title: Bilipschitz invariants for germs of holomorphic foliations

abstract:
  In this paper we study bilipschitz equivalences of germs of holomorphic
foliations in $(\mathbb{C}^2,0)$. We prove that the algebraic multiplicity of a
singularity is invariant by such equivalences. Moreover, for a large class of
singularities, we show that the projective holonomy representation is also a
bilipschitz invariant.


title:
Time-Reversal Symmetrization of Spontaneous Emission for High Fidelity
  Quantum State Transfer

abstract:
  We demonstrate the ability to control the spontaneous emission from a
superconducting qubit coupled to a cavity. The time domain profile of the
emitted photon is shaped into a symmetric truncated exponential. The experiment
is enabled by a qubit coupled to a cavity, with a coupling strength that can be
tuned in tens of nanoseconds while maintaining a constant dressed state
emission frequency. Symmetrization of the photonic wave packet will enable use
of photons as flying qubits for transfering the quantum state between atoms in
distant cavities.


title: Security Type Systems as Recursive Predicates

abstract:
  We show how security type systems from the literature of language-based
noninterference can be represented more directly as predicates defined by
structural recursion on the programs. In this context, we show how our uniform
syntactic criteria from previous work cover several previous type-system
soundness results.


title: Gravitationally Induced Dark Matter Asymmetry and Dark Nucleon Decay

abstract:
  The "gravitational baryogenesis" scenario is extended to generate both baryon
and dark matter asymmetries, in the matter dominated era corresponding to
post-inflationary reheating. A minimal extension requires a singlet fermion X
for dark matter and a singlet scalar S. With two or more hidden sector
fermions, the scenario can lead to nucleon decay into dark matter with a
lifetime of order 10^{34-36} yr, which is relevant for current or future
experiments. The correct multi-component relic density can be obtained if dark
matter fermions couple to a sub-GeV vector boson that weakly interacts with the
Standard Model through mixing. The typical inflationary scale in the scenario
is of order 10^{16} GeV which suggests that tensor mode perturbations could
potentially be within observational reach.


title:
Zen and the Science of Pattern Identification: An Inquiry into Bayesian
  Skepticism

abstract:
  Finding patterns in data is one of the most challenging open questions in
information science. The number of possible relationships scales
combinatorially with the size of the dataset, overwhelming the exponential
increase in availability of computational resources. Physical insights have
been instrumental in developing efficient computational heuristics. Using
quantum field theory methods and rethinking three centuries of Bayesian
inference, we formulated the problem in terms of finding landscapes of patterns
and solved this problem exactly. The generality of our calculus is illustrated
by applying it to handwritten digit images and to finding structural features
in proteins from sequence alignments without any presumptions about model
priors suited to specific datasets. Landscapes of patterns can be uncovered on
a desktop computer in minutes.


title: Spectral theory for the q-Boson particle system

abstract:
  We develop spectral theory for the generator of the q-Boson (stochastic)
particle system. Our central result is a Plancherel type isomorphism theorem
for this system. This theorem has various implications. It proves the
completeness of the Bethe ansatz for the q-Boson generator and consequently
enables us to solve the Kolmogorov forward and backward equations for general
initial data. Owing to a Markov duality with q-TASEP, this leads to moment
formulas which characterize the fixed time distribution of q-TASEP started from
general initial conditions. The theorem also implies the biorthogonality of the
left and right eigenfunctions.
  We consider limits of our q-Boson results to a discrete delta Bose gas
considered previously by van Diejen, as well as to another discrete delta Bose
gas that describes the evolution of moments of the semi-discrete stochastic
heat equation (or equivalently, the O'Connell-Yor semi-discrete directed
polymer partition function). A further limit takes us to the delta Bose gas
which arises in studying moments of the stochastic heat equation /
Kardar-Parisi-Zhang equation.

categories: math-ph cond-mat.stat-mech math.MP math.PR math.QA math.RT


title: The Chemical Composition of Praesepe (M44)

abstract:
  Star clusters have long been used to illuminate both stellar evolution and
Galactic evolution. They also hold clues to the chemical and nucleosynthetic
processes throughout the history of the Galaxy. We have taken high
signal-to-noise, high-resolution spectra of 11 solar-type stars in the Praesepe
open cluster to determine the chemical abundances of 16 elements: Li, C, O, Na,
Mg, Al, Si, Ca, Sc, Ti, V, Cr, Fe, Ni, Y, and Ba. We have determined Fe from Fe
I and Fe II lines and find [Fe/H] = +0.12 $\pm$0.04. We find that Li decreases
with temperature due to increasing Li depletion in cooler stars; it matches the
Li-temperature pattern found in the Hyades. The [C/Fe] and [O/Fe] abundances
are below solar and lower than the field star samples due to the younger age of
Praesepe (0.7 Gyr) than the field stars. The alpha-elements, Mg, Si, Ca, and
Ti, have solar ratios with respect to Fe, and are also lower than the field
star samples. The Fe-peak elements, Cr and Ni, track Fe and have solar values.
The neutron capture element [Y/Fe] is found to be solar, but [Ba/Fe] is
enhanced relative to solar and to the field stars. Three Praesepe giants were
studied by Carrera and Pancino; they are apparently enhanced in Na, Mg, and Ba
relative to the Praesepe dwarfs. The Na enhancement may indicate proton-capture
nucleosynthesis in the Ne -> Na cycling with dredge-up into the atmospheres of
the red giants.


title: The Status of the Search for Low Mass WIMPs: 2013

abstract:
  Using information from a recent dark matter symposium at Marina del Rey and
from various publications in 2012 and 2013, we discuss the most recent evidence
and constraints on low mass WIMPs. There are now five separate experimental
limits on such WIMPs, including a new paper on the XENON100 225 day exposure.
There are very different experimental methods with different backgrounds that
comprise this limit. We speculate on the possible sources of the reported low
mass WIMP signals and background. We present recent arguments concerning DAMA
that show the possible DM claims are likely misleading. We discuss the new CDMS
claims for a signal and question the very low ionization in these events. We
also discuss an analysis of XENON 100 data that uses information theory that
further excludes the CDMS results.


title: Preliminary results of ANAIS-25

abstract:
  The ANAIS (Annual Modulation with NaI(Tl) Scintillators) experiment aims at
the confirmation of the DAMA/LIBRA signal using the same target and technique
at the Canfranc Underground Laboratory. 250 kg of ultrapure NaI(Tl) crystals
will be used as a target, divided into 20 modules, each coupled to two
photomultipliers. Two NaI(Tl) crystals of 12.5 kg each, grown by Alpha Spectra
from a powder having a potassium level under the limit of our analytical
techniques, form the ANAIS-25 set-up. The background contributions are being
carefully studied and preliminary results are presented: their natural
potassium content in the bulk has been quantified, as well as the uranium and
thorium radioactive chains presence in the bulk through the discrimination of
the corresponding alpha events by PSA, and due to the fast commissioning, the
contribution from cosmogenic activated isotopes is clearly identified and their
decay observed along the first months of data taking. Following the procedures
established with ANAIS-0 and previous prototypes, bulk NaI(Tl) scintillation
events selection and light collection efficiency have been also studied in
ANAIS-25.


title: A differentiation theorem for uniform measures

abstract:
  Using the notion of higher-order Fourier dimension introduced in \cite{M2}
(which was a sort of psuedorandomness condition stemming from the Gowers norms
of Additive Combinatorics), we prove a maximal theorem and corresponding
differentiation theorem for singular measures on $\R^d$, $d=1,2,...$. This
extends results begun by Hardy and Littlewood for balls in $\R^d$ and continued
by Stein \cite{stein} for spheres in $\R^{d\geq 3}$ and Bourgain for circles in
$\R^2$, first considered for more general spaces in \cite{rubio}, and shown to
hold for some singular subsets of the reals for the first time in
\cite{LabaDiff}.
  Notably, unlike the more delicate of the previous results on differentiation
such as \cite{Bourgain} and \cite{LabaDiff}, the assumption of higher-order
Fourier dimension subsumes all of the geometric or combinatorial input
necessary for one to obtain our theorem, and suggests a new approach to some
problems in Harmonic Analysis.


title: Evaluation modules for the $q$-tetrahedron algebra

abstract:
  Let $\mathbb F$ denote an algebraically closed field, and fix a nonzero $q
\in \mathbb F$ that is not a root of unity. We consider the $q$-tetrahedron
algebra $\boxtimes_q$ over $\mathbb F$. It is known that each
finite-dimensional irreducible $\boxtimes_q$-module of type 1 is a tensor
product of evaluation modules. This paper contains a comprehensive description
of the evaluation modules for $\boxtimes_q$. This description includes the
following topics. Given an evaluation module $V$ for $\boxtimes_q$, we display
24 bases for $V$ that we find attractive. For each basis we give the matrices
that represent the $\boxtimes_q$-generators. We give the transition matrices
between certain pairs of bases among the 24. It is known that the cyclic group
$\Z_4$ acts on $\boxtimes_q$ as a group of automorphisms. We describe what
happens when $V$ is twisted via an element of $\Z_4$. We discuss how evaluation
modules for $\boxtimes_q$ are related to Leonard pairs of $q$-Racah type.


title: Application Behavior Enforcement Based On Network Characteristics

abstract:
  Every device defines the behavior of various applications running on it with
the help of user profiles or settings. What if a user wants different different
applications to run in different different networks. Then he cannot do this
because in todays existing operating systems the application profile, user
specific tool settings and any such system usage settings do not consider the
current network characteristics of the user or system and are therefore static
in nature.Therefore there is a need for an intelligent system which will
dynamically change or apply changes to the settings of various applications
running on the system considering the current network characteristics based on
user specifications. This paper presents an idea such that a user can set
different different applications in different different networks.This paper
presents how the user will get pop up messages when he visits to safe web
sites. And according to the users current network status he will get a pop up
message when he will go for download or stream audio or video files.


title:
Privatizing user credential information of Web services in a shared user
  environment

abstract:
  User credentials security is one of the most important tasks in Web World.
Most Web sites on the Internet that support user accounts store the users
credentials in a database. Now a days, most of the web browsers offer auto
login feature for the favorite web sites such as yahoo, google, gmail etc.
using these credential information. This facilitates the misuse of user
credentials. Privatizing user credential information of web services in a
shared user environment provides a feature enhancement where the root user will
be able to privatize his stored credentials by enforcing some masking
techniques such that even a user logs on to the system with root user
credentials, he will not be able to access privatized data. In case of web
browsers auto login feature, a root user can disable the feature manually by
deleting entries from web browsers' saved password list. But this involves
spending a considerable amount of time and the biggest problem is that he has
to insert those credentials once again when he next visits these websites. This
application resumes auto login feature whenever root user disable the masked
mode. The application includes two parts: Masked Application Mode and Disabling
the Masked Application Mode. When the system goes for masked application mode,
the other user will not be able to use the credentials of the root user.If the
other user tries to access any of the web pages which have been masked, the
other user will have to authenticate with his own credentials. Disabling the
masked mode requires authentication from the root user. As long as this
credential is not shared, masked mode can be disabled only by the root user.


title: Theory of temperature dependent phonon-renormalized properties

abstract:
  We present a general harmonic theory for the temperature dependence of
phonon-renormalized properties of solids. Firstly, we formulate a perturbation
theory in phonon-phonon interactions to calculate the phonon renormalization of
physical quantities. Secondly, we propose two new schemes for extrapolating
phonon zero-point corrections from temperature dependent data that improve the
accuracy by an order of magnitude compared to previous approaches. Finally, we
consider the low-temperature limit of the class of observables that includes
the electronic band gap, obtaining a $T^4$ dependence in three dimensions,
$T^2$ in two dimensions, and $T^{3/2}$ in one dimension.


title: Sull'origine della condizione di quantizzazione delle cariche dei dioni

abstract:
  It is shown that there is a simple way to get the quantization equation for
the electric and magnetic charges of dyons, $e_ig_j-g_ie_j=m(\hbar c)$, which
also shed light to the origin of such quantization.


title: Information sharing promotes prosocial behaviour

abstract:
  More often than not, bad decisions are bad regardless of where and when they
are made. Information sharing might thus be utilized to mitigate them. Here we
show that sharing the information about strategy choice between players
residing on two different networks reinforces the evolution of cooperation. In
evolutionary games the strategy reflects the action of each individual that
warrants the highest utility in a competitive setting. We therefore assume that
identical strategies on the two networks reinforce themselves by lessening
their propensity to change. Besides network reciprocity working in favour of
cooperation on each individual network, we observe the spontaneous emerge of
correlated behaviour between the two networks, which further deters defection.
If information is shared not just between individuals but also between groups,
the positive effect is even stronger, and this despite the fact that
information sharing is implemented without any assumptions with regards to
content.

categories: physics.soc-ph cond-mat.stat-mech cs.SI q-bio.PE


title:
Studying flux variability of the BL Lac object 1ES0806+524 with MAGIC in
  a multi-wavelength context

abstract:
  We present results of multi-wavelength (MWL) observations of the
high-frequency-peaked BL Lacertae (HBL) object 1ES 0806+524 (z=0.138).
Triggered by a high optical state, very high energy (VHE; E > 100 GeV)
observations were carried out with the MAGIC stereoscopic system from January
to March 2011. During the observations a relatively short VHE gamma-ray flare
was detected that lasted no longer than one night. To complement the VHE
observations, simultaneous MWL data were collected in high energy gamma-rays
using the \textit{Fermi Large Area Telescope (HE, 300 MeV - 100 GeV), in the
X-ray and UV band with the \textit{Swift} satellite, in the optical R--band
through observations with the KVA telescope and in the radio band using the
OVRO telescope. This constitutes the first time that such a broad band coverage
has been obtained for this source. We study the source properties through the
characterization of the spectral energy distribution (SED) and its evolution
through two different VHE flux states. The SED can be modeled with a simple
one-zone SSC model, resulting in parameters that are comparable to those
obtained for other HBLs.


title:
Projections for Two Higgs Doublet Models at the LHC and ILC: A Snowmass
  White Paper

abstract:
  The discovery of the 125 GeV Higgs boson and the measurement of its branching
ratios has initiated the exploration of the electroweak symmetry breaking
sector. There have been numerous studies exploring the restrictions these
results place on the parameter space of two Higgs doublet models. We extend
these results to include the full data set and study the expected sensitivity
that can be obtained with 300 and 3000 inverse femtobarn of integrated
luminosity. In addition, searches for a heavy Standard Model Higgs boson are
also considered. It is shown that the nonobservation of such a Higgs boson can
substantially narrow the allowed regions of parameter space in two Higgs
doublet models. Finally, projections for the ILC at the center of mass energy
250, 500, and 1000 GeV are investigated.


title: Statistical physics of black holes as quantum-mechanical systems

abstract:
  Some basic features of black-hole statistical mechanics are investigated,
assuming that black holes respect the principles of quantum mechanics. Care is
needed in defining an entropy S_bh corresponding to the number of microstates
of a black hole, given that the black hole interacts with its surroundings. An
open question is then the relationship between this entropy and the
Bekenstein-Hawking entropy S_BH. For a wide class of models with interactions
needed to ensure unitary quantum evolution, these interactions produce extra
energy flux beyond that predicted by Hawking. Arguments are then presented that
this results in an entropy S_bh that is smaller than S_BH. Correspondingly, in
such scenarios equilibrium properties of black holes are modified. We examine
questions of consistency of such an inequality; if it is not consistent, that
provides significant constraints on models for quantum-mechanical black hole
evolution.


title:
ESPOON$_{{ERBAC}}$: Enforcing Security Policies In Outsourced
  Environments

abstract:
  Data outsourcing is a growing business model offering services to individuals
and enterprises for processing and storing a huge amount of data. It is not
only economical but also promises higher availability, scalability, and more
effective quality of service than in-house solutions. Despite all its benefits,
data outsourcing raises serious security concerns for preserving data
confidentiality. There are solutions for preserving confidentiality of data
while supporting search on the data stored in outsourced environments. However,
such solutions do not support access policies to regulate access to a
particular subset of the stored data.
  For complex user management, large enterprises employ Role-Based Access
Controls (RBAC) models for making access decisions based on the role in which a
user is active in. However, RBAC models cannot be deployed in outsourced
environments as they rely on trusted infrastructure in order to regulate access
to the data. The deployment of RBAC models may reveal private information about
sensitive data they aim to protect. In this paper, we aim at filling this gap
by proposing \textbf{$\mathit{ESPOON_{ERBAC}}$} for enforcing RBAC policies in
outsourced environments. $\mathit{ESPOON_{ERBAC}}$ enforces RBAC policies in an
encrypted manner where a curious service provider may learn a very limited
information about RBAC policies. We have implemented $\mathit{ESPOON_{ERBAC}}$
and provided its performance evaluation showing a limited overhead, thus
confirming viability of our approach.


title: Auxiliary Gauge Mediation: A New Route to Mini-Split Supersymmetry

abstract:
  The discovery of a standard-model-like Higgs at 126 GeV and the absence of
squark signals thus far at the LHC both point towards a mini-split spectrum for
supersymmetry. Within standard paradigms, it is non-trivial to realize a
mini-split spectrum with heavier sfermions but lighter gauginos while
simultaneously generating Higgs sector soft terms of the correct magnitude,
suggesting the need for new models of supersymmetry breaking and mediation. In
this paper, we present a new approach to mini-split model building based on
gauge mediation by ``auxiliary groups'', which are the anomaly-free continuous
symmetries of the standard model in the limit of vanishing Yukawa couplings. In
addition to the well-known flavor SU(3)_F and baryon-minus-lepton U(1)_{B-L}
groups, we find that an additional U(1)_H acting on the Higgs doublets alone
can be used to generate Higgs soft masses and B-terms necessary for a complete
model of mini-split. Auxiliary gauge mediation is a special case of Higgsed
gauge mediation, and we review the resulting two-loop scalar soft terms as well
as three-loop gaugino masses. Along the way, we present a complete two-loop
calculation of A-terms and B-terms in gauge mediation, which---contrary to a
common misconception---includes a non-zero contribution at the messenger
threshold which can be sizable in models with light gauginos. We present
several phenomenologically acceptable mini-split spectra arising from auxiliary
gauge mediation and highlight a complete minimal model which realizes the
required spectrum and Higgs sector soft terms with a single U(1)_X auxiliary
gauge symmetry. We discuss possible experimental consequences.


title:
Simulating the quartic Galileon gravity model on adaptively refined
  meshes

abstract:
  We develop a numerical algorithm to solve the high-order nonlinear
derivative-coupling equation associated with the quartic Galileon model, and
implement it in a modified version of the RAMSES N-body code to study the
effect of the Galileon field on the large-scale matter clustering. The
algorithm is tested for several matter field configurations with different
symmetries, and works very well. This enables us to perform the first
simulations for a quartic Galileon model which provides a good fit to the
cosmic microwave background (CMB) anisotropy, supernovae and baryonic acoustic
oscillations (BAO) data. Our result shows that the Vainshtein mechanism in this
model is very efficient in suppressing the spatial variations of the scalar
field. However, the time variation of the effective Newtonian constant caused
by the curvature coupling of the Galileon field cannot be suppressed by the
Vainshtein mechanism. This leads to a significant weakening of the strength of
gravity in high-density regions at late times, and therefore a weaker matter
clustering on small scales. We also find that without the Vainshtein mechanism
the model would have behaved in a completely different way, which shows the
crucial role played by nonlinearities in modified gravity theories and the
importance of performing self-consistent N-body simulations for these theories.


title:
What produces the extended LINER-type emission in the NUGA galaxy NGC
  5850?

abstract:
  (Abridged) The role of low ionization nuclear emission region (LINER)
galaxies within the picture of active galactic nuclei (AGN) has been
controversial. It is still not clear whether they host an AGN in a low
accretion mode, or whether they are not active at all but dominated by
alternative ionization mechanisms, namely shocks, winds/outflows, or
photoionization by a post asymptotic giant branch (p-AGB) stellar population.
The detection of extended LINER-like emission was often taken as evidence of
ionization by stellar components but this has not been undisputed. We performed
optical integral field spectroscopic observations on the central approx. 4 kpc
of NGC 5850 using VIMOS at the VLT, which provides spatially-resolved spectra
for the gas emission and the stellar continuum. We derive and analyse emission
line and kinematic maps. We find the central few kpc of NGC 5850 to be
dominated by extended LINER-like emission. The emission-line ratios that are
sensitive to the ionization parameter increase with radial distance to the
nucleus. Therefore, the extended LINER-like emission in NGC 5850 is dominated
by ionization from distributed ionization sources, probably by stars on the
p-AGB. The LINER-like region is surrounded by emission that is classed as
'composite', likely due to a mixture of a LINER-like ionization pattern and
photoionization by low-level star formation. Two star-forming regions are
present in the 21"x19" field of view. One of them is located approximately in
the ring surrounding the kinematically decoupled core. The second one is close
to the nucleus and is the origin of a region of decreased emission line ratios
oriented radially outwards. We find the interstellar gas to have areas of steep
velocity gradients and a complex kinematic morphology, probably caused by the
lopsided (m=1) distribution of the gas. The inflow of gas toward the center
appears possible.


title: xTras: a field-theory inspired xAct package for Mathematica

abstract:
  We present the tensor computer algebra package xTras, which provides
functions and methods frequently needed when doing (classical) field theory.
Amongst others, it can compute contractions, make Ans\"atze, and solve
tensorial equations. It is built upon the tensor computer algebra system xAct,
a collection of packages for Mathematica.


title:
Spectral Parameters for Scattering Amplitudes in N=4 Super Yang-Mills
  Theory

abstract:
  Planar N=4 Super Yang-Mills theory appears to be a quantum integrable
four-dimensional conformal theory. This has been used to find equations
believed to describe its exact spectrum of anomalous dimensions. Integrability
seemingly also extends to the planar space-time scattering amplitudes of the
N=4 model, which show strong signs of Yangian invariance. However, in
contradistinction to the spectral problem, this has not yet led to equations
determining the exact amplitudes. We propose that the missing element is the
spectral parameter, ubiquitous in integrable models. We show that it may indeed
be included into recent on-shell approaches to scattering amplitude integrands,
providing a natural deformation of the latter. Under some constraints, Yangian
symmetry is preserved. Finally we speculate that the spectral parameter might
also be the regulator of choice for controlling the infrared divergences
appearing when integrating the integrands in exactly four dimensions.


title: Hypervelocity Star Candidates in the SEGUE G & K Dwarf Sample

abstract:
  We present 20 candidate hypervelocity stars from the Sloan Extension for
Galactic Understanding and Exploration (SEGUE) G and K dwarf samples. Previous
searches for hypervelocity stars have only focused on large radial velocities;
in this study we also use proper motions to select the candidates. We determine
the hypervelocity likelihood of each candidate by means of Monte Carlo
simulations, considering the significant errors often associated with high
proper motion stars. We find that nearly half of the candidates exceed their
escape velocities with at least 98% probability. Every candidate also has less
than a 25% chance of being a high-velocity fluke within the SEGUE sample. Based
on orbits calculated using the observed six-dimensional positions and
velocities, few, if any, of these candidates originate from the Galactic
center. If these candidates are truly hypervelocity stars, they were not
ejected by interactions with the Milky Way's supermassive black hole. This
calls for a more serious examination of alternative hypervelocity-star ejection
scenarios.


title:
Galaxy Zoo 2: detailed morphological classifications for 304,122
  galaxies from the Sloan Digital Sky Survey

abstract:
  We present the data release for Galaxy Zoo 2 (GZ2), a citizen science project
with more than 16 million morphological classifications of 304,122 galaxies
drawn from the Sloan Digital Sky Survey. Morphology is a powerful probe for
quantifying a galaxy's dynamical history; however, automatic classifications of
morphology (either by computer analysis of images or by using other physical
parameters as proxies) still have drawbacks when compared to visual inspection.
The large number of images available in current surveys makes visual inspection
of each galaxy impractical for individual astronomers. GZ2 uses classifications
from volunteer citizen scientists to measure morphologies for all galaxies in
the DR7 Legacy survey with m_r>17, in addition to deeper images from SDSS
Stripe 82. While the original Galaxy Zoo project identified galaxies as
early-types, late-types, or mergers, GZ2 measures finer morphological features.
These include bars, bulges, and the shapes of edge-on disks, as well as
quantifying the relative strengths of galactic bulges and spiral arms. This
paper presents the full public data release for the project, including measures
of accuracy and bias. The majority (>90%) of GZ2 classifications agree with
those made by professional astronomers, especially for morphological T-types,
strong bars, and arm curvature. Both the raw and reduced data products can be
obtained in electronic format at http://data.galaxyzoo.org .


title:
Electronic and vibronic properties of a discotic liquid-crystal and its
  charge transfer complex

abstract:
  Discotic liquid crystalline (DLC) charge transfer (CT) complexes combine
visible light absorption and rapid charge transfer characteristics within the
CT complex, being favorable properties for photovoltaic (PV) applications. We
present a detailed study of the electronic and vibrational properties of the
prototypic 1:1 mixture of discotic 2,3,6,7,10,11-hexakishexyloxytriphenylene
(HAT6) and 2,4,7-trinitro-9-fluorenone (TNF). It is shown that intermolecular
charge transfer occurs in the groundstate of the complex: a charge
delocalization of about 10-2 electron from the HAT6 core to TNF is deduced from
both Raman and our previous NMR measurements (Reference 32), implying the
presence of permanent dipoles at the donor-acceptor interface. A combined
analysis of density functional theory calculations, resonant Raman and UV-VIS
absorption measurements indicate that fast relaxation occurs in the UV region
due to intramolecular vibronic coupling of HAT6 quinoidal modes with lower
lying electronic states. Relatively slower relaxation in the visible region
CT-band of the complex is also indicated, which likely involves motions of the
TNF nitro groups. The fast quinoidal relaxation process in the hot UV band of
HAT6 relates to pseudo-Jahn-Teller interactions in a single benzene unit,
suggesting that the underlying vibronic coupling mechanism can be generic for
polyaromatic hydrocarbons. Both the presence of CT dipoles and relatively slow
relaxation processes in the CT band can be relevant concerning the design of
DLC based organic PV systems.


title:
MAGIC discovery and multiwavelength observations of the BL Lac 1ES
  1727+502

abstract:
  Blazars, active galactic nuclei whose jet axis is pointed towards the
observer, constitute the most numerous class of extragalactic very high energy
(VHE, E > 100\, GeV) gamma-ray emitters. The MAGIC experiment, a system of two
Imaging Atmospheric Cherenkov Telescopes located in the Canary Island of La
Palma (Northern hemisphere), with an energy threshold of 50 GeV, is a well
suited experiment for observations of such objects.
  Here we present the discovery of the BL Lac 1ES 1727+502 (z = 0.055) as VHE
source. This object was identified as a promising TeV candidate based on
archival data and the observation that lead to this detection was not triggered
by any high state alert in other wavebands. The MAGIC observations are
complemented by other observations are lower frequencies: optical data from the
KVA telescope, UV, optical and X-ray archival data taken with the instruments
on board the Swift satellite and high energy (HE, 300 MeV < E < 100 GeV) data
from the \textit{Fermi}-LAT instrument. We studied the spectral energy
distribution of 1ES 1727+502 and interpreted it with a one-zone synchrotron
self-Compton model with parameters that are typical for this class of sources.


title:
A Possible Formation Scenario for Dwarf Spheroidal Galaxies - II: A
  Parameter Study

abstract:
  Dwarf spheroidal (dSph) galaxies are considered the basic building blocks of
the galaxy formation process in the LCDM (Lambda Cold Dark Matter) hierarchical
cosmological model. These galaxies are believed to be the most dark matter (DM)
dominated systems known, have the lowest stellar content, and are poor in gas.
Many theories attempt to explain the formation of dSph galaxies resorting to
the fact that these galaxies are mainly found orbiting large galaxies or
invoking other mechanisms of interactions. Here we show the full set of
simulation as an extension of our fiducial model, where we study the formation
of classical dSph galaxies in isolation by dissolving star clusters within the
DM halo of the dwarf galaxy. In our parameter survey we adopt cored and cusped
DM halo profiles and consider different numbers of dissolving star clusters. We
investigate the dependency of observable quantities with different masses and
scale-lengths of the DM halo and different star formation efficiencies (SFE).
We find that our proposed scenario explains many features of the classical dSph
galaxies of the Milky Way, like their morphology and their dynamics. We see
trends how the surface brightness and the scale-length of the luminous
component vary with the parameters of our simulations. We also identify how
irregularities in their shape, i.e. clumpiness and ellipticity vary in our
simulations. In velocity space, we identify the parameters leading to flat
velocity dispersions curves. We recognize kinematically cold substructures in
velocity space, named fossil remnants and stemming from our unique initial
conditions, which alter the expected results. These streaming motions are
considered as a key feature for future observation with high resolution to
validate our scenario.


title:
The cyclic subgroup separability of certain generalized free products of
  two groups

abstract:
  Free products of two residually finite groups with amalgamated retracts are
considered. It is proved that a cyclic subgroup of such a group is not finitely
separable if, and only if, it is conjugated with a subgroup of a free factor
which is not finitely separable in this factor. A similar result is obtained
for the case of separability in the class of finite p-groups.


title: Tunneling decay of false vortices

abstract:
  We consider the decay of vortices trapped in the false vacuum of a theory of
scalar electrodynamics in 2+1 dimensions. The potential is inspired by models
with intermediate symmetry breaking to a metastable vacuum that completely
breaks a U(1) symmetry, while in the true vacuum the symmetry is unbroken. The
false vacuum is unstable through the formation of true vacuum bubbles; however,
the rate of decay can be extremely long. On the other hand, the false vacuum
can contain metastable vortex solutions. These vortices contain the true vacuum
inside in addition to a unit of magnetic flux and the appropriate topologically
nontrivial false vacuum outside. We numerically establish the existence of
vortex solutions which are classically stable; however, they can decay via
tunneling. In general terms, they tunnel to a configuration which is a large,
thin-walled vortex configuration that is now classically unstable to the
expansion of its radius. We compute an estimate for the tunneling amplitude in
the semi-classical approximation. We believe our analysis would be relevant to
superconducting thin films or superfluids.


title:
Initial Conditions for Numerical Relativity -- Introduction to numerical
  methods for solving elliptic PDEs

abstract:
  Numerical relativity became a powerful tool to investigate the dynamics of
binary problems with black holes or neutron stars as well as the very structure
of General Relativity. Although public numerical relativity codes are available
to evolve such systems, a proper understanding of the methods involved is quite
important. Here we focus on the numerical solution of elliptic partial
differential equations. Such equations arise when preparing initial data for
numerical relativity, but also for monitoring the evolution of black holes.
Because such elliptic equations play an important role in many branches of
physics, we give an overview of the topic, and show how to numerically solve
them with simple examples and sample codes written in C++ and Fortran90 for
beginners in numerical relativity or other fields requiring numerical
expertise.


title: G\"{o}del solution in $f(R,T)$ gravity

abstract:
  In this paper we study G\"{o}del universe in the framework of $f(R,T)$
modified theories of gravity, where $R$ is the curvature scalar and $T$ the
trace of the energy momentum tensor. We demonstrate that G\"{o}del solution
occurs in this modified theory and still we suggest a path to understanding the
smallness of the cosmological constant.


title:
Bounds for alpha-Optimal Partitioning of a Measurable Space Based on
  Several Efficient Partitions

abstract:
  We provide a two-sided inequality for the alpha-optimal partition value of a
measurable space according to n nonatomic finite measures. The result extends
and often improves Legut (1988) since the bounds are obtained considering
several partitions that maximize the weighted sum of the partition values with
varying weights, instead of a single one.


title:
A discrete to continuum analysis of dislocations in nanowire
  heterostructures

abstract:
  Epitaxially grown heterogeneous nanowires present dislocations at the
interface between the phases if their radius is big. We consider a
corresponding variational discrete model with quadratic pairwise atomic
interaction energy. By employing the notion of Gamma-convergence and a
geometric rigidity estimate, we perform a discrete to continuum limit and a
dimension reduction to a one-dimensional system. Moreover, we compare a
defect-free model and models with dislocations at the interface and show that
the latter are energetically convenient if the thickness of the wire is
sufficiently large.


title: Computational Rationalization: The Inverse Equilibrium Problem

abstract:
  Modeling the purposeful behavior of imperfect agents from a small number of
observations is a challenging task. When restricted to the single-agent
decision-theoretic setting, inverse optimal control techniques assume that
observed behavior is an approximately optimal solution to an unknown decision
problem. These techniques learn a utility function that explains the example
behavior and can then be used to accurately predict or imitate future behavior
in similar observed or unobserved situations.
  In this work, we consider similar tasks in competitive and cooperative
multi-agent domains. Here, unlike single-agent settings, a player cannot
myopically maximize its reward; it must speculate on how the other agents may
act to influence the game's outcome. Employing the game-theoretic notion of
regret and the principle of maximum entropy, we introduce a technique for
predicting and generalizing behavior.


title:
Theoretical Electronic and Rovibrational Studies for Anions of Interest
  to the DIBs

abstract:
  The dipole-bound excited state of the methylene nitrile anion (CH2CN-) has
been suggested as a candidate carrier for a diffuse interstellar band (DIB) at
803.8 nm. Its corresponding radical has been detected in the interstellar
medium (ISM), making the existence for the anion possible. This work applies
state-of-the-art ab initio methods such as coupled cluster theory to reproduce
accurately the electronic excitations for CH2CN- and the similar methylene
enolate anion, CH2CHO-. This same approach has been employed to indicate that
19 other anions may possess electronically excited states, five of which are
valence in nature. Concurrently, in order to assist in the detection of these
anions in the ISM, work has also been directed towards predicting vibrational
frequencies and spectroscopic constants for these anions through the use of
quartic force fields (QFFs). Theoretical rovibrational work on anions has thus
far included studies of CH2CN-, C3H-, and is currently ongoing for similar
systems.


title:
A General Optimization Technique for High Quality Community Detection in
  Complex Networks

abstract:
  Recent years have witnessed the development of a large body of algorithms for
community detection in complex networks. Most of them are based upon the
optimization of objective functions, among which modularity is the most common,
though a number of alternatives have been suggested in the scientific
literature. We present here an effective general search strategy for the
optimization of various objective functions for community detection purposes.
When applied to modularity, on both real-world and synthetic networks, our
search strategy substantially outperforms the best existing algorithms in terms
of final scores of the objective function; for description length, its
performance is on par with the original Infomap algorithm. The execution time
of our algorithm is on par with non-greedy alternatives present in literature,
and networks of up to 10,000 nodes can be analyzed in time spans ranging from
minutes to a few hours on average workstations, making our approach readily
applicable to tasks which require the quality of partitioning to be as high as
possible, and are not limited by strict time constraints. Finally, based on the
most effective of the available optimization techniques, we compare the
performance of modularity and code length as objective functions, in terms of
the quality of the partitions one can achieve by optimizing them. To this end,
we evaluated the ability of each objective function to reconstruct the
underlying structure of a large set of synthetic and real-world networks.


title: Stochastic Optimization for Machine Learning

abstract:
  It has been found that stochastic algorithms often find good solutions much
more rapidly than inherently-batch approaches. Indeed, a very useful rule of
thumb is that often, when solving a machine learning problem, an iterative
technique which relies on performing a very large number of
relatively-inexpensive updates will often outperform one which performs a
smaller number of much "smarter" but computationally-expensive updates.
  In this thesis, we will consider the application of stochastic algorithms to
two of the most important machine learning problems. Part i is concerned with
the supervised problem of binary classification using kernelized linear
classifiers, for which the data have labels belonging to exactly two classes
(e.g. "has cancer" or "doesn't have cancer"), and the learning problem is to
find a linear classifier which is best at predicting the label. In Part ii, we
will consider the unsupervised problem of Principal Component Analysis, for
which the learning task is to find the directions which contain most of the
variance of the data distribution.
  Our goal is to present stochastic algorithms for both problems which are,
above all, practical--they work well on real-world data, in some cases better
than all known competing algorithms. A secondary, but still very important,
goal is to derive theoretical bounds on the performance of these algorithms
which are at least competitive with, and often better than, those known for
other approaches.


title: Complex rotation numbers

abstract:
  We investigate the notion of complex rotation number which was introduced by
V.I.Arnold in 1978. Let $f: \mathbb R/\mathbb Z \to \mathbb R/\mathbb Z$ be an
orientation preserving circle diffeomorphism and let $\omega \in \mathbb
C/\mathbb Z$ be a parameter with positive imaginary part. Construct a complex
torus by glueing the two boundary components of the annulus $\{z \in \mathbb
C/\mathbb Z \mid 0< \Im(z)< \Im({\omega})\}$ via the map $f+{\omega}$. This
complex torus is isomorphic to $\mathbb C/(\mathbb Z+{\tau} \mathbb Z)$ for
some appropriate ${\tau} \in \mathbb C/\mathbb Z$.
  According to Moldavskis (2001), if the ordinary rotation number
$\operatorname{rot} (f+\omega_0)$ is Diophantine and if ${\omega}$ tends to
$\omega_0$ non tangentially to the real axis, then ${\tau}$ tends to
$\operatorname{rot} (f+\omega_0)$. We show that the Diophantine and non
tangential assumptions are unnecessary: if $\operatorname{rot} (f+\omega_0)$ is
irrational then ${\tau}$ tends to $\operatorname{rot} (f+\omega_0)$ as
${\omega}$ tends to $\omega_0$.
  This, together with results of N.Goncharuk (2012), motivates us to introduce
a new fractal set, given by the limit values of ${\tau}$ as ${\omega}$ tends to
the real axis. For the rational values of $\operatorname{rot} (f+\omega_0)$,
these limits do not necessarily coincide with $\operatorname{rot} (f+\omega_0)$
and form a countable number of analytic loops in the upper half-plane.


title: Electromagnetic force distribution inside matter

abstract:
  Using the Finite Difference Time Domain method, we solve Maxwell's equations
numerically and compute the distribution of electromagnetic fields and forces
inside material media. The media are generally specified by their dielectric
permittivity epsilon(w) and magnetic permeability mu(w), representing small,
transparent dielectric and magnetic objects such as platelets and micro-beads.
Using two formulations of the electromagnetic force-density, one due to H. A.
Lorentz [Collected Papers 2, 164 (1892)], the other due to A. Einstein and J.
Laub [Ann, Phys. 331, 541 (1908)], we show that the force-density distribution
inside a given object can differ substantially between the two formulations.
This is remarkable, considering that the total force experienced by the object
is always the same, irrespective of whether the Lorentz or the Einstein-Laub
formula is employed. The differences between the two formulations should be
accessible to measurement in deformable objects.


title: Magnetooptical properties of (Ga,Fe)N layers

abstract:
  Magnetooptical properties of (Ga,Mn)N layers containing various
concentrations of Fe-rich nanocrystals embedded in paramagnetic (Ga,Fe)N layers
are reported. Previous studies of such samples demonstrated that magnetization
consists of a paramagnetic contribution due to substitutional diluted Fe ions
as well as of ferromagnetic and antiferromagnetic components originating from
Fe-rich nanocrystals, whose relative abundance can be controlled by the grow
conditions. The nanocrystals are found to broaden and to reduce the magnitude
of the excitonic features. However, the ferromagnetic contribution, clearly
seen in SQUID magnetometry, is not revealed by magnetic circular dichroism
(MCD). Possible reasons for differences in magnetic response determined by MCD
and SQUID measurements are discussed.


title:
Hidden Parameter Markov Decision Processes: A Semiparametric Regression
  Approach for Discovering Latent Task Parametrizations

abstract:
  Control applications often feature tasks with similar, but not identical,
dynamics. We introduce the Hidden Parameter Markov Decision Process (HiP-MDP),
a framework that parametrizes a family of related dynamical systems with a
low-dimensional set of latent factors, and introduce a semiparametric
regression approach for learning its structure from data. In the control
setting, we show that a learned HiP-MDP rapidly identifies the dynamics of a
new task instance, allowing an agent to flexibly adapt to task variations.


title:
Evidence of Increased UV FeII Emission in Quasars in Candidate Overdense
  Regions

abstract:
  We present evidence for a skewed distribution of UV FeII emission in quasars
within candidate overdense regions spanning spatial scales of ~ 50 Mpc at 1.11
< z < 1.67, compared to quasars in field environments at comparable redshifts.
The overdense regions have an excess of high equivalent width sources (W2400 >
42 \AA), and a dearth of low equivalent width sources. There are various
possible explanations for this effect, including dust, Ly\alpha fluorescence,
microturbulence, and iron abundance. We find that the most plausible of these
is enhanced iron abundance in the overdense regions, consistent with an
enhanced star formation rate in the overdense regions compared to the field.


title:
Constraints on WIMP Annihilation for Contracted Dark Matter in the Inner
  Galaxy with the Fermi-LAT

abstract:
  We derive constraints on parameters of generic dark matter candidates by
comparing theoretical predictions with the gamma-ray emission observed by the
Fermi-LAT from the region around the Galactic Center. Our analysis is
conservative since it simply requires that the expected dark matter signal does
not exceed the observed emission. The constraints obtained in the likely case
that the collapse of baryons to the Galactic Center is accompanied by the
contraction of the dark matter are strong. In particular, we find that for bb
and \tau+\tau- or W+W- dark matter annihilation channels, the upper limits on
the annihilation cross section imply that the thermal cross section is excluded
for a Weakly Interacting Massive Particle (WIMP) mass smaller than about 700
and 500 GeV, respectively. For the \mu+ \mu- channel, where the effect of the
inverse Compton scattering is important, depending on models of the Galactic
magnetic field the exclusion of the thermal cross-section is for a WIMP mass
smaller than about 150 to 400 GeV. The upper limits on the annihilation cross
section of dark matter particles obtained are two orders of magnitude stronger
than without contraction. In the latter case our results are compatible with
the upper limits from the Galactic halo analysis reported by the Fermi-LAT
collaboration for the case in which the same conservative approach without
modeling of the astrophysical background is employed.


title: Transmission statistics in nonconservative disordered optical medium

abstract:
  We determine the cumulants of electromagnetic energy transmitted through
one-dimensional disordered medium with absorption or amplification. For this
purpose we derive the Keldysh nonlinear sigma-model action with a source term
that generates the energy current fluctuations. The fluctuations over the
ensemble of disorder realizations are found to decrease (increase) with
increasing absorption (amplification). In the conservative medium the
fluctuations can be related to the Dorokhov's distribution of transmission
coefficients.


title: Bridging Physics and Biology Teaching through Modeling

abstract:
  As the frontiers of biology become increasingly interdisciplinary, the
physics education community has engaged in ongoing efforts to make physics
classes more relevant to life sciences majors. These efforts are complicated by
the many apparent differences between these fields, including the types of
systems that each studies, the behavior of those systems, the kinds of
measurements that each makes, and the role of mathematics in each field.
Nonetheless, physics and biology are both sciences that rely on observations
and measurements to construct models of the natural world. In the present
theoretical article, we propose that efforts to bridge the teaching of these
two disciplines must emphasize shared scientific practices, particularly
scientific modeling. We define modeling using language common to both
disciplines and highlight how an understanding of the modeling process can help
reconcile apparent differences between the teaching of physics and biology. We
elaborate how models can be used for explanatory, predictive, and functional
purposes and present common models from each discipline demonstrating key
modeling principles. By framing interdisciplinary teaching in the context of
modeling, we aim to bridge physics and biology teaching and to equip students
with modeling competencies applicable across any scientific discipline.


title:
Uniform estimates for bilinear Hilbert transform and bilinear maximal
  functions associated to polynomials

abstract:
  We study the bilinear Hilbert transform and bilinear maximal functions
associated to polynomial curves and obtain uniform $L^r$ estimates for
$r>\frac{d-1}{d}$ and this index is sharp up to the end point.


title:
Statistical measure of complexity in compact stars with global charge
  neutrality

abstract:
  Recently, it has been suggested that a critical electrical field arises
during the gravitational collapse of massive stars leading to a vacuum
polarization. This, in turn, leads to the necessity of a reexamination of the
gravito-electrodynamical properties of compact stars of the class of neutron
stars. Rotondo, Rueda, Ruffini and Xue claim to have proved the impossibility
of local charge neutrality and then solved the coupled system of the general
relativistic Thomas-Fermi-Einstein-Maxwell equations for the structure of
neutron stars. Within the same approach of Avellar and Horvath (2012) we have
calculated how the global neutrality hypothesis affects the order/disorder of
these systems for a simple equation of state. We show the relative preference
of local vs. global conservation in terms of the obtained information content
of the systems under consideration.


title: Fixed-Parameter and Approximation Algorithms: A New Look

abstract:
  A Fixed-Parameter Tractable (\FPT) $\rho$-approximation algorithm for a
minimization (resp. maximization) parameterized problem $P$ is an FPT algorithm
that, given an instance $(x, k)\in P$ computes a solution of cost at most $k
\cdot \rho(k)$ (resp. $k/\rho(k)$) if a solution of cost at most (resp. at
least) $k$ exists; otherwise the output can be arbitrary. For well-known
intractable problems such as the W[1]-hard {Clique} and W[2]-hard {Set Cover}
problems, the natural question is whether we can get any \FPT-approximation. It
is widely believed that both {Clique} and {Set-Cover} admit no FPT
$\rho$-approximation algorithm, for any increasing function $\rho$. Assuming
standard conjectures such as the Exponential Time Hypothesis (ETH)
\cite{eth-paturi} and the Projection Games Conjecture (PGC) \cite{r3}, we make
the first progress towards proving this conjecture by showing that
  1. Under the ETH and PGC, there exist constants $F_1, F_2 >0$ such that the
{Set Cover} problem does not admit an FPT approximation algorithm with ratio
$k^{F_1}$ in $2^{k^{F_2}}\cdot \text{poly}(N,M)$ time, where $N$ is the size of
the universe and $M$ is the number of sets.
  2. Unless $\NP\subseteq \SUBEXP$, for every $1> \delta > 0$ there exists a
constant $F(\delta)>0$ such that {Clique} has no FPT cost approximation with
ratio $k^{1-\delta}$ in $2^{k^{F}}\cdot \text{poly}(n)$ time, where $n$ is the
number of vertices in the graph.
  In the second part of the paper we consider various W[1]-hard problems such
as {\dst}, {\dsf}, Directed Steiner Network and {\mec}. For all these problem
we give polynomial time $f(\text{OPT})$-approximation algorithms for some small
function $f$ (the largest approximation ratio we give is $\text{OPT}^2$).


title: A New Distributed DC-Programming Method and its Applications

abstract:
  We propose a novel decomposition framework for the distributed optimization
of Difference Convex (DC)-type nonseparable sum-utility functions subject to
coupling convex constraints. A major contribution of the paper is to develop
for the first time a class of (inexact) best-response-like algorithms with
provable convergence, where a suitably convexified version of the original DC
program is iteratively solved. The main feature of the proposed successive
convex approximation method is its decomposability structure across the users,
which leads naturally to distributed algorithms in the primal and/or dual
domain. The proposed framework is applicable to a variety of multiuser DC
problems in different areas, ranging from signal processing, to communications
and networking. As a case study, in the second part of the paper we focus on
two examples, namely: i) a novel resource allocation problem in the emerging
area of cooperative physical layer security; ii) and the renowned sum-rate
maximization of MIMO Cognitive Radio networks. Our contribution in this context
is to devise a class of easy-to-implement distributed algorithms with provable
convergence to stationary solution of such problems. Numerical results show
that the proposed distributed schemes reach performance close to (and sometimes
better than) that of centralized methods.


title: An all-optical feedback assisted steady state of an optomechanical array

abstract:
  We explore the effect of all-optical feedback on the steady state dynamics of
optomechanical arrays arising from various topologies. First we consider an
array comprised of a pair of independent optomechanical cavities coupled
reversibly via their optical modes. Next we consider an optomechanical network
formed from coupling two optical modes with interactions mediated via a common
mechanical mode. Finally we extend the analysis to a large network of N-coupled
optomechanical systems. Our results show implementing an-all optical feedback
loop in each arrangement can enhance the degree of steady state entanglement
between inter cavity optical and mechanical modes.


title: Decay of fermionic quasiparticles in one-dimensional quantum liquids

abstract:
  The low-energy properties of one-dimensional quantum liquids are commonly
described in terms of the Tomonaga-Luttinger liquid theory, in which the
elementary excitations are free bosons. To this approximation the theory can be
alternatively recast in terms of free fermions. In both approaches, small
perturbations give rise to finite lifetimes of excitations. We evaluate the
decay rate of fermionic excitations and show that it scales as the eighth power
of energy, in contrast to the much faster decay of bosonic excitations. Our
results can be tested experimentally by measuring the broadening of power-law
features in the density structure factor or spectral functions.


title:
Innovative Second-Generation Wavelets Construction With Recurrent Neural
  Networks for Solar Radiation Forecasting

abstract:
  Solar radiation prediction is an important challenge for the electrical
engineer because it is used to estimate the power developed by commercial
photovoltaic modules. This paper deals with the problem of solar radiation
prediction based on observed meteorological data. A 2-day forecast is obtained
by using novel wavelet recurrent neural networks (WRNNs). In fact, these WRNNS
are used to exploit the correlation between solar radiation and
timescale-related variations of wind speed, humidity, and temperature. The
input to the selected WRNN is provided by timescale-related bands of wavelet
coefficients obtained from meteorological time series. The experimental setup
available at the University of Catania, Italy, provided this information. The
novelty of this approach is that the proposed WRNN performs the prediction in
the wavelet domain and, in addition, also performs the inverse wavelet
transform, giving the predicted signal as output. The obtained simulation
results show a very low root-mean-square error compared to the results of the
solar radiation prediction approaches obtained by hybrid neural networks
reported in the recent literature.


title:
Direct test of the AdS/CFT correspondence by Monte Carlo studies of N=4
  super Yang-Mills theory

abstract:
  We perform nonperturbative studies of N=4 super Yang-Mills theory by Monte
Carlo simulation. In particular, we calculate the correlation functions of
chiral primary operators to test the AdS/CFT correspondence. Our results agree
with the predictions obtained from the AdS side that the SUSY
non-renormalization property is obeyed by the three-point functions but
\emph{not} by the four-point functions investigated in this paper. Instead of
the lattice regularization, we use a novel regularization of the theory based
on an equivalence in the large-N limit between the N=4 SU(N) theory on RxS^3
and a one-dimensional SU(N) gauge theory known as the plane-wave (BMN) matrix
model. The equivalence extends the idea of large-N reduction to a curved space
and, at the same time, overcomes the obstacle related to the center symmetry
breaking. The adopted regularization preserves 16 SUSY, which is crucial in
testing the AdS/CFT correspondence with the available computer resources. The
only SUSY breaking effects, which come from the momentum cutoff $\Lambda$ in R
direction, are made negligible by using sufficiently large $\Lambda$.


title:
Twist-bend heliconical chiral nematic liquid crystal phase of an achiral
  rigid bent-core mesogen

abstract:
  The chiral, heliconical (twist-bend) nematic ground state is reported in an
achiral, rigid, bent-core mesogen (UD68). Similar to the nematic twist-bend
(NTB) phase observed in bent molecular dimers, the NTB phase of UD68 forms
macroscopic, smectic-like focal-conic textures and exhibits nanoscale, periodic
modulation with no associated modulation of the electron density, i.e., without
a detectable lamellar x-ray reflection peak. The NTB helical pitch is pTB ~ 14
nm. When an electric field is applied normal to the helix axis, a weak
electroclinic effect is observed, revealing 50 um-scale left- and right-handed
domains in a chiral conglomerate.


title:
Exponential Quantum Spreading in a Class of Kicked Rotor Systems near
  High-Order Resonances

abstract:
  Long-lasting quantum exponential spreading was recently found in a simple but
very rich dynamical model, namely, an on-resonance double-kicked rotor model
[J. Wang, I. Guarneri, G. Casati, and J. B. Gong, Phys. Rev. Lett. 107, 234104
(2011)]. The underlying mechanism, unrelated to the chaotic motion in the
classical limit but resting on quasi-integrable motion in a pseudoclassical
limit, is identified for one special case. By presenting a detailed study of
the same model, this work offers a framework to explain long-lasting quantum
exponential spreading under much more general conditions. In particular, we
adopt the so-called "spinor" representation to treat the kicked-rotor dynamics
under high-order resonance conditions and then exploit the Born-Oppenheimer
approximation to understand the dynamical evolution. It is found that the
existence of a flat-band (or an effectively flat-band) is one important feature
behind why and how the exponential dynamics emerges. It is also found that a
quantitative prediction of the exponential spreading rate based on an
interesting and simple pseudoclassical map may be inaccurate. In addition to
general interests regarding the question of how exponential behavior in quantum
systems may persist for a long time scale, our results should motivate further
studies towards a better understanding of high-order resonance behavior in
delta-kicked quantum systems.


title:
Resonance asymptotics for asymptotically hyperbolic manifolds with
  warped-product ends

abstract:
  We study the spectral theory of asymptotically hyperbolic manifolds with ends
of warped product type. Our main result is an upper bound on the resonance
counting function with a geometric constant expressed in terms of the
respective Weyl constants for the core of the manifold and the base manifold
defining the ends.


title: Quantum Lakshmibai-Seshadri paths and root operators

abstract:
  We give an explicit description of the image of a quantum LS path, regarded
as a rational path, under the action of root operators, and show that the set
of quantum LS paths is stable under the action of the root operators. As a
by-product, we obtain a new proof of the fact that a projected level-zero LS
path is just a quantum LS path.


title: The number of edges of the edge polytope of a finite simple graph

abstract:
  Let $d \geq 3$ be an integer. It is known that the number of edges of the
edge polytope of the complete graph with $d$ vertices is $d(d-1)(d-2)/2$. In
this paper, we study the maximum possible number $\mu_d$ of edges of the edge
polytope arising from finite simple graphs with $d$ vertices. We show that
$\mu_{d}=d(d-1)(d-2)/2$ if and only if $3 \leq d \leq 14$. In addition, we
study the asymptotic behavior of $\mu_d$. Tran--Ziegler gave a lower bound for
$\mu_d$ by constructing a random graph. We succeeded in improving this bound by
constructing both a non-random graph and a random graph whose complement is
bipartite.


title:
The SLUGGS Survey: outer triaxiality of the Fast Rotator elliptical NGC
  4473

abstract:
  Systematic surveys of nearby early type galaxies (ETGs) using integral field
unit spectrograph (IFU) data have revealed that galaxies can hide interesting
structures only visible through kinematic studies. As part of their pioneering
work, the ATLAS3D team have shown that most morphologically elliptical galaxies
are centrally kinematically disk-like. Hence, while global morphology suggests
that ellipticals are ellipsoidal/triaxial in shape, their central kinematics
may be consistent with (inclined) oblate systems.
  Here we study the Fast Rotator elliptical galaxy: NGC 4473. Using slitlets,
we obtain galaxy light kinematics out to unprecedentedly large galactocentric
radii (2.5 effective radii). While we confirm the IFU results in the central
regions, we find that at large galactocentric radii NGC 4473 exhibits a
kinematic transition. In the outskirts, we observe clear minor and major axis
rotation, a tell-tale sign of triaxiality, which agrees well with the galaxy's
Hubble type.
  This outer "kinematically distinct halo" (KDH) may be expected from
simulations of galaxy formation, and in this system contains around one-third
of the stellar light. While this galaxy may be a special case, it suggests
further investigation of the outskirts of galaxies is needed to confirm the new
paradigm of galaxy classification.


title: Plasmonic generation of spin currents

abstract:
  Surface plasmons, free-electron collective oscillations in metallic
nanostructures, provide abundant routes to manipulate light-electron
interactions that can localize light energy and alter electromagnetic field
distributions at subwavelength scales. The research field of plasmonics thus
integrates nano-photonics with electronics. In contrast, electronics is also
entering a new era of spintronics, where spin currents play a central role in
driving devices. However, plasmonics and spin-current physics have so far been
developed independently. Here, we demonstrate the generation of spin currents
by surface plasmons. Using Au nanoparticles embedded in a Pt/BiY2Fe5O12 bilayer
film, we show that, when the Au nanoparticles fulfill the
surface-plasmon-resonance condition, spin currents are generated across the
Pt/BiY2Fe5O12 interface. This plasmonic spin pumping results from
nonequilibrium states of spins excited by surface-plasmon-induced evanescent
electromagnetic fields in the BiY2Fe5O12 layer. Such plasmonic spin pumping
will invigorate research on spin-current physics, and pave the way for future
spin-based plasmonic devices.


title:
On Uniform Positivity of Transition Densities of Small Noise Constrained
  Diffusions

abstract:
  Constrained diffusions in convex polyhedral domains with a general oblique
reflection field, and with a diffusion coefficient scaled by a small parameter,
are considered. Using an interior Dirichlet heat kernel lower bound estimate
for second order elliptic operators in bounded domains from [13], certain
uniform in the scaling parameter lower bounds on transition densities of such
constrained diffusions are established. These lower bounds together with
results from [1] give, under additional stability conditions, an exponential
leveling property, as the scaling parameter approaches zero, for exit times
from suitable bounded domains.


title:
Molecular theory for the phase equilibria and cluster distribution of
  associating fluids with small bond angles

abstract:
  We develop a new theory for associating fluids with multiple association
sites. The theory accounts for small bond angle effects such as steric
hindrance, ring formation and double bonding. The theory is validated against
monte carlo simulations for the case of a fluid of patchy colloid particles
with three patches and is found to be very accurate. Once validated, the theory
is applied to study the phase diagram of a fluid composed of three patch
colloids. It is found that bond angle has a significant effect on the phase
diagram and the very existence of a liquid - vapor transition.


title: Shape of matchbox manifolds

abstract:
  In this work, we develop shape expansions of minimal matchbox manifolds
without holonomy, in terms of branched manifolds formed from their leaves. Our
approach is based on the method of coding the holonomy groups for the foliated
spaces, to define leafwise regions which are transversely stable and are
adapted to the foliation dynamics. Approximations are obtained by collapsing
appropriately chosen neighborhoods onto these regions along a "transverse
Cantor foliation". The existence of the "transverse Cantor foliation" allows us
to generalize standard techniques known for Euclidean and fibered cases to
arbitrary matchbox manifolds with Riemannian leaf geometry and without
holonomy. The transverse Cantor foliations used here are constructed by purely
intrinsic and topological means, as we do not assume that our matchbox
manifolds are embedded into a smooth foliated manifold, or a smooth manifold.


title: Evasion Paths in Mobile Sensor Networks

abstract:
  Suppose that ball-shaped sensors wander in a bounded domain. A sensor doesn't
know its location but does know when it overlaps a nearby sensor. We say that
an evasion path exists in this sensor network if a moving intruder can avoid
detection. In "Coordinate-free coverage in sensor networks with controlled
boundaries via homology", Vin deSilva and Robert Ghrist give a necessary
condition, depending only on the time-varying connectivity data of the sensors,
for an evasion path to exist. Using zigzag persistent homology, we provide an
equivalent condition that moreover can be computed in a streaming fashion.
However, no method with time-varying connectivity data as input can give
necessary and sufficient conditions for the existence of an evasion path.
Indeed, we show that the existence of an evasion path depends not only on the
fibrewise homotopy type of the region covered by sensors but also on its
embedding in spacetime. For planar sensors that also measure weak rotation and
distance information, we provide necessary and sufficient conditions for the
existence of an evasion path.


title: Curve Shortening Flow and Smooth Projective Planes

abstract:
  In this paper, we study a family of curves on $S^2$ that defines a
two-dimensional smooth projective plane. We use curve shortening flow to prove
that any two-dimensional smooth projective plane can be smoothly deformed
through a family of smooth projective planes into one which is isomorphic to
the real projective plane. In addition, as a consequence of our main result, we
show that any two smooth embedded curves on $RP^2$ which intersect
transversally at exactly one point converge to two different geodesics under
the flow.


title:
New Method to Improve the Accelerating Gradient of Superconducting
  Cavity

abstract:
  Quench is a common phenomenon in a superconducting cavity and often limits
the accelerating gradient of the cavity. Accurate location of the quench site
can be located by second sound detection. For multi-cell superconducting
cavity, one defect may cause the cell with defect quenches and then the whole
cavity quenches. Now we proposed a new method to eliminate the bad influence of
the quench cell to the whole cavity.


title: Quantum Criticality in Electron-doped BaFe_{2-x}Ni_xAs_2

abstract:
  A quantum critical point (QCP) is a point in a system's phase diagram at
which an order is completely suppressed at absolute zero temperature (T). The
presence of a quantum critical point manifests itself in the finite-T physical
properties, and often gives rise to new states of matter. Superconductivity in
the cuprates and in heavy fermion materials is believed by many to be mediated
by fluctuations associated with a quantum critical point. In the
recently-discovered iron-pnictide high temperature superconductors, it is
unknown whether a QCP exists or not in a carrier-doped system. Here we report
transport and nuclear magnetic resonance (NMR) measurements on
BaFe_{2-x}Ni_xAs_2 (0 =< x =< 0.17). We find two critical points at x_{c1} =
0.10 and x_{c2} = 0.14. The electrical resistivity follows \rho = \rho_0 +
A*T^n, with n = 1 around x_{c1} and another minimal n = 1.1 at x_{c2}. By NMR
measurements, we identity x_{c1} to be a magnetic QCP and suggest that x_{c2}
is a new type of QCP associated with a nematic structural phase transition. Our
results suggest that the superconductivity in carrier-doped pnictides is
closely linked to the quantum criticality.


title: Disproving Heisenberg's error-disturbance relation

abstract:
  Recently, Busch, Lahti, and Werner (arXiv:1306.1565v1 [quant-ph]) claimed
that Heisenberg's error-disturbance relation can be proved in its original form
with new formulations of error and disturbance, in contrast to the theory
proposed by the present author and confirmed by recent experiments. Despite
their claim, it is shown here that a class of solvable models of position
measurement with explicit interaction Hamiltonians escape the
Busch-Lahti-Werner relation. It is also made clear where their proof fails.
Those models have unambiguously defined zero root-mean-square error and finite
root-mean-square disturbance in every input state and are naturally considered
to violate Heisenberg's error-disturbance relation in any conceivable
formulation.


title:
Knapsack Constrained Contextual Submodular List Prediction with
  Application to Multi-document Summarization

abstract:
  We study the problem of predicting a set or list of options under knapsack
constraint. The quality of such lists are evaluated by a submodular reward
function that measures both quality and diversity. Similar to DAgger (Ross et
al., 2010), by a reduction to online learning, we show how to adapt two
sequence prediction models to imitate greedy maximization under knapsack
constraint problems: CONSEQOPT (Dey et al., 2012) and SCP (Ross et al., 2013).
Experiments on extractive multi-document summarization show that our approach
outperforms existing state-of-the-art methods.


title:
The equivalence of information-theoretic and likelihood-based methods
  for neural dimensionality reduction

abstract:
  Stimulus dimensionality-reduction methods in neuroscience seek to identify a
low-dimensional space of stimulus features that affect a neuron's probability
of spiking. One popular method, known as maximally informative dimensions
(MID), uses an information-theoretic quantity known as "single-spike
information" to identify this space. Here we examine MID from a model-based
perspective. We show that MID is a maximum-likelihood estimator for the
parameters of a linear-nonlinear-Poisson (LNP) model, and that the empirical
single-spike information corresponds to the normalized log-likelihood under a
Poisson model. This equivalence implies that MID does not necessarily find
maximally informative stimulus dimensions when spiking is not well described as
Poisson. We provide several examples to illustrate this shortcoming, and derive
a lower bound on the information lost when spiking is Bernoulli in discrete
time bins. To overcome this limitation, we introduce model-based dimensionality
reduction methods for neurons with non-Poisson firing statistics, and show that
they can be framed equivalently in likelihood-based or information-theoretic
terms. Finally, we show how to overcome practical limitations on the number of
stimulus dimensions that MID can estimate by constraining the form of the
non-parametric nonlinearity in an LNP model. We illustrate these methods with
simulations and data from primate visual cortex.


title:
Resonance Identities for Closed Characteristics on Compact Star-shaped
  Hypersurfaces in ${\bf R}^{2n}$

abstract:
  Resonance relations among periodic orbits on given energy hypersurfaces are
very important for getting deeper understanding of the dynamics of the
corresponding Hamiltonian systems. In this paper, we establish two new
resonance identities for closed characteristics on every compact star-shaped
hypersurface $\Sigma$ in ${\bf R}^{2n}$ when the number of geometrically
distinct closed characteristics on $\Sigma$ is finite, which extend those
identities established by C. Viterbo in 1989 for star-shaped hypersurfaces
assuming in addition that all the closed characteristics and their iterates are
non-degenerate, and that by W. Wang, X. Hu and Y. Long in 2007 for strictly
convex hypersurfaces in ${\bf R}^{2n}$.


title:
Large-scale Coronal Propagating Fronts in Solar Eruptions as Observed by
  the Atmospheric Imaging Assembly on Board the Solar Dynamics
  Observatory\,--\,An Ensemble Study

abstract:
  This paper presents a study of a large sample of global disturbances in the
solar corona with characteristic propagating fronts as intensity enhancement,
similar to the phenomena that have often been referred to as EIT waves or EUV
waves. Now Extreme Ultraviolet (EUV) images obtained by the {\it Atmospheric
Imaging Assembly} (AIA) on board the {\it Solar Dynamics Observatory} (SDO)
provide a significantly improved view of these large-scale coronal propagating
fronts (LCPFs). Between April 2010 and January 2013, a total of 171 LCPFs have
been identified through visual inspection of AIA images in the 193 \AA\
channel. Here we focus on the 138 LCPFs that are seen to propagate across the
solar disk, first studying how they are associated with flares, coronal mass
ejections (CMEs) and type II radio bursts. We measure the speed of the LCPF in
various directions until it is clearly altered by active regions or coronal
holes. The highest speed is extracted for each LCPF. It is often considerably
higher than EIT waves. We do not find a pattern where faster LCPFs decelerate
and slow LCPFs accelerate. Furthermore, the speeds are not strongly correlated
with the flare intensity or CME magnitude, nor do they show an association with
type II bursts. We do not find a good correlation either between the speeds of
LCPFs and CMEs in a subset of 86 LCPFs observed by one or both of the {\it
Solar and Terrestrial Relations Observatory} (STEREO) spacecraft as limb
events.


title: Nonlocal cancellation of dispersion in Franson interferometry

abstract:
  Dispersion and its cancellation in entanglement-based nonlocal quantum
measurements are of fundamental and practical interests. We report the first
demonstration of cancellation of femtosecond-level dispersion by inverting the
sign of the differential dispersion between the long and short paths in only
one arm of a fiber-based Franson interferometer. We restore the otherwise
limited quantum visibility to an unprecedented 99.6%, and put time-energy
entanglement at the same level of quality as polarization entanglement for use
in quantum information processing applications.


title:
KAM rigidity for partially hyperbolic affine Z^k actions on the torus
  with a rank one factor

abstract:
  We show that ergodic affine abelian discrete actions on the torus, that have
a rank-one factor in their linear part, are locally rigid in a KAM sense if and
only if the rank one factor is trivial and the action is higher-rank
transversally to this factor. Since it has been proved by Damjanovic and Katok
that affine actions with higher-rank linear part are locally rigid, our result
completes the local rigidity picture for affine actions on the torus.


title:
Disk Inhomogeneities and the Origins of Planetary System Architectures
  and Observational Properties

abstract:
  Recent high-resolution observations show that protoplanetary disks have
various kinds of structural properties or inhomogeneities. These are the
consequence of a mixture of a number of physical and chemical processes taking
place in the disks. Here, we discuss the results of our comprehensive
investigations on how disk inhomogeneities affect planetary migration. We
demonstrate that disk inhomogeneities give rise to planet traps - specific
sites in protoplanetary disks at which rapid type I migration is halted. We
show that up to three types of traps (heat transitions, ice lines and dead
zones) can exist in a single disk, and that they move differently as the disk
accretion rate decreases with time. We also demonstrate that the position of
planet traps strongly depends on stellar masses and disk accretion rates. This
indicates that host stars establish preferred (initial) scales of their
planetary systems. Finally, we discuss the possible observational signatures of
disk inhomogeneities.


title:
Distributed Ranging and Localization for Wireless Networks via
  Compressed Sensing

abstract:
  Location-based services in a wireless network require nodes to know their
locations accurately. Conventional solutions rely on contention-based medium
access, where only one node can successfully transmit at any time in any
neighborhood. In this paper, a novel, complete, distributed ranging and
localization solution is proposed, which let all nodes in the network broadcast
their location estimates and measure distances to all neighbors simultaneously.
An on-off signaling is designed to overcome the physical half-duplex
constraint. In each iteration, all nodes transmit simultaneously, each
broadcasting codewords describing the current location estimate. From the
superposed signals from all neighbors, each node decodes their neighbors'
locations and also estimates their distances using the signal strengths. The
node then broadcasts its improved location estimates in the subsequent
iteration. Simulations demonstrate accurate localization throughout a large
network over a few thousand symbol intervals, suggesting much higher efficiency
than conventional schemes based on ALOHA or CSMA.


title: Dynamical Constraints on Exoplanets

abstract:
  Dynamical studies of new exoplanet systems are a critical component of the
discovery and characterisation process. Such studies can provide firmer
constraints on the parameters of the newly discovered planets, and may even
reveal that the proposed planets do not stand up to dynamical scrutiny. Here,
we demonstrate how dynamical studies can assist the characterisation of such
systems through two examples: QS Virginis and HD 73526.


title:
Direct Search for Right-handed Neutrinos and Neutrinoless Double Beta
  Decay

abstract:
  We consider an extension of the Standard Model by two right-handed neutrinos,
especially with masses lighter than charged $K$ meson. This simple model can
realize the seesaw mechanism for neutrino masses and also the baryogenesis by
flavor oscillations of right-handed neutrinos. We summarize the constraints on
right-handed neutrinos from direct searches as well as the big bang
nucleosynthesis. It is then found that the possible range for the
quasi-degenerate mass of right-handed neutrinos is $M_N \geq 163 \MeV$ for
normal hierarchy of neutrino masses, while $M_N = 188 \text{--} 269 \MeV$ and
$M_N \geq 285 \MeV$ for inverted hierarchy case. Furthermore, we find in the
latter case that the possible value of the Majorana phase is restricted for
$M_N = 188 \text{--} 350 \MeV$, which leads to the fact that the rate of
neutrinoless double beta decay is also limited.


title: Window effect in the power spectrum analysis of a galaxy redshift survey

abstract:
  We investigate the effect of the window function on the multipole power
spectrum in two different ways. First, we consider the convolved power spectrum
including the window effect, which is obtained by following the familiar (FKP)
method developed by Feldman, Kaiser and Peacock. We show how the convolved
multipole power spectrum is related to the original power spectrum, using the
multipole moments of the window function. Second, we investigate the
deconvolved power spectrum, which is obtained by using the Fourier
deconvolution theorem. In the second approach, we measure the multipole power
spectrum deconvolved from the window effect. We demonstrate how to deal with
the window effect in these two approaches, applying them to the Sloan Digital
Sky Survey (SDSS) luminous red galaxy (LRG) sample.


title:
Towards dynamical network biomarkers in neuromodulation of episodic
  migraine

abstract:
  Computational methods have complemented experimental and clinical
neursciences and led to improvements in our understanding of the nervous
systems in health and disease. In parallel, neuromodulation in form of electric
and magnetic stimulation is gaining increasing acceptance in chronic and
intractable diseases. In this paper, we firstly explore the relevant state of
the art in fusion of both developments towards translational computational
neuroscience. Then, we propose a strategy to employ the new theoretical concept
of dynamical network biomarkers (DNB) in episodic manifestations of chronic
disorders. In particular, as a first example, we introduce the use of
computational models in migraine and illustrate on the basis of this example
the potential of DNB as early-warning signals for neuromodulation in episodic
migraine.


title:
Application of Analog Network Coding to MIMO Two-Way Relay Channel in
  Cellular Systems

abstract:
  An efficient analog network coding transmission protocol is proposed in this
letter for a MIMO two way cellular network. Block signal alignment is first
proposed to null the inter-user interference for multi-antenna users, which
makes the dimensions of aligned space larger compared with the existing signal
alignment. Two algorithms are developed to jointly design the precoding
matrices at the relay and BS for outage optimization. Especially, the last
algorithm is designed to maximize the effective channel gain to the effective
noise gain ratio. The performance of this transmission protocol is also
verified by simulations.


title: Source Code Retrieval Using Sequence Based Similarity

abstract:
  Duplicated code has a negative impact on the quality of software systems and
should be detected at least. In this paper, we discuss an approach that
improves source code retrieval using the structural information about the
programs. We developed a lexical parser to extract control statements and
method identifiers from Java programs. We propose a similarity measure that is
defined by the ratio of the number of sequentially full matching statements to
the number of sequentially partial matching ones. The similarity measure is
considered to be an extension of a set based similarity index, e.g.,
Sorensen-Dice index. Our key contribution of this research is the development
of a similarity retrieval algorithm that derives meaningful search conditions
from a given sequence, and then performs retrieval using all of the derived
conditions. Experiments show that our retrieval model outperforms the other
retrieval models up to 90.9% in the number of retrieved methods.


title: Photodetachment near a repulsive center

abstract:
  We study the total photodetachment cross section of H$^-$ near a repulsive
center. An analytical formula for the photodetachment cross section is obtained
using the standard closed-orbit theory and extending it to the energy range
below the zero-field threshold. The formula is found to be accurate by
comparing with an exact quantum calculation. A comparison with the
photodetachment cross section in an effective homogeneous electric field is
made, and we discuss the similarities and differences of the two systems.


title:
Appreciable magnetic moment and energy density in single step normal
  route synthesized MnBi

abstract:
  We study the structural and magnetic properties of the MnBi inter-metallic
compound. The LTP (Low Temperature Phase) MnBi compound is successfully
synthesized in single step by vacuum encapsulation technique and rapid
quenching from phase formation temperature. The phase purity and the magnetic
moments of MnBi are highly dependent on heat treating schedule. The best phase
purity and the magnetic moment are found for a sample heat treated at 310oC for
48h. Rietveld fitted X-ray diffraction (XRD) patterns revealed that the studied
MnBi compound is crystallized in hexagonal P63/mmc space group with minute
presence of unreacted Bi and Mn phases. The scanning electron microscopy (SEM)
study is carried out to visualize the grains morphology and phase
identification. The bulk MnBi powder showed appreciable magnetic moment of
(62emu/g at 6Tesla) and maximum energy product (BHmax of 4.01MGOe at 6Tesla).
The magnetic properties of synthesized MnBi show that it could be a potential
candidate for rare earth free permanent magnets.


title: Electrical and Magnetic behaviour of PrFeAsO0.8F0.2 superconductor

abstract:
  The superconducting and ground state samples of PrFeAsO0.8F0.2 and PrFeAsO
have been synthesised via easy and versatile single step solid state reaction
route. X-ray & Reitveld refine parameters of the synthesised samples are in
good agreement to the earlier reported value of the structure. The ground state
of the pristine compound (PrFeAsO) exhibited a metallic like step in
resistivity below 150K followed by another step at 12K. The former is
associated with the spin density wave (SDW) like ordering of Fe spins and later
to the anomalous magnetic ordering for Pr moments. Both the resistivity
anomalies are absent in case of superconducting PrFeAsO0.8F0.2 sample. Detailed
high field (up to 12Tesla) electrical and magnetization measurements are
carried out for superconducting PrFeAsO0.8F0.2 sample. The PrFeAsO0.8F0.2
exhibited superconducting onset (Tconset) at around 47K with Tc({\rho} =0) at
38K. Though the Tconset remains nearly invariant, the Tc({\rho} =0) is
decreased with applied field, and the same is around 23K under applied field of
12Tesla. The upper critical field (Hc2) is estimated from the Ginzburg Landau
equation (GL) fitting, which is found to be ~ 182Tesla. Critical current
density (Jc) being calculated from high field isothermal magnetization (MH)
loops with the help of Beans critical state model, is found to be of the order
of 103 A/cm2. Summarily, the superconductivity characterization of single step
synthesised PrFeAsO0.8F0.2 superconductor is presented.


title: Fast Stochastic Alternating Direction Method of Multipliers

abstract:
  In this paper, we propose a new stochastic alternating direction method of
multipliers (ADMM) algorithm, which incrementally approximates the full
gradient in the linearized ADMM formulation. Besides having a low per-iteration
complexity as existing stochastic ADMM algorithms, the proposed algorithm
improves the convergence rate on convex problems from $O(\frac 1 {\sqrt{T}})$
to $O(\frac 1 T)$, where $T$ is the number of iterations. This matches the
convergence rate of the batch ADMM algorithm, but without the need to visit all
the samples in each iteration. Experiments on the graph-guided fused lasso
demonstrate that the new algorithm is significantly faster than
state-of-the-art stochastic and batch ADMM algorithms.


title: Timing Analysis of SSL/TLS Man in the Middle Attacks

abstract:
  Man in the middle attacks are a significant threat to modern e-commerce and
online communications, even when such transactions are protected by TLS. We
intend to show that it is possible to detect man-in-the-middle attacks on SSL
and TLS by detecting timing differences between a standard SSL session and an
attack we created.


title:
UV-excess sources with a red/IR-counterpart: low-mass companions, debris
  disks and QSO selection

abstract:
  We present the result of the cross-matching between UV-excess sources
selected from the UV-excess survey of the Northern Galactic Plane (UVEX) and
several infrared surveys (2MASS, UKIDSS and WISE). From the position in the
(J-H) vs. (H-K) colour-colour diagram we select UV-excess candidate white
dwarfs with an M-dwarf type companion, candidates that might have a lower mass,
brown-dwarf type companion, and candidates showing an infrared-excess only in
the K-band, which might be due to a debris disk. Grids of reddened DA+dM and
sdO+MS/sdB+MS model spectra are fitted to the U,g,r,i,z,J,H,K photometry in
order to determine spectral types and estimate temperatures and reddening. From
a sample of 964 hot candidate white dwarfs with (g-r)<0.2, the spectral energy
distribution fitting shows that ~2-4% of the white dwarfs have an M-dwarf
companion, ~2% have a lower-mass companion, and no clear candidates for having
a debris disk are found. Additionally, from WISE 6 UV-excess sources are
selected as candidate Quasi-Stellar Objects (QSOs). Two UV-excess sources have
a WISE IR-excess showing up only in the mid-IR W3 band of WISE, making them
candidate Luminous InfraRed Galaxies (LIRGs) or Sbc star-burst galaxies.


title:
Convergence of general composite iterative method for infinite family of
  nonexpansive mappings in Hilbert spaces

abstract:
  In this paper by using $W_{n}$-mapping, we introduce a composite iterative
method for finding a common fixed point for infinite family of nonexpansive
mappings and a solution of a certain variational inequality. Furthermore, the
strong convergence of the proposed iterative method is established. Finally,
some simulation examples are presented. Our results improve and extend the
previous results.


title: Maps preserving the fixed points of products of operators

abstract:
  Let $X$ be a complex Banach space with $\dim X\geq3$ and $B(X)$ the algebra
of all bounded linear operators on $X$. Suppose $\phi:B(X)\longrightarrow B(X)$
is a surjective map satisfying the following property:
$Fix(AB)=Fix(\phi(A)\phi(B)), (A, B\in B(X))$. Then the form of $\phi$ is
characterized, where $Fix(T)$ is the set of all fixed points of an operator
$T$.


title:
Photon and Neutrino Spectra of Time-Dependent Photospheric Models of
  Gamma-Ray Bursts

abstract:
  Thermal photons from the photosphere may be the primary source of the
observed prompt emission of gamma-ray bursts (GRBs). In order to produce the
observed non-thermal spectra, some kind of dissipation mechanism near the
photosphere is required. In this paper we numerically simulate the evolution of
the photon spectrum in a relativistically expanding shell with a time-dependent
numerical code. We consider two basic models. One is a leptonic model, where a
dissipation mechanism heats the thermal electrons maintaining their high
temperature. The other model involves a cascade process induced by
$pp$($pn$)-collisions which produce high-energy electrons, modify the thermal
spectrum, and emit neutrinos. The qualitative properties of the photon spectra
are mainly determined by the optical depth at which the dissipation mechanism
sets in. Too large optical depths lead to a broad and curved spectrum
contradicting the observations, while for optical depths smaller than unity the
spectral hardness becomes softer than observed. A significant shift of the
spectral peak energy to higher energies due to a large energy injection can
lead to an overly broad spectral shape. We show ideal parameter ranges for
which these models are able to reproduce the observed spectra. For the
$pn$-collision model, the neutrino fluence in the 10-100 GeV range is well
above the atmospheric neutrino fluence, but its detection is challenging for
presently available detectors.


title: Tunable Photoluminescence of Monolayer MoS2 via Chemical Doping

abstract:
  We demonstrate the tunability of the photoluminescence (PL) properties of
monolayer (1L)-MoS2 via chemical doping. The PL intensity of 1L-MoS2 was
drastically enhanced by the adsorption of p-type dopants with high electron
affinity, but reduced by the adsorption of n-type dopants. This PL modulation
results from switching between exciton PL and trion PL depending on carrier
density in 1L-MoS2. Achievement of the extraction and injection of carriers in
1L-MoS2 by this solution-based chemical doping method enables convenient
control of optical and electrical properties of atomically thin MoS2.


title:
Fast prediction and evaluation of gravitational waveforms using
  surrogate models

abstract:
  [Abridged] We propose a solution to the problem of quickly and accurately
predicting gravitational waveforms within any given physical model. The method
is relevant for both real-time applications and in more traditional scenarios
where the generation of waveforms using standard methods can be prohibitively
expensive. Our approach is based on three offline steps resulting in an
accurate reduced-order model that can be used as a surrogate for the
true/fiducial waveform family. First, a set of m parameter values is determined
using a greedy algorithm from which a reduced basis representation is
constructed. Second, these m parameters induce the selection of m time values
for interpolating a waveform time series using an empirical interpolant. Third,
a fit in the parameter dimension is performed for the waveform's value at each
of these m times. The cost of predicting L waveform time samples for a generic
parameter choice is of order m L + m c_f online operations where c_f denotes
the fitting function operation count and, typically, m << L. We generate
accurate surrogate models for Effective One Body (EOB) waveforms of
non-spinning binary black hole coalescences with durations as long as 10^5 M,
mass ratios from 1 to 10, and for multiple harmonic modes. We find that these
surrogates are three orders of magnitude faster to evaluate as compared to the
cost of generating EOB waveforms in standard ways. Surrogate model building for
other waveform models follow the same steps and have the same low online
scaling cost. For expensive numerical simulations of binary black hole
coalescences we thus anticipate large speedups in generating new waveforms with
a surrogate. As waveform generation is one of the dominant costs in parameter
estimation algorithms and parameter space exploration, surrogate models offer a
new and practical way to dramatically accelerate such studies without impacting
accuracy.


title: Soft spin dipole giant resonances in 40Ca

abstract:
  High resolution experimental data has been obtained for the
40,42,44,48Ca(3He,t)Sc charge exchange reaction at 420 MeV beam energy, which
favors the spin-isospin excitations. The measured angular distributions were
analyzed for each state separately, and the relative spin dipole strength has
been extracted for the first time. The low-lying spin-dipole strength
distribution in 40Sc shows some interesting periodic gross feature. It
resembles to a soft, dumped multi-phonon vibrational band with $\hbar\omega$=
1.8 MeV, which might be associated to pairing vibrations around $^{40}$Ca.