title: Device-independent quantum key distribution with spin-coupled cavities

abstract:
  Device-independent quantum key distribution (DIQKD) guarantees the security
of a shared key without any assumptions on the apparatus used, provided that
the observed data violate a Bell inequality. Such violation is challenging
experimentally due to channel losses and photo-detection inefficiencies. Here
we describe a realistic DIQKD protocol based on interaction between light and
spins stored in cavities, which allows a heralded mapping of polarisation
entanglement of light onto the spin. The spin state can subsequently be
measured with near unit efficiency. Heralding alleviates the effect of channel
loss, and as the protocol allows for local heralding, the spin decay is not
affected by the communication time between the parties, making Bell inequality
violation over an arbitrary distance possible. We compute the achievable key
rates of the protocol, based on recent estimates of experimentally accessible
parameter values and compare to the other known DIQKD protocol, which is
entirely optical. We find significant improvements in terms of key bits per
source use. For example we gain about five orders of magnitude over a distance
of 75km, for realistic parameter values.


title: Fractional Gradient Elasticity from Spatial Dispersion Law

abstract:
  Non-local elasticity models in continuum mechanics can be treated with two
different approaches: the gradient elasticity models (weak non-locality) and
the integral non-local models (strong non-locality). This article focuses on
the fractional generalization of gradient elasticity that allows us to describe
a weak non-locality of power-law type. We suggest a lattice model with spatial
dispersion of power-law type as a microscopic model of fractional gradient
elastic continuum. We prove that the continuous limit maps the equations for
lattice with this spatial dispersion into the continuum equations with
fractional Laplacians in the Riesz form. A weak non-locality of power-law type
in the non-local elasticity theory is derived from the fractional weak spatial
dispersion in the lattice model. The suggested continuum equations, which are
obtained from the lattice model, describe a fractional generalization of the
gradient elasticity. These equations of fractional elasticity are solved for
some special cases: sub-gradient elasticity and super-gradient elasticity.


title:
Boosting Higgs CP properties via VH Production at the Large Hadron
  Collider

abstract:
  We consider ZH and WH production at the Large Hadron Collider, where the
Higgs decays to a bb pair. We use jet substructure techniques to reconstruct
the Higgs boson and construct angular observables involving leptonic decay
products of the vector bosons. These efficiently discriminate between the
tensor structure of the HVV vertex expected in the Standard Model and that
arising from possible new physics, as quantified by higher dimensional
operators. This can then be used to examine the CP nature of the Higgs as well
as CP mixing effects in the HZZ and HWW vertices separately.


title: Quantum Collapse Bell Inequalities

abstract:
  We propose Bell inequalities for discrete or continuous quantum systems which
test the compatibility of quantum physics with an interpretation in terms of
deterministic hidden-variable theories. The wave function collapse that occurs
in a sequence of quantum measurements enters the upper bound via the concept of
quantum conditional probabilities. The resulting hidden-variable inequality is
applicable to an arbitrary observable that is decomposable into a weighted sum
of non-commuting projectors. We present local and non-local examples of
violation of generalized Bell inequalities in phase space, which sense the
negativity of the Wigner function.


title: Comparison of theoretical white dwarf cooling timescales

abstract:
  An accurate assessment of white dwarf cooling times is paramount to place
white dwarf cosmochronology of Galactic populations on more solid grounds. This
issue is particularly relevant in view of the enhanced observational
capabilities provided by the next generation of Extremely Large Telescopes,
that will offer more avenues to employ white dwarfs as probes of Galactic
evolution and test-beds of fundamental physics. We estimate for the first time
the consistency of results obtained from two independent and widely used
evolutionary codes (BaSTI and LPCODE) for white dwarf models with fixed mass
and chemical stratification, when the same input physics is employed in both
codes. We considered 0.55Msun white dwarf models with both pure carbon and
uniform carbon-oxygen (50/50 mass fractions) core. We have assessed for the
first time the maximum possible accuracy in the current estimates of white
dwarf cooling times, resulting only from the different implementations of the
stellar evolution equations and homogeneous input physics in two independent
stellar evolution codes. This accuracy amounts to 2% at luminosities lower than
log(L/L_{\sun})= -1.5$. This agreement is true for both pure carbon and uniform
carbon-oxygen stratification core models, and also when the release of latent
heat and carbon-oxygen phase separation are considered. This difference is
smaller than the uncertainties in cooling times due to the present
uncertainties in the white dwarf chemical stratification. We have also
determined quantitatively and explained the effect of varying equation of
state, low-temperature radiative opacities and electron conduction opacities in
our calculation. Finally, we extend the scope of our work by providing
tabulations of our cooling sequences and the required input physics, that can
be used as a comparison test of cooling times obtained from other white dwarf
evolutionary codes.


title: Synchronization in random balanced networks

abstract:
  Characterizing the in uence of network properties on the global emerging
behavior of interacting elements constitutes a central question in many areas,
from physical to social sciences. In this article we study a primary model of
disordered neuronal networks with excitatory-inhibitory structure and balance
constraints. We show how the interplay between structure and disorder in the
connectivity leads to a universal transition from trivial to synchronized
stationary or periodic states. This transition cannot be explained only through
the analysis of the spectral density of the connectivity matrix. We provide a
low dimensional approximation that shows the role of both the structure and
disorder in the dynamics.


title:
Measurement of the differential branching fraction of the decay
  $\Lambda_b^0\rightarrow\Lambda\mu^+\mu^-$

abstract:
  The differential branching fraction of the decay
$\Lambda_b^0\rightarrow\Lambda\mu^+\mu^-$ is measured as a function of the
square of the dimuon invariant mass, $q^2$. A yield of $78\pm12$
$\Lambda_b^0\rightarrow\Lambda\mu^+\mu^-$ decays is observed using data,
corresponding to an integrated luminosity of 1.0\,fb$^{-1}$, collected by the
LHCb experiment at a centre-of-mass energy of 7\,TeV. A significant signal is
found in the $q^2$ region above the square of the $J/\psi$ mass, while at
lower-$q^2$ values upper limits are set on the differential branching fraction.
Integrating the differential branching fraction over $q^2$, while excluding the
$J/\psi$ and $\psi(2S)$ regions, gives a branching fraction of
$\BF($\Lambda_b^0\rightarrow\Lambda\mu^+\mu^-$)=(0.96\pm 0.16\stat\pm
0.13\syst\pm 0.21 (\mathrm{norm}))\times 10^{-6}$, where the uncertainties are
statistical, systematic and due to the normalisation mode,
$$\Lambda_b^0\rightarrow J/psi\Lambda$, respectively.


title: A note on small cuts for a terminal

abstract:
  Given a graph $G = (V,E)$ and a terminal $s\in V$, a cut $X$ for $s$ is a
vertex set that contains $s$. We look for a cut that is small in two senses,
i.e., there are no more than $k$ vertices in $X$ and no more than $t$ edges
leaving $X$. Answering a question asked by Fomin et al. (arXiv:1304.6189), we
show the problem is fixed-parameter tractable parameterized by either $k$ or
$t$.


title: W/Z+Jets and W/Z+HF Production at the Tevatron

abstract:
  The CDF and D0 collaborations performed a comprehensive study of the
production of vector bosons, W and Z, in association with energetic jets.
Understanding the W/Z + jets and W/Z + c, b-jets processes is of paramount
importance for the top quark physics, for the Higgs boson measurements, and for
many new physics searches. In this contribution the most recent measurements of
the associated production of jets and vector bosons in Run II at the Tevatron
are presented. The measurements are compared to different perturbative QCD
predictions and to several Monte Carlo generators.


title: On steady solutions to vacuumless Newtonian models of compressible flow

abstract:
  We prove the existence of weak solutions to the steady compressible
Navier-Stokes system in the barotropic case for a class of pressure laws
singular at vacuum. We consider the problem in a bounded domain in R^2 with
slip boundary conditions. Due to appropriate construction of approximate
solutions used in proof, obtained density is bounded away from 0 (and
infinity). Owing to a classical result by P.-L. Lions, this implies that
density and gradient of velocity are at least H\"older continuous, which does
not generally hold for the classical isentropic model in the presence of
vacuum.


title:
Preamble-based Channel Estimation in FBMC/OQAM Systems: A Time-Domain
  Approach

abstract:
  Filter bank-based multicarrier (FBMC) systems based on offset QAM (FBMC/OQAM)
have recently attracted increased interest in several applications due to their
enhanced flexibility, higher spectral efficiency, and better spectral
containment compared to conventional OFDM. They suffer, however, from an
inter-carrier/inter-symbol interference that complicates signal processing
tasks such as channel estimation. Most of the methods reported thus far rely on
the assumption of (almost) flat subchannels to more easily tackle this problem,
addressing it in a way similar to OFDM. However, this assumption may be often
quite inaccurate, due to the high freq. selectivity of the channel and/or the
small number of subcarriers employed to cope with frequency dispersion in fast
fading. In such cases, severe error floors are exhibited at medium to high SNR
values, which cancel the advantage of FBMC over OFDM. Moreover, the existing
methods provide estimates of the subchannel responses, most commonly in the
frequency domain. The goal of this paper is to revisit this problem through an
alternative formulation that focuses on the estimation of the channel impulse
response itself and makes no assumption on the degree of frequency selectivity
of the subchannels. The possible gains in estimation performance offered by
such an approach are investigated through the design of optimal (in the MSE
sense) preambles, of both the full and sparse types, and of the smallest
possible duration of only one pilot FBMC symbol. Existing designs for flat
subchannels are then shown to result as special cases. Longer preambles,
consisting of two consecutive pilot FBMC symbols, are also analyzed. The
simulation results demonstrate significant improvements from the proposed
approach for both mildly and highly frequency selective channels. Most notably,
no error floors appear anymore over a quite wide range of SNR values.


title: On endotrivial modules for Lie superalgebras

abstract:
  Let $\mathfrak{g} = \mathfrak{g}_{\overline{0}} \oplus
\mathfrak{g}_{\overline{1}}$ be a Lie superalgebra over an algebraically closed
field, $k$, of characteristic 0. An endotrivial $\mathfrak{g}$-module, $M$, is
a $\mathfrak{g}$-supermodule such that $\operatorname{Hom}_k(M,M) \cong k_{ev}
\oplus P$ as $\mathfrak{g}$-supermodules, where $k_{ev}$ is the trivial module
concentrated in degree $\overline{0}$ and $P$ is a projective
$\mathfrak{g}$-supermodule. In the stable module category, these modules form a
group under the operation of the tensor product. We show that for an
endotrivial module $M$, the syzygies $\Omega^n(M)$ are also endotrivial, and
for certain Lie superalgebras of particular interest, we show that
$\Omega^1(k_{ev})$ and the parity change functor actually generate the group of
endotrivials. Additionally, for a broader class of Lie superalgebras, for a
fixed $n$, we show that there are finitely many endotrivial modules of
dimension $n$.


title: Unit spectra of K-theory from strongly self-absorbing C*-algebras

abstract:
  We give an operator algebraic model for the first group of the unit spectrum
$gl_1(KU)$ of complex topological K-theory, i.e. $[X, BGL_1(KU)]$, by bundles
of stabilized infinite Cuntz C*-algebras $O_{\infty} \otimes \K$. We develop
similar models for the localizations of $KU$ at a prime $p$ and away from $p$.
Our work is based on the $\mathcal{I}$-monoid model for the units of $K$-theory
by Sagave and Schlichtkrull and it was motivated by the goal of finding
connections between the infinite loop space structure of the classifying space
of the automorphism group of stabilized strongly self-absorbing C*-algebras
that arose in our generalization of the Dixmier-Douady theory and classical
spectra from algebraic topology.


title: Multi-cancer molecular signatures and their interrelationships

abstract:
  Although cancer is known to be characterized by several unifying biological
hallmarks, systems biology has had limited success in identifying molecular
signatures present in in all types of cancer. The current availability of rich
data sets from many different cancer types provides an opportunity for thorough
computational data mining in search of such common patterns. Here we report the
identification of 18 "pan-cancer" molecular signatures resulting from analysis
of data sets containing values from mRNA expression, microRNA expression, DNA
methylation, and protein activity, from twelve different cancer types. The
membership of many of these signatures points to particular biological
mechanisms related to cancer progression, suggesting that they represent
important attributes of cancer in need of being elucidated for potential
applications in diagnostic, prognostic and therapeutic products applicable to
multiple cancer types.


title:
A cellular basis for the generalized Temperly-Lieb Algebra and Mahler
  Measure

abstract:
  Just as the Temperley-Lieb algebra is a good place to compute the Jones
polynomial, the Kauffman bracket skein algebra of a disk with $2k$ colored
points on the boundary, each with color $n$, is a good place to compute the
$n^{th}$ colored Jones polynomial. Here, this colored skein algebra is shown to
be a cellular algebra and a set of separating Jucys-Murphy elements is
provided. This is done by explicitly providing the cellular basis and the
JM-elements. Having done this several results of Mathas on such algebras are
considered, including the construction of pairwise non-isomorphic irreducible
submodules and their corresponding primitive idempotents. These idempotents are
then used to define recursive elements of the colored skein algebra. Recursive
elements are of particular interest as they have been used to relate geometric
properties of link diagrams to the Mahler measure of the Jones polynomial. In
particular, a single proof is given for the result of Champanerkar and Kofman,
that the Mahler measure of the Jones and colored Jones polynomial converges
under twisting on some number of strands.


title: Smooth structures on non-orientable four-manifolds and free involutions

abstract:
  In this paper, we investigate existence of inequivalent smooth structures on
closed smooth non-orientable 4-manifolds building upon results of Akbulut,
Cappell-Shaneson, Fintushel-Stern, Gompf, and Stolz. We add to the number of
known constructions and provide new examples of exotic manifolds that are
obtained as an application of Gluck twists to the standard smooth structure.
Inspection of the smooth structure on the oriented 2-covers yields existence
results of orientation-reversing exotic free involutions.


title:
Effect of pressure cycling on Iron: Signatures of an electronic
  instability and unconventional superconductivity

abstract:
  High pressure electrical resistivity and x-ray diffraction experiments have
been performed on Fe single crystals. The crystallographic investigation
provides direct evidence that in the martensitic $bcc \rightarrow hcp$
transition at 14 GPa the $\lbrace 110\rbrace_{bcc}$ become the $\lbrace
002\rbrace_{hcp}$ directions. During a pressure cycle, resistivity shows a
broad hysteresis of 6.5 GPa, whereas superconductivity, observed between 13 and
31 GPa, remains unaffected. Upon increasing pressure an electronic instability,
probably a quantum critical point, is observed at around 19 GPa and, close to
this pressure, the superconducting $T_{c}$ and the isothermal resistivity
($0<T<300\,$K) attain maximum values. In the superconducting pressure domain,
the exponent $n = 5/3$ of the temperature power law of resistivity and its
prefactor, which mimics $T_{c}$, indicate that ferromagnetic fluctuations may
provide the glue for the Cooper pairs, yielding unconventional
superconductivity.


title: In-homogeneous Virus Spread in Networks

abstract:
  Our $N$-intertwined model (now called NIMFA) for virus spread in any network
with $N$ nodes is extended to a full heterogeneous setting. The metastable
steady-state nodal infection probabilities are specified in terms of a
generalized Laplacian, that possesses analogous properties as the classical
Laplacian in graph theory. The critical threshold that separates global network
infection from global network health is characterized via an $N$ dimensional
vector that makes the largest eigenvalue of a modified adjacency matrix equal
to unity. Finally, the steady-state infection probability of node $i$ is convex
in the own curing rate $\delta_{i}$, but concave in the curing rates
$\delta_{j}$ of the other nodes $1\leq j\neq i\leq N$ in the network.


title: On It\^o differential equation in rough path theory

abstract:
  The solution of rough differential equation, driven by the It\^o signature of
a continuous local martingale, exists uniquely a.s. when the vector field is
Lip(\beta) for \beta > 1, and coincides a.s. with the It\^o signature of the
solution of parallel stochastic differential equation. Moreover, the It\^o
solution can be recovered pathwisely by concatenating discounted Stratonovich
solutions.


title:
Time-monitoring Observations of the Ro-Vibrational Overtone CO bands in
  Young Stars

abstract:
  We present near-IR spectra of a sample of T Tauri, Herbig Ae/Be, and FU Ori
objects. Using the FSPEC instrument on the Bok 90-inch telescope, we obtained
K-band spectra with a resolution of ~3500. Here we present spectra of the
v=2->0 and v=3->1 bandheads of ro-vibrational transitions of carbon monoxide.
We observed these spectra over multiple epochs spaced by a few days and
approximately one month. Several of our targets show CO emission or absorption
features. However we see little evidence of variability in these features
across multiple epochs. We compare our results with previous observations, and
discuss the physical implications of non-variable CO emission across the
sampled timescales.


title:
Interplay between finite resources and local defect in an asymmetric
  simple exclusion process

abstract:
  When particle flux is regulated by multiple factors such as particle supply
and varying transport rate, it is important to identify the respective dominant
regimes. We extend the well-studied totally asymmetric simple exclusion model
to investigate the interplay between a controlled entrance and a local defect
site. The model mimics cellular transport phenomena where there is typically a
finite particle pool and non-uniform moving rates due to biochemical kinetics.
Our simulations reveal regions where, despite an increasing particle supply,
the current remains constant while particles redistribute in the system.
Exploiting a domain wall approach with mean-field approximation, we provide a
theoretical ground for our findings. The results in steady state current and
density profiles provide quantitative insights into the regulation of the
transcription and translation process in bacterial protein synthesis. We
investigate the totally asymmetric simple exclusion model with controlled
entrance and a defect site in the bulk to mimic the finite particle pool and
non-uniform moving rates in particle transport processes.


title:
Thermal entanglement in a two-qubit Ising chain subjected to
  Dzialoshinski-Moriya interaction

abstract:
  Thermal entanglement of a two-qubit Ising chain subjected to an external
magnetic field and Dzialoshinski-Moriya (DM) interaction is examined. The
effect of magnetic field, strength of DM interaction and temperature are
analyzed by adopting negativity of partial transpose as the measure of
entanglement. It is shown that when the DM interaction along the Ising axis is
considerable, thermal entanglement can be sustained for higher temperature. The
usefulness of longitudinal DM interaction over the one that is perpendicular to
the Ising axis, in the manipulation and control of entanglement at a feasible
temperature, is illustrated.


title: A Perceptual Alphabet for the 10-dimensional Phonetic-prosodic Space

abstract:
  We define an alphabet, the IHA, of the 10-D phonetic-prosodic space. The
dimensions of this space are perceptual observables, rather than articulatory
specifications. Speech is defined as a random chain in time of the 4-D phonetic
subspace, that is, a symbolic sequence, augmented with diacritics of the
remaining 6-D prosodic subspace. The definitions here are based on the model of
speech of oral billiards, and supersedes an earlier version. This paper only
enumerates the IHA in detail as a supplement to the exposition of oral
billiards in a separate paper. The IHA has been implemented as the target
random variable in a speech recognizer.


title: Conservative flows with various types of shadowing

abstract:
  In the present paper we study the C1-robustness of the three properties:
average shadowing, asymptotic average shadowing and limit shadowing within two
classes of conservative flows: the incompressible and the Hamiltonian ones. We
obtain that the first two properties guarantee dominated splitting (or partial
hyperbolicity) on the whole manifold, and the third one implies that the flow
is Anosov.


title:
Capacity Scaling in MIMO Systems with General Unitarily Invariant Random
  Matrices

abstract:
  We investigate the capacity scaling of MIMO systems with the system
dimensions. To that end, we quantify how the mutual information varies when the
number of antennas (at either the receiver or transmitter side) is altered. For
a system comprising $R$ receive and $T$ transmit antennas with $R>T$, we find
the following: By removing as many receive antennas as needed to obtain a
square system (provided the channel matrices before and after the removal have
full rank) the maximum resulting loss of mutual information over all
signal-to-noise ratios (SNRs) depends only on $R$, $T$ and the matrix of
left-singular vectors of the initial channel matrix, but not on its singular
values. In particular, if the latter matrix is Haar distributed the ergodic
rate loss is given by $\sum_{t=1}^{T}\sum_{r=T+1}^{R}\frac{1}{r-t}$ nats. Under
the same assumption, if $T,R\to \infty$ with the ratio $\phi\triangleq T/R$
fixed, the rate loss normalized by $R$ converges almost surely to $H(\phi)$
bits with $H(\cdot)$ denoting the binary entropy function. We also quantify and
study how the mutual information as a function of the system dimensions
deviates from the traditionally assumed linear growth in the minimum of the
system dimensions at high SNR.


title:
Generalizations of Ramanujan's reciprocity formula and the Askey-Wilson
  integral

abstract:
  By using two known transformation formulas for basic hypergeometric series,
we establish a direct extension of Bailey's $_6\psi_6$-series identity.
Subsequently, it and Milne's identity are employed to drive multi-variable
generalizations of Ramanujan's reciprocity formula. Then we utilize also
Milne's identity to deduce a multi-variable generalization of the Askey-Wilson
integral.


title: Introducing LETOR 4.0 Datasets

abstract:
  LETOR is a package of benchmark data sets for research on LEarning TO Rank,
which contains standard features, relevance judgments, data partitioning,
evaluation tools, and several baselines. Version 1.0 was released in April
2007. Version 2.0 was released in Dec. 2007. Version 3.0 was released in Dec.
2008. This version, 4.0, was released in July 2009. Very different from
previous versions (V3.0 is an update based on V2.0 and V2.0 is an update based
on V1.0), LETOR4.0 is a totally new release. It uses the Gov2 web page
collection (~25M pages) and two query sets from Million Query track of TREC
2007 and TREC 2008. We call the two query sets MQ2007 and MQ2008 for short.
There are about 1700 queries in MQ2007 with labeled documents and about 800
queries in MQ2008 with labeled documents. If you have any questions or
suggestions about the datasets, please kindly email us (letor@microsoft.com).
Our goal is to make the dataset reliable and useful for the community.


title:
On split products of quaternion algebras with involution in
  characteristic two

abstract:
  The question of whether a split tensor product of quaternion algebras with
involution over a field of characteristic two can be expressed as a tensor
product of split quaternion algebras with involution, is shown to have an
affirmative answer.


title: Hand Gesture Recognition Based on Karhunen-Loeve Transform

abstract:
  In this paper, we have proposed a system based on K-L Transform to recognize
different hand gestures. The system consists of five steps: skin filtering,
palm cropping, edge detection, feature extraction, and classification. Firstly
the hand is detected using skin filtering and palm cropping was performed to
extract out only the palm portion of the hand. The extracted image was then
processed using the Canny Edge Detection technique to extract the outline
images of palm. After palm extraction, the features of hand were extracted
using K-L Transform technique and finally the input gesture was recognized
using proper classifier. In our system, we have tested for 10 different hand
gestures, and recognizing rate obtained was 96%. Hence we propose an easy
approach to recognize different hand gestures.


title:
Mid-Infrared and X-ray luminosity correlations of X-ray point sources in
  NGC 1399

abstract:
  It is known that the IR and X-ray luminosities of Active Galactic Nuclei
(AGN) are correlated with L_{IR} ~ L_{X}. Moreover, the IR flux ratio between
the 5.8 and 3.6 \mu m bands is a good distinguishing characteristic of AGN or
AGN-like behaviour. On the other hand, Galactic X-ray binaries (GXB) are
under-luminous in the IR with L_{IR} << L_{X}. Since Ultra-luminous X-ray
sources in nearby galaxies may be an intermediate class between AGN and GXB, it
is interesting to study if their IR properties indicate which kind of objects
they resemble. We use Spitzer IRAC images to identify mid-IR counterparts of
bright X-ray sources, detected by Chandra in the elliptical galaxy NGC 1399. We
find that for sources with AGN-like IR flux ratios, the IR luminosity strongly
correlates with that in X-rays, L_{IR} ~ L_{X}, while for the others, there is
no correlation between the two. Some of the former objects may be background
AGN. If they are not strongly contaminated by background AGN, this result
extends the IR-X-ray luminosity correlation down to L_{X} ~ 10^{39} ergs/s. We
calculate their g-z colours and find that the bright X-ray sources with IR
counterparts are typically blue in optical color. This is in contrast to
typical X-ray sources, without IR counterparts which have predominantly red
optical counterparts. We highlight the need for IR or optical spectra of these
sources to distinguish background AGN and unveil the effect of the X-ray
emission on the different environments of these systems.


title: Trapped surfaces and nature of singularities in Lyra's geometry

abstract:
  Motivated by the geometrical interpretation of Brans-Dicke (BD) scalar field
which may also act as a torsion potential in Lyra geometry, we study the
effects of spacetime torsion on the dynamics of a collapsing massive star.
Taking the interior spacetime as the FLRW metric and the matter content as
spherically symmetric, homogeneous perfect fluid with the equation of state
(EoS) $p=w\rho$, we show that the collapse ends in a spacetime singularity
which is of the strong curvature type in the sense of Tipler. Whether the
trapped surfaces form during the dynamical evolution of the collapse depends on
the torsion parameter, related to the BD coupling parameter, and the EoS
subject to the conditions on physical reasonableness of the collapse
configuration. Hence, the space of torsion and EoS parameters is divided into
two portions, one for which the collapse process leads to the formation of
apparent horizon and the other for which the apparent horizon is failed to form
in the interior region. The nature of the singularity is examined from the
exterior perspective, by searching for the existence of radial null geodesics
reaching the faraway observers. Moreover, it is found that the effects of a
dynamical torsion can be transferred to the outside region of the collapsing
star, making the exterior region dynamic.


title: Extreme local extrema of two-dimensional discrete Gaussian free field

abstract:
  We consider the discrete Gaussian Free Field in a square box in $\mathbb Z^2$
of side length $N$ with zero boundary conditions and study the joint law of its
properly-centered extreme values ($h$) and their scaled spatial positions ($x$)
in the limit as $N\to\infty$. Restricting attention to extreme local maxima,
i.e., the extreme points that are maximal in an $r_N$-neighborhood thereof, we
prove that the associated process tends, whenever $r_N\to\infty$ and
$r_N/N\to0$, to a Poisson point process with intensity measure $Z(dx)e^{-\alpha
h}dh$, where $\alpha:= 2/\sqrt{g}$ with $g:=2/\pi$ and where $Z(dx)$ is a
random Borel measure on $[0,1]^2$. In particular, this yields an integral
representation of the law of the absolute maximum, similar to that found in the
context of Branching Brownian Motion. We give evidence that the random measure
$Z$ is a version of the derivative martingale associated with the continuum
Gaussian Free Field.


title:
Nature of the bad metallic behavior of Fe_{1.06}Te inferred from its
  evolution in the magnetic state

abstract:
  We investigate with angle resolved photoelectron spectroscopy the change of
the Fermi Surface (FS) and the main bands from the paramagnetic (PM) state to
the antiferromagnetic (AFM) occurring below 72 K in Fe_{1.06}Te. The evolution
is completely different from that observed in iron-pnictides as nesting is
absent. The AFM state is a rather good metal, in agreement with our magnetic
band structure calculation. On the other hand, the PM state is very anomalous
with a large pseudogap on the electron pocket that closes in the AFM state. We
discuss this behavior in connection with spin fluctuations existing above the
magnetic transition and the correlations predicted in the spin-freezing regime
of the incoherent metallic state.


title:
Effects of Publications in Proceedings on the Measure of the Core Size
  of Coauthors

abstract:
  Coauthors (CA) of a "lead investigator" (LI) can receive a rank (r) according
to their "importance" in having published joint publications with the LI. It is
commonly accepted, without any proof, that publications in peer review journals
and e.g. conference proceedings do not have the same "value" in a CV. Same for
papers contributed to encyclopedia and book chapters. It is here examined
whether the relationship between the number (J) of publications of some
scientist with her/his coauthors, ranked according to their decreasing
importance, i.e. $ J \propto 1/r^{\alpha} $, as found by Ausloos, still holds
if the overall publication list is broken into such specific types of
publications. Several authors, with different careers, but mainly having worked
in the field of statistical mechanics, are studied here to sort out answers to
the questions. The exponent $\alpha$ turns out to be weakly scientist
dependent, only if the maximum value of J and r is large and is $\sim +1$ then.
The $m_A$ core value, i.e. the core number of CAs, for proceedings only is
about half of the total one, i.e. when all publications are counted.
Contributions to the numerical values from both encyclopedia and book chapters
are marginal. The role of a time span on $m_A$ is also examined in two cases in
relation to career activity considerations. It can considered that the findings
serve as a contrasting point of view on how to quantify an individual
(publication) career as recently done by Petersen et al., here emphasizing the
collaboration size and evolution, rather than a citation count, moreover
specifying the type of publication. Through the various $m_A$'s one can
distinguish different behavior patterns of a scientist publication with CAs.


title:
Cell responses only partially shape cell-to-cell variations in protein
  abundances in Escherichia coli chemotaxis

abstract:
  Cell-to-cell variations in protein abundance in clonal cell populations are
ubiquitous in living systems. Since protein composition determines responses in
individual cells, it stands to reason that the variations themselves are
subject to selective pressures. But the functional role of these cell-to-cell
differences is not well understood. One way to tackle questions regarding
relationships between form and function is to perturb the form (e.g., change
the protein abundances) and observe the resulting changes in some function.
Here we take on the form-function relationship from the inverse perspective,
asking instead what specific constraints on cell-to-cell variations in protein
abundance are imposed by a given functional phenotype. We develop a maximum
entropy (MaxEnt) based approach to posing questions of this type, and
illustrate the method by application to the well characterized chemotactic
response in Escherichia coli (E. coli). We find that full determination of
observed cell-to-cell variations in protein abundances is not inherent in
chemotaxis itself, but in fact appears to be jointly imposed by the chemotaxis
program in conjunction with other factors, e.g., the protein synthesis
machinery and/or additional non-chemotactic cell functions such as cell
metabolism. These results illustrate the power of MaxEnt as a tool for the
investigation of relationships between biological form and function.


title: Magnetically generated spin-orbit coupling for ultracold atoms

abstract:
  We present a new technique for producing two- and three-dimensional
Rashba-type spin-orbit couplings for ultracold atoms without involving light.
The method relies on a sequence of pulsed inhomogeneous magnetic fields
imprinting suitable phase gradients on the atoms. For sufficiently short pulse
durations, the time-averaged Hamiltonian well approximates the Rashba
Hamiltonian. Higher order corrections to the energy spectrum are calculated
exactly for spin-1/2 and perturbatively for higher spins. The pulse sequence
does not modify the form of rotationally symmetric atom-atom interactions.
Finally, we present a straightforward implementation of this pulse sequence on
an atom chip.


title: A Lower Bound for the Fisher Information Measure

abstract:
  The problem how to approximately determine the absolute value of the Fisher
information measure for a general parametric probabilistic system is
considered. Having available the first and second moment of the system output
in a parametric form, it is shown that the information measure can be bounded
from below through a replacement of the original system by a Gaussian system
with equivalent moments. The presented technique is applied to a system of
practical importance and the potential quality of the bound is demonstrated.


title:
Limits on tensor type weak currents from nuclear and neutron
  $\beta$~decays

abstract:
  The limits on time-reversal invariant tensor-type weak currents from nuclear
and neutron $\beta$ decays are evaluated including most recent experimental
data. We find that $ -0.14 \times 10^{-2} < (C_T + C^\prime_T)/C_A < 1.4 \times
10^{-2} $ and $ -0.16 < (C_T - C^\prime_T)/C_A < 0.16$ (90% C.L.), while for
the case $C_T = C^\prime_T$ the limits are $ | C_T/C_A | < 3.7 \times 10^{-3}
$. These limits are shown to be more stringent than those from recent
measurements of the radiative pion decay. In addition, the sensitivity of
future $10^{-3}$-level correlation measurements is investigated.


title: The Muon Collider as a $H/A$ factory

abstract:
  We show that a muon collider is ideally suited for the study of heavy H/A
scalars, cousins of the Higgs boson found in two-Higgs doublet models and
required in supersymmetric models. The key aspects of H/A are: (1) they are
narrow, yet have a width-to-mass ratio far larger than the expected muon
collider beam-energy resolution, and (2) the larger muon Yukawa allows
efficient s-channel production. We study in detail a representative Natural
Supersymmetry model which has a 1.5 Tev H/A with $m_H$- $m_A$ = 10 Gev. The
large event rates at resonant peak allow the determination of the individual H
and A resonance parameters (including CP) and the decays into electroweakinos
provides a wealth of information unavailable to any other present or planned
collider.


title:
The effect of gravity on the stability of an evaporating dichloromethane
  liquid film

abstract:
  Zero gravity evaporation of a Dicholoromethane (DCM) liquid film is explored.
The resulting film dynamics are presented and a criterion for stable films is
described based on the long wave theory. It is concluded that films subject to
long wave instabilities shows the appearance of the mode of maximum growth rate
at rupture, irrespective of the initial condition or domain size conditions.
Films stable in Earth's gravity are destabilized in zero gravity.


title: Permutation Group Symmetry and Correlations

abstract:
  Correlation factors are constructed that are consistent with the permutation
symmetry group of N Fermions at given value of the filling factor.


title: Pseudocompact primitive topological inverse semigroups

abstract:
  In the paper we study pseudocompact primitive topological inverse semigroups.
We describe the structure of pseudocompact primitive topological inverse
semigroups and show that a Tychonoff product of a family of pseudocompact
primitive topological inverse semigroups is a pseudocompact topological space.
Also we prove that the Stone-\v{C}ech compactification of a pseudocompact
primitive topological inverse semigroup is a compact primitive topological
inverse semigroup.


title:
Estimates for the Thermal Width of Heavy Quarkonia in Strongly Coupled
  Plasmas from Holography

abstract:
  The gauge/gravity duality is used to investigate the imaginary part of the
heavy quark potential (defined via the rectangular Wilson loop) in strongly
coupled plasmas. This quantity can be used to estimate the width of heavy
quarkonia in a plasma at strong coupling. In this paper the thermal worldsheet
fluctuation method, proposed in [J.Noronha and A.Dumitru, Phys.\ Rev.\ Lett.\
{\bf 103}, 152304 (2009)], is revisited and general conditions for the
existence of an imaginary part for the heavy quark potential computed within
classical gravity models are obtained. We prove a general result that
establishes the connection between this imaginary part of the potential
determined holographically and the area law displayed by the Wilson loop in the
vacuum of confining gauge theories. We also determine the imaginary part of the
heavy quark potential in a strongly coupled plasma dual to Gauss-Bonnet
gravity. This provides an estimate of how the thermal width of heavy quarkonia
changes with the shear viscosity to entropy density ratio, $\eta/s$, at strong
coupling.


title: Spin pseudogap in Ni-doped SrCuO2

abstract:
  The S=1/2 spin chain material SrCuO2 doped with 1% S=1 Ni-impurities is
studied by inelastic neutron scattering. At low temperatures, the spectrum
shows a pseudogap \Delta ~ 8 meV, absent in the parent compound, and not
related to any structural phase transition. The pseudogap is shown to be a
generic feature of quantum spin chains with dilute defects. A simple model
based on this idea quantitatively accounts for the exprimental data measured in
the temperature range 2-300 K, and allows to represent the momentum-integrated
dynamic structure factor in a universal scaling form.


title:
Matrix Factorizations for Complete Intersections and Minimal Free
  Resolutions

abstract:
  Matrix factorizations of a hypersurface yield a description of the asymptotic
structure of minimal free resolutions over the hypersurface. We introduce a new
concept of matrix factorizations for complete intersections that allows us to
describe the asymptotic structure of minimal free resolutions over complete
intersections.


title: The Euler Characteristic of a Haken 4-Manifold

abstract:
  Haken n-manifolds are aspherical manifolds, defined and studied by B.
Foozwell and H. Rubinstein, that can be successively cut open along essential
codimension-one submanifolds until a disjoint union of n-cells is obtained.
Such manifolds come equipped with a boundary pattern, a particular kind of
decomposition of the boundary into codimension-zero submanifolds. We prove that
there is a certain numerical function phi(X^4) depending only on the boundary
and boundary pattern of the compact Haken 4-manifold X^4 (and vanishing if X^4
has empty boundary), such that for any compact Haken 4-manifold X^4 the Euler
characteristic satisfies the inequality chi(X^4) >= phi(X^4). In particular, if
X^{4} is a closed Haken 4-manifold, then chi(X^4) >= 0.


title: On the number of type change loci of a generalized complex structure

abstract:
  In this note, we describe a procedure to construct generalized complex
structures with an arbitrarily large number of type change loci on products of
the circle with a connected sum of closed 3-manifolds. The loci need not be
isotopic.


title: First-order formalism for flat branes in generalized N-field models

abstract:
  This work deals with braneworld scenarios obtained from N real scalar fields,
whose dynamics is generalized to include higher order power in the derivative
of the fields. For the scalar fields being driven by nonstandard dynamics, we
show how a first-order formalism can be obtained for flat brane in the presence
of several fields. We then illustrate our findings investigating distinct
potentials with one and two fields, obtaining stable standard and compact
solutions in the braneworld theory. In particular, we have found different
models describing the very same warp factor.


title: Whirling skirts and rotating cones

abstract:
  Steady, dihedrally symmetric patterns with sharp peaks may be observed on a
spinning skirt, lagging behind the material flow of the fabric. These
qualitative features are captured with a minimal model of traveling waves on an
inextensible, flexible, generalized-conical sheet rotating about a fixed axis.
Conservation laws are used to reduce the dynamics to a quadrature describing a
particle in a three-parameter family of potentials. One parameter is associated
with the stress in the sheet, aNoether is the current associated with
rotational invariance, and the third is a Rossby number which indicates the
relative strength of Coriolis forces. Solutions are quantized by enforcing a
topology appropriate to a skirt and a particular choice of dihedral symmetry. A
perturbative analysis of nearly axisymmetric cones shows that Coriolis effects
are essential in establishing skirt-like solutions. Fully non-linear solutions
with three-fold symmetry are presented which bear a suggestive resemblance to
the observed patterns.

categories: physics.class-ph cond-mat.soft math-ph math.MP nlin.PS


title: Decay of spin coherences in one-dimensional spin systems

abstract:
  Strategies to protect multi-qubit states against decoherence are difficult to
formulate because of their complex many-body dynamics. A better knowledge of
the decay dynamics would help in the construction of decoupling control
schemes. Here we use solid-state nuclear magnetic resonance techniques to
experimentally investigate the decay of coherent multi-spin states in linear
spin chains. Leveraging on the quasi-one-dimensional geometry of Fluorapatite
crystal spin systems, we can gain a deeper insight on the multi-spin states
created by the coherent evolution, and their subsequent decay, than it is
possible in 3D systems. We are then able to formulate an analytical model that
captures the key features of the decay. We can thus compare the decoherence
behavior for different initial states of the spin chain and link their decay
rate to the state characteristics, in particular their coherence and long-range
correlation among spins. Our experimental and theoretical study shows that the
spin chains undergo a rich dynamics, with a slower decay rate than for the 3D
case, and thus might be more amenable to decoupling techniques.


title:
Two-dimensional metal-insulator-transition as a potential fluctuation
  driven semiclassical transport phenomenon

abstract:
  We theoretically consider the carrier density tuned (apparent)
two-dimensional (2D) metal-insulator-transition (MIT) in semiconductor
heterostructure-based 2D carrier systems as arising from a classical
percolation phenomenon in the inhomogeneous density landscape created by the
long-range potential fluctuations induced by random quenched charged impurities
in the environment. The long-range Coulomb disorder inherent in semiconductors
produces strong potential fluctuations in the 2D system where a fraction of the
carriers gets trapped or classically localized, leading to a mixed 2-component
semiclassical transport behavior at intermediate densities where a fraction of
the carriers is mobile and another fraction immobile. At high carrier density,
all the carriers are essentially mobile whereas at low carrier density all the
carriers are essentially trapped since there is no possible percolating
transport path through the lake-and-mountain inhomogeneous potential landscape.
The low-density situation with no percolation would mimic an insulator whereas
the high-density situation with allowed percolating paths through the
lake-and-mountain energy landscape would mimic a metal with the system
manifesting an apparent MIT in between. We calculate the transport properties
as a function of carrier density, impurity density, impurity location, and
temperature using a 2-component (trapped and mobile carriers) effective medium
theory. Our theoretically calculated transport properties are in good
qualitative agreement with the experimentally observed 2D MIT phenomenology in
2D electron and hole systems. We find a high (low) density metallic
(insulating) temperature-dependence of the 2D resistivity, and an
intermediate-density crossover behavior which could be identified with the
experimentally observed 2D MIT.


title: Orthogonal units of the bifree double Burnside ring

abstract:
  The bifree double Burnside ring $B^\Delta(G,G)$ of a finite group $G$ has a
natural anti-involution. We study the group $B^\Delta_\circ(G,G)$ of orthogonal
units in $B^\Delta(G,G)$. It is shown that this group is always finite and
contains a subgroup isomorphic to $B(G)^\times\rtimes \Out(G)$, where
$B(G)^\times$ denotes the unit group of the Burnside ring of $G$ and $\Out(G)$
denotes the outer automorphism group of $G$. Moreover it is shown that if $G$
is nilpotent then $B^\Delta_\circ(G,G)\cong B(G)^\times\rtimes \Out(G)$. The
results can be interpreted as positive answers to questions on equivalences of
$p$-blocks of group algebras in the case that the block is the group algebra of
a $p$-group.


title: Priority arguments via true strages

abstract:
  We describe a variation of Ash's $\eta$-system, and give a new proof of Ash's
metatheorem. As an application, we prove a generalization of Ash and Knight's
theorem on pairs of structures.


title: Stopping Criterion for the Mean Shift Iterative Algorithm

abstract:
  Image segmentation is a critical step in computer vision tasks constituting
an essential issue for pattern recognition and visual interpretation. In this
paper, we propose a new stopping criterion for the mean shift iterative
algorithm by using images defined in Zn ring, with the goal of reaching a
better segmentation. We carried out also a study on the weak and strong of
equivalence classes between two images. An analysis on the convergence with
this new stopping criterion is carried out too.


title: CP asymmetries in three-body B+- decays to charged pions and kaons

abstract:
  CP asymmetries have been measured recently by the LHCb collaboration in
three-body $B^+$ decays to final states involving charged pions and kaons.
Large asymmetries with opposite signs at a level of about 60% have been
observed in $B^\pm\to \pi^\pm({\rm or} K^\pm)\pi^+\pi^-$ and $B^\pm \to \pi^\pm
K^+K^-$ for restricted regions in the Dalitz plots involving $\pi^+\pi^-$ and
$K^+K^-$ with low invariant mass. U-spin is shown to predict corresponding
$\Delta S=0$ and $\Delta S=1$ asymmetries with opposite signs and inversely
proportional to their branching ratios, in analogy with a successful relation
predicted thirteen years ago between asymmetries in $B_s\to K^-\pi^+$ and $B^0
\to K^+ \pi^-$. We compare these predictions with the measured integrated
asymmetries. Effects of specific resonant or non-resonant partial waves on
enhanced asymmetries for low-pair-mass regions of the Dalitz plot are studied
in $B^\pm \to \pi^\pm \pi^+\pi^-$. The closure of low-mass $\pi^+\pi^-$ and
$K^+K^-$ channels involving only $\pi\pi \leftrightarrow K\bar K$ rescattering
may explain by CPT approximately equal magnitudes and opposite signs measured
in $B^\pm\to \pi^\pm\pi^+\pi^-$ and $B^\pm \to \pi^\pm K^+K^-$.


title:
Localization at the Edge of 2D Topological Insulator by Kondo Impurities
  with Random Anisotropies

abstract:
  We consider chiral electrons moving along the 1D helical edge of a 2D
topological insulator and interacting with a disordered chain of Kondo
impurities. Assuming the electron-spin couplings of random anisotropies, we map
this system to the problem of the pinning of the charge density wave by the
disordered potential. This mapping proves that arbitrary weak anisotropic
disorder in coupling of chiral electrons with spin impurities leads to the
Anderson localization of the edge states.


title:
Electronic structure and charge transfer excited states of a
  multichromophoric antenna

abstract:
  The electronic structure of a multichromophoric molecular complex containing
two of each borondipyrromethane dye, Zn-tetraphenyl-porphyrin, bisphenyl
anthracene and a fullerene are studied using density functional theory. The
snowflake shaped molecule behaves like an antenna capturing photon at different
frequencies and transferring the photon energy to the porphyrin where electron
transfer occurs from the porphyrin to the fullerene. Molecular structure of
this large complex is first optimized using plane wave projector augmented wave
methodology. Subsequent electronic structure calculations are performed using
the real space methodology using an all electron pseudopotential basis set
containing total of 12478 basis functions. The results show that the HOMO and a
state below the HOMO are primarily localized on one of the porphyrins while the
LUMO resides mainly on the fullerene component of the complex. The energies of
the HOMO and LUMO states in the complex, as adjudged by the ionization
potential and the electron affinity values, show significant differences with
respect to their values in participating subunits in isolation. We have
systematically examined the effect of structural strain and the presence of
ligands on the ionization energy and the electron affinity. Finally, we have
calculated a few lowest charge transfer energies involving electronic
transitions from a the porphyrin component to the fullerene subunit of the
complex using the perturbative delta-SCF method. Our predicted value of the
lowest charge transfer excited state (1.67 eV) is comparable to the
experimental estimate of the charge transfer energy of a similar complex.


title: Greedy Clearing of Persistent Poissonian Dust

abstract:
  Given a Poisson point process on R, assign either one or two marks to each
point of this process, independently of the others. We study the motion of a
particle that jumps deterministically from its current location to the nearest
point of the Poisson point process which still contains at least one mark, and
removes one mark per each visit. A point of the Poisson point process which is
left with no marks is removed from the system. We prove that the presence of
any positive density of double marks leads to the eventual removal of every
Poissonian point.


title: Coupling--mass mapping of di-jet peak searches

abstract:
  We study hypothetical gauge bosons that may produce dijet resonances at the
LHC. Simple renormalizable models include leptophobic Z' bosons or colorons
that have flavor-independent couplings and decay into a color-singlet or -octet
quark-antiquark pair, respectively. We present the experimental results on
dijet resonances at hadron colliders as limits in the coupling-versus-mass
plane of a gauge boson associated with baryon number. This theoretical
framework facilitates a direct comparison of dijet resonance searches performed
at different center-of-mass energies or at different colliders.


title: Rapid Angular Expansion of the Ionized Core of CRL 618

abstract:
  CRL 618 is an object that exhibits characteristics of both AGB and post-AGB
star. It also displays a spectacular array of bipolar lobes with a dense
equatorial region, which makes it an excellent object to study the development
of asymmetries in evolved stars. In the recent decades, an elliptical compact
HII region located in the center of the nebula has been seen to be increasing
in size and flux. This seems to be due to the ionization of the circumstellar
envelope by the central star, and it would be indicating the beginning of the
planetary nebula phase for CRL 618. We analyzed interferometric radio continuum
data at ~5 and 22 GHz from observations carried out at seven epochs with the
VLA. We traced the increase of the flux of the ionized region over a period of
~26 years. We measured the dimensions of the HII region directly from the
brightness distribution images to determine the increase of its size over time.
For one of the epochs we analyzed observations at six frequencies from which we
estimated the electron density distribution. We carried out model calculations
of the spectral energy distribution at two different epochs to corroborate our
observational results. We found that the radio continuum flux and the size of
the ionized region have been increasing monotonically in the last three
decades. The size of the major axis of the HII region shows a dependance with
frequency, which has been interpreted as a result of a gradient of the electron
density in this direction. The growth of the HII region is due to the expansion
of an ionized wind whose mass-loss rate increased continuously for a period of
~100 years until a few decades ago, when the mass-loss rate experienced a
sudden decline. Our results indicate that the beginning of the ionization of
the circumstellar envelope began around 1971, which marks the start of the
planetary nebula phase of CRL 618.


title:
Fermi level influence on the adsorption at semiconductor surfaces - ab
  initio simulations

abstract:
  Chemical adsorption of the species at semiconductor surfaces is analyzed
showing the existence of the two contributions to adsorption energy: bond
creation and charge transfer. It is shown that the energy of quantum surface
states is affected by the electric field at the surface, nevertheless the
potential contribution of electron and nuclei cancels out. The charge transfer
contribution is Fermi level independent for pinned surfaces. Thus for Fermi
level pinned at the surface, the adsorption energy is independent on the Fermi
energy i.e. the doping in the bulk. The DFT simulations of adsorption of
hydrogen at clean GaN(0001) and silicon at SiC(0001) surfaces confirmed
independence of adsorption energy on the doping in the bulk. For the Fermi
level nonpinned surfaces the charge contribution depends on the position of
Fermi level in the bulk. Thus adsorption energy is sensitive to change of the
Fermi energy in the bulk, i.e. the doping. The DFT simulations of adsorption of
atomic hydrogen at 0.75 ML hydrogen covered GaN(0001) surface confirmed that
the adsorption energy may be changed by about 2 eV by the doping change from n-
to p-type.


title:
3D test particle simulations of the Galactic disks. The kinematical
  effects of the bar

abstract:
  Aims: To study the imprints of a rotating bar on the kinematics of stars in
the thin and thick disks throughout the Galaxy. Methods: We perform test
particle numerical simulations of the thin and thick disks in a 3D Galactic
potential that includes a halo, a bulge, thin and thick disks, and a Ferrers
bar. We analyze the resulting velocity distributions of populations
corresponding to both disks, for different positions in the Galaxy and for
different structural parameters of the bar. Results: We find that the velocity
distributions of the disks are affected by the bar, and that strong transient
effects are present for approximately 10 bar rotations after this is introduced
adiabatically. On long (more realistic) timescales, the effects of the bar are
strong on the kinematics of thin disk stars, and weaker on those in the thick
disk, but in any case significant. Furthermore, we find that it is possible to
trace the imprints of the bar also vertically and at least up to z ~ 1 kpc for
the thin disk and z ~ 2 kpc for the thick disk.


title: Null-Wave Giant Gravitons from Thermal Spinning Brane Probes

abstract:
  We construct and analyze thermal spinning giant gravitons in type II/M-theory
based on spherically wrapped black branes, using the method of thermal probe
branes originating from the blackfold approach. These solutions generalize in
different directions recent work in which the case of thermal (non-spinning)
D3-brane giant gravitons was considered, and reveal a rich phase structure with
various new properties. First of all, we extend the construction to M-theory,
by constructing thermal giant graviton solutions using spherically wrapped M2-
and M5-branes. More importantly, we switch on new quantum numbers, namely
internal spins on the sphere, which are not present in the usual extremal limit
for which the brane world volume stress tensor is Lorentz invariant. We examine
the effect of this new type of excitation and in particular analyze the
physical quantities in various regimes, including that of small temperatures as
well as low/high spin. As a byproduct we find new stationary dipole-charged
black hole solutions in AdS_m X S^n backgrounds of type II/M-theory. We finally
show, via a double scaling extremal limit, that our spinning thermal giant
graviton solutions lead to a novel null-wave zero-temperature giant graviton
solution with a BPS spectrum, which does not have an analogue in terms of the
conventional weakly coupled world volume theory.


title: Detecting Massive Galaxies at High Redshift using the Dark Energy Survey

abstract:
  The Dark Energy Survey (DES) will be unprecedented in its ability to probe
exceptionally large cosmic volumes to relatively faint optical limits.
Primarily designed for the study of comparatively low redshift (z<2) galaxies
with the aim of constraining dark energy, an intriguing byproduct of the survey
will be the identification of massive (>10^(12.0) M_sun) galaxies at z>~4. This
will greatly improve our understanding of how galaxies form and evolve. By both
passively evolving the low redshift mass function and extrapolating the
observed high redshift mass function, we find that such galaxies should be rare
but nonetheless present at early times, with predicted number densities of
~0.02 deg^-2. The unique combination of depth and coverage that DES provides
will allow the identification of such galaxies should they exist - potentially
identifying hundreds of such sources. We then model possible high redshift
galaxies and determine their detectability using the DES filter sets and
depths. We model sources with a broad range stellar properties and find that
for these galaxies to be detected they must be either sufficiently young, high
mass and/or relatively dust free (E(B-V)<0.45) - with these parameters jointly
affecting each galaxy's detectability. We also propose colour-colour selection
criteria for the identification of both pristine and dusty sources and find
that, although contamination fractions will be high, the most reliable
candidate massive high redshift galaxies are likely to be identifiable in the
DES data through prioritisation of colour-selected sources.


title:
A low-mass cut-off near the hydrogen burning limit for Salpeter-like
  initial mass functions in early-type galaxies

abstract:
  We conduct a detailed investigation of the properties of the stellar initial
mass function (IMF) in two massive early-type lens galaxies with velocity
dispersions of sigma ~245 km/s and sigma ~325 km/s, for which both HST imaging
and X-Shooter spectra are available. We compare the inferences obtained from
two fully independent methods: (i) a combined gravitational lensing and stellar
dynamics (L&D) analysis of the data sets employing self-consistent axisymmetric
models, and (ii) a spectroscopic simple stellar population (SSP) analysis of
optical line-strength indices, assuming single power-law IMFs. The results from
the two approaches are found to be in agreement within the 1-sigma
uncertainties. Both galaxies are consistent with having a Salpeter IMF
(power-law slope of x = 2.35), which is strongly favoured over a Chabrier IMF
(x = 1.8), with probabilities inferred from the joint analysis of 89% and 99%,
respectively. Bottom-heavy IMFs significantly steeper than Salpeter (x >= 3.0)
are ruled out with decisive evidence (Bayes factor B > 1000) for both galaxies,
as they exceed the total mass derived from the L&D constraints. Our analysis
allows, for the first time, the inference of the low-mass cut-off of the IMF
(M_low). Combining the joint L&D and SSP analyses of both galaxies, we infer an
IMF slope of x = 2.22 +/- 0.14, consistent with Salpeter IMF, and a low-mass
limit M_low = 0.13 +/- 0.03 M_sun, just above the hydrogen burning limit.


title: Inverse Compton X-ray signature of AGN feedback

abstract:
  Bright AGN frequently show ultra-fast outflows (UFOs) with outflow velocities
vout ~0.1c. These outflows may be the source of AGN feedback on their host
galaxies sought by galaxy formation modellers. The exact effect of the outflows
on the ambient galaxy gas strongly depends on whether the shocked UFOs cool
rapidly or not. This in turn depends on whether the shocked electrons share the
same temperature as ions (one temperature regime; 1T) or decouple (2T), as has
been recently suggested. Here we calculate the Inverse Compton spectrum emitted
by such shocks, finding a broad feature potentially detectable either in
mid-to-high energy X-rays (1T case) or only in the soft X-rays (2T). We argue
that current observations of AGN do not seem to show evidence for the 1T
component. The limits on the 2T emission are far weaker, and in fact it is
possible that the observed soft X-ray excess of AGN is partially or fully due
to the 2T shock emission. This suggests that UFOs are in the energy-driven
regime outside the central few pc, and must pump considerable amounts of not
only momentum but also energy into the ambient gas. We encourage X-ray
observers to look for the Inverse Compton components calculated here in order
to constrain AGN feedback models further.


title: A young hierarchical triple system harbouring a candidate debris disc

abstract:
  We report the detection of a wide young hierarchical triple system where the
primary has a candidate debris disc. The primary, TYC 5241-986-1 A, is a known
Tycho star which we classify as a late-K star with emission in the X-ray, near
and far-UV and H\alpha\ suggestive of youth. Its proper motion, photometric
distance (65-105 pc) and radial velocity lead us to associate the system with
the broadly defined Local Association of young stars but not specifically with
any young moving group. The presence of weak lithium absorption and X-ray and
calcium H and K emission support an age in the 20 to ~125 Myr range. The
secondary is a pair of M4.5+-0.5 dwarfs with near and far UV and H\alpha\
emission separated by approximately 1 arcsec (~65-105 AU projected separation)
which lie 145 arcsec (9200-15200 AU) from the primary. The primary has a WISE
22 micron excess and follow-up Herschel observations also detect an excess at
70 micron. The excess emissions are indicative of a 100-175 K debris disc. We
also explore the possibility that this excess could be due to a coincident
background galaxy and conclude that this is unlikely. Debris discs are
extremely rare around stars older than 15 Myr, hence if the excess is caused by
a disc this is an extremely novel system.


title: What Shapes Supernova Remnants?

abstract:
  Evidence has mounted that Type Ia and core-collapse (CC) supernovae (SNe) can
have substantial deviations from spherical symmetry; one such piece of evidence
is the complex morphologies of supernova remnants (SNRs). However, the relative
role of the explosion geometry and the environment in shaping SNRs remains an
outstanding question. Recently, we have developed techniques to quantify the
morphologies of SNRs, and we have applied these methods to the extensive X-ray
and infrared archival images available of Milky Way and Magellanic Cloud SNRs.
In this proceeding, we highlight some results from these studies, with
particular emphasis on SNR asymmetries and whether they arise from "nature"
versus "nurture".


title:
NuSTAR and Chandra Insight into the Nature of the 3-40 keV Nuclear
  Emission in NGC 253

abstract:
  We present results from three nearly simultaneous NuSTAR and Chandra
monitoring observations between 2012 Sep 2 and 2012 Nov 16 of local
star-forming galaxy NGC 253. The 3-40 keV NuSTAR intensity of the inner 20
arcsec (~400 pc) nuclear region varied by a factor of ~2 across the three
monitoring observations. The Chandra data reveal that the nuclear region
contains three bright X-ray sources, including a luminous (L2-10 keV ~ few x
10^39 erg/s) point source ~1 arcsec from the dynamical center of the galaxy
(within the 3sigma positional uncertainty of the dynamical center); this source
drives the overall variability of the nuclear region at energies >3 keV. We
make use of the variability to measure the spectra of this single hard X-ray
source when it was in bright states. The spectra are well described by an
absorbed (NH ~ 1.6 x 10^23 cm^-2) broken power-law model with spectral slopes
and break energies that are typical of ultraluminous X-ray sources (ULXs), but
not AGN. A previous Chandra observation in 2003 showed a hard X-ray point
source of similar luminosity to the 2012 source that was also near the
dynamical center (~0.4 arcsec); however, this source was offset from the 2012
source position by ~1 arcsec. We show that the probability of the 2003 and 2012
hard X-ray sources being unrelated is >>99.99% based on the Chandra spatial
localizations. Interestingly, the Chandra spectrum of the 2003 source (3-8 keV)
is shallower in slope than that of the 2012 hard X-ray source. Its proximity to
the dynamical center and harder Chandra spectrum indicate that the 2003 source
is a better AGN candidate than any of the sources detected in our 2012
campaign; however, we were unable to rule out a ULX nature for this source.
Future NuSTAR and Chandra monitoring would be well equipped to break the
degeneracy between the AGN and ULX nature of the 2003 source, if again caught
in a high state.


title: Holographic Phases of Renyi Entropies

abstract:
  We consider Renyi entropies of conformal field theories in flat space, with
the entangling surface being a sphere. The AdS/CFT correspondence relates this
Renyi entropy to that of a black hole with hyperbolic horizon; as the Renyi
parameter $n$ increases the temperature of the black hole decreases. If the CFT
possesses a sufficiently low dimension scalar operator the black hole will be
unstable to the development of hair. Thus, as $n$ is varied, the Renyi
entropies will exhibit a phase transition at a critical value of $n$. The
location of the phase transition, along with the spectrum of the reduced
density matrix $\rho$, depends on the dimension of the lowest dimension
non-trivial scalar operator in the theory.


title: Beyond the nuclear starburst? Clustered star formation in major mergers

abstract:
  Recent simulation work has successfully captured the formation of the star
clusters that have been observed in merging galaxies. These studies, however,
tend to focus on studying extreme starbursts, such as the Antennae galaxies. We
aim to establish whether there is something special occurring in these extreme
systems or whether the mechanism for cluster formation is present in all
mergers to a greater or lesser degree. We undertake a general study of
merger-induced star formation in a sample of 5 pc resolution adaptive mesh
refinement simulations of low redshift equal-mass mergers with randomly-chosen
orbital parameters. We find that there is an enhanced mass fraction of very
dense gas that appears as the gas density probability density function evolves
during the merger. This finding has implications for the interpretation of some
observations; a larger mass fraction of dense gas could account for the
enhanced HCN/CO ratios seen in ULIRGs and predicts that alpha_CO is lower in
mergers, as for a given mass of H_2, CO emission will increase in a denser
environment. We also find that as the star formation rate increases, there is a
correlated peak in the velocity dispersion of the gas, which we attribute to
increasing turbulence driven by the interaction itself. Star formation tends to
be clumpy: in some cases there is extended clumpy star formation, but even when
star formation is concentrated within the inner kpc (i.e. what may be
considered a nuclear starburst) it still often has a clumpy, rather than a
smooth, distribution. We find no strong evidence for a clear bimodality in the
Kennicutt-Schmidt relation for the average mergers simulated here. Instead,
they are typically somewhat offset above the predicted quiescent relation
during their starbursts.


title: The Lee-Wick Standard Model at Finite Temperature

abstract:
  The Lee-Wick Standard Model at temperatures near electroweak scale is
considered, with the aim of studying the electroweak phase transition. While
Lee-Wick theories possess states of negative norm, they are not pathological
but instead are treated by imposing particular boundary conditions and using
particular integration contours in the calculation of S-matrix elements. It is
not immediately clear how to extend this prescription to formulate the theory
at finite temperature; we explore two different pictures of finite-temperature
LW theories, and calculate the thermodynamic variables and the (one-loop)
thermal effective potential. We apply these results to study the Lee-Wick
Standard Model and find that the electroweak phase transition is a continuous
crossover, much like in the Standard Model. However, the high-temperature
behavior is modified due to cancellations between thermal corrections arising
from the negative- and positive-norm states.


title: Duality Symmetric String and M-Theory

abstract:
  We review recent developments in duality symmetric string theory. We begin
with the world sheet doubled formalism which describes strings in an extended
space time with extra coordinates conjugate to winding modes. This formalism is
T-duality symmetric and can accommodate non-geometric T-fold backgrounds which
are beyond the scope of Riemannian geometry. Vanishing of the conformal anomaly
of this theory can be interpreted as a set of spacetime equations for the
background fields. These equations follow from an action principle that has
been dubbed Double Field Theory (DFT). We review the aspects of generalised
geometry relevant for DFT. We outline recent extensions of DFT and explain how,
by relaxing the so-called strong constraint with a Scherk Schwarz ansatz, one
can obtain backgrounds that simultaneously depend on both the regular and
T-dual coordinates. This provides a purely geometric higher dimensional origin
to gauged supergravities that arise from non-geometric compactification. We
then turn to M-theory and describe recent progress in formulating an E_{n(n)}
U-duality covariant description of the dynamics. We describe how spacetime may
be extended to accommodate coordinates conjugate to brane wrapping modes and
the construction of generalised metrics in this extend space that unite the
bosonic fields of supergravity into a single object. We review the action
principles for these theories and their novel gauge symmetries. We also
describe how a Scherk Schwarz reduction can be applied in the M-theory context
and the resulting relationship to the embedding tensor formulation of maximal
gauged supergravities.


title: Tiling the integer lattice with translated sublattices

abstract:
  When $\mathbb{Z}^d$ is represented as a finite disjoint union of translated
integer sublattices, the translated sublattices must possess some special
properties. Such a representation is called a \emph{lattice tiling}. We develop
a theoretical framework, based on multiple residues and dual groups, to provide
a set of necessary and sufficient conditions for such a lattice tiling to
exist. We also investigate the question of when a lattice tiling must possess
at least two translated sublattices which are translates of one another.


title: Pion distribution amplitude from lattice-QCD

abstract:
  A method is explained through which a pointwise accurate approximation to the
pion's valence-quark distribution amplitude (PDA) may be obtained from a
limited number of moments. In connection with the single nontrivial moment
accessible in contemporary simulations of lattice-regularised quantum
chromodynamics (QCD), the method yields a PDA that is a broad concave function
whose pointwise form agrees with that predicted by Dyson-Schwinger equation
analyses of the pion. Under leading-order evolution, the PDA remains broad to
energy scales in excess of 100 GeV, a feature which signals persistence of the
influence of dynamical chiral symmetry breaking. Consequently, the asymptotic
distribution, \phi_\pi^asy(x), is a poor approximation to the pion's PDA at all
such scales that are either currently accessible or foreseeable in experiments
on pion elastic and transition form factors. Thus, related expectations based
on \phi_\pi^asy(x) should be revised.


title:
Non-Linear Integral Equations for the SL(2,R)/U(1) black hole sigma
  model

abstract:
  It was previously established that the critical staggered XXZ spin chain
provides a lattice regularization of the black hole CFT. We reconsider the
continuum limit of this spin chain with the exact method of non-linear integral
equations (NLIEs), paying particular attention to the effects of a singular
integration kernel. With the help of the NLIEs, we rederive the continuous
black hole spectrum, but also numerically match the density of states of the
spin chain with that of the CFT, which is a new result. Finally, we briefly
discuss the integrable structure of the black hole CFT and the identification
of its massive integrable perturbation on the lattice.

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


title: Order-by-disorder in classical oscillator systems

abstract:
  We consider classical nonlinear oscillators on hexagonal lattices. When the
coupling between the elements is repulsive, we observe coexisting states, each
one with its own basin of attraction. These states differ by their degree of
synchronization and by patterns of phase-locked motion. When disorder is
introduced into the system by additive or multiplicative Gaussian noise, we
observe a non-monotonic dependence of the degree of order in the system as a
function of the noise intensity: intervals of noise intensity with low
synchronization between the oscillators alternate with intervals where more
oscillators are synchronized. In the latter case, noise induces a higher degree
of order in the sense of a larger number of nearly coinciding phases. This
order-by-disorder effect is reminiscent to the analogous phenomenon known from
spin systems. Surprisingly, this non-monotonic evolution of the degree of order
is found not only for a single interval of intermediate noise strength, but
repeatedly as a function of increasing noise intensity. We observe noise-driven
migration of oscillator phases in a rough potential landscape.


title: Topological phase states of the SU(3) QCD

abstract:
  We consider the topologically nontrivial phase states and the corresponding
topological defects in the SU(3) d-dimensional quantum chromodynamics (QCD).
The homotopy groups for topological classes of such defects are calculated
explicitly. We have shown that the three nontrivial groups are pi_3 SU(3)=Z,
pi_5 SU(3)=Z, and pi_6 SU(3)=Z_6 if 3 < d < 6. The latter result means that we
are dealing exactly with six topologically different phase states. The
topological invariants for d=3,5,6 are described in detail.


title:
A note on noninner automorphisms of order $p$ for finite $p$-groups of
  coclass 2

abstract:
  In this note, the existence of noninner automorphisms of order 2 for finite
2-groups of coclass 2 is proved. Combining our result with a recent one due to
Y. Guerboussa and M. Reguiat (see arXiv:1301.0085), we prove that every finite
$p$-group of coclass 2 has a noninner automorphism of order $p$ leaving the
center elementwise fixed.


title:
Intrinsic decoherence and purity in a Bose quantum fluid in a triple
  well potential

abstract:
  We consider a quantum Bose fluid confined in a triple well potential in 1D
within the exact N-body Bose-Hubbard model to investigate the phenomena of
intrinsic decoherence and loss of purity. Our study is done by following the
time evolution of one-body properties in an N-particle closed environment. We
do an exhaustive exploration of initial conditions to characterize these
phenomena. Here we illustrate our main findings with a set of relevant Fock and
SU(3) coherent states. Our study shows that signatures of stationarity and
maximal mixing are a direct consequence of the inter-particle interactions in
the closed system and become evident as the number of particles is increased.
This fact is confirmed by quantifying the deviations from stationarity by means
of a matrix norm.


title: Magnetically Active Stars in Taurus-Auriga: Activity and Rotation

abstract:
  A sample of 70 magnetically active stars toward the Taurus-Auriga
star-forming region has been investigated. The positions of the sample stars on
the Rossby diagram have been analyzed. All stars are shown to be in the regime
of a saturated dynamo, where the X-ray luminosity reaches its maximum and does
not depend on the Rossby number. A correlation has been found between the
lithium line equivalent width and the age of a solar-mass (from 0.7 to 1.2
Msun) pre-main-sequence star. The older the age, the smaller the Li line
equivalent width. Analysis of the long-term photometric variability of these
stars has shown that the photometric activity of the youngest stars is
appreciably higher than that of the older objects from the sample. This result
can be an indirect confirmation of the evolution of the magnetic field in
pre-main-sequence stars from predominantly dipole and axisymmetric to multipole
and nonaxisymmetric.


title: The KdV equation on the half-line: The Dirichlet to Neumann map

abstract:
  We consider initial-boundary value problems for the KdV equation $u_t + u_x +
6uu_x + u_{xxx} = 0$ on the half-line $x \geq 0$. For a well-posed problem, the
initial data $u(x,0)$ as well as one of the three boundary values $\{u(0,t),
u_x(0,t), u_{xx}(0,t)\}$ can be prescribed; the other two boundary values
remain unknown. We provide a characterization of the unknown boundary values
for the Dirichlet as well as the two Neumann problems in terms of a system of
nonlinear integral equations. The characterizations are effective in the sense
that the integral equations can be solved perturbatively to all orders in a
well-defined recursive scheme.


title:
Bellman approach to the one-sided bumping for weighted estimates of
  Calder\'on--Zygmund operators

abstract:
  We give again (see also arXiv:1112.0676) a proof of weighted estimate of any
Calder\'on-Zygmund operator. This is under a universal sharp sufficient
condition that is weaker than the so-called bump condition. Bump conjecture was
recently solved independently and simultaneously by A. Lerner (arXiv:1202.1860)
and Nazarov--Reznikov-Treil-Volberg (arXiv:1202.2406). The latter paper uses
the Bellman approach. Immediately a very natural and seemingly simple question
arises how to strengthen the bump conjecture result by weakening its
assumptions in a natural symmetric way. This is what we are dealing with here.
However we meet an unexpected and, in our opinion, deep obstacle, that allows
us to achieve only a partial result. The result of the present article is
slightly stronger than the one in arXiv:1112.0676. Our proof consists of two
main parts: reduction to a simple model operator, construction of Bellman
function for estimating this simple operator. The newer feature is that the
domain of definition of our Bellman function is infinitely dimensional.


title: Spatially-Resolved Millimeter-Wavelength Maps of Neptune

abstract:
  We present maps of Neptune in and near the CO (2-1) rotation line at 230.538
GHz. These data, taken with the Combined Array for Research in Millimeter-wave
Astronomy (CARMA) represent the first published spatially-resolved maps in the
millimeter. At large (~5 GHz) offsets from the CO line center, the majority of
the emission originates from depths of 1.1-4.7 bar. We observe a latitudinal
gradient in the brightness temperature at these frequencies, increasing by 2-3
K from 40 degrees N to the south pole. This corresponds to a decrease in the
gas opacity of about 30% near the south pole at altitudes below 1 bar, or a
decrease of order a factor of 50 in the gas opacity at pressures greater than 4
bar. We look at three potential causes of the observed gradient: variations in
the tropospheric methane abundance, variations in the H2S abundance, and
deviations from equilibrium in the ortho/para ratio of hydrogen. At smaller
offsets (0-213 MHz) from the center of the CO line, lower atmospheric pressures
are probed, with contributions from mbar levels down to several bars. We find
evidence of latitudinal variations at the 2-3% level in the CO line, which are
consistent with the variations in zonal-mean temperature near the tropopause
found by Conrath et al. (1998) and Orton et al. (2007).


title: The Electron Capture $^{163}$Ho Experiment ECHo

abstract:
  The determination of the absolute scale of the neutrino masses is one of the
most challenging questions in particle physics. Different approaches are
followed to achieve a sensitivity on neutrino masses in the sub-eV range. Among
them, experiments exploring the beta decay and electron capture processes of
suitable nuclides can provide necessary information on the electron neutrino
mass value. In this talk we present the Electron Capture 163-Ho experiment
ECHo, which aims to investigate the electron neutrino mass in the sub-eV range
by means of the analysis of the calorimetrically measured energy spectrum
following the electron capture process of 163-Ho. A high precision and high
statistics spectrum will be measured by means of low temperature magnetic
calorimeter arrays. We present preliminary results obtained with a first
prototype of single channel detectors as well as the participating groups and
their on-going developments.

categories: physics.ins-det hep-ex nucl-ex physics.atom-ph


title: LHC Signatures of Warped-space Vectorlike Quarks

abstract:
  We study the LHC signatures of TeV scale vectorlike quarks $b'$, $t'$ and
$\chi$ with electromagnetic charges -1/3, 2/3 and 5/3 that appear in many
beyond the standard model (BSM) extensions. We consider warped
extra-dimensional models and analyze the phenomenology of such vectorlike
quarks that are the custodial partners of third generation quarks. In addition
to the usually studied pair-production channels which depend on the strong
coupling, we put equal emphasis on single production channels that depend on
electroweak couplings and on electroweak symmetry breaking induced mixing
effects between the heavy vectorlike quarks and standard model quarks. We
identify new promising $gg$-initiated pair and single production channels and
find the luminosity required for discovering these states at the LHC. For these
channels, we propose a cut that allows one to extract the relevant electroweak
couplings. Although the motivation is from warped models, we present many of
our results model-independently.


title: Hadron melting and QCD thermodynamics

abstract:
  We study in this paper mechanisms of hadron melting based on the spectral
representation of hadronic quantum channels, and examine the hadron width
dependence of the pressure. The findings are applied to a statistical hadron
model of QCD thermodynamics, where hadron masses are distributed by the
Hagedorn model and a uniform mechanism for producing hadron widths is assumed.
According to this model the hadron - quark gluon plasma transition occurs at
$T\approx 200$-250 MeV, the numerically observable $T_c=156$ MeV crossover
temperature is relevant for the onset of the hadron melting process.


title:
CP Violation in $B^0_s \to K^-\pi^+$, $B^0 \to K^+\pi^-$ Decays and
  Tests for SU(3) Flavor Symmetry Predictions

abstract:
  The LHCb collaboration has recently measured the first direct CP violation in
$B^0_s$ decays with a rate asymmetry $A_{CP}(B^0_s\to K^- \pi^+)$ given by
$0.27 \pm 0.04(stat)\pm 0.01(syst)$. At the same time they also made the most
precise measurement for $A_{CP}(B^0 \to K^+ \pi^-) = -0.080\pm 0.007(stat)\pm
0.003(syst)$. These data confirm the predicted relation, $A_{CP}(B^0 \to K^+
\pi^-)/A_{CP}(B^0_s \to K^- \pi^+) = - Br(B^0_s\to K^- \pi^+)\tau_{B^0}/Br(B^0
\to K^+ \pi^-)\tau_{B^0_s}$, in the standard model with SU(3) flavor symmetry.
We discuss possible modifications due to SU(3) breaking effects to this
relation. There are several other similar relations in B decays. Using current
available data we study whether relevant relations hold in $B^0$ and $B^0_s$ to
$PP$ and $PV$ decays. Here $P$ and $V$ indicate pesudoscalar and vector mesons
in the flavor octet representations.


title:
Neutrino spin oscillations in matter under the influence of
  gravitational and electromagnetic fields

abstract:
  We derive the new quasi-classical equation for the description of the spin
evolution of a neutrino propagating in a curved space-time and interacting with
a background matter and an external electromagnetic field. This equation is
used to analyze neutrino spin oscillations in these external backgrounds. We
obtain the effective Hamiltonian and the transition probability for
oscillations of neutrinos when they move in the vicinity of a rotating black
hole, surrounded by an accretion disk, and interact with an external magnetic
field. The appearance of new resonances in neutrino spin oscillations in this
system is considered. The approximate treatment of spin oscillations of
radially propagating ultra high energy neutrinos is developed. We also discuss
the applications of our results to the description of neutrino spin
oscillations in realistic astrophysical media.


title:
Local potential approximation for the renormalization group flow of
  fermionic field theories

abstract:
  The second functional derivative of the effective potential of pure fermionic
field theories is rewritten in a factorized form which facilitates the
evaluation of the renormalisation flow rate of the effective action in the
Wetterich equation. It is applied to the Local Potential Approximation in
cases, when the effective potential depends on scalar composites built from the
fermions. The procedure is demonstrated explicitly on the example of the
$N_f$-flavor Gross-Neveu model and the one-flavor chiral Nambu--Jona-Lasinio
model.


title: Are giant tornadoes the legs of solar prominences?

abstract:
  Observations in the 171 AA channel of the Atmospheric Imaging Assembly of the
space-borne Solar Dynamics Observatory show tornadoes-like features in the
atmosphere of the Sun. These giant tornadoes appear as dark, elongated and
apparently rotating structures in front of a brighter background. This
phenomenon is thought to be produced by rotating magnetic field structures that
extend throughout the atmosphere. We characterize giant tornadoes through a
statistical analysis of properties like spatial distribution, lifetimes, and
sizes. A total number of 201 giant tornadoes are detected in a period of 25
days, suggesting that on average about 30 events are present across the whole
Sun at a time close to solar maximum. Most tornadoes appear in groups and seem
to form the legs of prominences, thus serving as plasma sources/sinks.
Additional Halpha observations with the Swedish 1-m Solar Telescope imply that
giant tornadoes rotate as a structure although clearly exhibiting a thread-like
structure. We observe tornado groups that grow prior to the eruption of the
connected prominence. The rotation of the tornadoes may progressively twist the
magnetic structure of the prominence until it becomes unstable and erupts.
Finally, we investigate the potential relation of giant tornadoes to other
phenomena, which may also be produced by rotating magnetic field structures. A
comparison to cyclones, magnetic tornadoes and spicules implies that such
events are more abundant and short-lived the smaller they are. This comparison
might help to construct a power law for the effective atmospheric heating
contribution as function of spatial scale.


title: Densely Defined Multiplication on the Sobolev Space

abstract:
  Following Sarason's classification of the densely defined multiplication
operators over the Hardy space, we classify the densely defined multipliers
over the Sobolev space, $W^{1,2}[0,1]$. In this paper we find that the
collection of such multipliers for the Sobolev space is exactly the Sobolev
space itself. This sharpens a result of Shields concerning bounded multipliers.
The densely defined multiplication operators over the subspace $W_0 = \{f \in
W^{1,2}[0,1] : f(0)=f(1)=0 \}$ are also classified. In this case the densely
defined multiplication operators can be written as a ratio of functions in
$W_0$ where the denominator is non-vanishing. This is proved using a
contructive argument.


title: Large Margin Low Rank Tensor Analysis

abstract:
  Other than vector representations, the direct objects of human cognition are
generally high-order tensors, such as 2D images and 3D textures. From this
fact, two interesting questions naturally arise: How does the human brain
represent these tensor perceptions in a "manifold" way, and how can they be
recognized on the "manifold"? In this paper, we present a supervised model to
learn the intrinsic structure of the tensors embedded in a high dimensional
Euclidean space. With the fixed point continuation procedures, our model
automatically and jointly discovers the optimal dimensionality and the
representations of the low dimensional embeddings. This makes it an effective
simulation of the cognitive process of human brain. Furthermore, the
generalization of our model based on similarity between the learned low
dimensional embeddings can be viewed as counterpart of recognition of human
brain. Experiments on applications for object recognition and face recognition
demonstrate the superiority of our proposed model over state-of-the-art
approaches.


title: Localization of disordered bosons and magnets in random fields

abstract:
  We study localization properties of disordered bosons and spins in random
fields at zero temperature. We focus on two representatives of different
symmetry classes, hard-core bosons (XY magnets) and Ising magnets in random
transverse fields, and contrast their physical properties. We describe
localization properties using a locator expansion on general lattices. For 1d
Ising chains, we find non-analytic behavior of the localization length as a
function of energy at \omega = 0, $\xi^{-1}(\omega) = \xi^{-1}(0) + A
|\omega|^\alpha$, with $\alpha$ vanishing at criticality. This contrasts with
the much smoother behavior predicted for XY magnets. We use these results to
approach the ordering transition on Bethe lattices of large connectivity K,
which mimic the limit of high dimensionality. In both models, in the
paramagnetic phase with uniform disorder, the localization length is found to
have a local maximum at \omega = 0. For the Ising model, we find activated
scaling at the phase transition, in agreement with infinite randomness studies.
In the Ising model long range order is found to arise due to a delocalization
and condensation initiated at \omega = 0, without a closing mobility gap. We
find that Ising systems establish order on much sparser (fractal) subgraphs
than XY models. Possible implications of these results for finite-dimensional
systems are discussed.


title:
Precisely Verifying the Null Space Conditions in Compressed Sensing: A
  Sandwiching Algorithm

abstract:
  In this paper, we propose new efficient algorithms to verify the null space
condition in compressed sensing (CS). Given an $(n-m) \times n$ ($m>0$) CS
matrix $A$ and a positive $k$, we are interested in computing $\displaystyle
\alpha_k = \max_{\{z: Az=0,z\neq 0\}}\max_{\{K: |K|\leq k\}}$ ${\|z_K
\|_{1}}{\|z\|_{1}}$, where $K$ represents subsets of $\{1,2,...,n\}$, and $|K|$
is the cardinality of $K$. In particular, we are interested in finding the
maximum $k$ such that $\alpha_k < {1}{2}$. However, computing $\alpha_k$ is
known to be extremely challenging. In this paper, we first propose a series of
new polynomial-time algorithms to compute upper bounds on $\alpha_k$. Based on
these new polynomial-time algorithms, we further design a new sandwiching
algorithm, to compute the \emph{exact} $\alpha_k$ with greatly reduced
complexity. When needed, this new sandwiching algorithm also achieves a smooth
tradeoff between computational complexity and result accuracy. Empirical
results show the performance improvements of our algorithm over existing known
methods; and our algorithm outputs precise values of $\alpha_k$, with much
lower complexity than exhaustive search.

categories: cs.IT cs.LG cs.SY math.IT math.OC stat.ML


title:
Bethe ansatz description of edge-localization in the open-boundary XXZ
  spin chain

abstract:
  At large values of the anisotropy \Delta, the open-boundary Heisenberg
spin-1/2 chain has eigenstates displaying localization at the edges. We present
a Bethe ansatz description of this `edge-locking' phenomenon in the entire
\Delta>1 region. We focus on the simplest spin sectors, namely the highly
polarized sectors with only one or two overturned spins, i.e., one-particle and
two-particle sectors. Edge-locking is associated with pure imaginary solutions
of the Bethe equations, which are not commonly encountered in periodic chains.
In the one-particle case, at large anisotropies there are two eigenstates with
imaginary Bethe momenta, related to localization at the two edges. For any
finite chain size, one of the two solutions become real as the anisotropy is
lowered below a certain value. For two particles, a richer scenario is
observed, with eigenstates having the possibility of both particles locked on
the same or different edge, one locked and the other free, and both free either
as single magnons or as bound composites corresponding to `string' solutions.
For finite chains, some of the edge-locked spins get delocalized at certain
values of the anisotropy (`exceptional points'), corresponding to imaginary
solutions becoming real. We characterize these phenomena thoroughly by
providing analytic expansions of the Bethe momenta for large chains, large
anisotropy, and near the exceptional points. In the large-chain limit all the
exceptional points coalesce at the isotropic point (\Delta=1) and edge-locking
becomes stable in the whole \Delta>1 region.

categories: cond-mat.str-el cond-mat.stat-mech math-ph math.MP


title: Deconstruction of Resolution Effects in Angle-Resolved Photoemission

abstract:
  We study how the energy and momentum resolution of angle-resolved
photoemission spectroscopy (ARPES) affects the linewidth, Fermi crossing,
velocity, and curvature of the measured band structure. Based on the fact that
the resolution smooths out the spectra, acting as a low-pass filter, we develop
an iterative simulation scheme that compensates for resolution effects and
allows the fundamental physical parameters to be accurately extracted. By
simulating a parabolic band structure of Fermi-liquid quasiparticles, we show
that this method works for an energy resolution up to 100 meV and a momentum
resolution equal to twice the energy resolution scaled by the Fermi velocity.
Our analysis acquires particular relevance in the hard and soft x-ray regimes,
where a degraded resolution limits the accuracy of the extracted physical
parameters, making it possible to study how the electronic excitations are
modified when the ARPES probing depth increases beyond the surface.