title: On direct summands of homological functors on length categories

abstract:
  We show that direct summands of certain additive functors arising as
bifunctors with a fixed argument in an abelian category are again of that form
whenever the fixed argument has finite length or, more generally, satisfies the
descending chain condition on images of nested endomorphisms. In particular,
this provides a positive answer to a conjecture of M. Auslander in the case of
categories of finite modules over artin algebras. This implies that the
covariant Ext functors are the only injectives in the category of defect-zero
finitely presented functors on such categories.


title:
Dynamical coherence of partially hyperbolic diffeomorphisms of tori
  isotopic to Anosov

abstract:
  We show that partially hyperbolic diffeomorphisms of $d$-dimensional tori
isotopic to an Anosov diffeomorphism, where the isotopy is contained in the set
of partially hyperbolic diffeomorphisms, are dynamically coherent. Moreover, we
show a \textit{global stability result}, i.e. every partially hyperbolic
diffeomorphism as above is \textit{leaf-conjugate} to the linear one. As a
consequence, we obtain intrinsic ergodicity and measure equivalence for
partially hyperbolic diffeomorphisms with one-dimensional center direction that
are isotopic to Anosov diffeomorphisms through such a path.


title:
Computer vision applications for coronagraphic optical alignment and
  image processing

abstract:
  Modern coronagraphic systems require very precise alignment between optical
components and can benefit greatly from automated image processing. We discuss
three techniques commonly employed in the fields of computer vision and image
analysis as applied to the Gemini Planet Imager, a new facility instrument for
the Gemini South Observatory. We describe how feature extraction and clustering
methods can be used to aid in automated system alignment tasks, and also
present a search algorithm for finding regular features in science images used
for calibration and data processing. Along with discussions of each technique,
we present our specific implementation and show results of each one in
operation.


title: AdS/CFT and its Applications

abstract:
  In this thesis we study some applications of the gauge/gravity
correspondence. In chapter 1 we introduce the gauge/gravity conjecture focusing
on the aspects that will be relevant in the rest of the work, in chapter 2 we
extend the Gubser-Klebanov-Polyakov-Witten (GKPW) prescription generalizing it
to gravity backgrounds with two boundaries. In chapter 3 we discuss the
Maldacena-Rey prescription to compute the quark-antiquark (and
monopole-antimonopole) potential in some gravity backgrounds duals to conformal
and non-conformal field theories. In particular, we analyze the stability of
the classical solutions under small fluctuations. In chapter 4 we study the
thermodynamic properties and the entanglement entropy of the 2+1 dimensional
$p$ and $p+ip$ superconductors through their dual gravity backgrounds. We
analyze the limit where the number of charged degrees of freedom is comparable
with the total number of degrees of freedom, which means that the backreaction
on the geometry due to the non-Abelian gauge field is relevant.


title: Filtering the Maximum Likelihood for Multiscale Problems

abstract:
  Filtering and parameter estimation under partial information for multiscale
problems is studied in this paper. After proving mean square convergence of the
nonlinear filter to a filter of reduced dimension, we establish that the
conditional (on the observations) log-likelihood process has a correction term
given by a type of central limit theorem. To achieve this we assume that the
operator of the (hidden) fast process has a discrete spectrum and an
orthonormal basis of eigenfunctions. Based on these results, we then propose to
estimate the unknown parameters of the model based on the limiting
log-likelihood, which is an easier function to optimize because it of reduced
dimension. We also establish consistency and asymptotic normality of the
maximum likelihood estimator based on the reduced log-likelihood. Simulation
results illustrate our theoretical findings.


title: Cold dust in giant barred galaxy NGC1365

abstract:
  Observations of galaxies at sub-millimeter wavelengths, where the emission is
mainly due to cold dust, are required to constrain the dust physical properties
and provide important insight on the gas content of galaxies. We mapped NGC1365
at 870um with LABOCA, the Large APEX Bolometer Camera, allowing us to probe the
central mass concentration as well as the rate at which the gas flows to the
center. We obtained the dust physical properties both globally and locally for
different locations in the galaxy. A 20 K modified black body represents about
98% of the total dust content of the galaxy, the rest can be represented by a
warmer dust component of 40 K. The bar exhibits an east-west asymmetry in the
dust distribution: The eastern bar is heavier than the western bar by more than
a factor of 4. Integrating the dust SED, we derive a total infrared (IR)
luminosity of 9.8 x 10^{10} L_{\odot} leading to a dust-enshrouded star
formation rate of ~16.7 M_{\odot} per year in NGC1365. We derive the gas mass
from the measurements of the dust emission resulting in a CO-to-H2 conversion
factor of X_{CO}~1.2x10^{20} mol cm^{-2} (K km s^{-1})^{-1} in the central disk
including the bar. Taking into account the metallicity variation, the central
gas mass concentration is only ~20% at R<40" (3.6 kpc). On the other hand, the
time-scale with which the gas flows into the center, ~300 Myr, is rather short.
This indicates that the current central mass in NGC1365 is evolving fast due to
the strong bar.


title: Freely Independent Random Variables with Non-Atomic Distributions

abstract:
  We examine the distributions of non-commutative polynomials of non-atomic,
freely independent random variables. In particular, we obtain an analogue of
the Strong Atiyah Conjecture for free groups thus proving that the measure of
each atom of any $n \times n$ matricial polynomial of non-atomic, freely
independent random variables is an integer multiple of $n^{-1}$. In addition,
we show that the Cauchy transform of the distribution of any matricial
polynomial of freely independent semicircular variables is algebraic and thus
the polynomial has a distribution that is real-analytic except at a finite
number of points.


title: FCNC in the minimal 3-3-1 model revisited

abstract:
  We show that in the minimal 3-3-1 model the flavor changing neutral currents
(FCNCs) do not impose necessarily strong constraints on the mass of the
$Z^\prime$ of the model if we also consider the neutral scalar contributions to
such processes, like the neutral mesons mass difference and rare semileptonic
decays. We first obtain numerical values for all the mixing matrices of the
model i.e., the unitary matrices that rotate the left- and right-handed quarks
in each charge sector which give the correct mass of all the quarks and the CKM
mixing matrix. Then, we find that there is a range of parameters in which the
neutral scalar contributions to these processes may interfere with those of the
$Z^\prime$, implying this vector boson may be lighter than it has been thought.


title:
Efficient Accelerated Coordinate Descent Methods and Faster Algorithms
  for Solving Linear Systems

abstract:
  In this paper we show how to accelerate randomized coordinate descent methods
and achieve faster convergence rates without paying per-iteration costs in
asymptotic running time. In particular, we show how to generalize and
efficiently implement a method proposed by Nesterov, giving faster asymptotic
running times for various algorithms that use standard coordinate descent as a
black box. In addition to providing a proof of convergence for this new general
method, we show that it is numerically stable, efficiently implementable, and
in certain regimes, asymptotically optimal.
  To highlight the computational power of this algorithm, we show how it can
used to create faster linear system solvers in several regimes:
  - We show how this method achieves a faster asymptotic runtime than conjugate
gradient for solving a broad class of symmetric positive definite systems of
equations.
  - We improve the best known asymptotic convergence guarantees for Kaczmarz
methods, a popular technique for image reconstruction and solving
overdetermined systems of equations, by accelerating a randomized algorithm of
Strohmer and Vershynin.
  - We achieve the best known running time for solving Symmetric Diagonally
Dominant (SDD) system of equations in the unit-cost RAM model, obtaining an O(m
log^{3/2} n (log log n)^{1/2} log (log n / eps)) asymptotic running time by
accelerating a recent solver by Kelner et al.
  Beyond the independent interest of these solvers, we believe they highlight
the versatility of the approach of this paper and we hope that they will open
the door for further algorithmic improvements in the future.


title:
Charmonium moving through a strongly coupled QCD plasma: a holographic
  perspective

abstract:
  We study the properties of charmonium in a strongly coupled QCD-like plasma
at finite momentum. As a basis for this study, a "bottom-up" holographic model
is used which has been previously shown to reproduce charmonium phenomenology
in vacuum and give a reasonable dissociation temperature at zero momentum. The
finite momentum spectral functions are presented and found to be consistent
with recent lattice results. The in-medium dispersion relation and momentum
dependence of decay width of J/Psi have also been studied. We find no signature
of a subluminal limiting velocity from the dispersion relation, while we note
that the dissociation temperature decreases with momentum faster than previous
holographic models. Based upon the dissociation temperature, a maximum momentum
for J/Psi in medium is identified and its phenomenological implications on
J/Psi suppression are discussed.


title:
Solution of the NLO BFKL Equation and a Strategy for Solving the
  All-Order BFKL Equation

abstract:
  We derive the solution of the NLO BFKL equation by constructing its
eigenfunctions perturbatively, using an expansion around the LO BFKL
(conformal) eigenfunctions. This method can be used to construct a solution of
the BFKL equation with the kernel calculated to an arbitrary order in the
coupling constant.


title:
Speech: A Challenge to Digital Signal Processing Technology for
  Human-to-Computer Interaction

abstract:
  This software project based paper is for a vision of the near future in which
computer interaction is characterized by natural face-to-face conversations
with lifelike characters that speak, emote, and gesture. The first step is
speech. The dream of a true virtual reality, a complete human-computer
interaction system will not come true unless we try to give some perception to
machine and make it perceive the outside world as humans communicate with each
other. This software project is under development for listening and replying
machine (Computer) through speech. The Speech interface is developed to convert
speech input into some parametric form (Speech-to-Text) for further processing
and the results, text output to speech synthesis (Text-to-Speech)


title:
Improving Receiver Performance of Diffusive Molecular Communication with
  Enzymes

abstract:
  This paper studies the mitigation of intersymbol interference in a diffusive
molecular communication system using enzymes that freely diffuse in the
propagation environment. The enzymes form reaction intermediates with
information molecules and then degrade them so that they cannot interfere with
future transmissions. A lower bound expression on the expected number of
molecules measured at the receiver is derived. A simple binary receiver
detection scheme is proposed where the number of observed molecules is sampled
at the time when the maximum number of molecules is expected. Insight is also
provided into the selection of an appropriate bit interval. The expected bit
error probability is derived as a function of the current and all previously
transmitted bits. Simulation results show the accuracy of the bit error
probability expression and the improvement in communication performance by
having active enzymes present.


title: A Krein Quantization Approach to Klein Paradox

abstract:
  In this paper we first introduce the famous Klein paradox. Afterwards by
proposing the Krein quantization approach and taking the negative modes into
account, we will show that the expected and exact current densities, could be
achieved without confronting any paradox.


title:
Evidence for Dust Destruction from the Early-time Colour Change of GRB
  120119A

abstract:
  We present broadband observations and analysis of Swift gamma-ray burst (GRB)
120119A. Our early-time afterglow detections began under 15 s after the burst
in the host frame (redshift z = 1.73), and they yield constraints on the burst
energetics and local environment. Late-time afterglow observations of the burst
show evidence for a moderate column of dust (A_V ~ 1.1 mag) similar to, but
statistically distinct from, dust seen along Small Magellanic Cloud sightlines.
Deep late-time observations reveal a dusty, rapidly star-forming host galaxy.
Most notably, our early-time observations exhibit a significant red-to-blue
colour change in the first ~200 s after the trigger at levels heretofore unseen
in GRB afterglows. This colour change, which is coincident with the final
phases of the prompt emission, is a hallmark prediction of the photodestruction
of dust in GRB afterglows. We test whether dust-destruction signatures are
significantly distinct from other sources of colour change, namely a change in
the intrinsic spectral index {\beta}. We find that a time-varying power-law
spectrum alone cannot adequately describe the observed colour change, and
allowing for dust destruction (via a time-varying A_V) significantly improves
the fit. While not definitively ruling out other possibilities, this event
provides the best support yet for the direct detection of dust destruction in
the local environment of a GRB.


title:
Effective action of 6D F-Theory with U(1) factors: Rational sections
  make Chern-Simons terms jump

abstract:
  We derive the six-dimensional (1,0) effective action arising from F-theory on
an elliptically fibered Calabi-Yau threefold with multiple sections. The
considered theories admit both non-Abelian and Abelian gauge symmetries. Our
derivation employs the M-theory to F-theory duality in five-dimensions after
circle reduction. Five-dimensional gauge and gravitational Chern-Simons terms
are shown to arise at one-loop by integrating out massive Coulomb branch and
Kaluza-Klein modes. In the presence of a non-holomorphic zero section, we find
an improved systematic for performing the F-theory limit by using the concept
of the extended relative Mori cone. In this situation Kaluza-Klein modes can
become lighter than Coulomb branch modes and a jump in the Chern-Simons levels
occurs. By determining Chern-Simons terms for various threefold examples we are
able to compute the complete six-dimensional charged matter spectrum and show
consistency with six-dimensional anomalies.


title: A quantitative witness for Greenberger-Horne-Zeilinger entanglement

abstract:
  Along with the vast progress in experimental quantum technologies there is an
increasing demand for the quantification of entanglement between three or more
quantum systems. Theory still does not provide adequate tools for this purpose.
The objective is, besides the quest for exact results, to develop operational
methods that allow for efficient entanglement quantification. Here we put
forward an analytical approach that serves both these goals. We provide a
simple procedure to quantify Greenberger-Horne-Zeilinger--type multipartite
entanglement in arbitrary three-qubit states. For two qubits this method is
equivalent to Wootters' seminal result [Phys. Rev. Lett. 80, 2245 (1998)]. It
establishes a close link between entanglement quantification and entanglement
detection by witnesses, and can be generalised both to higher dimensions and to
more than three parties.


title:
The HST eXtreme Deep Field XDF: Combining all ACS and WFC3/IR Data on
  the HUDF Region into the Deepest Field Ever

abstract:
  The eXtreme Deep Field (XDF) combines data from ten years of observations
with the HST Advanced Camera for Surveys (ACS) and the Wide-Field Camera 3
Infra-Red (WFC3/IR) into the deepest image of the sky ever in the
optical/near-IR. Since the initial observations on the Hubble Ultra-Deep Field
(HUDF) in 2003, numerous surveys and programs, including supernova followup,
HUDF09, CANDELS, and HUDF12 have contributed additional imaging data across the
HUDF region. Yet these have never been combined and made available as one
complete ultra-deep optical and near-infrared image dataset. We do so now for
the eXtreme Deep Field (XDF) program. Our new and improved processing
techniques provide higher quality reductions of the total dataset. All WFC3
near-IR and optical ACS data sets have been fully combined and accurately
matched, resulting in the deepest imaging ever taken at these wavelengths
ranging from 29.1 to 30.3 AB mag (5sigma in a 0.35" diameter aperture) in 9
filters. The gains in the optical for the four filters done in the original ACS
HUDF correspond to a typical improvement of 0.15 mag, with gains of 0.25 mag in
the deepest areas. Such gains are equivalent to adding ~130 to ~240 orbits of
ACS data to the HUDF. Improved processing alone results in a typical gain of
~0.1 mag. Our 5sigma (optical+near-IR) SExtractor catalogs reveal about 14140
sources in the full field and about 7121 galaxies in the deepest part of the
XDF (the HUDF09 region). The XDF is the deepest image of the universe ever
taken, reaching, in the combined image for a flat f_nu source, to 31.2 AB mag
5sigma (32.9 at 1sigma) in a 0.35" diameter aperture.


title:
Gravitational Waveforms for Precessing, Quasi-circular Binaries via
  Multiple Scale Analysis and Uniform Asymptotics: The Near Spin Alignment Case

abstract:
  We calculate analytical gravitational waveforms in the time- and
frequency-domain for precessing quasi-circular binaries with spins of arbitrary
magnitude, but nearly aligned with the orbital angular momentum. We first
derive an analytical solution to the precession equations by expanding in the
misalignment angle and using multiple scale analysis to separate timescales. We
then use uniform asymptotic expansions to analytically Fourier transform the
time-domain waveform, thus extending the stationary-phase approximation, which
fails when precession is present. The resulting frequency-domain waveform
family has a high overlap with numerical waveforms obtained by direct
integration of the post-Newtonian equations of motion and discrete Fourier
transformations. Such a waveform family lays the foundations for the accurate
inclusion of spin precession effects in analytical gravitational waveforms, and
thus, it can aid in the detection and parameter estimation of gravitational
wave signals from the inspiral phase of precessing binary systems.


title:
HiggsSignals: Confronting arbitrary Higgs sectors with measurements at
  the Tevatron and the LHC

abstract:
  HiggsSignals is a Fortran90 computer code that allows to test the
compatibility of Higgs sector predictions against Higgs rates and masses
measured at the LHC or the Tevatron. Arbitrary models with any number of Higgs
bosons can be investigated using a model-independent input scheme based on
HiggsBounds. The test is based on the calculation of a chi-squared measure from
the predictions and the measured Higgs rates and masses, with the ability of
fully taking into account systematics and correlations for the signal rate
predictions, luminosity and Higgs mass predictions. It features two
complementary methods for the test. First, the peak-centered method, in which
each observable is defined by a Higgs signal rate measured at a specific
hypothetical Higgs mass, corresponding to a tentative Higgs signal. Second, the
mass-centered method, where the test is evaluated by comparing the signal rate
measurement to the theory prediction at the Higgs mass predicted by the model.
The program allows for the simultaneous use of both methods, which is useful in
testing models with multiple Higgs bosons. The code automatically combines the
signal rates of multiple Higgs bosons if their signals cannot be resolved by
the experimental analysis. We compare results obtained with HiggsSignals to
official ATLAS and CMS results for various examples of Higgs property
determinations and find very good agreement. A few examples of HiggsSignals
applications are provided, going beyond the scenarios investigated by the LHC
collaborations. For models with more than one Higgs boson we recommend to use
HiggsSignals and HiggsBounds in parallel to exploit the full constraining power
of Higgs search exclusion limits and the measurements of the signal seen at
around 125.5 GeV.


title:
Interferometric radii of bright Kepler stars with the CHARA Array:
  {\theta} Cygni and 16 Cygni A and B

abstract:
  We present the results of long-baseline optical interferometry observations
using the Precision Astronomical Visual Observations (PAVO) beam combiner at
the Center for High Angular Resolution Astronomy (CHARA) Array to measure the
angular sizes of three bright Kepler stars: {\theta} Cygni, and both components
of the binary system 16 Cygni. Supporting infrared observations were made with
the Michigan Infrared Combiner (MIRC) and Classic beam combiner, also at the
CHARA Array. We find limb-darkened angular diameters of 0.753+/-0.009 mas for
{\theta} Cyg, 0.539+/-0.007 mas for 16 Cyg A and 0.490+/-0.006 mas for 16 Cyg
B. The Kepler Mission has observed these stars with outstanding photometric
precision, revealing the presence of solar-like oscillations. Due to the
brightness of these stars the oscillations have exceptional signal-to-noise,
allowing for detailed study through asteroseismology, and are well constrained
by other observations. We have combined our interferometric diameters with
Hipparcos parallaxes, spectrophotometric bolometric fluxes and the
asteroseismic large frequency separation to measure linear radii ({\theta} Cyg:
1.48+/-0.02 Rsun, 16 Cyg A: 1.22+/-0.02 Rsun, 16 Cyg B: 1.12+/-0.02 Rsun),
effective temperatures ({\theta} Cyg: 6749+/-44 K, 16 Cyg A: 5839+/-42 K, 16
Cyg B: 5809+/-39 K), and masses ({\theta} Cyg: 1.37+/-0.04 Msun, 16 Cyg A:
1.07+/-0.05 Msun, 16 Cyg B: 1.05+/-0.04 Msun) for each star with very little
model dependence. The measurements presented here will provide strong
constraints for future stellar modelling efforts.


title: Stream-orbit misalignment I: The dangers of orbit-fitting

abstract:
  Tidal streams don't, in general, delineate orbits. A stream-orbit
misalignment is expected to lead to biases when using orbit-fitting to
constrain models for the Galactic potential. In this first of two papers we
discuss the expected magnitude of the misalignment and the resulting dangers of
using orbit-fitting algorithms to constrain the potential. We summarize data
for known streams which should prove useful for constraining the Galactic
potential, and compute their actions in a realistic Galactic potential. We go
on to discuss the formation of tidal streams in angle-action space, and explain
why, in general, streams do not delineate orbits. The magnitude of the
stream-orbit misalignment is quantified for a logarithmic potential and a
multi-component Galactic potential. Specifically, we focus on the expected
misalignment for the known streams. By introducing a two-parameter family of
realistic Galactic potentials we demonstrate that assuming these streams
delineate orbits can lead to order one errors in the halo flattening and
halo-to-disc force ratio at the Sun. We present a discussion of the dependence
of these results on the progenitor mass, and demonstrate that the misalignment
is mass-independent for the range of masses of observed streams. Hence,
orbit-fitting does not yield better constraints on the potential if one uses
narrower, lower-mass streams.


title:
Constraints on Dark Matter Protohalos in Effective Theories and
  Neutrinophilic Dark Matter

abstract:
  The mass of primordial dark matter (DM) protohalos remains unknown. However,
the missing satellites problem may be an indication that they are quite large.
In this paper, we use effective field theory to map constraints on dark
matter-SM interactions into limits on the mass of DM protohalos. Given that
leptons remain in the thermal bath until late times, we focus on their
interactions with DM. To illustrate the method, we use the null results of LEP
missing energy searches along with Fermi-LAT searches for DM annihilation in
nearby dwarf galaxies, to derive limits on the protohalo mass, $\lesssim
(10^{-6}-10^{-1}) M_{\odot}$, with the range depending on the DM mass and the
operator. Thus, if DM is to remain thermally coupled until late times and
account for the missing satellites, charged lepton interactions are
insufficient. This motivates neutrinophilic DM, which can have protohalo masses
orders of magnitude larger, with constraints arising from Planck, IceCube and
unpublished Super-K data. We show that effective neutrinophilic models offer a
solution to the missing satellites problem for sub-GeV DM masses with larger
than WIMP-sized annihilation cross sections.


title:
Stream-orbit misalignment II: A new algorithm to constrain the Galactic
  potential

abstract:
  In the first of these two papers we demonstrated that assuming streams
delineate orbits can lead to order one errors in potential parameters for
realistic Galactic potentials. Motivated by the need for an improvement on
orbit-fitting, we now present an algorithm for constraining the Galactic
potential using tidal streams without assuming that streams delineate orbits.
This approach is independent of the progenitor mass so is valid for all
observed tidal streams. The method makes heavy use of angle-action variables
and seeks the potential which recovers the expected correlations in angle
space. We demonstrate that the method can correctly recover the parameters of a
simple two-parameter logarithmic potential by analysing an N-body simulation of
a stream. We investigate the magnitude of the errors in observational data for
which the method can still recover the correct potential and compare this to
current and future errors in data. The errors in the observables of individual
stars for current and near future data are shown to be too large for the direct
use of this method, but when the data are averaged in bins on the sky, the
resulting averaged data are accurate enough to constrain correctly the
potential parameters for achievable observational errors. From pseudo-data with
errors comparable to those that will be furnished in the era of Gaia (20 per
cent distance errors, 1.2 mas/yr proper motion errors, and 10 km/s
line-of-sight velocity errors) we recover the circular velocity, V_c=220 km/s,
and the flattening of the potential, q=0.9, to be V_c=223+/-10km/s and
q=0.91+/-0.09.


title:
Dust-obscured star-formation in the outskirts of XMMU J2235.3-2557, a
  massive galaxy cluster at z=1.4

abstract:
  Star-formation in the galaxy populations of local massive clusters is reduced
with respect to field galaxies, and tends to be suppressed in the core region.
Indications of a reversal of the star-formation--density relation have been
observed in a few z >1.4 clusters. Using deep imaging from 100-500um from PACS
and SPIRE onboard Herschel, we investigate the infrared properties of
spectroscopic and photo-z cluster members, and of Halpha emitters in XMMU
J2235.3-2557, one of the most massive, distant, X-ray selected clusters known.
Our analysis is based mostly on fitting of the galaxies spectral energy
distribution in the rest-frame 8-1000um. We measure total IR luminosity,
deriving star formation rates (SFRs) ranging from 89-463 Msun/yr for 13
galaxies individually detected by Herschel, all located beyond the core region
(r >250 kpc). We perform a stacking analysis of nine star-forming members not
detected by PACS, yielding a detection with SFR=48 Msun/yr. Using a color
criterion based on a star-forming galaxy SED at the cluster redshift we select
41 PACS sources as candidate star-forming cluster members. We characterize a
population of highly obscured SF galaxies in the outskirts of XMMU
J2235.3-2557. We do not find evidence for a reversal of the SF-density relation
in this massive, distant cluster.


title: Quantum spectral curve for AdS_5/CFT_4

abstract:
  We present a new formalism, alternative to the old TBA-like approach, for
solution of the spectral problem of planar N = 4 SYM. It takes a concise form
of a non-linear matrix Riemann-Hilbert problem in terms of a few Q-functions.
We demonstrate the formalism for two types of observables - local operators at
weak coupling and cusped Wilson lines in a near BPS limit.


title: $Hb\bar{b}$ production in Composite Higgs Models

abstract:
  New vector-like quarks with electric charge 2/3 and -1/3 can be singly
produced at hadron colliders through the exchange of a color octet vector
resonance in models of strong electroweak symmetry breaking. We show that
electroweak symmetry breaking effects can have a significant impact on the
decay pattern of these new quarks. In particular, single production of charge
-1/3 fermion resonances, mediated by a color octet vector resonance, typically
results in an $H b\bar{b}$ final state with a sizeable cross section and very
distinctive kinematics. We consider the leading $H\to b\bar{b}$ decay and show
that the $4b$ signal can be very efficiently disentangled from the background:
heavy octet masses of up to 3 TeV can be tested with the data already collected
at the LHC and up to 5 TeV with an integrated luminosity of 100 fb$^{-1}$ at
$\sqrt{s}=14$ TeV. We also discuss the kinematical differences between the
$Hb\bar{b}$ production in models of strong electroweak symmetry breaking and
supersymmetric models and the implications on the phenomenology of non-minimal
composite Higgs models.


title:
On boundary fusion and functional relations in the Baxterized affine
  Hecke algebra

abstract:
  We construct boundary type operators satisfying fused reflection equation for
arbitrary representations of the Baxterized affine Hecke algebra. These
operators are analogues of the fused reflection matrices in solvable half-line
spin chain models. We show that these operators lead to a family of commuting
transfer matrices of Sklyanin type. We derive fusion type functional relations
for these operators for two families of representations.


title: Can dark energy viscosity be detected with the Euclid survey?

abstract:
  Recent work has demonstrated that it is important to constrain the dynamics
of cosmological perturbations, in addition to the evolution of the background,
if we want to distinguish among different models of the dark sector. Especially
the anisotropic stress of the (possibly effective) dark energy fluid has been
shown to be an important discriminator between modified gravity and dark energy
models. In this paper we use approximate analytical solutions of the
perturbation equations in the presence of viscosity to study how the
anisotropic stress affects the weak lensing and galaxy power spectrum. We then
forecast how sensitive the photometric and spectroscopic Euclid surveys will be
to both the speed of sound and the viscosity of our effective dark energy fluid
when using weak lensing tomography and the galaxy power spectrum. We find that
Euclid alone can only constrain models with very small speed of sound and
viscosity, while it will need the help of other observables in order to give
interesting constraints on models with a sound speed close to one. This
conclusion is also supported by the expected Bayes factor between models.


title:
Quiescent Galaxies in the 3D-HST Survey: Spectroscopic Confirmation of a
  Large Number of Galaxies with Relatively Old Stellar Populations at z~2

abstract:
  Quiescent galaxies at z~2 have been identified in large numbers based on
rest-frame colors, but only a small number of these galaxies have been
spectroscopically confirmed to show that their rest-frame optical spectra show
either strong Balmer or metal absorption lines. Here, we median stack the
rest-frame optical spectra for 171 photometrically-quiescent galaxies at 1.4 <
z < 2.2 from the 3D-HST grism survey. In addition to Hbeta (4861A), we
unambiguously identify metal absorption lines in the stacked spectrum,
including the G-band (4304A), Mg I (5175A), and Na I (5894A). This finding
demonstrates that galaxies with relatively old stellar populations already
existed when the universe was ~3 Gyr old, and that rest-frame color selection
techniques can efficiently select them. We find an average age of 1.3^0.1_0.3
Gyr when fitting a simple stellar population to the entire stack. We confirm
our previous result from medium-band photometry that the stellar age varies
with the colors of quiescent galaxies: the reddest 80% of galaxies are
dominated by metal lines and have a relatively old mean age of 1.6^0.5_0.4 Gyr,
whereas the bluest (and brightest) galaxies have strong Balmer lines and a
spectroscopic age of 0.9^0.2_0.1 Gyr. Although the spectrum is dominated by an
evolved stellar population, we also find [OIII] and Hbeta emission.
Interestingly, this emission is more centrally concentrated than the continuum
with L_[OIII] = 1.7 +/- 0.3 x 10^40 erg s^-1, indicating residual central star
formation or nuclear activity.


title: Analytic Solution of Bremsstrahlung TBA II: Turning on the Sphere Angle

abstract:
  We find an exact analytical solution of the Y-system describing a cusped
Wilson line in the planar limit of N=4 SYM. Our explicit solution describes
anomalous dimensions of this family of observables for any value of the `t
Hooft coupling and arbitrary R-charge L of the local operator inserted on the
cusp in a near-BPS limit. Our finding generalizes the previous results of one
of the authors & Sever and passes several nontrivial tests. First, for a
particular case L=0 we reproduce the predictions of localization techniques.
Second, we show that in the classical limit our result perfectly reproduces the
existing prediction from classical string theory. In addition, we made a
comparison with all existing weak coupling results and we found that our result
interpolates smoothly between these two very different regimes of AdS/CFT. As a
byproduct we found a generalization of the essential parts of the FiNLIE
construction for the gamma-deformed case and discuss our results in the
framework of the novel ${\bf P}\mu$-formulation of the spectral problem.


title: NuSTAR discovery of a 3.76-second transient magnetar near Sagittarius A*

abstract:
  We report the discovery of 3.76-s pulsations from a new burst source near Sgr
A* observed by the NuSTAR Observatory. The strong signal from SGR J1745-29
presents a complex pulse profile modulated with pulsed fraction 27+/-3 % in the
3-10 keV band. Two observations spaced 9 days apart yield a spin-down rate of
Pdot = (6.5+/-1.4)x10^{-12}. This implies a magnetic field B = 1.6x10^14 G,
spin-down power Edot = 5x10^33 erg/s, and characteristic age P/2Pdot = 9x10^3
yr, for the rotating dipole model. However, the current Pdot may be erratic,
especially during outburst. The flux and modulation remained steady during the
observations and the 3-79 keV spectrum is well fitted by a combined blackbody
plus power-law model with temperature kT_BB = 0.96+/-0.02 keV and photon index
= 1.5+/-0.4, respectively. The neutral hydrogen column density (nH ~ 1.4x10^23
cm^{-2}) measured by NuSTAR and Swift suggests that SGR J1745-29 is located at
or near the Galactic Center. The lack of an X-ray counterpart in the published
Chandra survey catalog sets a quiescent 2-8 keV luminosity limit of Lx ~< 10^32
erg/s. The bursting, timing, and spectral properties indicate a transient
magnetar undergoing an outburst with 2-79 keV luminosity up to 3.5x10^35 erg/s
for a distance of 8 kpc. SGR J1745-29 joins a growing subclass of transient
magnetars, indicating that many magnetars in quiescence remain undetected in
the X-ray band or have been detected as high-B radio pulsars. The peculiar
location of SGR J1745-29 has important implications for the formation and
dynamics of neutron stars in the Galactic Center region.


title: Semantic-based Anomalous Pattern Discovery in Moving Object Trajectories

abstract:
  In this work, we investigate a novel semantic approach for pattern discovery
in trajectories that, relying on ontologies, enhances object movement
information with event semantics. The approach can be applied to the detection
of movement patterns and behaviors whenever the semantics of events occurring
along the trajectory is, explicitly or implicitly, available. In particular, we
tested it against an exacting case scenario in maritime surveillance, i.e., the
discovery of suspicious container transportations.
  The methodology we have developed entails the formalization of the
application domain through a domain ontology, extending the Moving Object
Ontology (MOO) described in this paper. Afterwards, movement patterns have to
be formalized, either as Description Logic (DL) axioms or queries, enabling the
retrieval of the trajectories that follow the patterns.
  In our experimental evaluation, we have considered a real world dataset of 18
Million of container events describing the deed undertaken in a port to
accomplish the shipping (e.g., loading on a vessel, export operation).
Leveraging events, we have reconstructed almost 300 thousand container
trajectories referring to 50 thousand containers travelling along three years.
We have formalized the anomalous itinerary patterns as DL axioms, testing
different ontology APIs and DL reasoners to retrieve the suspicious
transportations.
  Our experiments demonstrate that the approach is feasible and efficient. In
particular, the joint use of Pellet and SPARQL-DL enables to detect the
trajectories following a given pattern in a reasonable time with big size
datasets.


title: Evading the Lyth Bound in Hybrid Natural Inflation

abstract:
  Generically, the gravitational-wave or tensor-mode contribution to the
primordial curvature spectrum of inflation is tiny if the field-range of the
inflaton is much smaller than the Planck scale. We show that this pessimistic
conclusion is naturally avoided in a rather broad class of small-field models.
More specifically, we consider models where an axion-like shift symmetry keeps
the inflaton potential flat (up to non-perturbative cosine-shaped modulations),
but inflation nevertheless ends in a waterfall-regime, as is typical for hybrid
inflation. In such hybrid natural inflation scenarios (examples are provided by
Wilson line inflation and fluxbrane inflation), the slow-roll parameter
$\epsilon$ can be sizable during an early period (relevant for the CMB
spectrum). Subsequently, $\epsilon$ quickly becomes very small before the
tachyonic instability eventually terminates the slow roll regime. In this
scenario, one naturally generates a considerable tensor-mode contribution in
the curvature spectrum, collecting nevertheless the required amount of
e-foldings during the final period of inflation. While non-observation of
tensors by Planck is certainly not a problem, a discovery in the medium to long
term future is realistic.


title:
Microphase separation as the cause of structural complexity in 2D
  liquids

abstract:
  Complex behavior in glassforming liquids is associated with formation of a
mosaic of different structures. Using bond order parameters together with
topological characteristics of the bond network, we show that in the mosaic of
crystalline and amorphous clusters found in a 2D liquid the difference between
structural sub- components translates into a difference between two coexisting
phases. We suggest that the observed microphase separated mosaic is a 2D
realization of what is usually invoked to explain special features found in 3D
complex liquids. Conditions favoring mosaic stability are discussed; these
conditions include a new type of critical behavior and long-range correlations
between sub-component clusters.


title:
Bulk Entanglement Spectrum Reveals Quantum Criticality within a
  Topological State

abstract:
  A quantum phase transition is usually achieved by tuning physical parameters
in a Hamiltonian at zero temperature. Here, we demonstrate that the ground
state of a topological phase itself encodes critical properties of its
transition to a trivial phase. To extract this information, we introduce a
partition of the system into two subsystems both of which extend throughout the
bulk in all directions. The resulting bulk entanglement spectrum has a
low-lying part that resembles the excitation spectrum of a bulk Hamiltonian,
which allows us to probe a topological phase transition from a single
wavefunction by tuning either the geometry of the partition or the entanglement
temperature. As an example, this remarkable correspondence between topological
phase transition and entanglement criticality is rigorously established for
integer quantum Hall states.


title:
Transponder delay effect in light time calculations for deep space
  navigation

abstract:
  During the last decade, the precision in the tracking of spacecraft has
constantly improved. The discovery of few astrometric anomalies, such as the
Pioneer and Earth flyby anomalies, stimulated further analysis of the operative
modeling currently adopted in Deep Space Navigation (DSN). Our study shows that
some traditional approximations lead to neglect tiny terms that could have
consequences in the orbit determination of a probe in specific configurations
such as during an Earth flyby. Therefore, we suggest here a way to improve the
light time calculation used for probe tracking.


title: Two New Long-Period Hot Subdwarf Binaries with Dwarf Companions

abstract:
  Hot subdwarf stars with F-K main sequence binary companions have been known
for decades, but the first orbital periods for such systems were published just
recently. Current observations suggest that most have long periods, on the
order of years, and that some are or once were hierarchical triple systems. As
part of a survey with the Hobby-Eberly Telescope, we have been monitoring the
radial velocities of several composite-spectra binaries since 2005 in order to
determine their periods, velocities, and eccentricities. Here we present
observations and orbital solutions for two of these systems, PG 1449+653 and PG
1701+359. Similar to the other sdB+F/G/K binaries with solved orbits, their
periods are long, 909 d and 734 d, respectively, and pose a challenge to
current binary population synthesis models of hot subdwarf stars. Intrigued by
their relatively large systemic velocities, we also present a kinematical
analysis of both targets and find that neither is likely a member of the
Galactic thin disk.


title: Non-linear and chaotic dynamo regimes

abstract:
  An update is given on the current status of solar and stellar dynamos. At
present, it is still unclear why stellar cycle frequencies increase with
rotation frequency in such a way that their ratio increases with stellar
activity. The small-scale dynamo is expected to operate in spite of a small
value of the magnetic Prandtl number in stars. Whether or not the global
magnetic activity in stars is a shallow or deeply rooted phenomenon is another
open question. Progress in demonstrating the presence and importance of
magnetic helicity fluxes in dynamos is briefly reviewed, and finally the role
of nonlocality is emphasized in modeling stellar dynamos using the mean-field
approach. On the other hand, direct numerical simulations have now come to the
point where the models show solar-like equatorward migration that can be
compared with observations and that need to be understood theoretically.


title: Majorana fermions and non-locality

abstract:
  Localized Majorana fermions emerge in many topologically ordered systems and
exhibit exchange statistics of Ising anyons. This enables noise-resistant
implementation of a limited set of operations by braiding and fusing Majorana
fermions. Unfortunately, these operations are incapable of implementing
universal quantum computation. We show that, regardless of these limitations,
Majorana fermions could be used to demonstrate non-locality (correlations
incompatible with a local hidden variable theory) in experiments using only
topologically protected operations. We also demonstrate that our proposal is
optimal in terms of resources, with 10 Majorana fermions shown to be both
necessary and sufficient for demonstrating bipartite non-locality. Furthermore,
we identify severe restrictions on the possibility of tripartite non-locality.
We comment on the potential of such entangled systems to be used in quantum
information protocols.


title: Interstellar detection of c-C3D2

abstract:
  We report the first interstellar detection of c-C3D2. The doubly deuterated
cyclopropenylidene, a carbene, has been detected toward the starless cores TMC-
1C and L1544 using the IRAM 30m telescope. The J(Ka,Kc) = 3(0,3)-2(1,2),
3(1,3)-2(0,2), and 2(2,1)-1(1,0) transitions of this species have been observed
at 3 mm in both sources. The expected 1:2 intensity ratio has been found in the
3(0,3)-2(1,2) and 3(1,3)-2(0,2) lines, belonging to the para and ortho species
respectively. We also observed lines of the main species, c-C3H2, the singly
deuterated c-C3HD, and the species with one 13C off of the principal axis of
the molecule, c-H13CC2H. The lines of c-C3D2 have been observed with high
signal to noise ratio, better than 7.5 sigma in TMC-1C and 9 sigma in L1544.
The abundance of doubly deuterated cyclopropenylidene with respect to the
normal species is found to be (0.4 - 0.8)% in TMC-1C and (1.2 - 2.1)% in L1544.
The deuteration of this small hydrocarbon ring is analysed with a comprehensive
gas-grain model, the first including doubly deuterated species. The observed
abundances of c-C3D2 can be explained solely by gas-phase processes, supporting
the idea that c-C3H2 is a good indicator of gas-phase deuteration.


title: A Classical Version of the Non-Abelian Gauge Anomaly

abstract:
  We show that a version of the covariant gauge anomaly for a 3+1 dimensional
chiral fermion interacting with a non-Abelian gauge field can be obtained from
the classical Hamiltonian flow of its probability distribution in phase space.
The only quantum input needed is the Berry phase that arises from the direction
of the spin being slaved to the particle's momentum.


title:
Joint Topic Modeling and Factor Analysis of Textual Information and
  Graded Response Data

abstract:
  Modern machine learning methods are critical to the development of
large-scale personalized learning systems that cater directly to the needs of
individual learners. The recently developed SPARse Factor Analysis (SPARFA)
framework provides a new statistical model and algorithms for machine
learning-based learning analytics, which estimate a learner's knowledge of the
latent concepts underlying a domain, and content analytics, which estimate the
relationships among a collection of questions and the latent concepts. SPARFA
estimates these quantities given only the binary-valued graded responses to a
collection of questions. In order to better interpret the estimated latent
concepts, SPARFA relies on a post-processing step that utilizes user-defined
tags (e.g., topics or keywords) available for each question. In this paper, we
relax the need for user-defined tags by extending SPARFA to jointly process
both graded learner responses and the text of each question and its associated
answer(s) or other feedback. Our purely data-driven approach (i) enhances the
interpretability of the estimated latent concepts without the need of
explicitly generating a set of tags or performing a post-processing step, (ii)
improves the prediction performance of SPARFA, and (iii) scales to large
test/assessments where human annotation would prove burdensome. We demonstrate
the efficacy of the proposed approach on two real educational datasets.


title:
Binned Hubble parameter measurements and the cosmological
  deceleration-acceleration transition

abstract:
  Weighted mean and median statistics techniques are used to combine 23
independent lower redshift, $z<1.04$, Hubble parameter, $H(z)$, measurements
and determine binned forms of $H(z)$. When these are combined with 5 higher
redshift, $1.3\leqslant z \leqslant 2.3$, $H(z)$ measurements the resulting
constraints on cosmological parameters, of three cosmological models, that
follow from the weighted-mean binned data are almost identical to those derived
from analyses using the 28 independent $H(z)$ measurements. This is consistent
with what is expected if the lower redshift measurements errors are Gaussian.
Plots of the binned weighted-mean $H(z)/(1+z)$ versus $z$ data are consistent
with the presence of a cosmological deceleration-acceleration transition at
redshift $z_{\rm da}=0.74 \pm 0.05$ \citep{farooq3}, which is expected in
cosmological models with present-epoch energy budget dominated by dark energy
as in the standard spatially-flat $\Lambda$CDM cosmological model.


title: The Dynamically Extended Mind -- A Minimal Modeling Case Study

abstract:
  The extended mind hypothesis has stimulated much interest in cognitive
science. However, its core claim, i.e. that the process of cognition can extend
beyond the brain via the body and into the environment, has been heavily
criticized. A prominent critique of this claim holds that when some part of the
world is coupled to a cognitive system this does not necessarily entail that
the part is also constitutive of that cognitive system. This critique is known
as the "coupling-constitution fallacy". In this paper we respond to this
reductionist challenge by using an evolutionary robotics approach to create a
minimal model of two acoustically coupled agents. We demonstrate how the
interaction process as a whole has properties that cannot be reduced to the
contributions of the isolated agents. We also show that the neural dynamics of
the coupled agents has formal properties that are inherently impossible for
those neural networks in isolation. By keeping the complexity of the model to
an absolute minimum, we are able to illustrate how the coupling-constitution
fallacy is in fact based on an inadequate understanding of the constitutive
role of nonlinear interactions in dynamical systems theory.


title: Multi-wavelength studies of the gamma-ray pulsar PSR J1907+0602

abstract:
  PSR J1907+0602 is a radio-faint, 107-ms GeV gamma-ray pulsar that was
discovered with the Fermi LAT in a blind pulsar search. PSR J1907+0602 is
located near the bright, extended TeV gamma-ray source MGRO J1908+06 which may
be an associated pulsar wind nebula. We present an analysis of XMM-Newton X-ray
data and EVLA radio data of the pulsar. We detect a faint X-ray source
coincident with the gamma-ray pulsar and investigate its spectral and timing
properties. We also find marginal evidence for a bow shock in the X-ray images.
The pulsar was not detected with the EVLA, and we derive upper limits on the
time-averaged radio flux in multiple frequency bands.


title: Edges, Orbifolds, and Seiberg-Witten Theory

abstract:
  Seiberg-Witten theory is used to obtain new obstructions to the existence of
Einstein metrics on 4-manifolds with conical singularities along an embedded
surface. In the present article, the cone angle is required to be of the form
2(pi)/p, where p is a positive integer, but we conjecture that similar results
will also hold in greater generality.


title: An Improved Three-Weight Message-Passing Algorithm

abstract:
  We describe how the powerful "Divide and Concur" algorithm for constraint
satisfaction can be derived as a special case of a message-passing version of
the Alternating Direction Method of Multipliers (ADMM) algorithm for convex
optimization, and introduce an improved message-passing algorithm based on
ADMM/DC by introducing three distinct weights for messages, with "certain" and
"no opinion" weights, as well as the standard weight used in ADMM/DC. The
"certain" messages allow our improved algorithm to implement constraint
propagation as a special case, while the "no opinion" messages speed
convergence for some problems by making the algorithm focus only on active
constraints. We describe how our three-weight version of ADMM/DC can give
greatly improved performance for non-convex problems such as circle packing and
solving large Sudoku puzzles, while retaining the exact performance of ADMM for
convex problems. We also describe the advantages of our algorithm compared to
other message-passing algorithms based upon belief propagation.


title: Sum list coloring, the sum choice number, and sc-greedy graphs

abstract:
  Let G=(V,E) be a graph and let f be a function that assigns list sizes to the
vertices of G. It is said that G is f-choosable if for every assignment of
lists of colors to the vertices of G for which the list sizes agree with f,
there exists a proper coloring of G from the lists. The sum choice number is
the minimum of the sum of list sizes for f over all choosable functions f for
G. The sum choice number of a graph is always at most the sum |V|+|E|. When the
sum choice number of G is equal to this upper bound, G is said to be sc-greedy.
In this paper, we determine the sum choice number of all graphs on five
vertices, show that trees of cycles are sc-greedy, and present some new general
results about sum list coloring.


title: Hydrodynamical Simulations of the Barred Spiral Galaxy NGC 1097

abstract:
  NGC 1097 is a nearby barred spiral galaxy believed to be interacting with the
elliptical galaxy NGC 1097A located to its northwest. It hosts a Seyfert 1
nucleus surrounded by a circumnuclear starburst ring. Two straight dust lanes
connected to the ring extend almost continuously out to the bar. The other ends
of the dust lanes attach to two main spiral arms. To provide a physical
understanding of its structural and kinematical properties, two-dimensional
hydrodynamical simulations have been carried out. Numerical calculations reveal
that many features of the gas morphology and kinematics can be reproduced
provided that the gas flow is governed by a gravitational potential associated
with a slowly rotating strong bar. By including the self-gravity of the gas
disk in our calculation, we have found the starburst ring to be gravitationally
unstable which is consistent with the observation in \citet{hsieh11}. Our
simulations show that the gas inflow rate is 0.17 M$_\sun$ yr$^{-1}$ into the
region within the starburst ring even after its formation, leading to the
coexistence of both a nuclear ring and a circumnuclear disk.


title: Collisions with other Universes: the Optimal Analysis of the WMAP data

abstract:
  An appealing theory is that our current patch of universe was born as a
nucleation bubble from a phase of false vacuum eternal inflation. We search for
evidence for this theory by looking for the signal imprinted on the CMB that is
generated when another bubble "universe" collides with our own. We create an
efficient and optimal estimator for the signal in the WMAP 7-year data. We find
no detectable signal, and constrain the amplitude, a, of the initial curvature
perturbation that would be generated by a collision: -4.66 \times 10^{-8} < a
(\sin{\thetabubble})^{4/3} < 4.73 \times 10^{-8} [Mpc^{-1}] at 95% confidence
where \thetabubble is the angular radius of the bubble signal.


title:
The proof of the Kontsevich periodicity conjecture on noncommutative
  birational transformations

abstract:
  For an arbitrary associative unital ring $R$, let $J_1$ and $J_2$ be the
following noncommutative birational partly defined involutions on the set
$M_3(R)$ of $3\times 3$ matrices over $R$: $J_1(M)=M^{-1}$ (the usual matrix
inverse) and $J_2(M)_{jk}=(M_{kj})^{-1}\,$ (the transpose of the Hadamard
inverse).
  We prove the following surprising conjecture by Kontsevich saying that
$(J_2\circ J_1)^3$ is the identity map modulo the ${\rm Diag}_{L} \times
\rm{Diag}_R$ action $(D_1,D_2)(M)=D_1^{-1}MD_2$ of pairs of invertible diagonal
matrices.
  That is, we show that for each $M$ in the domain where $(J_2\circ J_1)^3$ is
defined, there are invertible diagonal $3\times 3$ matrices $D_1=D_1(M)$ and
$D_2=D_2(M)$ such that $(J_2\circ J_1)^3(M)=D_1^{-1}MD_2.$

categories: math.RA math-ph math.DS math.MP math.QA math.RT


title: Multiple hypergeometric series -- Appell series and beyond

abstract:
  This survey article (which will appear as a chapter in the book ``Computer
Algebra in Quantum Field Theory: Integration, Summation and Special
Functions'', Springer-Verlag) provides a small collection of basic material on
multiple hypergeometric series of Appell-type and of more general series of
related type.


title: Bifurcations of transition states: Morse bifurcations

abstract:
  A transition state for a Hamiltonian system is a closed, invariant, oriented,
codimension-2 submanifold of an energy-level that can be spanned by two compact
codimension-1 surfaces of unidirectional flux whose union, called a dividing
surface, locally separates the energy-level into two components and has no
local recrossings. For this to happen robustly to all smooth perturbations, the
transition state must be normally hyperbolic. The dividing surface then has
locally minimal geometric flux through it, giving an upper bound on the rate of
transport in either direction. Transition states diffeomorphic to $\mathbb
S^{2m-3}$ are known to exist for energies just above any index-1 critical point
of a Hamiltonian of $m$ degrees of freedom, with dividing surfaces $\mathbb
S^{2m-2}$. The question addressed here is what qualitative changes in the
transition state, and consequently the dividing surface, may occur as the
energy or other parameters are varied? We find that there is a class of systems
for which the transition state becomes singular and then regains normal
hyperbolicity with a change in diffeomorphism class. These are Morse
bifurcations. Various examples are considered. Firstly, some simple examples in
which transition states connect or disconnect, and the dividing surface may
become a torus or other. Then, we show how sequences of Morse bifurcations
producing various interesting forms of transition state and dividing surface
are present in reacting systems, by considering a hypothetical class of
bimolecular reactions in gas phase.

categories: nlin.CD math-ph math.DS math.MP physics.chem-ph


title: Detection of HI in distant galaxies using spectral stacking

abstract:
  Using the Parkes radio telescope, we study the 21cm neutral hydrogen (HI)
properties of a sample of galaxies with redshifts z<0.13 extracted from the
optical 2dF Galaxy Redshift Survey (2dFGRS). Galaxies at 0.04<z<0.13 are
studied using new Parkes observations of a 42deg^2 field near the South
Galactic Pole (SGP). A spectral stacking analysis of the 3,277 2dFGRS objects
within this field results in a convincing 12sigma detection. For the
low-redshift sample at 0<z<0.04, we use the 15,093 2dFGRS galaxies observed by
the HI Parkes All-Sky Survey (HIPASS) and find a 31sigma stacked detection. We
measure average HI masses of (6.93 +/- 0.17)*10^9 h^{-2} Msun and (1.48 +/-
0.03)*10^9 h^{-2} Msun for the SGP and HIPASS samples, respectively. Accounting
for source confusion and sample bias, we find a cosmic HI mass density of
Omega_HI=(3.19_{-0.59} ^{+0.43})*10^{-4} h^{-1} for the SGP sample and
(2.82_{-0.59}^{+0.30})*10^{-4} h^{-1} for the HIPASS sample. This suggests no
(12 +/- 23%) evolution in the cosmic HI density over the last ~1h^{-1} Gyr. Due
to the very large effective volumes, cosmic variance in our determination of
Omega_HI is considerably lower than previous estimates. Our stacking analysis
reproduces and quantifies the expected trends in the HI mass and mass-to-light
ratio of galaxies with redshift, luminosity and colour.


title: Phase Conjugation in Quantum Optomechanics

abstract:
  We analyze the phase conjugate coupling of a pair of optomechanical
oscillator modes driven by the time-dependent beat-note due to a two-color
optical field. The dynamics of the direct and phase conjugate modes exhibit
familiar time-reversed qualities, leading to opposite sign temperatures for the
modes in the classical regime of operation, but these features are limited by
quantum effects due to the non-commutative nature of quantum mechanical
operators. The effects are measurable by read-out of the oscillator via a
qubit. As a potential application of this system in sensing, we discuss a
protocol applying phase-conjugate swaps to cancel external forces acting on the
system.


title: Optimal analysis of azimuthal features in the CMB

abstract:
  We present algorithms for searching for azimuthally symmetric features in CMB
data. Our algorithms are fully optimal for masked all-sky data with
inhomogeneous noise, computationally fast, simple to implement, and make no
approximations. We show how to implement the optimal analysis in both Bayesian
and frequentist cases. In the Bayesian case, our algorithm for evaluating the
posterior likelihood is so fast that we can do a brute-force search over
parameter space, rather than using a Monte Carlo Markov chain. Our motivating
example is searching for bubble collisions, a pre-inflationary signal which can
be generated if multiple tunneling events occur in an eternally inflating
spacetime, but our algorithms are general and should be useful in other
contexts.


title: Goldstone Bosons as Fractional Cosmic Neutrinos

abstract:
  It is suggested that Goldstone bosons may be masquerading as fractional
cosmic neutrinos, contributing about 0.39 to what is reported as the effective
number of neutrino types in the era before recombination. The broken symmetry
associated with these Goldstone bosons is further speculated to be the
conservation of the particles of dark matter.


title:
Superfluid, staggered state, and Mott insulator of repulsively
  interacting three-component fermionic atoms in optical lattices

abstract:
  We review our theoretical analysis of repulsively interacting three-component
fermionic atoms in optical lattices. We discuss quantum phase transitions at
around half filling with a balanced population by focusing on Mott transitions,
staggered ordering, and superfluidity. At half filling (with 3/2 atoms per
site), characteristic Mott transitions are induced by the anisotropic
interactions, where two-particle repulsions between any two of the three colors
have different strengths. At half filling, two types of staggered ordered
states appear at low temperatures depending on the anisotropy of the
interactions. As the temperature increases, phase transitions occur from the
staggered ordered states to the unordered Mott states. Deviating from half
filling, an exotic superfluid state appears close to a regime in which the Mott
transition occurs. We explain the origin of these phase transitions and present
the finite-temperature phase diagrams.


title: Electroweak Baryogenesis with a Supersymmetric Sector

abstract:
  We study a model with an exotic new sector strongly coupled to the Higgs
boson, in which supersymmetry is introduced to protect the quartic coupling
from a large running and avoid potential vacuum stability problem. The
fermionic components present vector like mass terms, through which the Higgs
diphoton decay branching ratio can be tuned. The bosonic components trigger a
strongly first order electroweak phase transition. We find a large parameter
region of effective Yukawa coupling $y\gtrsim2$ and mass parameters $m_f\sim
m_s$ of a few hundred GeV, that can simultaneously accommodate the diphoton
excess and electroweak baryogenesis, without vacuum stability and electroweak
precision measurement problems.


title:
Surface tension of the core-crust interface of neutron stars with global
  charge neutrality

abstract:
  It has been shown recently that taking into account strong, weak,
electromagnetic, and gravitational interactions, and fulfilling the global
charge neutrality of the system, a transition layer will happen between the
core and crust of neutron stars, at the nuclear saturation density. We use
relativistic mean field theory together with the Thomas-Fermi approximation to
study the detailed structure of this transition layer and calculate its surface
and Coulomb energy. We find that the surface tension is proportional to a
power-law function of the baryon number density in the core bulk region. We
also analyze the influence of the electron component and the gravitational
field on the structure of the transition layer and the value of the surface
tension to compare and contrast with known phenomenological results in nuclear
physics. Based on the above results we study the instability against
Bohr-Wheeler surface deformations in the case of neutron stars obeying global
charge neutrality. Assuming the core-crust transition at nuclear density
$\rho_{core}\approx 2.7 * 10^{14}$ g cm$^{-3}$, we find that the instability
sets the upper limit to the crust density, $\rho_{crust}^{crit}\approx 1.2 *
10^{14}$ g cm$^{-3}$. This result implies a nonzero lower limit to the maximum
electric field of the core-crust transition surface and makes inaccessible a
limit of quasilocal charge neutrality in the limit $\rho_{crust}=\rho_{core}$.
The general framework presented here can be also applied to study the stability
of sharp phase transitions in hybrid stars as well as in strange stars, both
bare and with outer crust. The results of this work open the way to a more
general analysis of the stability of these transition surfaces, accounting for
other effects such as gravitational binding, centrifugal repulsion, magnetic
field induced by rotating electric field, and therefore magnetic dipole-dipole
interactions.


title: Infinite Volume Limit for Correlation functions in the Dipole Gas

abstract:
  We study a classical lattice dipole gas with low activity in dimension $d
\geq 3$. We investigate long distance properties by a renormalization group
analysis. We prove that various correlation functions have an infinite volume
limit. We also get estimates on the decay of correlation functions.


title: Statistics of extreme objects in the Juropa Hubble Volume simulation

abstract:
  We present the first results from the JUropa huBbLE volumE (Jubilee) project,
based a large N-body, dark matter-only cosmological simulation with a volume of
$V=(6 h^{-1}\mathrm{Gpc})^3$, containing 6000$^3$ particles, performed within
the concordance $\Lambda$CDM cosmological model. The simulation volume is
sufficient to probe extremely large length scales in the universe, whilst at
the same time the particle count is high enough so that dark matter haloes down
to $1.5\times10^{12} h^{-1}\mathrm{M}_\odot$ can be resolved. At $z = 0$ we
identify over 400 million haloes. The cluster mass function is derived using
three different halofinders and compared to fitting functions in the
literature. The distribution of clusters of maximal mass across redshifts
agrees well with predicted masses of extreme objects, and we explicitly confirm
that the Poisson distribution is very good at describing the distribution of
rare clusters. The Poisson distribution also matches well the level to which
cosmic variance can be expected to affect number counts of high mass clusters.
We find that objects like the Bullet cluster exist in the far-tail of the
distribution of mergers in terms of relative collisional speed. We also derive
the number counts of voids in the simulation box for $z = 0$, $0.5$ and $1$.


title: State transition induced by self-steepening and self phase-modulation

abstract:
  We present a rational solution for a mixed nonlinear Schr\"odinger (MNLS)
equation. This solution has two free parameters $a$ and $b$ representing the
contributions of self-steepening and self phase-modulation (SPM) of an
associated physical system. It describes five soliton states: a paired
bright-bright soliton, single soliton, a paired bright-grey soliton, a paired
bright-black soliton, and a rogue wave state. We show that the transition among
these five states is induced by self-steepening and SPM through tuning the
values of $a$ and $b$. This is a unique and potentially fundamentally important
phenomenon in a physical system described by the MNLS equation.


title: Minimal noise subsystems

abstract:
  The existence of a decoherence-free subspace/subsystem (DFS) requires that
the noise possesses a symmetry. In this work we consider noise models in which
perturbations break this symmetry, so that the DFS for the unperturbed model
experiences noise. We ask whether in this case there exist subspaces/subsystems
that have less noise than the original DFS. We develop a numerical method to
search for such minimal noise subsystems and apply it to a number of examples.
For the examples we examine, we find that if the perturbation is local noise
then there is no better subspace/subsystem than the original DFS. We also show
that if the noise model remains collective, but is perturbed in a way that
breaks the symmetry, then the minimal noise subsystem is distinct from the
original DFS, and improves upon it.


title: Analytical Approach to Parallel Repetition

abstract:
  We propose an analytical framework for studying parallel repetition, a basic
product operation for one-round two-player games. In this framework, we
consider a relaxation of the value of a game, $\mathrm{val}_+$, and prove that
for projection games, it is both multiplicative (under parallel repetition) and
a good approximation for the true value.
  These two properties imply a parallel repetition bound as $$
\mathrm{val}(G^{\otimes k}) \approx \mathrm{val}_+(G^{\otimes k}) =
\mathrm{val}_+(G)^{k} \approx \mathrm{val}(G)^{k}. $$
  Using this framework, we can also give a short proof for the NP-hardness of
Label-Cover$(1,\delta)$ for all $\delta>0$, starting from the basic PCP
theorem.
  We prove the following new results:
  - A parallel repetition bound for projection games with small soundness.
Previously, it was not known whether parallel repetition decreases the value of
such games. This result implies stronger inapproximability bounds for Set-Cover
and Label-Cover.
  - An improved bound for few parallel repetitions of projection games, showing
that Raz's counterexample is tight even for a small number of repetitions.
  Our techniques also allow us to bound the value of the direct product of
multiple games, namely, a bound on $\mathrm{val}(G_1\otimes ...\otimes G_k)$
for different projection games $G_1,...,G_k$.


title: Modeling Temporal Activity Patterns in Dynamic Social Networks

abstract:
  The focus of this work is on developing probabilistic models for user
activity in social networks by incorporating the social network influence as
perceived by the user. For this, we propose a coupled Hidden Markov Model,
where each user's activity evolves according to a Markov chain with a hidden
state that is influenced by the collective activity of the friends of the user.
We develop generalized Baum-Welch and Viterbi algorithms for model parameter
learning and state estimation for the proposed framework. We then validate the
proposed model using a significant corpus of user activity on Twitter. Our
numerical studies show that with sufficient observations to ensure accurate
model learning, the proposed framework explains the observed data better than
either a renewal process-based model or a conventional uncoupled Hidden Markov
Model. We also demonstrate the utility of the proposed approach in predicting
the time to the next tweet. Finally, clustering in the model parameter space is
shown to result in distinct natural clusters of users characterized by the
interaction dynamic between a user and his network.

categories: physics.soc-ph cs.SI physics.data-an stat.AP


title: Bulk Viscosity Effects in Event-by-Event Relativistic Hydrodynamics

abstract:
  Bulk viscosity effects on the collective flow harmonics in heavy ion
collisions are investigated, on an event by event basis, using a newly
developed 2+1 Lagrangian hydrodynamic code named v-USPhydro which implements
the Smoothed Particle Hydrodynamics (SPH) algorithm for viscous hydrodynamics.
A new formula for the bulk viscous corrections present in the distribution
function at freeze-out is derived starting from the Boltzmann equation for
multi-hadron species. Bulk viscosity is shown to enhance the collective flow
Fourier coefficients from $v_2(p_T)$ to $v_5(p_T)$ when $% p_{T}\sim 1-3$ GeV
even when the bulk viscosity to entropy density ratio, $% \zeta/s$, is
significantly smaller than $1/(4\pi)$.


title: Homage \`{a} A. M. Gleason et I. J. Schark

abstract:
  We study the maximal ideal space of $H^\infty(B)$, where $B$ is the unit ball
of $\CC^n$. Following the lead of Gleason and Schark, we analyze Gleason parts,
fibers, the S\u{\i}lov boundary, and other aspects of this Banach algebra. Our
work here makes good use of the inner functions construction of Aleksandrov and
Hakim/L{\o} w/Sibony, particularly as formulated by Rudin.


title: Restricted Admissible Limit for Domains of Finite Type

abstract:
  We investigate the boundary behavior of holomorphic functions with respect to
a family of curves in a domain of finite type. This work is a generalization of
\u{C}irka's classical result on the unit ball and it supplements the result by
Cima and Krantz on the Lindel\"{o}f principle for general domains. See [KRA2]
for some recent developments in this subject


title: How often should you clean your room?

abstract:
  We introduce and study a combinatorial optimization problem motivated by the
question in the title. In the simple case where you use all objects in your
room equally often, we investigate asymptotics of the optimal time to clean up
in terms of the number of objects in your room. In particular, we prove a
logarithmic upper bound, solve an approximate version of this problem, and
conjecture a precise logarithmic asymptotic.


title:
Investigating the relationship between biodiversity and ecosystem
  multifunctionality: Challenges and solutions

abstract:
  Extensive research shows that more species-rich assemblages are generally
more productive and efficient in resource use than comparable assemblages with
fewer species. But the question of how diversity simultaneously affects the
wide variety of ecological functions that ecosystems perform remains relatively
understudied, and it presents several analytical and empirical challenges that
remain unresolved. In particular, researchers have developed several disparate
metrics to quantify multifunctionality, each characterizing different aspects
of the concept, and each with pros and cons. We compare four approaches to
characterizing multifunctionality and its dependence on biodiversity,
quantifying 1) magnitudes of multiple individual functions separately, 2) the
extent to which different species promote different functions, 3) the average
level of a suite of functions, and 4) the number of functions that
simultaneously exceed a critical threshold. We illustrate each approach using
data from the pan-European BIODEPTH experiment and the R multifunc package
developed for this purpose, evaluate the strengths and weaknesses of each
approach, and implement several methodological improvements. We conclude that a
extension of the fourth approach that systematically explores all possible
threshold values provides the most comprehensive description of
multifunctionality to date. We outline this method and recommend its use in
future research.


title:
An Adaptive Statistical Non-uniform Quantizer for Detail Wavelet
  Components in Lossy JPEG2000 Image Compression

abstract:
  The paper presents a non-uniform quantization method for the Detail
components in the JPEG2000 standard. Incorporating the fact that the
coefficients lying towards the ends of the histogram plot of each Detail
component represent the structural information of an image, the quantization
step sizes become smaller at they approach the ends of the histogram plot. The
variable quantization step sizes are determined by the actual statistics of the
wavelet coefficients. Mean and standard deviation are the two statistical
parameters used iteratively to obtain the variable step sizes. Moreover, the
mean of the coefficients lying within the step size is chosen as the quantized
value, contrary to the deadzone uniform quantizer which selects the midpoint of
the quantization step size as the quantized value. The experimental results of
the deadzone uniform quantizer and the proposed non-uniform quantizer are
objectively compared by using Mean-Squared Error (MSE) and Mean Structural
Similarity Index Measure (MSSIM), to evaluate the quantization error and
reconstructed image quality, respectively. Subjective analysis of the
reconstructed images is also carried out. Through the objective and subjective
assessments, it is shown that the non-uniform quantizer performs better than
the deadzone uniform quantizer in the perceptual quality of the reconstructed
image, especially at low bitrates. More importantly, unlike the deadzone
uniform quantizer, the non-uniform quantizer accomplishes better visual quality
with a few quantized values.


title: Review of Anisotropic Terahertz Material Response

abstract:
  Anisotropy is ubiquitous in solids and enhanced in low-dimensional materials.
In response to an electromagnetic wave, anisotropic absorptive and refractive
properties result in dichroic and birefringent optical phenomena both in the
linear and nonlinear optics regimes. Such material properties have led to a
diverse array of useful polarization components in the visible and
near-infrared, but mature technology is non-existent in the terahertz (THz).
Here, we review several novel types of anisotropic material responses observed
in the THz frequency range, including both linear and circular anisotropy,
which have long-term implications for the development of THz polarization
optics. We start with the extreme linear anisotropy of macroscopically aligned
carbon nanotubes, arising from their intrinsically anisotropic dynamic
conductivity. Magnetically induced anisotropy will then be reviewed, including
the giant Faraday effects observed in semiconductors, semimetals, and
two-dimensional electron systems.


title: Extraction of attosecond time delay using the soft photon approximation

abstract:
  We use the soft photon approximation to extract the Wigner time delay from
atomic two-color photoionization experiments. Unlike the strong field
approximation, the present method does not require introduction of the
Coulomb-laser coupling corrections and enables one to extract the Wigner time
delay directly from attosecond time delay measurements.


title: Type A Images of Galois Representations and Maximality

abstract:
  Given a compatible system of n-dimension l-adic Galois representations
arising from \'etale cohomology of any complete, non-singular variety, we prove
that for sufficiently large prime l, type A Galois image (in the Cartan-Killing
classification) is in some sense maximal in its Zariski closure in GL(n).


title:
Sustainable Ecosystem Planning Based on Discrete Stochastic Dynamic
  Programming and Evolutionary Game Theory

abstract:
  This paper proposed a discrete stochastic dynamic programming (SDP) model for
sustainable ecosystem (SE) planning of the Loess Plateau in Northwestern,
China, and analyzed the ecological resource planning by the evolutionary game
model in the decision-making process. The main objective is to explore a new
approach of SE planning from a viewpoint of discrete SDP and evolutionary game
theory, with a specific application in the area of ecological resource planning
such as water management problems. In contrast to previous work, the proposed
SDP method focuses on the transition probability matrix of the ecosystem in a
statistic sense, and uses the DP algorithm to obtain the optimal ecological
resource planning strategies among multi-subsystems, then analyzes impacts of
decision between different users. Firstly, the application background and the
concept of SE planning are introduced. Then, a brief overview of existing
theory for analyzing sustainable ecosystem is presented. Furthermore, a
SDP-based mathematical model and its application to water resource planning of
central areas of Loess Plateau are presented as an example. Finally,
supplementary analysis of impacts between different users in SE planning as a
game playing is provided.


title: On the universality of cognitive tests

abstract:
  The analysis of the adaptive behaviour of many different kinds of systems
such as humans, animals and machines, requires more general ways of assessing
their cognitive abilities. This need is strengthened by increasingly more tasks
being analysed for and completed by a wider diversity of systems, including
swarms and hybrids. The notion of universal test has recently emerged in the
context of machine intelligence evaluation as a way to define and use the same
cognitive test for a variety of systems, using some principled tasks and
adapting the interface to each particular subject. However, how far can
universal tests be taken? This paper analyses this question in terms of
subjects, environments, space-time resolution, rewards and interfaces. This
leads to a number of findings, insights and caveats, according to several
levels where universal tests may be progressively more difficult to conceive,
implement and administer. One of the most significant contributions is given by
the realisation that more universal tests are defined as maximisations of less
universal tests for a variety of configurations. This means that universal
tests must be necessarily adaptive.


title: HTTP Mailbox - Asynchronous RESTful Communication

abstract:
  We describe HTTP Mailbox, a mechanism to enable RESTful HTTP communication in
an asynchronous mode with a full range of HTTP methods otherwise unavailable to
standard clients and servers. HTTP Mailbox allows for broadcast and multicast
semantics via HTTP. We evaluate a reference implementation using ApacheBench (a
server stress testing tool) demonstrating high throughput (on 1,000 concurrent
requests) and a systemic error rate of 0.01%. Finally, we demonstrate our HTTP
Mailbox implementation in a human assisted web preservation application called
"Preserve Me".


title: Classical and quantum flux energy conditions for quantum vacuum states

abstract:
  The classical energy conditions are known to not be fundamental physics --
they are typically violated by semiclassical quantum effects. Consequently,
some effort has gone into finding possible semiclassical replacements for the
classical energy conditions -- the most well developed being the Ford-Roman
quantum inequalities. In the current article we shall instead develop classical
and quantum versions of a "flux energy condition" (FEC and QFEC) based on the
notion of constraining the possible fluxes measured by timelike observers. The
naive classical FEC will be seen to be satisfied in some situations, and even
for some quantum vacuum states, while its quantum analogue (the QFEC) is
satisfied (for naturally defined quantum vacuum states) under a rather wide
range of conditions. The situation for completely general (nonvacuum) quantum
states is less clear.


title:
Nearly Cloaking the Full Maxwell Equations: Cloaking Active Contents
  with General Conducting Layers

abstract:
  The regularized near-cloak via the transformation optics approach in the
time-harmonic electromagnetic scattering is considered. This work extends the
existing studies mainly in two aspects. First, it presents a near-cloak
construction by incorporating a much more general conducting layer between the
cloaked and cloaking regions. This might be of significant practical importance
when production fluctuations occur. Second, it allows the cloaked contents to
be both passive and active with an applied current inside. In assessing the
near-cloaking performance, comprehensive and sharp estimates are derived for
the scattering amplitude in terms of the asymptotic regularization parameter
and the material tensors of the conducting layer. The scattering estimates are
independent of the passive/active contents being cloaked, which implies that
one could nearly cloak arbitrary contents by using the proposed near-cloak
construction.


title:
Stochastic extension of the Lanczos method for nuclear shell-model
  calculations with variational Monte Carlo method

abstract:
  We propose a new variational Monte Carlo (VMC) approach based on the Krylov
subspace for large-scale shell-model calculations. A random walker in the VMC
is formulated with the $M$-scheme representation, and samples a small number of
configurations from a whole Hilbert space stochastically. This VMC framework is
demonstrated in the shell-model calculations of $^{48}$Cr and $^{60}$Zn, and we
discuss its relation to a small number of Lanczos iterations. By utilizing the
wave function obtained by the conventional particle-hole-excitation truncation
as an initial state, this VMC approach provides us with a sequence of
systematically improved results.


title:
Synthetic horizontal branch morphology for different metallicities and
  ages under tidally enhanced stellar wind

abstract:
  It is believed that, except for metallicity, some other parameters are needed
to explain the horizontal branch (HB) morphology of globular clusters (GCs).
Furthermore, these parameters are considered to be correlated with the mass
loss of the red giant branch (RGB) stars. In our previous work, we proposed
that tidally enhanced stellar wind during binary evolution may affect the HB
morphology by enhancing the mass loss of the red giant primary. As a further
study, we now investigate the effects of metallicity and age on HB morphology
by considering tidally enhanced stellar winds during binary evolution. We
incorporated the tidally enhanced-stellar-wind model into Eggleton's stellar
evolution code to study the binary evolution. To study the effects of
metallicity and age on our final results, we conducted two sets of model
calculations: (i) for a fixed age, we used three metallicities, namely
Z=0.0001, 0.001, and 0.02. (ii) For a fixed metallicity, Z=0.001, we used five
ages in our model calculations: 14, 13, 12, 10, and 7 Gyr. We found that HB
morphology of GCs becomes bluer with decreasing metallicity, and old GCs
present bluer HB morphology than young ones. These results are consistent with
previous work. Although the envelope-mass distributions of zero-age HB stars
produced by tidally enhanced stellar wind are similar for different
metallicities, the synthetic HB under tidally enhanced stellar wind for Z=0.02
presented a distinct gap between red and blue HB. However, this feature was not
seen clearly in the synthetic HB for Z=0.001 and 0.0001. We also found that
higher binary fractions may make HB morphology become bluer, and we discussed
the results with recent observations.


title: Systematic study of the singularity mechanism in heavy quarkonium decays

abstract:
  We investigate in detail the role of heavy meson loops in the transition from
$J^{PC}=1^{--}$ sources to candidates for QCD "exotics", such as $Z_c(3900)$,
$Z_b(10610)$ and $Z_b'(10650)$. We demonstrate that, if a vector state strongly
couples to a heavy meson pair in an $S$--wave and this system decays to another
heavy meson pair (e.g. via pion emission), again in an $S$-wave, the pertinent
diagrams get enhanced significantly, if the intermediate states are (near)
on--shell and have small relative momenta. In a limited kinematic range this
mechanism generates "singularity regions" that lead to the creation of a large
number of low energy heavy meson pairs, providing an ideal environment for the
formation of hadron-hadron bound states or resonances. For instance, we predict
that the signals for $Z_b$ and $Z_b'$ should be a lot stronger in
$\Upsilon(6S)$ decays due to this mechanism, if these states are indeed
hadron-hadron resonances. The findings of this work should be valuable for
deepening our understanding of the nature of the mentioned states.


title: Inferring Team Strengths Using a Discrete Markov Random Field

abstract:
  We propose an original model for inferring team strengths using a Markov
Random Field, which can be used to generate historical estimates of the
offensive and defensive strengths of a team over time. This model was designed
to be applied to sports such as soccer or hockey, in which contest outcomes
take value in a limited discrete space. We perform inference using a
combination of Expectation Maximization and Loopy Belief Propagation. The
challenges of working with a non-convex optimization problem and a
high-dimensional parameter space are discussed. The performance of the model is
demonstrated on professional soccer data from the English Premier League.


title: Structure of Near-Threshold s-Wave Resonances

abstract:
  We study the structure of two-body s-wave bound states as well as resonances
in the threshold energy region. We focus on the single-channel scattering where
the scattering length and the effective range are given by real numbers. It is
shown that, in the energy region where the effective range expansion is valid,
the properties of resonances are constrained only by the position of the pole.
We find that the compositeness defined through the analytic continuation of the
field renormalization constant is pure imaginary and normalized for resonances.
We discuss the interpretation of this quantity by examining the structure of
the hadron resonance Lambda_c(2595) in the pi Sigma_c scattering. We show that
the Lambda_c(2595) resonance requires an unnaturally large effective range and
hence it is not likely a pi Sigma_c molecule.


title: Holographic superconductors with hyperscaling violation

abstract:
  We investigate holographic superconductors in asympototically geometries with
hyperscaling violation. The mass of the scalar field decouples from the UV
dimension of the dual scalar operator and can be chosen as negative as we want,
without disturbing the Breitenlohner-Freedman bound. We first numerically find
that the scalar condenses below a critical temperature and a gap opens in the
real part of the conductivity, indicating the onset of superconductivity. We
further analytically explore the effects of the hyperscaling violation on the
superconducting transition temperature. We find that the critical temperature
increases with the increasing of hyperscaling violation.


title: l-independence for Compatible Systems of (mod l) Representations

abstract:
  Let K be a number field. For any system of semisimple mod l Galois
representations {\phi_l:Gal_K->GL_N(F_l)} arising from \'etale cohomology,
there exists a finite normal extension L of K such that if we denote
\phi_l(Gal_K) and \phi_l(Gal_L) by respectively \Gamma_l and \gamma_l for all
l, and let S_l be the F_l-semisimple subgroup of GL_N associated to \gamma_l
(or \Gamma_l) by Nori [No87] for all sufficiently large l, then the following
statements hold for all sufficiently large l:
  A(i) The formal character of S_l->GL_N is independent of l and is equal to
the formal character of the tautological representation of the derived group of
the identity component of the monodromy group of the corresponding
semi-simplified l-adic Galois representation.
  A(ii) The non-cyclic composition factors of \gamma_l and S_l(F_l) are
identical. Therefore, the composition factors of \gamma_l are finite simple
groups of Lie type of characteristic l and cyclic groups.
  B(i) The total l-rank rk_l\Gamma_l of \Gamma_l is equal to the rank of S_l
and is therefore independent of l.
  B(ii) The A_n-type l-rank rk_l^{A_n}\Gamma_l of \Gamma_l for n belonging to
N\{1,2,3,4,5,7,8} and the parity of (rk_l^{A_4}\Gamma_l)/4 are independent of
l.


title:
Influence of the photon beam position on incident SR intensity at SXMCD
  endstation

abstract:
  A small fluctuation of the photon beam position will affect the
characteristics of the synchrotron radiation (SR) intensity and polarization
when it enters the end-station through the related beamline. In this paper, by
changing the electron orbit equilibrium position in the vertical direction, we
have measured the corresponding changes in the absorption strength of the SR
with a gold mesh in different chopper aperture positions. It is found that for
three aperture positions, the absorption intensity of the gold mesh shows a
good Gaussian distribution as the photon beam position moves, while the ratio
of the SR intensity passing through the upper and lower apertures shows a
monotonous variation. This suggests a new method for estimating the circular
polarization degree of SR originating from the bending magnet based on our
current measurement.


title:
Electrostatic repulsion-driven crystallization model arising from
  filament networks

abstract:
  The crystallization of bundles in filament networks interacting via
long-range repulsions in confinement is described by a phenomenological model.
The model demonstrates the formation of the hexagonal crystalline order via the
interplay of the confinement potential and the filament-filament repulsion. Two
distinct crystallization mechanisms in the short- and large- screening length
regimes are discussed, and the phase diagram is obtained. Simulation of large
bundles predicts the existence of topological defects within the bundled
filaments. This electrostatic repulsion-driven crystallization model arising
from studying filament networks can even find a more general context extending
to charged colloidal systems.


title: Expressing Algorithms As Concise As Possible via Computability Logic

abstract:
  This paper proposes a new approach to defining and expressing algorithms: the
notion of {\it task logical} algorithms. This notion allows the user to define
an algorithm for a task $T$ as a set of agents who can collectively perform
$T$. This notion considerably simplifies the algorithm development process and
can be seen as an integration of the sequential pseudocode and logical
algorithms. This observation requires some changes to algorithm development
process. We propose a two-step approach: the first step is to define an
algorithm for a task $T$ via a set of agents that can collectively perform $T$.
The second step is to translate these agents into (higher-order) computability
logic.


title: Probing the structure of entanglement with entanglement moments

abstract:
  We introduce and define a set of functions on pure bipartite states called
entanglement moments. Usual entanglement measures tell you if two systems are
entangled, while entanglement moments tell you both if and how two systems are
entangled. They are defined with respect to a measurement basis in one system
(e.g., a measuring device), and output numbers describing how a system (e.g., a
qubit) is entangled with that measurement basis. The moments utilize different
distance measures on the Hilbert space of the measured system, and can be
generalized to any N-dimensional Hilbert space. As an application, they can
distinguish between projective and non-projective measurements. As a particular
example, we take the Rabi model's eigenstates and calculate the entanglement
moments as well as the full distribution of entanglement.


title:
LabelRankT: Incremental Community Detection in Dynamic Networks via
  Label Propagation

abstract:
  An increasingly important challenge in network analysis is efficient
detection and tracking of communities in dynamic networks for which changes
arrive as a stream. There is a need for algorithms that can incrementally
update and monitor communities whose evolution generates huge realtime data
streams, such as the Internet or on-line social networks. In this paper, we
propose LabelRankT, an online distributed algorithm for detection of
communities in large-scale dynamic networks through stabilized label
propagation. Results of tests on real-world networks demonstrate that
LabelRankT has much lower computational costs than other algorithms. It also
improves the quality of the detected communities compared to dynamic detection
methods and matches the quality achieved by static detection approaches. Unlike
most of other algorithms which apply only to binary networks, LabelRankT works
on weighted and directed networks, which provides a flexible and promising
solution for real-world applications.


title:
Resolving the outer density profile of dark matter halo in Andromeda
  galaxy

abstract:
  Large-scale faint structure detected by the recent observations in the halo
of the Andromeda galaxy (M31) provides an attractive window to explore the
structure of outer cold dark matter (CDM) halo in M31. Using an N-body
simulation of the interaction between an accreting satellite galaxy and M31, we
investigate the mass density profile of the CDM halo. We find the sufficient
condition of the outer density profile of CDM halo in M31 to reproduce the
Andromeda giant stream and the shells at the east and west sides of M31. The
result indicates that the density profile of the outer dark matter halo of M31
is a steeper than the prediction of the theory of the structure formation based
on the CDM model.


title: Stochastic quantization of conformally coupled scalar in AdS

abstract:
  We explore the relation between stochastic quantization and holographic
Wilsonian renormalization group flow further by studying conformally coupled
scalar in $AdS_{d+1}$. We establish one to one mapping between the radial flow
of its double trace deformation and stochastic 2-point correlation function.
This map is shown to be identical, up to a suitable field re-definition of the
bulk scalar, to the original proposal in arXiv:1209.2242.