title:
Demonstrating Lattice-Symmetry-Protection in Topological Crystalline
  Superconductors

abstract:
  We propose to study the lattice-symmetry protection of Majorana zero bound
modes in topological crystalline superconductors (SCs). With an induced
$s$-wave superconductivity in the $(001)$-surface of the topological
crystalline insulator Pb$_{1-x}$Sn$_x$Te, which has a C$_4$ rotational
symmetry, we show a new class of 2D topological SC with four Majorana modes
obtained in each vortex core, while only two of them are protected by the
cyclic symmetry. Furthermore, applying an in-plane external field can break the
four-fold symmetry and lifts the Majorana modes to finite energy states in
general. Surprisingly, we show that even the C$_4$ symmetry is broken, two
Majorana modes are restored exactly one time whenever the in-plane field varies
$\pi/2$, i.e. $1/4$-cycle in the direction. This novel phenomenon has a
profound connection to the four-fold cyclic symmetry of the original
crystalline SC and uniquely demonstrates the lattice-symmetry protection of the
Majorana modes. We further generalize these results to the system with generic
C$_{2N}$ symmetry, and show that the symmetry class of the topological
crystalline SC can be demonstrated by the $2N$ times of restoration of two
Majorana modes when the external symmetry-breaking field varies one cycle in
direction.


title:
Energy spectrum of bottom- and charmed-flavored mesons from polarized
  top quark decay $t(\uparrow)\rightarrow W^+ + B/D+X$ at ${\cal O}(\alpha_s)$

abstract:
  We consider the decay of a polarized top quark into a stable $W^+$ boson and
charmed-flavored (D) or bottom-flavored (B) hadrons, via
$t(\uparrow)\rightarrow W^++D/B+X$. We study the angular distribution of the
scaled-energy of B/D-hadrons at next-to-leading order (NLO) considering the
contribution of bottom and gluon fragmentations into the heavy mesons B and D.
To obtain the energy spectrum of B/D-hadrons we present our analytical
expressions for the parton-level differential decay widths of
$t(\uparrow)\rightarrow b+W^+(+g)$ at NLO. Comparison of our predictions with
data at the LHC enable us to test the universality and scaling violations of
the B- and D-hadron fragmentation functions (FFs). These can also be used to
determine the polarization states of top quarks and since the energy
distributions depend on the ratio $m_W /m_t$ we advocate the use of such
angular decay measurements for the determination of the top quark's mass.


title: Analyzing spiral structure in a galactic disk with a gaseous component

abstract:
  Using GADGET2, we performed an SPH+N-body simulation of a galactic disk with
stellar and gas particles. This simulation allows to compare the spiral
structure in the different disk components. Also, we performed a simulation
without gaseous component to explore the effects of the gas in the spiral
pattern of the stars.


title:
Recent advances on information transmission and storage assisted by
  noise

abstract:
  The interplay between nonlinear dynamic systems and noise has proved to be of
great relevance in several application areas. In this presentation, we focus on
the areas of information transmission and storage. We review some recent
results on information transmission through nonlinear channels assisted by
noise. We also present recent proposals of memory devices in which noise plays
an essential role. Finally, we discuss new results on the influence of noise in
memristors.


title: Effect of isospin asymmetry in nuclear system

abstract:
  The effect of $\delta-$ and $\omega-\rho-$meson cross couplings on asymmetry
nuclear systems are analyzed in the frame-work of an effective Field theory
motivated relativistic mean field formalism. The calculations are done on top
of the G2 parameter set, where these contributions are absent. We calculate the
root mean square radius, binding energy, single particle energy (for the
$1^{st}$ and last occupied orbits), density and spin-orbit interaction
potential for some selected nuclei and evaluate the $L_{sym}-$ and $E_{sym}-$
coefficients for nuclear matter as function of $\delta-$ and
$\omega-\rho-$meson coupling strengths. As expected, the influence of these
effects are negligible for symmetry nuclear system and these effects are very
important for systems with large isospin asymmetry.


title: Extensions of Hamiltonian systems dependent on a rational parameter

abstract:
  The technique of "extension" allows to build $(n+1)$-dimensional Hamiltonian
systems with a non-trivial polynomial in the momenta first integral of any
given degree starting from a $n$-dimensional Hamiltonian satisfying some
additional properties. Until now, the application of the method was restricted
to integer values of a certain fundamental parameter determining the degree of
the additional first integral. In this article we show how this technique can
be generalized to any rational value of the same parameter. Several examples
are given, among them the anisotropic oscillator and a special case of the
Tremblay-Turbiner-Winternitz system.


title:
Modulated phases and devil's staircases in a layered mean-field version
  of the ANNNI model

abstract:
  We investigate the phase diagram of a spin-$1/2$ Ising model on a cubic
lattice, with competing interactions between nearest and next-nearest neighbors
along an axial direction, and fully connected spins on the sites of each
perpendicular layer. The problem is formulated in terms of a set of
noninteracting Ising chains in a position-dependent field. At low temperatures,
as in the standard mean-feild version of the Axial-Next-Nearest-Neighbor Ising
(ANNNI) model, there are many distinct spatially commensurate phases that
spring from a multiphase point of infinitely degenerate ground states. As
temperature increases, we confirm the existence of a branching mechanism
associated with the onset of higher-order commensurate phases. We check that
the ferromagnetic phase undergoes a first-order transition to the modulated
phases. Depending on a parameter of competition, the wave number of the striped
patterns locks in rational values, giving rise to a devil's staircase. We
numerically calculate the Hausdorff dimension $D_{0}$ associated with these
fractal structures, and show that $D_{0}$ increases with temperature but seems
to reach a limiting value smaller than $D_{0}=1$.


title:
Atomic mass dependence of hadron production in semi-inclusive deep
  inelastic lepton-nucleus scattering

abstract:
  Hadron production in lepton-nucleus deep inelastic scattering is studied in a
quark energy loss model. The leading-order computations for hadron multiplicity
ratios are presented and compared with the selected HERMES pions production
data with the quark hadronization occurring outside the nucleus by means of the
hadron formation time. It is found that the obtained energy loss per unit
length is $0.440 \pm 0.013$ GeV/fm for an outgoing quark by the global fit. It
is confirmed that the atomic mass number dependence of hadron attenuation is
theoretically and experimentally in good agreement with the $A^{2/3}$ power law
for quark hadronization occurring outside the nucleus.


title:
Exploring the origin, the nature and the dynamical behaviour of distant
  stars in galaxy models

abstract:
  We explore the regular or chaotic nature of orbits moving in the meridional
plane of an axially symmetric galactic gravitational model with a disk, a dense
spherical nucleus and some additional perturbing terms corresponding to
influence from nearby galaxies. In order to obtain this we use the Smaller
ALingment Index (SALI) technique integrating extensive samples of orbits. Of
particular interest is the study of distant, remote stars moving in large
galactocentric orbits. Our extensive numerical experiments indicate that the
majority of the distant stars perform chaotic orbits. However, there are also
distant stars displaying regular motion as well. Most distant stars are ejected
into the galactic halo on approaching the dense and massive nucleus. We study
the influence of some important parameters of the dynamical system, such as the
mass of the nucleus and the angular momentum, by computing in each case the
percentage of regular and chaotic orbits. A second order polynomial
relationship connects the mass of the nucleus and the critical angular momentum
of the distant star. Some heuristic semi-theoretical arguments to explain and
justify the numerically derived outcomes are also given. Our numerical
calculations suggest that the majority of distant stars spend their orbital
time in the halo where it is easy to be observed. We present evidence that the
main cause for driving stars to distant orbits is the presence of the dense
nucleus combined with the perturbation caused by nearby galaxies. The origin of
young O and B stars observed in the halo is also discussed.


title: Stability of charged thin-shell wormholes in (2 + 1) dimensions

abstract:
  In this paper we construct charged thin-shell wormholes in (2+1)-dimensions
applying the cut-and -paste technique implemented by Visser, from a BTZ black
hole which was discovered by Banados, Teitelboim and Zanelli, and the surface
stress are determined using the Darmois-Israel formalism at the wormhole
throat. We analyzed the stability of the shell considering phantom-energy or
generalised Chaplygin gas equation of state for the exotic matter at the
throat. We also discussed the linearized stability of charged thin-shell
wormholes around the static solution.


title:
Collection-behavior based Multi-parameter Posted Pricing Mechanism for
  Crowd Sensing

abstract:
  Crowd sensing is a new paradigm which leverages a large number of
sensor-equipped mobile phones to collect sensing data. To attract more
participants to provide good quality, bidding mechanisms that solicit the
Vickrey-Clarke-Groves (VCG) mechanism and its variants are natural fits for
crowd sensing applications in mobile social networks. However, in practical
continuous crowd sensing applications, where bids cannot be solicited and only
posted pricing mechanisms can be implemented. Obviously, these mechanisms for
continuous crowd sensing are not applicable. To tackle the issue, we propose a
collection-behavior based multi-parameter posted pricing mechanism, not only to
consider extensive user participating and sensing data submission quality under
given budget constraints by applying all-pay auctions and posted pricing
mechanisms, but also to maximize the coverage utilities by applying crowd
aversion. Simulation results indicate that incentive mechanisms in our proposed
framework outperform the best existing solution.


title: New Class of N-dimensional Braneworlds

abstract:
  The new class of the non-stationary solutions to the system of N-dimensional
equations for coupled gravitational and massless scalar field is found. The
model represents a single (N-1)-brane in a space-time with one large (infinite)
and (N-5) small (compact) space-like extra dimensions. In some particular cases
the model corresponds to the gravitational and scalar field standing waves
bounded by the brane. These braneworlds can be relevant in string and other
higher dimensional models.


title: Multivalued Logic Circuit Design for Binary Logic Interface

abstract:
  Binary logic and devices have been in used since inception with advancement
and technology and millennium gate design era. The development in binary logic
has become tedious and cumbersome. Multivalued logic enables significant more
information to be packed within a single digit. The design and development of
logic circuit becomes very compact and easier. Attempts are being made to
fabricate multivalued logic based devices. Since present devices can be
implemented only in binary system,it is necessary to evolve a system that can
built the circuit in multivalued logic system and convert in binary logic
system. In multivalued logic system logic gates differ in different logic
system, a quaternary has become mature in terms of logic algebra and gates.
Hence logic design based on above system can be done using standard procedure.
In this dissertation a logic circuit design entry based on multivalued logic
system has been taken up that can provide the ease of circuit design in
multivalued system and output as binary valued circuit. The named "MVL-DEV"
offers editing, storage and conversion into binary facility.


title: Massive Query Expansion by Exploiting Graph Knowledge Bases

abstract:
  Keyword based search engines have problems with term ambiguity and vocabulary
mismatch. In this paper, we propose a query expansion technique that enriches
queries expressed as keywords and short natural language descriptions. We
present a new massive query expansion strategy that enriches queries using a
knowledge base by identifying the query concepts, and adding relevant synonyms
and semantically related terms. We propose two approaches: (i) lexical
expansion that locates the relevant concepts in the knowledge base; and, (ii)
topological expansion that analyzes the network of relations among the
concepts, and suggests semantically related terms by path and community
analysis of the knowledge graph. We perform our expansions by using two
versions of the Wikipedia as knowledge base, concluding that the combination of
both lexical and topological expansion provides improvements of the system's
precision up to more than 27%.


title:
The Return of the Proplyds - Understanding the Dynamics of Ionization
  Triggered Stars

abstract:
  Proplyds and stars inside HII-regions are a well studied phenomenon. It is
possible that they were triggered by the expansion of the HII-region itself.
Here, we present calculations on the dynamics of HII-regions. We show that the
triggered stars that form in the expanding shell of swept up material around
the HII region rarely return into the HII regions on timescales that are
inferred for the proplyds and observed young stars. However, in very dense
environments like Orion, the triggered stars return in time. Thus, our model
can explain why proplyds are barely observed in other HII regions. We propose
that the properties of young stellar objects in HII regions in general depend
critically on the distance from the massive, ionizing central star cluster.
Closest in, there are proplyds, where the disk of a young star interacts
directly with the feedback of the massive star. Further out are Class II
protostars, where the ionization already removed the envelope. Even further
away, one should find Class I stars, which either have been triggered by the
ionizing radiation or pre-existed and have not lost their envelope yet. This
radial sequence is not necessarily an age sequence but rather a result of the
dwindling importance of stellar winds and ionizing radiation with distance. We
investigate the observational signature of triggered star formation and find
that the stellar distribution for ionization triggered star formation shows a
distinct feature, a peak at the current position of the ionization front.
Therefore, it is generally possible to tell triggered and in situ distributions
of stars apart.


title:
Effective field theory models for nonviolent information transfer from
  black holes

abstract:
  Transfer of quantum information from the interior of a black hole to its
atmosphere is described, in models based on effective field theory. This
description illustrates that such transfer need not be violent to the
semiclassical geometry or to infalling observers, and in particular can avoid
producing a singular horizon or "firewall." One can specifically quantify the
rate of information transfer, and show that a rate necessary to unitarize black
hole evaporation produces a relatively mild modification to the stress tensor
near the horizon. In an exterior description of the transfer, the new
interactions responsible for it are approximated by "effective sources" acting
on fields in the black hole atmosphere. If the necessary interactions couple to
general modes in the black hole atmosphere, one also finds a straightforward
mechanism for information transfer rates to increase when a black hole is
mined, avoiding paradoxical behavior. Correspondence limits are discussed, in
the presence of such new interactions, for both small black holes and large
ones; the near-horizon description of the latter is approximately that of
Rindler space.


title:
Variability of Massive Stars with Known Spectral Types in the Small
  Magellanic Cloud Using 8 Years of OGLE-III Data

abstract:
  We present a variability study of 4646 massive stars in the Small Magellanic
Cloud (SMC) with known spectral types from the catalog of Bonanos et al. (2010)
using the light curves from the OGLE-III database. The goal is to exploit the
time domain information available through OGLE-III to gain insight into the
processes that govern the evolution of massive stars. This variability survey
of massive stars with known spectral types is larger than any previous survey
by a factor of 7. We find that 60% of our sample (2766 stars) show no
significant variability and 40% (1880 stars) exhibit variability distributed as
follows: 807 stars display low-amplitude stochastic variability with
fluctuations in I-band of up to 0.05 mag, 443 stars present irregular
variability of higher amplitude (76% of these are reported as variables for the
first time), 205 are eclipsing binaries (including 101 newly discovered
systems), 50 are candidate rotating variables, 126 are classical Cepheids, 188
stars exhibit short-term sinusoidal periodicity (P < 3 days) making them
candidate "slowly pulsating B stars" and non-radial Be pulsators, and 61
periodic stars exhibit longer periods. We demonstrate the wealth of information
provided in the time domain, by doubling the number of known massive eclipsing
binary systems and identifying 189 new candidate early-type Be and 20 Oe stars
in the SMC. In addition, we find that ~80% of Be stars are photometrically
variable in the OGLE-III time domain and provide evidence that short-term
pulsating stars with additional photometric variability are rotating close to
their break-up velocity.


title:
A CANDELS - 3D-HST Synergy: Resolved Star Formation Patterns at 0.7 < z
  < 1.5

abstract:
  We analyze the resolved stellar populations of 473 massive star-forming
galaxies at 0.7 < z < 1.5, with multi-wavelength broad-band imaging from
CANDELS and Halpha surface brightness profiles at the same kiloparsec
resolution from 3D-HST. Together, this unique data set sheds light on how the
assembled stellar mass is distributed within galaxies, and where new stars are
being formed. We find the Halpha morphologies to resemble more closely those
observed in the ACS I band than in the WFC3 H band, especially for the larger
systems. We next derive a novel prescription for Halpha dust corrections, which
accounts for extra extinction towards HII regions. The prescription leads to
consistent SFR estimates and reproduces the observed relation between the
Halpha/UV luminosity ratio and visual extinction, both on a pixel-by-pixel and
on a galaxy-integrated level. We find the surface density of star formation to
correlate with the surface density of assembled stellar mass for spatially
resolved regions within galaxies, akin to the so-called 'main sequence of star
formation' established on a galaxy-integrated level. Deviations from this
relation towards lower equivalent widths are found in the inner regions of
galaxies. Clumps and spiral features, on the other hand, are associated with
enhanced Halpha equivalent widths, bluer colors, and higher specific star
formation rates compared to the underlying disk. Their Halpha/UV luminosity
ratio is lower than that of the underlying disk, suggesting the ACS clump
selection preferentially picks up those regions of elevated star formation
activity that are the least obscured by dust. Our analysis emphasizes that
monochromatic studies of galaxy structure can be severely limited by
mass-to-light ratio variations due to dust and spatially inhomogeneous star
formation histories.


title:
A new method for detecting velocity shifts and distortions between
  optical spectra

abstract:
  Recent quasar spectroscopy from the VLT and Keck telescopes suggests that
fundamental constants may not actually be constant. To better confirm or refute
this result, systematic errors between telescopes must be minimized. We present
a new method to directly compare spectra of the same object and measure any
velocity shifts between them. This method allows for the discovery of
wavelength-dependent velocity shifts between spectra, i.e. velocity
distortions, that could produce spurious detections of cosmological variations
in fundamental constants. This "direct comparison" method has several
advantages over alternative techniques: it is model-independent (cf.
line-fitting approaches), blind, in that spectral features do not need to be
identified beforehand, and it produces meaningful uncertainty estimates for the
velocity shift measurements. In particular, we demonstrate that, when comparing
echelle-resolution spectra with unresolved absorption features, the uncertainty
estimates are reliable for signal-to-noise ratios >7 per pixel. We apply this
method to spectra of quasar J2123-0050 observed with Keck and the VLT and find
no significant distortions over long wavelength ranges (~1050 Angstroms)
greater than ~180 m/s. We also find no evidence for systematic velocity
distortions within echelle orders greater than 500 m/s. Moreover, previous
constraints on cosmological variations in the proton--electron mass ratio
should not have been affected by velocity distortions in these spectra by more
than 4.0 +/- 4.2 parts per million. This technique may also find application in
measuring stellar radial velocities in search of extra-solar planets and
attempts to directly observe the expansion history of the Universe using quasar
absorption spectra.


title:
Point invariants of third-order ODEs and hyper-CR Einstein-Weyl
  structures

abstract:
  We characterize Lorentzian three-dimensional hyper-CR Einstein-Weyl
structures in terms of invariants of the associated third order ordinary
differential equations.


title: Higgs Bosons in the Standard Model and Beyond

abstract:
  In these proceedings I cover the latest results on the production and decay
of the recently discovered Higgs boson. While the spin and properties of the
new boson, such as its mass and couplings to bosons and fermions, are covered
in a separate report, I focus on individual results in the main channels we use
to study the properties of the new boson and to search for its possible
cousins, with the focus on the latest results from the LHC and the Tevatron
collaborations.


title: The velocity shear and vorticity across redshifts and non-linear scales

abstract:
  The evolution of the large scale distribution of matter in the universe is
often characterized by the density field. Here we take a complimentary approach
and characterize it using the cosmic velocity field, specifically the
deformation of the velocity field. The deformation tensor is decomposed into
its symmetric component (known as the "shear tensor") and its anti-symmetric
part (the "vorticity"). Using a high resolution cosmological simulation we
examine the relative orientations of the shear and the vorticity as a function
of spatial scale and redshift. The shear is found to be remarkable stable to
the choice of scale, while the vorticity is found to quickly decay with
increasing spatial scale or redshift. The vorticity emerges out of the linear
regime randomly oriented with respect to the shear eigenvectors. Non-linear
evolution drives the vorticity to lie within the plane defined by the
eigenvector of the fastest collapse. Within that plane the vorticity first gets
aligned with the middle eigenvector and then it moves to be preferentially
aligned with the third eigenvector, of slowest collapse. Finally a scale of
"non-linearity" to be used when calculating properties of the non-linear
deformation tensor at different redshifts is suggested.


title: Do radio relics challenge diffusive shock acceleration?

abstract:
  Radio relics in galaxy clusters are thought to be associated with powerful
shock waves that accelerate particles via diffusive shock acceleration (DSA).
Among the particles accelerated by DSA, relativistic protons should outnumber
electrons by a large factor. While the relativistic electrons emit synchrotron
emission detectable in the radio band, the protons interact with the thermal
gas to produce gamma-rays in hadronic interactions. Using simple models for the
propagation of shock waves through clusters, the distribution of thermal gas
and the efficiency of DSA, we find that the resulting hadronic $\gamma$-ray
emission lies very close or above the upper limits from the FERMI data on
nearby clusters. This suggests that the relative acceleration efficiency of
electrons and protons is at odds with predictions from DSA. The inclusion of
re-accelerated "fossil" particles does not seem to solve the problem. Our study
highlights a possible tension of the commonly assumed scenario for the
formation of radio relics and we discuss possible solutions to the problem.


title: Bulk-Edge Correspondence in 2+1-Dimensional Abelian Topological Phases

abstract:
  The same bulk two-dimensional topological phase can have multiple distinct,
fully-chiral edge phases. We show that this can occur in the integer quantum
Hall states at $\nu=8$ and 12, with experimentally-testable consequences. We
show that this can occur in Abelian fractional quantum Hall states as well,
with the simplest examples being at $\nu=8/7, 12/11, 8/15, 16/5$. We give a
general criterion for the existence of multiple distinct chiral edge phases for
the same bulk phase and discuss experimental consequences. Edge phases
correspond to lattices while bulk phases correspond to genera of lattices.
Since there are typically multiple lattices in a genus, the bulk-edge
correspondence is typically one-to-many; there are usually many stable fully
chiral edge phases corresponding to the same bulk. We explain these
correspondences using the theory of integral quadratic forms. We show that
fermionic systems can have edge phases with only bosonic low-energy excitations
and discuss a fermionic generalization of the relation between bulk topological
spins and the central charge. The latter follows from our demonstration that
every fermionic topological phase can be represented as a bosonic topological
phase, together with some number of filled Landau levels. Our analysis shows
that every Abelian topological phase can be decomposed into a tensor product of
theories associated with prime numbers $p$ in which every quasiparticle has a
topological spin that is a $p^n$-th root of unity for some $n$. It also leads
to a simple demonstration that all Abelian topological phases can be
represented by $U(1)^N$ Chern-Simons theory parameterized by a K-matrix.


title: Integrability in N=2 superconformal gauge theories

abstract:
  Any N=2 superconformal gauge theory (including N=4 SYM) contains a set of
local operators made only out of fields in the N=2 vector multiplet that is
closed under renormalization to all loops, namely the SU(2,1|2) sector. For
planar N=4 SYM the spectrum of local operators can be obtained by mapping the
problem to an integrable model (a spin chain in perturbation theory), in
principle for any value of the coupling constant. We present a diagrammatic
argument that for any planar N=2 superconformal gauge theory the SU(2,1|2)
Hamiltonian acting on infinite spin chains is identical to all loops to that of
N=4 SYM, up to a redefinition of the coupling constant. Thus, this sector is
integrable and anomalous dimensions can be, in principle, read off from the N=4
ones up to this redefinition.


title:
Searching for large-scale structures around high-redshift radio galaxies
  with Herschel

abstract:
  This paper presents the first results of a far-infrared search for
protocluster-associated galaxy overdensities using the SPIRE instrument
on-board the {\it Herschel} Space Observatory. Large ($\sim$400 arcmin$^{2}$)
fields surrounding 26 powerful high-redshift radio galaxies ($2.0 < z < 4.1$;
$L_{\rm 500 MHz} > 10^{28.5}$ WHz$^{-1}$) are mapped at 250, 350 and 500\mic to
give a unique wide-field sample.
  On average the fields have a higher than expected, compared to blank fields,
surface density of 500\mic sources within 6 comoving Mpc of the radio galaxy.
The analysis is then restricted to potential protocluster members only, which
are identified using a far-infrared colour selection; this reveals significant
overdensities of galaxies in 2 fields, neither of which are previously known
protoclusters. The probability of finding 2 overdensities of this size by
chance, given the number of fields observed is $5 \times 10^{-4}$.
Overdensities here exist around radio galaxies with $L_{\rm 500 MHz} \gtrsim
10^{29}$ WHz$^{-1}$ and $z < 3$. The radial extent of the average far-infrared
overdensity is found to be $\sim$6 comoving Mpc.
  Comparison with predictions from numerical simulations shows that the
overdensities are consistent with having masses $> 10^{14}$Msolar. However, the
large uncertainty in the redshift estimation means that it is possible that
these far-infrared overdensities consist of several structures across the
redshift range searched.


title:
X-ray Bright Active Galactic Nuclei in Massive Galaxy Clusters II: The
  Fraction of Galaxies Hosting Active Nuclei

abstract:
  We present a measurement of the fraction of cluster galaxies hosting X-ray
bright Active Galactic Nuclei (AGN) as a function of clustercentric distance
scaled in units of $r_{500}$. Our analysis employs high quality Chandra X-ray
and Subaru optical imaging for 42 massive X-ray selected galaxy cluster fields
spanning the redshift range of $0.2 < z < 0.7$. In total, our study involves
176 AGN with bright ($R <23$) optical counterparts above a $0.5-8.0$ keV flux
limit of $10^{-14} \rm{erg} \ \rm{cm}^{-2} \ \rm{s}^{-1}$. When excluding
central dominant galaxies from the calculation, we measure a cluster-galaxy AGN
fraction in the central regions of the clusters that is $\sim 3 $ times lower
that the field value. This fraction increases with clustercentric distance
before becoming consistent with the field at $\sim 2.5 r_{500}$. Our data
exhibit similar radial trends to those observed for star formation and
optically selected AGN in cluster member galaxies, both of which are also
suppressed near cluster centers to a comparable extent. These results strongly
support the idea that X-ray AGN activity and strong star formation are linked
through their common dependence on available reservoirs of cold gas.


title: Anomalous Anisotropies of Cosmic Rays from Turbulent Magnetic Fields

abstract:
  The propagation of cosmic rays (CRs) in turbulent interstellar magnetic
fields is typically described as a spatial diffusion process. This formalism
predicts only a small deviation from an isotropic CR distribution in the form
of a dipole in the direction of the CR density gradient or relative background
flow. We show that the existence of a global CR dipole moment necessarily
generates a spectrum of higher multipole moments in the local CR distribution.
These "anomalous" anisotropies are a direct consequence of Liouville's theorem
in the presence of a local turbulent magnetic field. We show that the
predictions of this model are in excellent agreement with the observed power
spectrum of multi-TeV CRs.


title: Holographic Entanglement Entropy for General Higher Derivative Gravity

abstract:
  We propose a general formula for calculating the entanglement entropy in
theories dual to higher derivative gravity where the Lagrangian is a
contraction of Riemann tensors. Our formula consists of Wald's formula for the
black hole entropy, as well as corrections involving the extrinsic curvature.
We derive these corrections by noting that they arise from naively higher order
contributions to the action which are enhanced due to would-be logarithmic
divergences. Our formula reproduces the Jacobson-Myers entropy in the context
of Lovelock gravity, and agrees with existing results for general
four-derivative gravity.
  We emphasize that the formula should be evaluated on a particular bulk
surface whose location can in principle be determined by solving the equations
of motion with conical boundary conditions. This may be difficult in practice,
and an alternative method is desirable. A natural prescription is simply
minimizing our formula, analogous to the Ryu-Takayanagi prescription for
Einstein gravity. We show that this is correct in several examples including
Lovelock and general four-derivative gravity.


title:
Short $\mathsf{Res}^*(\mathsf{polylog})$ refutations if and only if
  narrow $\mathsf{Res}$ refutations

abstract:
  In this note we show that any $k$-CNF which can be refuted by a
quasi-polynomial $\mathsf{Res}^*(\mathsf{polylog})$ refutation has a "narrow"
refutation in $\mathsf{Res}$ (i.e., of poly-logarithmic width). We also show
the converse implication: a narrow Resolution refutation can be simulated by a
short $\mathsf{Res}^*(\mathsf{polylog})$ refutation.
  The author does not claim priority on this result. The technical part of this
note bears similarity with the relation between $d$-depth Frege refutations and
tree-like $d+1$-depth Frege refutations outlined in (Kraj\'i\v{c}ek 1994,
Journal of Symbolic Logic 59, 73). Part of it had already been specialized to
$\mathsf{Res}$ and $\mathsf{Res}(k)$ in (Esteban et al. 2004, Theor. Comput.
Sci. 321, 347).


title:
Stochastic Gradient Descent, Weighted Sampling, and the Randomized
  Kaczmarz algorithm

abstract:
  We obtain an improved finite-sample guarantee on the linear convergence of
stochastic gradient descent for smooth and strongly convex objectives,
improving from a quadratic dependence on the conditioning $(L/\mu)^2$ (where
$L$ is a bound on the smoothness and $\mu$ on the strong convexity) to a linear
dependence on $L/\mu$. Furthermore, we show how reweighting the sampling
distribution (i.e. importance sampling) is necessary in order to further
improve convergence, and obtain a linear dependence in the average smoothness,
dominating previous results. We also discuss importance sampling for SGD more
broadly and show how it can improve convergence also in other scenarios. Our
results are based on a connection we make between SGD and the randomized
Kaczmarz algorithm, which allows us to transfer ideas between the separate
bodies of literature studying each of the two methods. In particular, we recast
the randomized Kaczmarz algorithm as an instance of SGD, and apply our results
to prove its exponential convergence, but to the solution of a weighted least
squares problem rather than the original least squares problem. We then present
a modified Kaczmarz algorithm with partially biased sampling which does
converge to the original least squares solution with the same exponential
convergence rate.


title:
High Energy Collision of Particles in the Vicinity of Extremal Black
  Holes in Higher Dimensions: Banados-Silk-West Process as Linear Instability
  of Extremal Black Holes

abstract:
  We study high energy particle collisions around the higher dimensional black
holes. It is shown that the center of mass energy can be arbitrarily large in
the vicinity of the event horizon like the Banados, Silk and West (BSW) process
in four dimensions if the following two conditions are satisfied: (i) the
horizon is extremal and (ii) the parameters of either of the two colliding
particles are fine-tuned, which is called a critical particle condition. We
also show that a test particle which satisfies the critical particle condition
can reach the event horizon from a distant region for a simple case. Finally,
we discuss the relation between the BSW process and the linear instability of
test fields around the extremal black holes, the latter of which has been
recently found by Aretakis.


title: Electrodynamics of Black Holes in STU Supergravity

abstract:
  External magnetic fields can probe the composite structure of black holes in
string theory. With this motivation we study magnetised four-charge black holes
in the STU model, a consistent truncation of maximally supersymmetric
supergravity with four types of electromagnetic fields. We employ solution
generating techniques to obtain Melvin backgrounds, and black holes in these
backgrounds. For an initially electrically charged static black hole immersed
in magnetic fields, we calculate the resultant angular momenta and analyse
their global structure. Examples are given for which the ergoregion does not
extend to infinity. We calculate magnetic moments and gyromagnetic ratios via
Larmor's formula. Our results are consistent with earlier special cases. A
scaling limit and associated subtracted geometry in a single surviving magnetic
field is shown to lift to $AdS_3\times S^2$. Magnetizing magnetically charged
black holes give static solutions with conical singularities representing
strings or struts holding the black holes against magnetic forces. In some
cases it is possible to balance these magnetic forces.


title: Bayesian analysis of multiple direct detection experiments

abstract:
  Bayesian methods offer a coherent and efficient framework for implementing
uncertainties into induction problems. In this article, we review how this
approach applies to the analysis of dark matter direct detection experiments.
In particular we discuss the exclusion limit of XENON100 and the debated hints
of detection under the hypothesis of a WIMP signal. Within parameter inference,
marginalizing consistently over uncertainties to extract robust posterior
probability distributions, we find that the claimed tension between XENON100
and the other experiments can be partially alleviated in isospin violating
scenario, while elastic scattering model appears to be compatible with the
frequentist statistical approach. We then move to model comparison, for which
Bayesian methods are particularly well suited. Firstly, we investigate the
annual modulation seen in CoGeNT data, finding that there is weak evidence for
a modulation. Modulation models due to other physics compare unfavorably with
the WIMP models, paying the price for their excessive complexity. Secondly, we
confront several coherent scattering models to determine the current best
physical scenario compatible with the experimental hints. We find that
exothermic and inelastic dark matter are moderatly disfavored against the
elastic scenario, while the isospin violating model has a similar evidence.
Lastly the Bayes' factor gives inconclusive evidence for an incompatibility
between the data sets of XENON100 and the hints of detection. The same question
assessed with goodness of fit would indicate a 2 sigma discrepancy. This
suggests that more data are therefore needed to settle this question.


title: Overlimiting Current and Shock Electrodialysis in Porous Media

abstract:
  Most electrochemical processes, such as electrodialysis, are limited by
diffusion, but in porous media, surface conduction and electro-osmotic flow
also contribute to ionic fluxes. In this paper, we report experimental evidence
for surface-driven over-limiting current (faster than diffusion) and
deionization shocks (propagating salt removal) in a porous medium. The
apparatus consists of a silica glass frit (1 mm thick with 500 nm mean pore
size) in an aqueous electrolyte (CuSO$_4$ or AgNO$_3$) passing ionic current
from a reservoir to a cation-selective membrane (Nafion). The current-voltage
relation of the whole system is consistent with a proposed theory based on the
electro-osmotic flow mechanism over a broad range of reservoir salt
concentrations (0.1 mM - 1.0 M), after accounting for (Cu) electrode
polarization and pH-regulated silica charge. Above the limiting current,
deionized water ($\approx 10 \mu$ $M$) can be continuously extracted from the
frit, which implies the existence of a stable shock propagating against the
flow, bordering a depleted region that extends more than 0.5mm across the
outlet. The results suggest the feasibility of "shock electrodialysis" as a new
approach to water desalination and other electrochemical separations.


title: Cascading Failures in Networks with Proximate Dependent Nodes

abstract:
  We study the mutual percolation of a system composed of two interdependent
random regular networks. We introduce a notion of distance to explore the
effects of the proximity of interdependent nodes on the cascade of failures
after an initial attack. We find a non-trivial relation between the nature of
the transition through which the networks disintegrate and the parameters of
the system, which are the degree of the nodes and the maximum distance between
interdependent nodes. We explain this relation by solving the problem
analytically for the relevant set of cases.


title:
Detection of warm and diffuse baryons in large scale structure from the
  cross-correlation of gravitational lensing and the thermal Sunyaev-Zeldovich
  effect

abstract:
  We report the first detection of a correlation between gravitational lensing
by large scale structure and the thermal Sunyaev-Zeldovich (tSZ) effect. Using
the mass map from the Canada France Hawaii Telescope Lensing Survey (CFHTLenS)
and a newly-constructed tSZ map from Planck, we measure a non-zero correlation
between the two maps out to one degree angular separation on the sky, with an
overall significance of 6 sigma. The tSZ maps are formed in a manner that
removes primary cosmic microwave background fluctuations and minimizes residual
contamination by galactic and extragalactic dust emission, and by CO line
emission. We perform numerous tests to show that our measurement is immune to
these residual contaminants. The resulting correlation function is consistent
with the existence of a warm baryonic gas tracing the large scale structure
with a bias b_gas. Given the shape of the lensing kernel, our signal
sensitivity peaks at a redshift z~0.4, where half a degree separation on the
sky corresponds to a physical scale of ~10 Mpc. The amplitude of the signal
constrains the product (b_gas/1)(T_e / 0.1 keV)(n_e / 1 m^-3)=2.01\pm 0.31\pm
0.21, at redshift zero. Our study suggests that a substantial fraction of the
"missing" baryons in the universe may reside in a low density warm plasma that
traces dark matter.


title: Architecture of the Florida Power Grid as a Complex Network

abstract:
  We study the Florida high-voltage power grid as a technological network
embedded in space. Measurements of geographical lengths of transmission lines,
the mixing of generators and loads, the weighted clustering coefficient, as
well as the organization of edge conductance weights show a complex
architecture quite different from random-graph models usually considered. In
particular, we introduce a parametrized mixing matrix to characterize the
mixing pattern of generators and loads in the Florida Grid, which is
intermediate between the random mixing case and the semi-bipartite case where
generator-generator transmission lines are forbidden. Our observations motivate
an investigation of optimization (design) principles leading to the structural
organization of power grids. We thus propose two network optimization models
for the Florida Grid as a case study. Our results show that the Florida Grid is
optimized not only by reducing the construction cost (measured by the total
length of power lines), but also through reducing the total pairwise edge
resistance in the grid, which increases the robustness of power transmission
between generators and loads against random line failures. We then embed our
models in spatial areas of different aspect ratios and study how this geometric
factor affects the network structure, as well as the box-counting fractal
dimension of the grids generated by our models.


title:
A family of steady two-phase generalized Forchheimer flows and their
  linear stability analysis

abstract:
  We model multi-dimensional two-phase flows of incompressible fluids in porous
media using generalized Forchheimer equations and the capillary pressure.
Firstly, we find a family of steady state solutions whose saturation and
pressure are radially symmetric and velocities are rotation-invariant. Their
properties are investigated based on relations between the capillary pressure,
each phase's relative permeability and Forchheimer polynomial. Secondly, we
analyze the linear stability of those steady states.
  The linearized system is derived and reduced to a parabolic equation for the
saturation. This equation has a special structure depending on the steady
states which we exploit to prove two new forms of the lemma of growth of
Landis-type in both bounded and unbounded domains. Using these lemmas,
qualitative properties of the solution of the linearized equation are studied
in details. In bounded domains, we show that the solution decays exponentially
in time. In unbounded domains, in addition to their stability, the solution
decays to zero as the spatial variables tend to infinity. The Bernstein


title: Photoactivated Colloidal Dockers for Cargo Transportation

abstract:
  We introduce a self-propelled colloidal hematite docker that can be steered
to a small particle cargo many times its size, dock, transport the cargo to a
remote location, and then release it. The self-propulsion and docking are
reversible and activated by visible light. The docker can be steered either by
a weak uniform magnetic field or by nanoscale tracks in a textured substrate.
The light-activated motion and docking originate from osmotic/phoretic particle
transport in a concentration gradient of fuel, hydrogen peroxide, induced by
the photocatalytic activity of the hematite. The docking mechanism is versatile
and can be applied to various materials and shapes. The hematite dockers are
simple single-component particles and are synthesized in bulk quantities. This
system opens up new possibilities for designing complex micrometer-size
factories as well as new biomimetic systems.


title:
Produktion einzelner Top-Quarks in n\"achst-zu-n\"achstf\"uhrender
  Ordnung der QCD: Der Beitrag der Einschleifenamplituden quadriert

abstract:
  Top quark physics are an appropriate laboratory to study phenomena of the
Standard Model and to test the limits of this theory. To obtain a higher
precision for top quark predictions, the next-to-next-to-leading order (NNLO)
in the pertubative expansion of the top quark production cross-section has to
be calculated. The next-to-leading order (NLO) results are already available
and provide a rather good accuracy. But this precision might be accidental,
because at NLO not all the possible colour exchanges which occur at the
one-loop level are considered and they could have significant impact on the
cross-section and its differential distributions. In order to have precise
predictions of the single top quark production the complete NNLO calculation is
necessary. In this thesis the contributions of the one-loop amplitudes squared
in NNLO are calculated for one production channel ($\textit{t}$-channel). The
other possible production channels of the single top quark are also
investigated. With the presented setup well known results in literature are
reproduced. Intermediate results are calculated with different independent
methods and, if possible, compared with results from literature. The occurring
ultraviolet divergencies are dealt with in conventional dimensional
regularisation (CDR) in the $\bar{\text{MS}}$ scheme ("Modified Minimal
Substraction Scheme"). The final result still has infrared divergencies. An
anti-commuting scheme for the calculation with the $\gamma_5$ matrix in CDR is
used. An alternative scheme for the treatment of $\gamma_5$ is the Larin
scheme, which will be introduced and discussed.


title: Correlation and variable importance in random forests

abstract:
  This paper is about variable selection with the random forests algorithm in
presence of correlated predictors. In high-dimensional regression or
classification frameworks, variable selection is a difficult task, that becomes
even more challenging in the presence of highly correlated predictors. Firstly
we provide a theoretical study of the permutation importance measure for an
additive regression model. This allows us to describe how the correlation
between predictors impacts the permutation importance. Our results motivate the
use of the Recursive Feature Elimination (RFE) algorithm for variable selection
in this context. This algorithm recursively eliminates the variables using
permutation importance measure as a ranking criterion. Next various simulation
experiments illustrate the efficiency of the RFE algorithm for selecting a
small number of variables together with a good prediction error. Finally, this
selection algorithm is tested on the Landsat Satellite data from the UCI
Machine Learning Repository.


title:
Field Theory of Nematicity in the Spontaneous Quantum Anomalous Hall
  effect

abstract:
  We derive from a microscopic model the effective theory of nematic order in a
system with a spontaneous quantum anomalous Hall effect in two dimensions.
Starting with a model of two-component fermions (a spinor field) with a
quadratic band crossing and short range four-fermion marginally relevant
interactions we use a 1/N expansion and bosonization methods to derive the
effective field theory for the hydrodynamic modes associated with the conserved
currents and with the local fluctuations of the nematic order parameter. We
focus on the vicinity of the quantum phase transition from the isotropic Mott
Chern insulating phase to a phase in which time-reversal symmetry breaking
coexists with nematic order, the nematic Chern insulator. The topological
sector of the effective field theory is a BF/Chern-Simons gauge theory. We show
that the nematic order parameter field couples with the Maxwell-type terms of
the gauge fields as the space components of a locally fluctuating metric
tensor. The nematic field has $z=2$ dynamic scaling exponent. The low energy
dynamics of the nematic order parameter is found to be governed by a Berry
phase term. By means of a detailed analysis of the coupling of the spinor field
of the fermions to the changes of their local frames originating from
long-wavelength lattice deformations we calculate the Hall viscosity of this
system and show that in this system is not the same as the Berry phase term in
the effective action of the nematic field, but both are related to the concept
of torque Hall viscosity which we introduce here.


title:
High-Resolution Three-Dimensional Simulations of Core-Collapse
  Supernovae in Multiple Progenitors

abstract:
  Three-dimensional simulations of core-collapse supernovae are granting new
insight into the as-yet uncertain mechanism that drives successful explosions.
While there is still debate about whether explosions are obtained more easily
in 3D than in 2D, it is undeniable that there exist qualitative and
quantitative differences between the results of 3D and 2D simulations. We
present an extensive set of high-resolution one-, two-, and three-dimensional
core-collapse supernova simulations with multispecies neutrino leakage carried
out in two different progenitors. Our simulations confirm the results of Couch
(2013) indicating that 2D explodes more readily than 3D. We argue that this is
due to the inadequacies of 2D to accurately capture important aspects of the
three-dimensional dynamics. We find that without artificially enhancing the
neutrino heating rate we do not obtain explosions in 3D. We examine the
development of neutrino-driven convection and the standing accretion shock
instability and find that, in separate regimes, either instability can
dominate. We find evidence for growth of the standing accretion shock
instability for both 15-$M_\odot$ and 27-$M_\odot$ progenitors, however, it is
weaker in 3D exploding models. The growth rate of both instabilities is
artificially enhanced along the symmetry axis in 2D as compared with our
axis-free 3D Cartesian simulations. Our work highlights the growing consensus
that core-collapse supernovae must be studied in 3D if we hope to solve the
mystery of how the explosions are powered.


title: High density piecewise syndeticity of sumsets

abstract:
  Renling Jin proved that if A and B are two subsets of the natural numbers
with positive Banach density, then A+B is piecewise syndetic. In this paper, we
prove that, under various assumptions on positive lower or upper densities of A
and B, there is a high density set of witnesses to the piecewise syndeticity of
A+B. Most of the result are shown to hold more generally for subsets of Z^d.
The key technical tool is a Lebesgue density theorem for measure spaces induced
by cuts in the nonstandard integers.


title:
A Distributed Control Problem for a Three-Dimensional Lagrangian
  Averaged Navier-Stiokes-{\alpha} MODEL

abstract:
  A distributed optimal control problem with final observation for a three-
dimensional Lagrange averaged Navier-Stokes-? model is studied. The solvability
of the optimal control problem is proved and the first-order optimality
conditions are estab- lished. Moreover, by using the Lagrange multipliers
method, an optimality system in a weak and a strong form is derived.


title:
The scaling behavior of the insulator to plateau transition in
  topological band model

abstract:
  The scaling behavior of the quantum phase transition from an insulator to a
quantum Hall plateau state has often been examined within systems realizing
Landau levels. We study the topological transition in energy band models with
nonzero Chern number, which have the same topological property as a Landau
level. We find that the topological band generally realizes the same
universality class as the integer quantum Hall system in magnetic field for
strong enough disorder scattering. Furthermore, the symmetry of the transition
characterized by the relations: $\sigma_{xy}(E)=1-\sigma_{xy}(-E)$ for the Hall
conductance and $\sigma_{xx}(E)=\sigma_{xx}(-E)$ for the longitudinal
conductance is observed near the transition region. We also establish that the
finite temperature dependence of the Hall conductance is determined by the
inelastic scattering relaxation time, while the localization exponent $\nu$
remains unchanged by such scattering.


title: Cosmic ray propagation in galactic turbulence

abstract:
  We revisit propagation of galactic cosmic rays (CRs) in light of recent
advances in CR diffusion theory in realistic interstellar turbulence. We use a
tested model of turbulence in which it has been shown that fast modes dominate
scattering of CRs. As a result, propagation becomes inhomogeneous and
environment dependent. By adopting the formalism of the nonlinear theory
developed by Yan & Lazarian, we calculate the diffusion of CRs
self-consistently from first principles. We assume a two- phase model for the
Galaxy to account for different damping mechanisms of the fast modes, and we
find that the energy dependence of the diffusion coefficient is mainly affected
by medium properties. We show that it gives a correct framework to interpret
some of the recent CR puzzles.


title:
Remarks on analyticity and unitarity in the presence of a Strongly
  Interacting Light Higgs

abstract:
  Applying the three axiomatic criteria of Lorentz invariance, analyticity and
unitarity to scattering amplitudes involving the Goldstone bosons and the Higgs
boson, we derive a general sum rule for the Strongly Interacting Light Higgs
Lagrangian. This sum rule connects the IR coefficient $c_H$ to the UV
properties of the theory, and can be used, for instance, to capture the role of
resonances in processes like $V_{\rm L}V_{\rm L}\to hh$ and $V_{\rm L}V_{\rm
L}\to V_{\rm L}V_{\rm L}$, with $V=W^{\pm},Z$.


title: Minimal Submanifolds asymptotic to AdS4xS2 in AdS5xS5

abstract:
  In this work, as an attempt in understanding the interplay between
deformations of the external and internal spaces associated with the
probe-brane embedding submanifold, we construct the zero-temperature phase
diagram for the coupled phase between two two-dimensional defects stacked
parallel in a four-dimensional ambient spacetime. Different UV parameters are
turned on for different defects. We study the system in the quenched strong
coupling limit, using holography with probe brane approximation, realized
explicitly through the D3/D5 system. This coupled phase is holographic dual to
the presence of spontaneous symmetry breaking of the individual ultraviolet
flavor symmetries associated with the double heterostructure of the defect
layers. We characterize this solution by its infrared geometric data, and
present the numerical result showing a first-order phase transition between the
asymmetrically coupled phase and the more mundane decoupled phase.


title: Hexagon Wilson Loop OPE and Harmonic Polylogarithms

abstract:
  A recent, integrability-based conjecture in the framework of the Wilson loop
OPE for N=4 SYM theory, predicts the leading OPE contribution for the hexagon
MHV remainder function and NMHV ratio function to all loops, in integral form.
We prove that these integrals evaluate to a particular basis of harmonic
polylogarithms, at any order in the weak coupling expansion. The proof
constitutes an algorithm for the direct computation of the integrals, which we
employ in order to obtain the full (N)MHV OPE contribution in question up to 6
loops, and certain parts of it up to 12 loops. We attach computer-readable
files with our results, as well as an algorithm implementation which may be
readily used to generate higher-loop corrections. The feasibility of obtaining
the explicit kinematical dependence of the first term in the OPE in principle
at arbitrary loop order, offers promise for the suitability of this approach as
a non-perturbative description of Wilson loops/scattering amplitudes.


title: Super-resolution photoacoustic imaging through a scattering wall

abstract:
  Imaging through opaque, highly scattering walls is a long sought after
capability with potential applications in a variety of fields. The use of
wavefront shaping to compensate for scattering has brought a renewed interest
as a potential solution to this problem. A key to the practicality of any
imaging technique is the capability to focus light without direct access behind
the scattering wall. Here, we address this problem using photoacoustic feedback
for wavefront optimization. By combining the spatially non-uniform sensitivity
of the ultrasound transducer to the generated photoacoustic waves with an
evolutionary competition among optical modes, the speckle field develops a
single, high intensity focus significantly smaller than the acoustic focus used
for feedback. Notably, this method is not limited by the size of the absorber
to form a sub-acoustic optical focus. We demonstrate imaging behind a
scattering medium with up to ten times improvement in signal-to-noise ratio
(SNR) and five to six times sub-acoustic resolution. The results presented here
open up opportunities for 3D imaging applications in the diffusive regime
beyond the sound wave diffraction-limited resolution, including medical
imaging, photothermal therapy, neuroscience, and optogenetics.


title:
A squeeze-like operator approach to position-dependent mass in quantum
  mechanics

abstract:
  We provide a squeeze-like transformation that allows one to remove a position
dependent mass from the Hamiltonian. Methods to solve the Schr\"{o}dinger
equation may then be applied to find the respective eigenvalues and
eigenfunctions. As an example, we consider a position-dependent-mass that leads
to the integrable Morse potential and therefore to well-known solutions.


title: A Kernel for Hierarchical Parameter Spaces

abstract:
  We define a family of kernels for mixed continuous/discrete hierarchical
parameter spaces and show that they are positive definite.


title: Super cosmic variance from mode-coupling: A worked example

abstract:
  If the entire post-inflationary patch is large compared to our Hubble volume
even a small level of non-Gaussianity can cause statistics of the primordial
curvature field in our Hubble volume to be biased by mode-coupling. We
explicitly compute the variation of locally measured statistics of the
primordial curvature $\zeta$ from non-Gaussian mode coupling within a specific
inflationary scenario: the curvaton model with a quadratic curvaton potential.
This "super cosmic variance" is calculated in two ways: (i) as a super observer
who has access to the curvature perturbation field across the entire
post-inflationary patch and therefore sees local statistics as biased by mode
coupling and (ii) as a local observer who sees the statistics of $\zeta$
determined by the local values of quantities in their Hubble patch. The two
calculations agree and show that in the quadratic curvaton model patch-to-patch
differences in statistics of $\zeta$ can be interpreted entirely as a shift in
the value of the curvaton field at freeze out. Applying the same arguments to
single-field slow-roll inflation gives a simple picture of how non-Gaussian
mode-coupling between the curvature perturbations on very different physical
scales must vanish in the attractor limit.


title: Interpolating from Bianchi Attractors to Lifshitz and AdS Spacetimes

abstract:
  We construct classes of smooth metrics which interpolate from Bianchi
attractor geometries of Types II, III, VI and IX in the IR to Lifshitz or
$AdS_2 \times S^3$ geometries in the UV. While we do not obtain these metrics
as solutions of Einstein gravity coupled to a simple matter field theory, we
show that the matter sector stress-energy required to support these geometries
(via the Einstein equations) does satisfy the weak, and therefore also the
null, energy condition. Since Lifshitz or $AdS_2 \times S^3$ geometries can in
turn be connected to $AdS_5$ spacetime, our results show that there is no
barrier, at least at the level of the energy conditions, for solutions to arise
connecting these Bianchi attractor geometries to $AdS_5$ spacetime. The
asymptotic $AdS_5$ spacetime has no non-normalizable metric deformation turned
on, which suggests that furthermore, the Bianchi attractor geometries can be
the IR geometries dual to field theories living in flat space, with the
breaking of symmetries being either spontaneous or due to sources for other
fields. Finally, we show that for a large class of flows which connect two
Bianchi attractors, a C-function can be defined which is monotonically
decreasing from the UV to the IR as long as the null energy condition is
satisfied. However, except for special examples of Bianchi attractors
(including AdS space), this function does not attain a finite and non-vanishing
constant value at the end points.


title: Competing p-wave orders

abstract:
  We construct electrically charged, asymptotically $AdS_5$ black hole
solutions that are dual to $d=4$ CFTs in a superfluid phase with either p-wave
or $(p+ip)$-wave order. The two types of black holes have non-vanishing charged
two-form in the bulk and appear at the same critical temperature in the
unbroken phase. Both the p-wave and the $(p+ip)$-wave phase can be
thermodynamically preferred, depending on the mass and charge of the two-form,
and there can also be first order transitions between them. The p-wave black
holes have a helical structure and some of them exhibit the phenomenon of pitch
inversion as the temperature is decreased. Both the p-wave and the
$(p+ip)$-wave black holes have zero entropy density ground states at zero
temperature and we identify some new ground states which exhibit scaling
symmetry, including a novel scenario for the emergence of conformal symmetry in
the IR.


title: Magnetic models on various topologies

abstract:
  A brief review is given on the study of the thermodynamic properties of spin
models defined on different topologies like small-world, scale-free networks,
random graphs and regular and random lattices. Ising, Potts and Blume-Capel
models are considered. They are defined on complex lattices comprising
Appolonian, Barab\'asi-Albert, Voronoi-Delauny and small-world networks. The
main emphasis is given on the corresponding phase transitions, transition
temperatures, critical exponents and universality, compared to those obtained
by the same models on regular Bravais lattices.


title:
Statistical Curse of the Second Half Rank, Eulerian numbers and Stirling
  numbers

abstract:
  I describe the occurence of Eulerian numbers and Stirling numbers of the
second kind in the combinatorics of the Statistical Curse of the Second Half
Rank problem.

categories: math.ST cond-mat.stat-mech math.HO stat.TH


title: Astrometry in the Galactic Center with the Thirty Meter Telescope

abstract:
  We report on the expected astrometric performance of the Thirty Meter
Telescope's InfraRed Imaging Spectrometer (IRIS) as determined using simulated
images of the Galactic center. This region of the Galaxy harbors a supermassive
black hole and a dense nuclear stellar cluster, thus providing an ideal
laboratory for testing crowded-field astrometry with the IRIS imager.
Understanding the sources of astrometric error is also important for making
precision measurements of the short-period stars orbiting the supermassive
black hole in order to probe the curvature of space-time as predicted by
General Relativity. Various sources of error are investigated, including
read-out and photon noise, spatially variable point spread functions,
confusion, static distortion for the IRIS imager, and the quadratic probe arm
distortion. Optical distortion is the limiting source of error for bright stars
(K < 15), while fainter sources will be limited by the effects of source
confusion. A detailed astrometric error budget for the Galactic center science
case is provided.


title: Production of EMRIs in Supermassive Black Hole Binaries

abstract:
  We consider the formation of extreme mass-ratio inspirals (EMRIs) sourced
from a stellar cusp centred on a primary supermassive black hole (SMBH) and
perturbed by an inspiraling less massive secondary SMBH. The problem is
approached numerically, assuming the stars are non-interacting over these short
timescales and performing an ensemble of restricted three-body integrations.
From these simulations we see that not only can EMRIs be produced during this
process, but the dynamics are also quite rich. In particular, most of the EMRIs
are produced through a process akin to the Kozai-Lidov mechanism, but with
strong effects due to the non-Keplerian stellar potential, general relativity,
and non-secular oscillations in the angular momentum on the orbital timescale
of the binary SMBH system.


title: Trading inference effort versus size in CNF Knowledge Compilation

abstract:
  Knowledge Compilation (KC) studies compilation of boolean functions f into
some formalism F, which allows to answer all queries of a certain kind in
polynomial time. Due to its relevance for SAT solving, we concentrate on the
query type "clausal entailment" (CE), i.e., whether a clause C follows from f
or not, and we consider subclasses of CNF, i.e., clause-sets F with special
properties. In this report we do not allow auxiliary variables (except of the
Outlook), and thus F needs to be equivalent to f.
  We consider the hierarchies UC_k <= WC_k, which were introduced by the
authors in 2012. Each level allows CE queries. The first two levels are
well-known classes for KC. Namely UC_0 = WC_0 is the same as PI as studied in
KC, that is, f is represented by the set of all prime implicates, while UC_1 =
WC_1 is the same as UC, the class of unit-refutation complete clause-sets
introduced by del Val 1994. We show that for each k there are (sequences of)
boolean functions with polysize representations in UC_{k+1}, but with an
exponential lower bound on representations in WC_k. Such a separation was
previously only know for k=0. We also consider PC < UC, the class of
propagation-complete clause-sets. We show that there are (sequences of) boolean
functions with polysize representations in UC, while there is an exponential
lower bound for representations in PC. These separations are steps towards a
general conjecture determining the representation power of the hierarchies PC_k
< UC_k <= WC_k. The strong form of this conjecture also allows auxiliary
variables, as discussed in depth in the Outlook.


title:
Full characterisation of attractors of two intersected asynchronous
  Boolean automata cycles

abstract:
  The understanding of Boolean automata networks dynamics takes an important
place in various domains of computer science such as computability, complexity
and discrete dynamical systems. In this paper, we make a step further in this
understanding by focusing on their cycles, whose necessity in networks is known
as the brick of their complexity. We present new results that provide a
characterisation of the transient and asymptotic dynamics, i.e. of the
computational abilities, of asynchronous Boolean automata networks composed of
two cycles that intersect at one automaton, the so-called double-cycles. To do
so, we introduce an efficient formalism inspired by algorithms to define long
sequences of updates, that allows a better description of their dynamics than
previous works in this area.


title:
Optimal Distributed Control of Reactive Power via the Alternating
  Direction Method of Multipliers

abstract:
  We formulate the control of reactive power generation by photovoltaic
inverters in a power distribution circuit as a constrained optimization that
aims to minimize reactive power losses subject to finite inverter capacity and
upper and lower voltage limits at all nodes in the circuit. When voltage
variations along the circuit are small and losses of both real and reactive
powers are small compared to the respective flows, the resulting optimization
problem is convex. Moreover, the cost function is separable enabling a
distributed, on-line implementation with node-local computations using only
local measurements augmented with limited information from the neighboring
nodes communicated over cyber channels. Such an approach lies between the fully
centralized and local policy approaches previously considered. We explore
protocols based on the dual ascent method and on the Alternating Direction
Method of Multipliers (ADMM) and find that the ADMM protocol performs
significantly better.


title: Achievements of the ATLAS Upgrade Planar Pixel Sensors R&D Project

abstract:
  To extend the physics reach of the LHC, accelerator upgrades are planned
which will increase the integrated luminosity to beyond 3000 fb^-1 and the
pile-up per bunch-crossing by a factor 5 to 10. To cope with the increased
occupancy and radiation damage, the ATLAS experiment plans to introduce an
all-silicon inner tracker with the HL-LHC upgrade. To investigate the
suitability of pixel sensors using the proven planar technology for the
upgraded tracker, the ATLAS Upgrade Planar Pixel Sensor R&D Project (PPS) was
established comprising 19 institutes and more than 80 scientists. Main areas of
research are the performance assessment of planar pixel sensors with different
designs and substrate thicknesses up to the HL-LHC fluence, the achievement of
slim or active edges to provide low geometric inefficiencies without the need
for shingling of modules and the exploration of possibilities for cost
reduction to enable the instrumentation of large areas. This paper gives an
overview of recent accomplishments and ongoing work of the R&D project.


title: Hamiltonian analysis for linearly acceleration-dependent Lagrangians

abstract:
  We study the constrained Ostrogradski-Hamilton framework for the equations of
motion provided by mechanical systems described by second-order derivative
actions with a linear dependence in the accelerations. We stress out the
peculiar features provided by the surface terms arising for this type of
theories and we discuss some important properties for this kind of actions in
order to pave the way for the construction of a well defned quantum counterpart
by means of canonical methods. In particular, we analyse in detail the
constraint structure for these theories and its relation to the inherent
conserved quantities where the associated energies together with a Noether
charge may be identifed. The constraint structure is fully analyzed without the
introduction of auxiliary variables, as proposed in recent works involving
higher order Lagrangians. Finally, we also provide some examples where our
approach is explicitly applied and emphasize the way in which our original
arrangement results in propitious for the Hamiltonian formulation of covariant
feld theories.


title:
Rate of Convergence and Large Deviation for the Infinite Color P\'olya
  Urn Schemes

abstract:
  In this work we consider the \emph{infinite color urn model} associated with
a bounded increment random walk on $\Zbold^d$. This model was first introduced
by Bandyopadhyay and Thacker (2013). We prove that the rate of convergence of
the expected configuration of the urn at time $n$ with appropriate centering
and scaling is of the order ${\mathcal O}\left(\frac{1}{\sqrt{\log n}}\right)$.
Moreover we derive bounds similar to the classical Berry-Essen bound. Further
we show that for the expected configuration a \emph{large deviation principle
(LDP)} holds with a good rate function and speed $\log n$.


title:
Development of Edgeless Silicon Pixel Sensors on p-type substrate for
  the ATLAS High-Luminosity Upgrade

abstract:
  In view of the LHC upgrade for the High Luminosity Phase (HL-LHC), the ATLAS
experiment is planning to replace the Inner Detector with an all-Silicon
system. The n-in-p bulk technology represents a valid solution for the modules
of most of the layers, given the significant radiation hardness of this option
and the reduced cost. The large area necessary to instrument the outer layers
will demand to tile the sensors, a solution for which the inefficient region at
the border of each sensor needs to be reduced to the minimum size. This paper
reports on a joint R&D project by the ATLAS LPNHE Paris group and FBK Trento on
a novel n-in-p edgeless planar pixel design, based on the deep-trench process
available at FTK.


title: Possible Anderson localization in a holographic superconductor

abstract:
  We study the effect of disorder in a holographic superconductor by
introducing a quasi-periodic chemical potential. When the condensation of the
superconductor is sufficiently small compared with the strength of disorder, we
find that there exists a discontinuous phase transition from superconducting
state to normal state with increasing disorder strength. For relatively large
condensation, we find that disorder suppress but not completely destroy
superconductivity. This model may provide a holographic realization of Anderson
Localization in two-dimensional superconductor.


title:
Analogues of Mathai-Quillen forms in sheaf cohomology and applications
  to topological field theory

abstract:
  We construct sheaf-cohomological analogues of Mathai-Quillen forms, that is,
holomorphic bundle-valued differential forms whose cohomology classes are
independent of certain deformations, and which are believed to possess
Thom-like properties. Ordinary Mathai-Quillen forms are special cases of these
constructions, as we discuss. These sheaf-theoretic variations arise physically
in A/2 and B/2 pseudo-topological field theories, and we comment on their
origin and role.


title:
Determination, Calculation and Representation of the Upper and Lower
  Sealing Zones During Virtual Stenting of Aneurysms

abstract:
  In this contribution, a novel method for stent simulation in preoperative
computed tomography angiography (CTA) acquisitions of patients is presented
where the sealing zones are automatically calculated and visualized. The method
is eligible for non-bifurcated and bifurcated stents (Y-stents). Results of the
proposed stent simulation with an automatic calculation of the sealing zones
for specific diseases (abdominal aortic aneurysms (AAA), thoracic aortic
aneurysms (TAA), iliac aneurysms) are presented. The contribution is organized
as follows. Section 2 presents the proposed approach. In Section 3,
experimental results are discussed. Section 4 concludes the contribution and
outlines areas for future work.


title:
Picosecond all-optical switching in hydrogenated amorphous silicon
  microring resonators

abstract:
  We utilize cross-phase modulation to observe all-optical switching in
microring resonators fabricated with hydrogenated amorphous silicon (a-Si:H).
Using 2.7-ps pulses from a mode-locked fiber laser in the telecom C-band, we
observe optical switching of a cw telecom-band probe with full-width at
half-maximum switching times of 14.8 ps, using approximately 720 fJ of energy
deposited in the microring. In comparison with telecom-band optical switching
in undoped crystalline silicon microrings, a-Si:H exhibits substantially higher
switching speeds due to reduced impact of free-carrier processes.


title:
The linear hyperbolic initial and boundary value problems in a domain
  with corners

abstract:
  In this article, we consider linear hyperbolic Initial and Boundary Value
Problems (IBVP) in a rectangle (or possibly curvilinear polygonal domains) in
both the constant and variable coefficients cases. We use semigroup method
instead of Fourier analysis to achieve the well-posedness of the linear
hyperbolic system, and we find by diagonalization that there are only two
elementary modes in the system which we call hyperbolic and elliptic modes. The
hyperbolic system in consideration is either symmetric or
Friedrichs-symmetrizable.


title: Toward Full LHC Coverage of Natural Supersymmetry

abstract:
  We argue that combining just a handful of searches for new physics at Run I
of the LHC is sufficient to exclude most supersymmetric extensions of the
Standard Model in which the gluino is kinematically accessible and the spectrum
is natural. Such models typically give rise to significant MET, top quarks
and/or high object multiplicity, and we show that having even one of these
signatures generally results in stringent limits. We also identify, among
models that lack these signatures, the few gaps in coverage remaining, and
propose search strategies to close these gaps. Our results are general and
independent of the details of the spectrum, assumptions about minimality,
R-parity, etc. Our analysis strategy should remain applicable when the LHC
moves to higher energy. Central to our argument are ATLAS and CMS searches for
many jets and low MET, a proposed lepton + many jets search, an ATLAS search
for 6-7 high-pT jets, and a reexamination of the control and signal regions of
the CMS black hole search.


title:
Storage of ultracold neutrons in the UCN$\tau$ magneto-gravitational
  trap

abstract:
  The UCN$\tau$ experiment is designed to measure the lifetime $\tau_{n}$ of
the free neutron by trapping ultracold neutrons (UCN) in a
magneto-gravitational trap. An asymmetric bowl-shaped NdFeB magnet Halbach
array confines low-field-seeking UCN within the apparatus, and a set of
electromagnetic coils in a toroidal geometry provide a background "holding"
field to eliminate depolarization-induced UCN loss caused by magnetic field
nodes. We present a measurement of the storage time $\tau_{store}$ of the trap
by storing UCN for various times, and counting the survivors. The data are
consistent with a single exponential decay, and we find $\tau_{store}=860\pm19$
s: within $1 \sigma$ of current global averages for $\tau_{n}$. The storage
time with the holding field deactiveated is found to be $\tau_{store}=470 \pm
160$ s; this decreased storage time is due to the loss of UCN which undergo
Majorana spin-flips while being stored. We discuss plans to increase the
statistical sensitivity of the measurement and investigate potential systematic
effects.


title: Calmness modulus of linear semi-infinite programs

abstract:
  Our main goal is to compute or estimate the calmness modulus of the argmin
mapping of linear semi-infinite optimization problems under canonical
perturbations, i.e., perturbations of the objective function together with
continuous perturbations of the right-hand-side of the constraint system (with
respect to an index ranging in a compact Hausdorff space). Specifically, we
provide a lower bound on the calmness modulus for semi-infinite programs with
unique optimal solution which turns out to be the exact modulus when the
problem is finitely constrained. The relationship between the calmness of the
argmin mapping and the same property for the (sub)level set mapping (with
respect to the objective function), for semi-infinite programs and without
requiring the uniqueness of the nominal solution, is explored too, providing an
upper bound on the calmness modulus of the argmin mapping. When confined to
finitely constrained problems, we also provide a computable upper bound as it
only relies on the nominal data and parameters, not involving elements in a
neighborhood. Illustrative examples are provided.


title:
Shearing a glass and the role of pin-delay in models of interface
  depinning

abstract:
  When a disordered solid is sheared, yielding is followed by the onset of
intermittent response that is characterized by slip in local regions usually
labeled shear-transformation zones (STZ). Such intermittent response resembles
the behavior of earthquakes or contact depinning, where a well-defined
landscape of pinning disorder prohibits the deformation of an elastic medium.
Nevertheless, a disordered solid is evidently different in that pinning
barriers of particles are due to neighbors that are also subject to motion.
Microscopic yielding leads to destruction of the local microstructure and local
heating. It is natural to assume that locally a liquid emerges for a finite
timescale before cooling down to a transformed configuration. For including
this characteristic transient in glass depinning models, we propose a general
mechanism that involves a "pin-delay" time Tpd, during which each region that
slipped evolves as a fluid. The new timescale can be as small as a single
avalanche time-step. We demonstrate that the inclusion of this mechanism causes
a drift of the critical exponents towards higher values for the slip sizes
$\tau$, until a transition to permanent shear-banding behavior happens causing
almost oscillatory, stick-slip response. Moreover, it leads to a proliferation
of large events that are highly inhomogeneous and resemble sharp slip band
formation. Our model appears to be qualitatively consistent with recent
experiments and simulations of disordered solids under shear.

categories: cond-mat.mtrl-sci cond-mat.dis-nn cond-mat.soft nlin.AO


title:
Metal-insulator transition in antiferromagnetic $Ba_{1-x}K_xMn_2As_2$
  $(0\le x\le0.4)$ single crystals studied by $^{55}$Mn and $^{75}$As NMR

abstract:
  The magnetic structure and metal-insulator transition in antiferromagnetic
(AFM) BaMn2As2 and Ba1-xKxMn2As2 single crystals have been investigated by 55Mn
and 75As nuclear magnetic resonance (NMR) measurements. In the parent AFM
insulator BaMn2As2 with a Neel temperature TN = 625 K, we observed a 55Mn
zero-field NMR (ZFNMR) spectrum and confirmed the G-type AFM structure from the
field dependence of the 55Mn spectra and 75As-NMR spectra below TN. In
hole-doped crystals with x > 0.01, similar 55Mn ZFNMR spectra were observed and
the AFM state was revealed to be robust up to x = 0.4 with the ordered moment
nearly independent of x. The nuclear spin-lattice relaxation rates (1/T1) for
both nuclei in the doped samples follow the Korringa relation T1T = const.,
indicating a metallic state. This confirms the coexistence of AFM ordered
localized Mn spins and conduction carriers from a microscopic point of view.
From the x-dependence of (T1T)^(-1/2) for both nuclei, we conclude that this
transition is caused by vanishing of the hole concentration as the transition
is approached from the metallic side.


title: About [q]-regularity properties of collections of sets

abstract:
  We examine three primal space local Hoelder type regularity properties of
finite collections of sets, namely, [q]-semiregularity, [q]-subregularity, and
uniform [q]-regularity as well as their quantitative characterizations.
Equivalent metric characterizations of the three mentioned regularity
properties as well as a sufficient condition of [q]-subregularity in terms of
Frechet normals are established. The relationships between [q]-regularity
properties of collections of sets and the corresponding regularity properties
of set-valued mappings are discussed.


title:
Minimax Optimal Convergence Rates for Estimating Ground Truth from
  Crowdsourced Labels

abstract:
  Crowdsourcing has become a primary means for label collection in many
real-world machine learning applications. A classical method for inferring the
true labels from the noisy labels provided by crowdsourcing workers is
Dawid-Skene estimator. In this paper, we prove convergence rates of a projected
EM algorithm for the Dawid-Skene estimator. The revealed exponent in the rate
of convergence is shown to be optimal via a lower bound argument. Our work
resolves the long standing issue of whether Dawid-Skene estimator has sound
theoretical guarantees besides its good performance observed in practice. In
addition, a comparative study with majority voting illustrates both advantages
and pitfalls of the Dawid-Skene estimator.


title: Scaling the smoothness of the IGM

abstract:
  We use, for the first time, the Detrend Fluctuation Analysis (DFA) to study
the correlation properties of the transmitted flux fluctuations, in the
Lyman-$\alpha$ (Ly$\alpha$) Forest along the lines of sight (LOS) to QSOs, at
different space scales. We consider in our analysis the transmitted flux in the
intergalactic medium over the redshift range 2 $\leq$ z $\leq$ 4.5 from a
sample of 45 high-quality medium resolution (R $\sim$ 4300) quasar spectra
obtained with Echelle Spectrograph and Imager (ESI) mounted on the Keck II 10-m
telescope, and from a sample of 19 high-quality high resolution (R $\sim$
50000) quasar spectra obtained with Ultra-Violet and Visible Echelle
Spectrograh (UVES) mounted on the ESO KUEYEN 8.2 m telescope. The result of the
DFA method applied to both datasets, shows that there exists a difference in
the correlation properties between the short and long-range regimes: the slopes
of the transmitted flux fluctuation function are different on small and large
scales. The scaling exponents, $\alpha_{1}$ = 1.635$\pm$ 0.115 and $\alpha_{2}$
= 0.758$\pm$ 0.085 for the ESI/Keck sample and $\alpha_{1}$ = 1.763 $\pm 0.128$
and $\alpha_{2}$ = 0.798 $\pm 0.084$ for the UVES/VLT sample for the short and
long range regime respectively. The transition between the two regims is
observed at about $\sim 1.4 h^{-1} Mpc$ (comoving). The fact that $\alpha_{1}$
is always larger than $\alpha_{2}$ for each spectrum supports the common view
that the Universe is smoother on large scales than on small scales. The non
detection of considerable variations in the scaling exponents from LOS to LOS
confirms that anisotropies cannot be ubiquitous, at least on these scales.


title: Conditioning the logistic branching process on non-extinction

abstract:
  We consider a birth and death process in which death is due to both `natural
death' and to competition between individuals, modelled as a quadratic function
of population size. The resulting `logistic branching process' has been
proposed as a model for numbers of individuals in populations competing for
some resource, or for numbers of species. However, because of the quadratic
death rate, even if the intrinsic growth rate is positive, the population will,
with probability one, die out in finite time. There is considerable interest in
understanding the process conditioned on non-extinction.
  In this paper, we exploit a connection with the ancestral selection graph of
population genetics to find expressions for the transition rates in the
logistic branching process conditioned on survival until some fixed time $T$,
in terms of the distribution of a certain one-dimensional diffusion process at
time $T$. We also find the probability generating function of the Yaglom
distribution of the process and rather explicit expressions for the transition
rates for the so-called Q-process, that is the logistic branching process
conditioned to stay alive into the indefinite future. For this process, one can
write down the joint generator of the (time-reversed) total population size and
what in population genetics would be called the `genealogy' and in
phylogenetics would be called the `reconstructed tree' of a sample from the
population.
  We explore some ramifications of these calculations numerically.


title: Contextual Hypergraph Modelling for Salient Object Detection

abstract:
  Salient object detection aims to locate objects that capture human attention
within images. Previous approaches often pose this as a problem of image
contrast analysis. In this work, we model an image as a hypergraph that
utilizes a set of hyperedges to capture the contextual properties of image
pixels or regions. As a result, the problem of salient object detection becomes
one of finding salient vertices and hyperedges in the hypergraph. The main
advantage of hypergraph modeling is that it takes into account each pixel's (or
region's) affinity with its neighborhood as well as its separation from image
background. Furthermore, we propose an alternative approach based on
center-versus-surround contextual contrast analysis, which performs salient
object detection by optimizing a cost-sensitive support vector machine (SVM)
objective function. Experimental results on four challenging datasets
demonstrate the effectiveness of the proposed approaches against the
state-of-the-art approaches to salient object detection.


title: Lambda (1405) photoproduction based on chiral unitary model

abstract:
  Recent CLAS data for the pi Sigma invariant mass distributions (line-shapes)
in the gamma p -> K^+ pi Sigma reaction are theoretically investigated. The
line-shapes have peaks associated with the Lambda(1405) excitation. Our model
consists of gauge invariant photo-production mechanisms, and the chiral unitary
model that gives the rescattering amplitudes where Lambda(1405) is contained.
It is found that, while the pi Sigma line-shape data in the Lambda(1405) region
are successfully reproduced by our model for all the charge states, the
production mechanism is not so simple that we need to introduce parameters
associated with short-range dynamics to fit the data. Our detailed analysis
suggests that the nonresonant background contribution is not negligible, and
its sizable effect shifts the Lambda(1405) peak position by several MeV. We
also analyze the data using a Breit-Wigner amplitudes instead of those from the
chiral unitary model. We find that the fitted Breit-Wigner parameters are
closer to the higher pole position for Lambda(1405) of the chiral unitary
model. This work sets a starting point for a fuller analysis in which
line-shape as well as K^+ angular distribution data are simultaneously analyzed
for extracting Lambda(1405) pole(s).


title: Quad-equations and auto-B\"acklund transformations of NLS-type systems

abstract:
  Treating an integrable quad-equation along with its two generalised
symmetries as a compatible system allows one to construct an auto-B\"acklund
transformation for solutions of the related NLS-type system. A fixed periodic
reduction of the quad-equation yields a quasi-periodic reduction of its
generalised symmetries that turn them into differential constraints compatible
with the NLS-type system.


title: Quantized Stationary Control Policies in Markov Decision Processes

abstract:
  For a large class of Markov Decision Processes, stationary (possibly
randomized) policies are globally optimal. However, in Borel state and action
spaces, the computation and implementation of even such stationary policies are
known to be prohibitive. In addition, networked control applications require
remote controllers to transmit action commands to an actuator with low
information rate. These two problems motivate the study of approximating
optimal policies by quantized (discretized) policies. To this end, we introduce
deterministic stationary quantizer policies and show that such policies can
approximate optimal deterministic stationary policies with arbitrary precision
under mild technical conditions, thus demonstrating that one can search for
$\varepsilon$-optimal policies within the class of quantized control policies.
We also derive explicit bounds on the approximation error in terms of the rate
of the approximating quantizers. We extend all these approximation results to
randomized policies. These findings pave the way toward applications in optimal
design of networked control systems where controller actions need to be
quantized, as well as for new computational methods for generating
approximately optimal decision policies in general (Polish) state and action
spaces for both discounted cost and average cost.


title:
Characterization of the KOI-94 System with Transit Timing Variation
  Analysis: Implication for the Planet-Planet Eclipse

abstract:
  The KOI-94 system is a closely-packed, multi-transiting planetary system
discovered by the Kepler space telescope. It is known as the first system that
exhibited a rare event called a "planet-planet eclipse (PPE)," in which two
planets partially overlap with each other in their double-transit phase. In
this paper, we constrain the parameters of the KOI-94 system with an analysis
of the transit timing variations (TTVs). Such constraints are independent of
the radial velocity (RV) analysis recently performed by Weiss and coworkers,
and valuable in examining the reliability of the parameter estimate using TTVs.
We numerically fit the observed TTVs of KOI-94c, KOI-94d, and KOI-94e for their
masses, eccentricities, and longitudes of periastrons, and obtain the best-fit
parameters including $m_{\rm c} = 9.4_{-2.1}^{+2.4} M_{\oplus}$, $m_{\rm d} =
52.1_{-7.1}^{+6.9} M_{\oplus}$, $m_{\rm e} = 13.0_{-2.1}^{+2.5} M_{\oplus}$,
and $e \lesssim 0.1$ for all the three planets. While these values are mostly
in agreement with the RV result, the mass of KOI-94d estimated from the TTV is
significantly smaller than the RV value $m_{\rm d} = 106 \pm 11 M_{\oplus}$. In
addition, we find that the TTV of the outermost planet KOI-94e is not well
reproduced in the current modeling. We also present analytic modeling of the
PPE and derive a simple formula to reconstruct the mutual inclination of the
two planets from the observed height, central time, and duration of the
brightening caused by the PPE. Based on this model, the implication of the
results of TTV analysis for the time of the next PPE is discussed.


title:
Total energy calculations using DFT+DMFT: computing the pressure phase
  diagram of the rare earth nickelates

abstract:
  A full implementation of the $ab$ $initio$ density functional plus dynamical
mean field theory (DFT+DMFT) formalism to perform total energy calculations and
structural relaxations is proposed and implemented. The method is applied to
the structural and metal-insulator transitions of the rare earth nickelate
perovskites as a function of rare earth ion, pressure, and temperature. In
contrast to previous DFT and DFT+$U$ theories, the present method accounts for
the experimentally observed structure of $La$NiO$_3$ and the insulating nature
of the other perovskites, and quantitatively reproduces the metal-insulator and
structural phase diagram in the plane of pressure and rare earth element. The
temperature dependence of the energetics of the phase transformation indicates
that the thermal transition is driven by phonon entropy effects.


title: Some new periodic Golay pairs

abstract:
  Periodic Golay pairs are a generalization of ordinary Golay pairs. They can
be used to construct Hadamard matrices. A positive integer $v$ is a (periodic)
Golay number if there exists a (periodic) Golay pair of length $v$. Taking into
the account the results obtained in this note and an yet unpublished new
result, there are only seven known periodic Golay numbers which are definitely
not Golay numbers, namely 34,50,58,68,72,74,82. We construct here periodic
Golay pairs of lengths 74,122,164,202,226. It is apparently unknown whether
122,164,202,226 are Golay numbers. The smallest length for which the existence
of periodic Golay pairs is undecided is now 90.


title: Triviality and Split of Vector Bundles on Rationally Connected Varieties

abstract:
  In this paper, we give a simple proof of a triviality criterion due to
I.Biswas and J.Pedro and P.Dos Santos. We also prove a vector bundle on a
homogenous space is trivial if and only if the restrictions of the vector
bundle to Schubert lines are trivial. Using this result and Chern classes of
vector bundles, we give a general criterion of a uniform vector bundle on a
homogenous space to be splitting. As an application, we prove a uniform vector
bundle on classical Grassmannians and quadrics of low rank is splitting.


title:
Applications of p-adic analysis for bounding periods of subvarieties
  under etale maps

abstract:
  Using methods of p-adic analysis we give a different proof of Burnside's
problem for automorphisms of quasiprojective varieties X defined over a field
of characteristic 0. More precisely, we show that any finitely generated
torsion subgroup of Aut(X) is finite. In particular this yields effective
bounds for the size of torsion of any semiabelian variety over a finitely
generated field of characteristic 0. More precisely, we obtain effective bounds
for the length of the orbit of a preperiodic subvariety under the action of an
etale map.