
source signal to destination which then combines its received signals from the
multiple relays. We derive closed-form intercept probability expressions of the
proposed AFbORS and DFbORS (i.e., P-AFbORS and P-DFbORS) as well as the
T-AFbORS, TDFbORS, T-AFbMRC and T-DFbMRC schemes in the presence of
eavesdropping attack. We further conduct an asymptotic intercept probability
analysis to evaluate the diversity order performance of relay selection schemes
and show that no matter which relaying protocol is considered (i.e., AF and
DF), the traditional and proposed optimal relay selection approaches both
achieve the diversity order M where M represents the number of relays. In
addition, numerical results show that for both AF and DF protocols, the
intercept probability performance of proposed optimal relay selection is
strictly better than that of the traditional relay selection and multiple relay
combining methods.


title: Topological insulators in strained graphene at weak interaction

abstract:
  The nature of the electronic ground states in strained undoped graphene at
weak interaction between electrons is discussed. After providing a lattice
realization of the strain-induced axial magnetic field we numerically find the
self-consistent solution for the time reversal symmetry breaking quantum
anomalous Hall order-parameter, at weak second-nearest-neighbor repulsion
between spinless fermions. The anomalous Hall state is obtained in both uniform
and nonuniform axial magnetic fields, with the spatial profile of the
order-parameter resembling that of the axial field itself. When the electron
spin is included, the time reversal symmetric anomalous spin Hall state becomes
slightly preferred energetically at half filling, but the additional anomalous
Hall component should develop at a finite doping.


title:
AGN and QSOs in the eROSITA All-Sky Survey -- Part II: The large-scale
  structure

abstract:
  The four-year X-ray all-sky survey (eRASS) of the eROSITA telescope aboard
the Spektrum-Roentgen-Gamma satellite will detect ~3 million active galactic
nuclei (AGN) with a median redshift of z~1 and a typical luminosity of
L_(0.5-2.0 keV) ~ 10^(44) erg/s. We show that this unprecedented AGN sample,
complemented with redshift information, will supply us with outstanding
opportunities for large-scale structure research. For the first time, detailed
redshift- and luminosity-resolved studies of the bias factor for X-ray selected
AGN will become possible. The eRASS AGN sample will not only improve the
redshift- and luminosity-resolution of these studies, but will also expand
their luminosity range beyond L_(0.5-2.0 keV) ~ 10^(44) erg/s, thus enabling a
direct comparison of the clustering properties of luminous X-ray AGN and
optical quasars. These studies will dramatically improve our understanding of
the AGN environment, triggering mechanisms, the growth of supermassive black
holes and their co-evolution with dark matter halos.
  The eRASS AGN sample will become a powerful cosmological probe. It will
enable detecting baryonic acoustic oscillations (BAOs) for the first time with
X-ray selected AGN. With the data from the entire extragalactic sky, BAO will
be detected at a >~10sigma confidence level in the full redshift range and with
~8sigma confidence in the 0.8 < z < 2.0 range, which is currently not covered
by any existing BAO surveys. To exploit the full potential of the eRASS AGN
sample, photometric and spectroscopic surveys of large areas and a sufficient
depth will be needed.


title:
Dark matter density profile and galactic metric in Eddington-inspired
  Born-Infeld gravity

abstract:
  We consider the density profile of pressureless dark matter in
Eddington-inspired Born-Infeld (EiBI) gravity. The gravitational field
equations are investigated for a spherically symmetric dark matter galactic
halo, by adopting a phenomenological tangential velocity profile for test
particles moving in stable circular orbits around the galactic center. The
density profile and the mass distribution, as well as the general form of the
metric tensor is obtained by numerically integrating the gravitational field
equations, and in an approximate analytical form by using the Newtonian limit
of the theory. In the weak field limit the dark matter density distribution is
described by the Lane-Emden equation with polytropic index $n=1$, and is
non-singular at the galactic center. The parameter $\kappa $ of the theory is
determined so that that the theory could provide a realistic description of the
dark matter halos. The gravitational properties of the dark matter halos are
also briefly discussed in the Newtonian approximation.


title: VLT/FORS2 observations of four high-luminosity ULX candidates

abstract:
  We obtained VLT/FORS2 spectra of the optical counterparts of four
high-luminosity (L_X >= 10^40 erg/s) ULX candidates from the catalog of Walton
(2011). We first determined accurate positions for the X-ray sources from
archival Chandra observations and identified counterparts in archival optical
observations that are sufficiently bright for spectroscopy with an 8 meter
telescope. From the spectra we determine the redshifts to the optical
counterparts and emission line ratios. One of the candidate ULXs, in the spiral
galaxy ESO 306-003, appears to be a bona fide ULX in an HII region. The other
three sources, near the elliptical galaxies NGC 533 and NGC 741 and in the ring
galaxy AM 0644-741, turn out to be background AGN with redshifts of 1.85, 0.88
or 1.75 and 1.40 respectively. Our findings confirm the trend of a high
probability of finding background AGN for systems with a ratio of
log(F_X/F_opt) in the range of -1 to 1.


title: On the Origin of Gravitational Lorentz Covariance

abstract:
  We provide evidence that general relativity is the unique spatially covariant
effective field theory of the transverse, traceless graviton degrees of
freedom. The Lorentz covariance of general relativity, having not been assumed
in our analysis, is thus plausibly interpreted as an accidental or emergent
symmetry of the gravitational sector.


title:
On the operation of the chemothermal instability in primordial
  star-forming clouds

abstract:
  We investigate the operation of the chemothermal instability in primordial
star-forming clouds with a suite of three-dimensional, moving-mesh simulations.
In line with previous studies, we find that the gas at the centre of
high-redshift minihaloes becomes chemothermally unstable as three-body
reactions convert the atomic hydrogen into a fully molecular gas. The
competition between the increasing rate at which the gas cools and the
increasing optical depth to H2 line emission creates a characteristic dip in
the cooling time over the free-fall time on a scale of 100 au. As a result, the
free-fall time decreases to below the sound-crossing time, and the cloud may
become gravitationally unstable and fragment on a scale of a few tens of au
during the initial free-fall phase. In three of the nine haloes investigated,
secondary clumps condense out of the parent cloud, which will likely collapse
in their own right before they are accreted by the primary clump. In the other
haloes, fragmentation at such an early stage is less likely. However, given
that previous simulations have shown that the infall velocity decreases
substantially once the gas becomes rotationally supported, the amount of time
available for perturbations to develop may be much greater than is evident from
the limited period of time simulated here.


title: The Observed Squeezed Limit of Cosmological Three-Point Functions

abstract:
  The squeezed limit of the three-point function of cosmological perturbations
is a powerful discriminant of different models of the early Universe. We
present a conceptually simple and complete framework to relate any primordial
bispectrum in this limit to late time observables, such as the CMB temperature
bispectrum and the scale-dependent halo bias. We employ a series of convenient
coordinate transformations to capture the leading non-linear effects of
cosmological perturbation theory on these observables. This makes crucial use
of Fermi Normal Coordinates and their conformal generalization, which we
introduce here and discuss in detail. As an example, we apply our formalism to
standard slow-roll single-field inflation. We show explicitly that Maldacena's
results for the squeezed limits of the scalar bispectrum [proportional to
(ns-1) in comoving gauge] and the tensor-scalar-scalar bispectrum lead to no
deviations from a Gaussian universe, except for projection effects. In
particular, the primordial contributions to the squeezed CMB bispectrum and
scale dependent halo bias vanish, and there are no primordial "fossil"
correlations between long-wavelength tensor perturbations and small-scale
perturbations. The contributions to observed correlations are then only due to
projection effects such as gravitational lensing and redshift perturbations.

categories: astro-ph.CO astro-ph.GA gr-qc hep-ph hep-th


title: Intrinsic plasmons in 2D Dirac materials

abstract:
  We consider theoretically, using the random phase approximation (RPA),
low-energy intrinsic plasmons for two-dimensional (2D) systems obeying
Dirac-like linear chiral dispersion with the chemical potential set precisely
at the charge neutral Dirac point. The "intrinsic Dirac plasmon" energy has the
characteristic $q^{1/2}$ dispersion in the 2D wave-vector $q$, but vanishes as
$T^{1/2}$ in temperature for both monolayer and bilayer graphene. The intrinsic
plasmon becomes overdamped for a fixed $q$ as $T -> 0$ since the level
broadening (i.e. the decay of the plasmon into electron-hole pairs due to
Landau damping) increases as $T^{-1/2}$ as temperature decreases, however, the
plasmon mode remains well-defined at any fixed $T$ (no matter how small) as $q
-> 0$. We find the intrinsic plasmon to be well-defined as long as $q < k_B
T/e^2$. We give analytical results for low and high temperatures, and numerical
RPA results for arbitrary temperatures, and consider both single-layer and
double-layer intrinsic Dirac plasmons. We provide extensive comparison and
contrast between intrinsic and extrinsic graphene plasmons, and critically
discuss the prospects for experimentally observing intrinsic Dirac point
graphene plasmons.


title:
Morphology with Light Profile Fitting of Confirmed Cluster Galaxies at
  z=0.84

abstract:
  We perform a morphological study of 124 spectroscopically confirmed cluster
galaxies in the z=0.84 galaxy cluster RX J0152.7-1357. Our classification
scheme includes color information, visual morphology, and 1-component and
2-component light profile fitting derived from Hubble Space Telescope riz
imaging. We adopt a modified version of a detailed classification scheme
previously used in studies of field galaxies and found to be correlated with
kinematic features of those galaxies. We compare our cluster galaxy
morphologies to those of field galaxies at similar redshift. We also compare
galaxy morphologies in regions of the cluster with different dark-matter
density as determined by weak-lensing maps. We find an early-type fraction for
the cluster population as a whole of 47%, about 2.8 times higher than the
field, and similar to the dynamically young cluster MS 1054 at similar
redshift. We find the most drastic change in morphology distribution between
the low and intermediate dark matter density regions within the cluster, with
the early type fraction doubling and the peculiar fraction dropping by nearly
half. The peculiar fraction drops more drastically than the spiral fraction
going from the outskirts to the intermediate-density regions. This suggests
that many galaxies falling into clusters at z~0.8 may evolve directly from
peculiar, merging, and compact systems into early-type galaxies, without having
the chance to first evolve into a regular spiral galaxy.


title:
RKKY interactions and anomalous Hall effect in metallic rare-earth
  pyrochlores

abstract:
  Motivated by experiments on Pr2Ir2O7, we consider metallic pyrochlore systems
A2B2O7, where the A-sites are occupied by rare-earth local moments and the
B-sites host 5d transition metal ions with itinerant strongly spin-orbit
coupled electrons. Assuming non-Kramers doublets on the A-site, we derive the
RKKY interaction between them mediated by the B-site itinerant electrons and
find extended non-Heisenberg interactions. Analyzing a simplified model of the
RKKY interaction, we uncover a local moment phase with coexisting spiral
Ising-like magnetic dipolar and XY-like quadrupolar ordering. This state breaks
time-reversal and lattice symmetries, and reconstructs the B-site electronic
band structure, producing a Weyl Metallic phase with an intrinsic anomalous
Hall effect and an undetectably small magnetization. We discuss implications of
our results for Pr2Ir2O7.


title:
Constrained simulations of the Antennae Galaxies: Comparison with
  Herschel-PACS observations

abstract:
  We present a set of hydro-dynamical numerical simulations of the Antennae
galaxies in order to understand the origin of the central overlap starburst.
Our dynamical model provides a good match to the observed nuclear and overlap
star formation, especially when using a range of rather inefficient stellar
feedback efficiencies (0.01 < q_EoS < 0.1). In this case a simple conversion of
local star formation to molecular hydrogen surface density motivated by
observations accounts well for the observed distribution of CO. Using radiative
transfer post-processing we model synthetic far-infrared spectral energy
distributions (SEDs) and two-dimensional emission maps for direct comparison
with Herschel-PACS observations. For a gas-to-dust ratio of 62:1 and the best
matching range of stellar feedback efficiencies the synthetic far-infrared SEDs
of the central star forming region peak at values of ~65 - 81 Jy at 99 - 116
um, similar to a three-component modified black body fit to infrared
observations. Also the spatial distribution of the far-infrared emission at 70
um, 100 um, and 160 um compares well with the observations: >50% (> 35%) of the
emission in each band is concentrated in the overlap region while only < 30% (<
15%) is distributed to the combined emission from the two galactic nuclei in
the simulations (observations). As a proof of principle we show that parameter
variations in the feedback model result in unambiguous changes both in the
global and in the spatially resolved observable far-infrared properties of
Antennae galaxy models. Our results strengthen the importance of direct,
spatially resolved comparative studies of matched galaxy merger simulations as
a valuable tool to constrain the fundamental star formation and feedback
physics.


title:
Maps of CMB lensing deflection from N-body simulations in Coupled Dark
  Energy Cosmologies

abstract:
  We produce lensing potential and deflection-angle maps in order to simulate
CMB weak-lensing via ray-tracing through the COupled Dark Energy Cosmological
Simulations (CoDECS). The constructed maps reflect the N-body cosmic structures
on a range of scales going from the arcminute to the degree scale. We
investigate the variation of the lensing pattern due to the DE dynamics,
characterised by different background and perturbation behaviours as a
consequence of the interaction between the DE field and CDM. We study the
results from three models differing in the background and perturbations
evolution, with the purpose to isolate their imprints in the lensing
observables. The scenarios investigated include a reference LCDM cosmology, a
standard coupled DE (cDE) scenario, and a "bouncing" cDE scenario. For the
standard cDE scenario, we find that differences in the lensing potential result
from two effects: the enhanced growth of linear CDM density fluctuations with
respect to the LCDM case, and the modified nonlinear dynamics of collapsed
structures induced by the DE-CDM interaction. As a consequence, CMB lensing
highlights the DE impact in the cosmological expansion, even in the degenerate
case where the amplitude of the linear matter density perturbations,
parametrised through sigma_8, is the same in both the standard cDE and LCDM
cosmologies. For the bouncing scenario, we find that the two opposite
behaviours of the lens density contrast and of the matter abundance lead to a
counter-intuitive effect, making the power of the lensing signal lower by 10%
than in the LCDM scenario. Moreover, we compare the behaviour of CDM and
baryons in CoDECS separately, in order to isolate effects coming from the
coupling with the DE component. We find that, in the bouncing scenario, baryons
show an opposite trend with respect to CDM, due to the coupling of the latter
with the DE component. [abridged]


title: Pulsars Cannot Account for the Inner Galaxy's GeV Excess

abstract:
  Using data from the Fermi Gamma-Ray Space Telescope, a spatially extended
component of gamma rays has been identified from the direction of the Galactic
Center, peaking at energies of ~2-3 GeV. More recently, it has been shown that
this signal is not confined to the innermost hundreds of parsecs of the Galaxy,
but instead extends to at least ~3 kpc from the Galactic Center. While the
spectrum, intensity, and angular distribution of this signal is in good
agreement with predictions from annihilating dark matter, it has also been
suggested that a population of unresolved millisecond pulsars could be
responsible for this excess GeV emission from the Inner Galaxy. In this paper,
we consider this later possibility in detail. Comparing the observed spectral
shape of the Inner Galaxy's GeV excess to the spectrum measured from 37
millisecond pulsars by Fermi, we find that these sources exhibit a spectral
shape that is much too soft at sub-GeV energies to accommodate this signal. We
also construct population models to describe the spatial distribution and
luminosity function of the Milky Way's millisecond pulsars. After taking into
account constraints from the observed distribution of Fermi sources (including
both sources known to be millisecond pulsars, and unidentified sources which
could be pulsars), we find that millisecond pulsars can account for no more
than ~10% of the Inner Galaxy's GeV excess. Each of these arguments strongly
disfavor millisecond pulsars as the source of this signal.

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


title: Multi-centered D1-D5 solutions at finite B-moduli

abstract:
  We study the fate of two-centered D1-D5 systems on T^4 away from the singular
supergravity point in the moduli space. We do this by considering a background
D1-D5 black hole with a self-dual B-field moduli turned on and treating the
second center in the probe limit in this background. We find that in general
marginal bound states at zero moduli become metastable at finite B-moduli,
demonstrating a breaking of supersymmetry. However, we also find evidence that
when the charges of both centers are comparable, the effects of supersymmetry
breaking become negligible. We show that this effect is independent of string
coupling and thus it should be possible to reproduce this in the CFT at weak
coupling. We comment on the implications for the fuzzball proposal.


title: Implicit contractive maps in ordered metric spaces

abstract:
  Further extensions are given to the fixed point result (for implicit
contractions) due to Altun and Simsek [Fixed Point Th. Appl., Volume 2010,
Article ID 621469]. Some connections with related statements in the area due to
Agarwal, El-Gebeily and O'Regan [Appl. Anal., 87 (2008), 109-116] are also
discussed. Finally, the old approach in Turinici [An. St. Univ. "A. I. Cuza"
Iasi, 22 (1976), 177-180] is presented, for historical reasons.


title:
Warm Spitzer Photometry of Three Hot Jupiters: HAT-P-3b, HAT-P-4b and
  HAT-P-12b

abstract:
  We present Warm Spitzer/IRAC secondary eclipse time series photometry of
three short-period transiting exoplanets, HAT-P-3b, HAT-P-4b and HAT-P-12b, in
both the available 3.6 and 4.5 micron bands. HAT-P-3b and HAT-P-4b are
Jupiter-mass, objects orbiting an early K and an early G dwarf stars,
respectively. For HAT-P-3b we find eclipse depths of 0.112%+0.015%-0.030% (3.6
micron) and 0.094%+0.016%-0.009% (4.5 micron). The HAT-P-4b values are
0.142%+0.014%-0.016% (3.6 micron) and 0.122%+0.012%-0.014% (4.5micron). The two
planets' photometry is consistent with inefficient heat redistribution from
their day to night sides (and low albedos), but it is inconclusive about
possible temperature inversions in their atmospheres. HAT-P-12b is a
Saturn-mass planet and is one of the coolest planets ever observed during
secondary eclipse, along with hot Neptune GJ 436b and hot Saturn WASP-29b. We
are able to place 3$\sigma$ upper limits on the secondary eclipse depth of
HAT-P-12b in both wavelengths: < 0.042% (3.6 micron) and <0.085% (4.5 micron).
We discuss these results in the context of the {\it Spitzer} secondary eclipse
measurements of GJ 436b and WASP-29b. It is possible that we do not detect the
eclipses of HAT-P-12b due to high eccentricity, but find that weak planetary
emission in these wavelengths is a more likely explanation. We place 3 sigma
upper limits on the |e cos(omega)| quantity (where e is eccentricity and omega
is the argument of periapsis) for HAT-P-3b (<0.0081) and HAT-P-4b (<0.0042),
based on the secondary eclipse timings.


title: Dust Scattering and the Radiation Pressure Force in the M82 Superwind

abstract:
  Radiation pressure on dust grains may be an important physical mechanism
driving galaxy-wide superwinds in rapidly star-forming galaxies. We calculate
the combined dust and gas Eddington ratio (Gamma) for the archetypal superwind
of M82. By combining archival GALEX data, a standard dust model, Monte Carlo
dust scattering calculations, and the Herschel map of the dust surface density
distribution, the observed FUV/NUV surface brightness in the outflow constrains
both the total UV luminosity escaping from the starburst along its minor axis
(L_*, UV) and the flux-mean opacity, thus allowing a calculation of Gamma. We
find that L_(*, UV) ~ 1-6*10^42 ergs s^-1, ~2-12 times greater than the UV
luminosity observed from our line of sight. On a scale of 1-3 kpc above the
plane of M82, we find that Gamma ~ 0.01 - 0.06. On smaller scales (~0.25-0.5
kpc), where the enclosed mass decreases, our calculation of L_(*, UV) implies
that Gamma ~ 0.1 with factor of few uncertainties. Within the starburst itself,
we estimate the single-scattering Eddington ratio to be of order unity. Thus,
although radiation pressure is weak compared to gravity on kpc scales above the
plane of M82, it may yet be important in launching the observed outflow. We
discuss the primary uncertainties in our calculation, the sensitivity of Gamma
to the dust grain size distribution, and the time evolution of the wind
following M82's recent starburst episodes.


title: A Bayesian analysis pipeline for continuous GW sources in the PTA band

abstract:
  The direct detection of Gravitational Waves (GWs) by Pulsar Timing Arrays
(PTAs) is very likely within the next decade. While the stochastic GW
background is a promising candidate for detection it is also possible that
single resolvable sources may be detectable as well. In this work we will focus
on the detection and characterization of single GW sources from supermassive
black hole binaries (SMBHBs). We introduce a fully Bayesian data analysis
pipeline that is meant to carry out a search, characterization, and evaluation
phase. This will allow us to rapidly locate the global maxima in parameter
space, map out the posterior, and finally weigh the evidence of a GW detection
through a Bayes Factor. Here we will make use of an adaptive metropolis (AM)
algorithm and parallel tempering. We test this algorithm on realistic simulated
data that are representative of modern PTAs.


title: Theoretical Model of Superconducting Spintronic SIsFS Devices

abstract:
  Motivated by recent progress in development of cryogenic memory compatible
with single flux quantum (SFQ) circuits we have performed a theoretical study
of magnetic SIsFS Josephson junctions, where 'S' is a bulk superconductor, 's'
is a thin superconducting film, 'F' is a metallic ferromagnet and 'I' is an
insulator. We calculate the Josephson current as a function of s and F layers
thickness, temperature and exchange energy of F film. We outline several modes
of operation of these junctions and demonstrate their unique ability to have
large product of a critical current $I_{C}$ and a normal-state resistance
$R_{N}$ in the $\pi$ state, comparable to that in SIS tunnel junctions commonly
used in SFQ circuits. We develop a model describing switching of the Josephson
critical current in these devices by external magnetic field. The results are
in good agreement with the experimental data for
Nb-Al/AlO${_x}$-Nb-Pd$_{0.99}$Fe$_{0.01}$-Nb junctions.


title:
Strong Convergence to the homogenized limit of parabolic equations with
  random coefficients II

abstract:
  This paper is concerned with the study of solutions to discrete parabolic
equations in divergence form with random coefficients, and their convergence to
solutions of a homogenized equation.
  In [11] rate of convergence results in homogenization and estimates on the
difference between the averaged Green's function and the homogenized Green's
function for random environments which satisfy a Poincar\'{e} inequality were
obtained. Here these results are extended to certain environments in which
correlations can have arbitrarily small power law decay. Similar results for
discrete elliptic equations were obtained in [12].


title:
Solution of the monomer-dimer model on locally tree-like graphs.
  Rigorous results

abstract:
  We consider the monomer-dimer model on sequences of random graphs locally
convergent to trees. We prove that the monomer density converges almost surely,
in the thermodynamic limit, to an analytic function of the monomer activity. We
characterise this limit as the expectation of the solution of a fixed point
distributional equation and we give an explicit expression for the limiting
pressure per particle.


title: Stochastic flows on metric graphs

abstract:
  We study a simple stochastic differential equation driven by one Brownian
motion on a general oriented metric graph whose solutions are stochastic flows
of kernels. Under some condition, we describe the laws of all solutions. This
work is a natural continuation of some previous papers by Hajri, Hajri-Raimond
and Le Jan-Raimond where some particular graphs have been considered.


title: The Monomial Conjecture and Order Ideals

abstract:
  In this article first we prove that a special case of the order ideal
conjecture, originating from the work of Evans and Griffith in
equicharacteristic, implies the monomial conjecture due to M. Hochster. We
derive a necessary and sufficient condition for the validity of this special
case in terms certain syzygis of canonical modules of normal domains possessing
free summands. We also prove some special cases of this observation.


title: Physical Theories with Average Symmetry

abstract:
  This Letter probes the existence of physical laws invariant only in average
when subjected to some transformation. The concept of a symmetry transformation
is broadened to include corruption by random noise and average symmetry is
introduced by considering functions which are invariant only in average under
these transformations. It is then shown that actions with average symmetry obey
a modified version of Noether's Theorem with dissipative currents. The relation
of this with possible violations of physical symmetries, as for instance
Lorentz invariance in some quantum gravity theories, is briefly commented.


title:
Time Invariant Error Bounds for Modified-CS based Sparse Signal Sequence
  Recovery

abstract:
  In this work, we obtain performance guarantees for modified-CS and for its
improved version, modified-CS-Add-LS-Del, for recursive reconstruction of a
time sequence of sparse signals from a reduced set of noisy measurements
available at each time. Under mild assumptions, we show that the support
recovery error of both algorithms is bounded by a time-invariant and small
value at all times. The same is also true for the reconstruction error. Under a
slow support change assumption, (i) the support recovery error bound is small
compared to the support size; and (ii) our results hold under weaker
assumptions on the number of measurements than what $\ell_1$ minimization for
noisy data needs. We first give a general result that only assumes a bound on
support size, number of support changes and number of small magnitude nonzero
entries at each time. Later, we specialize the main idea of these results for
two sets of signal change assumptions that model the class of problems in which
a new element that is added to the support either gets added at a large initial
magnitude or its magnitude slowly increases to a large enough value within a
finite delay. Simulation experiments are shown to back up our claims.


title:
Organic superconductors: the need to go beyond effective 1/2-filled band
  models

abstract:
  A frustrated, effective 1/2-filled band Hubbard-Heisenberg model has been
proposed to describe the strongly dimerized charge-transfer solid families
kappa-(ET)_2X and Z[Pd(dmit)_2]_2. In addition to unconventional
superconductivity these materials also exhibit antiferromagnetism, candidate
spin-liquid phases, and in the case of Z=EtMe_3P, a so-called valence-bond
solid phase. We show that neither superconductivity nor the valence-bond solid
phase occurs within the Hubbard-Heisenberg model, indicating that the effective
1/2-filled band model is unsuitable for these materials.


title:
Microscopic studies of the normal and superconducting state of
  Ca3Ir4Sn13

abstract:
  We report on muon spin rotation (muSR) studies of the superconducting and
magnetic properties of the ternary intermetallic stannide Ca3Ir4Sn13. This
material has recently been the focus of intense research activity due to a
proposed interplay of ferromagnetic spin fluctuations and superconductivity. In
the temperature range T=1.6-200 K, we find that the zero-field muon relaxation
rate is very low and does not provide evidence for spin fluctuations on the
muSR time scale. The field-induced magnetization cannot be attributed to
localized magnetic moments. In particular, our muSR data reveal that the
anomaly observed in thermal and transport properties at T*~38 K is not of
magnetic origin. Results for the transverse-field muon relaxation rate at
T=0.02-12 K, suggest that superconductivity emerges out of a normal state that
is not of a Fermi-liquid type. This is unusual for an electronic system lacking
partially filled f-electron shells. The superconducting state is dominated by a
nodeless order parameter with a London penetration depth of lambda=385(1) nm
and the electron-phonon pairing interaction is in the strong-coupling limit.


title: Proton superconductivity and the masses of neutron stars

abstract:
  The unexpected temperature evolution of the neutron star in the Cassiopeia A
supernova remnant (Cas A, for short) has renewed tremendous interest in the
cooling mechanisms of neutron stars. In particular, the formation of
superconducting protons and superfluid neutrons deep inside the cores of
neutron stars have become focal points of the discussion. The purpose of this
letter is to add a new aspect to this discussion, which focuses on the
connection between proton superconductivity and the masses of neutron stars.
  Assuming (as is currently the case) that the temperature evolution of Cas A
is largely controlled by superconducting protons, we study a series of
phenomenological proton-pairing models to determine how deep into the stellar
core superconducting protons actually penetrate. This allows us to establish a
heretofore unknown relationship between the mass of the neutron star in Cas A
and the penetration depth of the superconducting proton phase. This
relationship can be used to either predict the depth of the superconducting
proton phase, or, conversely, determine the mass of Cas A from a reliable
calculation of the size of the proton superconducting phase in superdense
neutron star matter. We emphasize that the strategy outlined in this paper can
be applied to any other neutron star of similar age, whose temperature might be
reliably monitored over a several years period. High-mass neutron stars, such
as the recently discovered neutron stars J1614-2230 ($1.97 \pm 0.04\, \msun$)
and J0348+0432 ($2.01 \pm 0.04 \, \msun$), appear particularly appealing as a
significant fraction of the protons in their cores may be superconducting.


title:
UV observations of the globular cluster M10 from HST and GALEX. The BSS
  population

abstract:
  We present a combination of high-resolution Hubble Space Telescope and
wide-field ground-based and Galaxy Evolution Explorer data of the Galactic
Globular Cluster M10 (NGC6254). By using this large data-set we determined the
center of gravity of the cluster and we built its density profile from star
counts over its entire radial extension. We find that the density profile is
well reproduced by a single-mass King model with structural parameters c=1.41
and r_c=41". We also studied the Blue Straggler Star population and its radial
distribution. We count a total number of 120 BSS within the tidal radius. Their
radial distribution is bimodal: highly peaked in the cluster center, decreasing
at intermediate distances and rising again outwards. We discuss these results
in the context of the dynamical clock scheme presented by Ferraro et al. (2012)
and of recent results about the radial distribution of binary systems in this
cluster.


title:
Non-resonant magnetohydrodynamics streaming instability near magnetized
  relativistic shocks

abstract:
  We present in this paper both a linear study and numerical relativistic MHD
simulations of the non-resonant streaming instability occurring in the
precursor of relativistic shocks. In the shock front restframe, we perform a
linear analysis of this instability in a likely configuration for
ultra-relativistic shock precursors. This considers magneto-acoustic waves
having a wave vector perpendicular to the shock front and the large scale
magnetic field. Our linear analysis is achieved without any assumption on the
shock velocity and is thus valid for all velocity regimes. In order to check
our calculation, we also perform relativistic MHD simulations describing the
propagation of the aforementioned magneto-acoustic waves through the shock
precursor. The numerical calculations confirm our linear analysis, which
predicts that the growth rate of the instability is maximal for
ultra-relativistic shocks and exhibits a wavenumber dependence $\propto
k_x^{1/2}$. Our numerical simulations also depict the saturation regime of the
instability where we show that the magnetic amplification is moderate but
nevertheless significant ($\delta B/B\leq 10$). This latter fact may explain
the presence of strong turbulence in the vicinity of relativistic magnetized
shocks. Our numerical approach also introduces a convenient means to handle
isothermal (ultra-)relativistic MHD conditions.


title:
Bound entangled states with a private key and their classical
  counterpart

abstract:
  Entanglement is a fundamental resource for quantum information processing. In
its pure form, it allows quantum teleportation and sharing classical secrets.
Realistic quantum states are noisy and their usefulness is only partially
understood. Bound-entangled states are central to this question---they have no
distillable entanglement, yet sometimes still have a private classical key. We
present a construction of bound-entangled states with private key based on
classical probability distributions. From this emerge states possessing a new
classical analogue of bound entanglement, distinct from the long-sought bound
information. We also find states of smaller dimensions and higher key rates
than previously known. Our construction has implications for classical
cryptography: we show that existing protocols are insufficient for extracting
private key from our distributions due to their "bound-entangled" nature. We
propose a simple extension of existing protocols that can extract key from
them.


title:
Validity of commonly used formula of nucleation work for bubble
  nucleation

abstract:
  Nishioka and Kusaka [J. Chem. Phys. 96 (1992) 5370 (1992)] showed that the
commonly used formula, W = n({\mu}^{\alpha}-{\mu}^{\beta}) + {\gamma}A, for
work of formation of critical nucleus is derived by integrating the isothermal
Gibbs-Duhem relation for the incompressible nucleating phase, such as an
incompressible liquid phase nucleation in a vapor phase. In their paper as wel
as in a subsequent paper [Li, Nishioka, and Holcomb, J. Cryst. Growth 171
(1997) 259] it was stated that the commonly used formula was valid for an
incompressible nucleating phase and no longer held for such as a bubble
nucleation. In this paper, we will amend this statement; that is, the commonly
used formula is shown to hold for incompressible parent phase, such as a bubble
nucleation in an incompressible parent phase.


title: Elliptic and magneto-elliptic instabilities of disk vortices

abstract:
  Vortices are the fundamental units of turbulent flow. Understanding their
stability properties therefore provides fundamental insights on the nature of
turbulence itself. In this contribution I briefly review the phenomenological
aspects of the instability of elliptic streamlines, in the hydro (elliptic
instability) and hydromagnetic (magneto-elliptic instability) regimes. Vortex
survival in disks is a balance between vortex destruction by these mechanisms,
and vortex production by others, namely, the Rossby wave instability and the
baroclinic instability.


title:
An O2If*/WN6 Star Catch in the Act in a Compact Hii region in the
  Starburst Cluster NGC 3603

abstract:
  In this paper I report the discovery of an O2If*/WN6 star probably still
partially embedded in its parental cocoon in the star-burst cluster NGC 3603.
From the observed size of the associated compact Hii region, it was possible to
derive a probable dynamic age of no more than 600,000 years. Using the computed
visual extinction value Av ~ 6 magnitudes, an absolute visual magnitude Mv
=-5.7 mag is obtained, which for the assumed heliocentric distance of 7.6 kpc
results in a bolometric luminosity of ~ 8x10^5 Lsun. Also from the V magnitude
and the V-I color of the new star, and previous models for NGC3603's massive
star population, we estimate its mass for the binary (O2If*/WN6 + O3If) and the
single-star case (O2If*/WN6). In the former, it was found that the initial mass
of each component possibly exceeded 80 Msun and 40 Msun, while in the latter
MTT 58's initial mass possibly was in excess of 100 Msun.


title:
New Physics Contribution to $B_s \to \mu^+ \mu^-$ within R-Parity
  Violating Supersymmetric Models

abstract:
  We re-visit the problem of New Physics (NP) contribution to the branching
ratio of the $B_s \to \mu^+ \mu^-$ decay in light of the recent observation of
this decay by LHCb. We consider R-parity violating (RPV) supersymmetric models
as a primary example - recently one has reported stringent constraints on the
products of the RPV coupling constants that account for the $B_s \to \mu^+
\mu^-$ transition at the tree level. We argue that despite the LHCb measurement
of the $B(B_s \to \mu^+ \mu^-)$ is in a remarkable agreement with the Standard
Model (SM) prediction, there is still room for a significant New Physics
contribution to the $B(B_s \to \mu^+ \mu^-)$, as the sign of the $B_s \to \mu^+
\mu^-$ transition amplitude may be opposite to that of the Standard Model;
alternatively the amplitude may have a large phase. We conduct our analysis
mainly for the case of real RPV couplings. We find that taking into account the
scenario with the sign flip of the $B_s \to \mu^+ \mu^-$ amplitude (as compared
to that of the SM) makes the bounds on the RPV coupling products significantly
weaker. Also, we discuss briefly how our results are modified if the RPV
couplings have large phases. In particular, we examine the dependence of the
derived bounds on the phase of the NP amplitude.


title: A Novel Method of Solving Linear Programs with an Analog Circuit

abstract:
  We present the design of an analog circuit which solves linear programming
(LP) problems. In particular, the steady-state circuit voltages are the
components of the LP optimal solution. The paper shows how to construct the
circuit and provides a proof of equivalence between the circuit and the LP
problem. The proposed method is used to implement a LP-based Model Predictive
Controller by using an analog circuit. Simulative and experimental results show
the effectiveness of the proposed approach.


title: Off-Path Hacking: The Illusion of Challenge-Response Authentication

abstract:
  Everyone is concerned about the Internet security, yet most traffic is not
cryptographically protected. The usual justification is that most attackers are
only off-path and cannot intercept traffic; hence, challenge-response
mechanisms suffice to ensure authenticity. Usually, the challenges re-use
existing `unpredictable' header fields to protect widely-deployed protocols
such as TCP and DNS. We argue that this practice may often only give an
illusion of security. We present recent off-path TCP injection and DNS
poisoning attacks, enabling attackers to circumvent existing challenge-response
defenses. Both TCP and DNS attacks are non-trivial, yet very efficient and
practical. The attacks foil widely deployed security mechanisms, such as the
Same Origin Policy, and allow a wide range of exploits, e.g., long-term caching
of malicious objects and scripts. We hope that this article will motivate
adoption of cryptographic mechanisms such as SSL/TLS, IPsec and DNSSEC, and of
correct, secure challenge-response mechanisms.


title:
Inference in Kingman's Coalescent with Particle Markov Chain Monte Carlo
  Method

abstract:
  We propose a new algorithm to do posterior sampling of Kingman's coalescent,
based upon the Particle Markov Chain Monte Carlo methodology. Specifically, the
algorithm is an instantiation of the Particle Gibbs Sampling method, which
alternately samples coalescent times conditioned on coalescent tree structures,
and tree structures conditioned on coalescent times via the conditional
Sequential Monte Carlo procedure. We implement our algorithm as a C++ package,
and demonstrate its utility via a parameter estimation task in population
genetics on both single- and multiple-locus data. The experiment results show
that the proposed algorithm performs comparable to or better than several
well-developed methods.


title: The entropy of a hole in spacetime

abstract:
  We compute the gravitational entropy of 'spherical Rindler space', a
time-dependent, spherically symmetric generalization of ordinary Rindler space,
defined with reference to a family of observers traveling along non-parallel,
accelerated trajectories. All these observers are causally disconnected from a
spherical region H (a 'hole') located at the origin of Minkowski space. The
entropy evaluates to S = A/4G, where A is the area of the spherical
acceleration horizon, which coincides with the boundary of H. We propose that S
is the entropy of entanglement between quantum gravitational degrees of freedom
supporting the interior and the exterior of the sphere H.


title:
On description of the correlation between multiplicities in windows
  separated in azimuth and rapidity

abstract:
  The forward-backward (FB) multiplicity correlations in two windows separated
in rapidity and azimuth are analyzed in the framework of the model with
independent identical emitters (strings). Along with the short-range
contribution, originating from the correlation between particles produced by a
single string, the long-range contribution, originating from the fluctuation in
the number of strings, is taken into account. The connection of the FB
multiplicity correlation coefficient with the two-particle correlation function
and the di-hadron correlation analysis is traced. It's also shown that the
direct azimuthal flow leads to the forward ridge structure in the resulting
two-particle correlation function.


title:
Precision Measurement Method for Branching Fractions of Excited P1/2
  States Applied to 40Ca+

abstract:
  We present a method for measuring branching fractions for the decay of $J =
1/2$ atomic energy levels to lower-lying states based on time-resolved
recording of the atom's fluorescence during a series of population transfers.
We apply this method to measure the branching fractions for the decay of the
4$^{2}$P$_{1/2}$ state of $^{40}$\Ca to the 4$^{2}$S$_{1/2}$ and
3$^{2}$D$_{3/2}$ states to be \branching\ and \branchingsm, respectively. The
measurement scheme requires that at least one of the lower-lying states be
long-lived. The method is insensitive to fluctuations in laser light intensity
and magnetic field and is readily applicable to various atomic species due to
its simplicity. Our result distinguishes well among existing state-of-the-art
theoretical models of \Ca.


title:
ATLAS Tile Calorimeter Readout Electronics Upgrade Program for the High
  Luminosity LHC

abstract:
  The Tile Calorimeter (TileCal) is the hadronic calorimeter covering the most
central region of the ATLAS experiment at LHC. The TileCal readout consists of
about 10000 channels. The ATLAS upgrade program is divided in three phases: The
Phase~0 occurs during 2013-2014, Phase~1 during 2018-1019 and finally Phase~2,
which is foreseen for 2022-2023, whereafter the peak luminosity will reach 5-7
x 10$^{34}$ cm$^2$s$^{-1}$ (HL-LHC). The main TileCal upgrade is focused on the
Phase~2 period. The upgrade aims at replacing the majority of the on- and
off-detector electronics so that all calorimeter signals are directly digitized
and sent to the off-detector electronics in the counting room. All new
electronics must be able to cope with the increased radiation levels. An
ambitious upgrade development program is pursued to study different electronics
options. Three options are presently being investigated for the front-end
electronic upgrade. The first option is an improved version of the present
system built using commercial components, the second alternative is based on
the development of a dedicated ASIC (Application Specific Integrated Circuit)
and the third is the development of a new version of the QIE (Charge Integrator
and Encoder) based on the one developed for Fermilab. All three options will
use the same readout and control system using high speed (up to 40 Gb/s) links
for communication and clock synchronization. For the off-detector electronics a
new back-end architecture is being developed. A demonstrator prototype read-out
for a slice of the calorimeter with most of the new electronics, but still
compatible with the present system, is planned to be inserted in ATLAS already
in mid 2014 (at the end of the Phase~0 upgrade).


title: Nonlinearity Computation for Sparse Boolean Functions

abstract:
  An algorithm for computing the nonlinearity of a Boolean function from its
algebraic normal form (ANF) is proposed. By generalizing the expression of the
weight of a Boolean function in terms of its ANF coefficients, a formulation of
the distances to linear functions is obtained. The special structure of these
distances can be exploited to reduce the task of nonlinearity computation to
solving an associated binary integer programming problem. The proposed
algorithm can be used in cases where applying the Fast Walsh transform is
infeasible, typically when the number of input variables exceeds 40.


title: Comment on "Fringe Visibility and Which-Way Information: An Inequality"

abstract:
  We comment on one of the earliest derivations of the so-called wave-particle
duality relation. Our aim is to point out a slight technical flaw in the proof,
fixing it. Neither the physical content of the duality relation nor its
validity is thereby questioned.


title:
The response of reduced models of multiscale dynamics to small external
  perturbations

abstract:
  In real-world geophysical applications (such as predicting the climate
change), the reduced models of real-world complex multiscale dynamics are used
to predict the response of the actual multiscale climate to changes in various
global atmospheric and oceanic parameters. However, while a reduced model may
be adjusted to match a particular dynamical regime of a multiscale process, it
is unclear why it should respond to external perturbations in the same way as
the underlying multiscale process itself. In the current work, the authors
study the statistical behavior of a reduced model of the linearly coupled
multiscale Lorenz 96 system in the vicinity of a chosen dynamical regime by
perturbing the reduced model via a set of forcing parameters and observing the
response of the reduced model to these external perturbations. Comparisons are
made to the response of the underlying multiscale dynamics to the same set of
perturbations. Additionally, practical viability of linear response
approximation via the Fluctuation-Dissipation theorem is studied for the
reduced model.


title:
Spatial Templates for Studies of Patterns and Interactions in
  Dielectric-Barrier Discharges

abstract:
  We use various electrode layouts to tailor the profile of the electric field
in a two-dimensional (2D) dielectric-barrier-discharge system, thereby creating
spatial templates for the lateral distribution of discharge filaments. Our
discussion focuses on the formation of patterns and the interactions between
filaments in several template configurations. Hexagonal and square lattice
templates produce patterns reminiscent of the surface phases of adatoms on
crystal surfaces. For the square lattice, a lateral displacement between
opposing lattice electrodes modifies the pattern-forming behavior of the
system. In a stripe-electrode arrangement, each discharge filament terminates
in two dissimilar footprints, and the resulting pattern exhibits smectic
behavior. A circular ring template establishes periodic boundary conditions and
produces a new pattern in which adjacent filament footprints differ in shape.
Finally, electrodes featuring isolated and twinned pins are used to investigate
the pairing and clustering of filaments. We find that under certain conditions,
filament pairs may stabilize at either of two characteristic bonding distances.
We also study the range of distances over which a filament will either prevent
the ignition of or annihilate nearby filaments.


title:
Geometric properties of upper level sets of Lelong numbers on projective
  spaces

abstract:
  Let $T$ be a positive closed current of unit mass on the complex projective
space $\mathbb P^n$. For certain values $\alpha<1$, we prove geometric
properties of the set of points in $\mathbb P^n$ where the Lelong number of $T$
exceeds $\alpha$. We also consider the case of positive closed currents of
bidimension (1,1) on multiprojective spaces.


title: Mathematics Hidden Behind the Two Coefficients of Babylonian Mathematics

abstract:
  In the present paper I shall reveal two circular figures hidden behind the
Susa mathematical text no.3,lines 5 and 6 with my own analysis of the text.


title:
Interference Aware Channel Assignmnet Using Edge Coloring in
  Multi-Channel Multi-Radio Wireless Mesh Networks

abstract:
  Recently multi-channel multi-radio wireless mesh networks are considered a
reliable and cost effective way for internet access in wide area. A major
research challenge in this network is selecting least interference channel from
available channel and then assigning it to radio efficiently. Many algorithms
and methods have been developed for channel assignment to maximize network
throughput using orthogonal channels. Recent research and testbed experiments
proved that POC based channel assignment allows more flexibility in wireless
spectrum sharing. In this paper, we represent the channel assignment as a graph
edge coloring problem using POC. The signal-to-noise interference ratio is
measured to avoid interference from neighbouring transmission, when we assign
channel to link. Simulation result shows that our proposed method improves
network throughput and performance. Keywords:
  Wireless Mesh Networks, Multi-Radio, Multi-Channel, Partially Overlapping
Channels, Signal-to-noise interference


title:
Algebraic independence of multipliers of periodic orbits in the space of
  polynomial maps of one variable

abstract:
  We consider a space of complex polynomials of degree $n\ge 3$ with $n-1$
distinguished periodic orbits. We prove that the multipliers of these periodic
orbits considered as algebraic functions on that space, are algebraically
independent over the field of complex numbers.


title: Precoding-Based Network Alignment For Three Unicast Sessions

abstract:
  We consider the problem of network coding across three unicast sessions over
a directed acyclic graph, where each sender and the receiver is connected to
the network via a single edge of unit capacity. We consider a network model in
which the middle of the network only performs random linear network coding, and
restrict our approaches to precoding-based linear schemes, where the senders
use precoding matrices to encode source symbols. We adapt a precoding-based
interference alignment technique, originally developed for the wireless
interference channel, to construct a precoding-based linear scheme, which we
refer to as as a {\em precoding-based network alignment scheme (PBNA)}. A
primary difference between this setting and the wireless interference channel
is that the network topology can introduce dependencies between elements of the
transfer matrix, which we refer to as coupling relations, and can potentially
affect the achievable rate of PBNA. We identify all possible such coupling
relations, and interpret these coupling relations in terms of network topology
and present polynomial-time algorithms to check the presence of these coupling
relations. Finally, we show that, depending on the coupling relations present
in the network, the optimal symmetric rate achieved by precoding-based linear
scheme can take only three possible values, all of which can be achieved by
PBNA.


title:
Role of the Non-Collinear Polarizer Layer in Spin Transfer Torque
  Switching Processes

abstract:
  We have recently reported that the spin transfer torque switching current
density is very sensitive to not only the junction sizes but also the exchange
stiffness constants of the free layer according to the micromagnetic
simulations. The results are very complicate and far from the macro-spin model
because of the non-coherent spin switching processes. The dependence of the
switching current density on the junction sizes and the exchange stiffness
constants becomes systematic when we employ the non-collinear polarizer layer.
It is found that the non-collinear polarizer layer enhances the coherency of
the spin dynamics by breaking symmetric spin configurations.


title:
Computing a k-sparse n-length Discrete Fourier Transform using at most
  4k samples and O(k log k) complexity

abstract:
  Given an $n$-length input signal $\mbf{x}$, it is well known that its
Discrete Fourier Transform (DFT), $\mbf{X}$, can be computed in $O(n \log n)$
complexity using a Fast Fourier Transform (FFT). If the spectrum $\mbf{X}$ is
exactly $k$-sparse (where $k<<n$), can we do better? We show that
asymptotically in $k$ and $n$, when $k$ is sub-linear in $n$ (precisely, $k
\propto n^{\delta}$ where $0 < \delta <1$), and the support of the non-zero DFT
coefficients is uniformly random, we can exploit this sparsity in two
fundamental ways (i) {\bf {sample complexity}}: we need only $M=rk$
deterministically chosen samples of the input signal $\mbf{x}$ (where $r < 4$
when $0 < \delta < 0.99$); and (ii) {\bf {computational complexity}}: we can
reliably compute the DFT $\mbf{X}$ using $O(k \log k)$ operations, where the
constants in the big Oh are small and are related to the constants involved in
computing a small number of DFTs of length approximately equal to the sparsity
parameter $k$. Our algorithm succeeds with high probability, with the
probability of failure vanishing to zero asymptotically in the number of
samples acquired, $M$.


title: Dictionary learning based image enhancement for rarity detection

abstract:
  Image enhancement is an important image processing technique that processes
images suitably for a specific application e.g. image editing. The conventional
solutions of image enhancement are grouped into two categories which are
spatial domain processing method and transform domain processing method such as
contrast manipulation, histogram equalization, homomorphic filtering. This
paper proposes a new image enhance method based on dictionary learning.
Particularly, the proposed method adjusts the image by manipulating the rarity
of dictionary atoms. Firstly, learn the dictionary through sparse coding
algorithms on divided sub-image blocks. Secondly, compute the rarity of
dictionary atoms on statistics of the corresponding sparse coefficients.
Thirdly, adjust the rarity according to specific application and form a new
dictionary. Finally, reconstruct the image using the updated dictionary and
sparse coefficients. Compared with the traditional techniques, the proposed
method enhances image based on the image content not on distribution of pixel
grey value or frequency. The advantages of the proposed method lie in that it
is in better correspondence with the response of the human visual system and
more suitable for salient objects extraction. The experimental results
demonstrate the effectiveness of the proposed image enhance method.


title: Interior Estimates for the $n$-dimensional Abreu's Equation

abstract:
  We study the Abreu's equation in n-dimensional polytopes and derive interior
estimates of solutions under the assumption of the uniform K-stability.


title:
Coarse-graining the calcium dynamics on a stochastic reaction-diffusion
  lattice model

abstract:
  We develop a coarse grained (CG) approach for efficiently simulating calcium
dynamics in the endoplasmic reticulum membrane based on a fine stochastic
lattice gas model. By grouping neighboring microscopic sites together into CG
cells and deriving CG reaction rates using local mean field approximation, we
perform CG kinetic Monte Carlo (kMC) simulations and find the results of CG-kMC
simulations are in excellent agreement with that of the microscopic ones.
Strikingly, there is an appropriate range of coarse proportion $m$,
corresponding to the minimal deviation of the phase transition point compared
to the microscopic one. For fixed $m$, the critical point increases
monotonously as the system size increases, especially, there exists scaling law
between the deviations of the phase transition point and the system size.
Moreover, the CG approach provides significantly faster Monte Carlo simulations
which are easy to implement and are directly related to the microscopics, so
that one can study the system size effects at the cost of reasonable
computational time.