title: Nucleation-free $3D$ rigidity

abstract:
  When all non-edge distances of a graph realized in $\mathbb{R}^{d}$ as a {\em
bar-and-joint framework} are generically {\em implied} by the bar (edge)
lengths, the graph is said to be {\em rigid} in $\mathbb{R}^{d}$. For $d=3$,
characterizing rigid graphs, determining implied non-edges and {\em dependent}
edge sets remains an elusive, long-standing open problem.
  One obstacle is to determine when implied non-edges can exist without
non-trivial rigid induced subgraphs, i.e., {\em nucleations}, and how to deal
with them.
  In this paper, we give general inductive construction schemes and proof
techniques to generate {\em nucleation-free graphs} (i.e., graphs without any
nucleation) with implied non-edges. As a consequence, we obtain (a) dependent
graphs in $3D$ that have no nucleation; and (b) $3D$ nucleation-free {\em
rigidity circuits}, i.e., minimally dependent edge sets in $d=3$. It
additionally follows that true rigidity is strictly stronger than a tractable
approximation to rigidity given by Sitharam and Zhou
\cite{sitharam:zhou:tractableADG:2004}, based on an inductive combinatorial
characterization.
  As an independently interesting byproduct, we obtain a new inductive
construction for independent graphs in $3D$. Currently, very few such inductive
constructions are known, in contrast to $2D$.


title: Computing Covers of Plane Forests

abstract:
  Let $\phi$ be a function that maps any non-empty subset $A$ of $\mathbb{R}^2$
to a non-empty subset $\phi(A)$ of $\mathbb{R}^2$. A $\phi$-cover of a set
$T=\{T_1, T_2, \dots, T_m\}$ of pairwise non-crossing trees in the plane is a
set of pairwise disjoint connected regions such that each tree $T_i$ is
contained in some region of the cover, and each region of the cover is either
(1) $\phi(T_i)$ for some $i$, or (2) $\phi(A \cup B)$, where $A$ and $B$ are
constructed by either (1) or (2), and $A \cap B \neq \emptyset$.
  We present two properties for the function $\phi$ that make the $\phi$-cover
well-defined. Examples for such functions $\phi$ are the convex hull and the
axis-aligned bounding box. For both of these functions $\phi$, we show that the
$\phi$-cover can be computed in $O(n\log^2n)$ time, where $n$ is the total
number of vertices of the trees in $T$.


title: On Multiplicative Matrix Channels over Finite Chain Rings

abstract:
  Motivated by physical-layer network coding, this paper considers
communication in multiplicative matrix channels over finite chain rings. Such
channels are defined by the law $Y =A X$, where $X$ and $Y$ are the input and
output matrices, respectively, and $A$ is called the transfer matrix. It is
assumed a coherent scenario in which the instances of the transfer matrix are
unknown to the transmitter, but available to the receiver. It is also assumed
that $A$ and $X$ are independent. Besides that, no restrictions on the
statistics of $A$ are imposed. As contributions, a closed-form expression for
the channel capacity is obtained, and a coding scheme for the channel is
proposed. It is then shown that the scheme can achieve the capacity with
polynomial time complexity and can provide correcting guarantees under a
worst-case channel model. The results in the paper extend the corresponding
ones for finite fields.


title:
On Gaussians, Zeros, and Linear Combinations of L-functions. Part A:
  Entire Functions of Beurling-Selberg Type and Probability Distributions

abstract:
  This is the first installment in a series of papers devoted to examining
certain aspects of the asymptotic value distribution and distribution of zeros
manifested by members of a broad class of linear combinations of L-functions in
the vicinity of the critical line Re(s) = 1/2. The results that we ultimately
plan to discuss will entail a certain amount of probabilistic underpinning.
$\hspace{.16em}$Entire functions of Beurling-Selberg type turn out to provide a
very convenient inroad into the type of technical estimate that one needs.
$\hspace{.16em}$In the present paper, after first reviewing the basic
properties of these functions, we'll proceed to develop several relatively
simple (but highly suggestive) probabilistic examples in which the functions'
efficacy can be rather plainly seen. The path we take has the added advantage
of enabling several key ideas for later developments to already become visible
in an embryonic form.


title:
Vacuum decay and the transmission resonances in space-dependent electric
  fields

abstract:
  We investigate the decay of quantum electrodynamical (QED) vacuum in
arbitrary space-dependent electric fields. In particular, we analyze the
resonance peaks of the positron emission spectrum for the external fields with
subcycle structure. For this, we study the transmission probability in the
framework of scattering approach to vacuum pair production. In
under-the-barrier scattering regime, we show that the width of a transmission
resonance can be enhanced when the effective scattering potential contains
multiple wells. Such a broadening in the resonance width corresponds to a
decrease in the tunneling time. This may be relevant for observing the vacuum
decay at shorter timescales before the external field is adiabatically turned
off. In above-the-barrier scattering regime, we give a set of coupled
differential equations for the numerical computation of the Bogoliubov
coefficients.


title: Local Rank Modulation for Flash Memories

abstract:
  Local rank modulation scheme was suggested recently for representing
information in flash memories in order to overcome drawbacks of rank
modulation. For $s\leq t\leq n$ with $s|n$, $(s,t,n)$-LRM scheme is a local
rank modulation scheme where the $n$ cells are locally viewed through a sliding
window of size $t$ resulting in a sequence of small permutations which requires
less comparisons and less distinct values. The distance between two windows
equals to $s$. To get the simplest hardware implementation the case of sliding
window of size two was presented. Gray codes and constant weight Gray codes
were presented in order to exploit the full representational power of the
scheme. In this work, a tight upper-bound for cyclic constant weight Gray code
in $(1,2,n)$-LRM scheme where the weight equals to $2$ is given. Encoding,
decoding and enumeration of $(1,3,n)$-LRM scheme is studied.


title:
Pegasus: A New Hybrid-Kinetic Particle-in-Cell Code for Astrophysical
  Plasma Dynamics

abstract:
  We describe Pegasus, a new hybrid-kinetic particle-in-cell code tailored for
the study of astrophysical plasma dynamics. The code incorporates an
energy-conserving particle integrator into a stable, second-order--accurate,
three-stage predictor-predictor-corrector integration algorithm. The
constrained transport method is used to enforce the divergence-free constraint
on the magnetic field. A delta-f scheme is included to facilitate a
reduced-noise study of systems in which only small departures from an initial
distribution function are anticipated. The effects of rotation and shear are
implemented through the shearing-sheet formalism with orbital advection. These
algorithms are embedded within an architecture similar to that used in the
popular astrophysical magnetohydrodynamics code Athena, one that is modular,
well-documented, easy to use, and efficiently parallelized for use on thousands
of processors. We present a series of tests in one, two, and three spatial
dimensions that demonstrate the fidelity and versatility of the code.


title:
On Lyapunov-Krasovskii Functionals for Switched Nonlinear Systems with
  Delay

abstract:
  We present a set of results concerning the existence of Lyapunov-Krasovskii
functionals for classes of nonlinear switched systems with time-delay. In
particular, we first present a result for positive systems that relaxes
conditions recently described in \cite{SunWang} for the existence of L-K
functionals. We also provide related conditions for positive coupled
differential-difference positive systems and for systems of neutral type that
are not necessarily positive. Finally, corresponding results for discrete-time
systems are described.


title:
Unveiling recurrent jets of the ULX Holmberg II X-1: evidence for a
  massive stellar-mass black hole?

abstract:
  We report on the discovery of an apparent triple radio structure hidden
inside the radio bubble of the ultraluminous X-ray source Holmberg II X-1. The
morphology is consistent with a collimated jet structure, which is observed to
emit optically thin synchrotron radiation. The central component has a steep
radio spectrum and is brighter than the outer components indicating a renewed
radio activity. We estimate a minimum time-averaged jet power of 2 x 10^{39}
erg/s that is associated with a time-averaged isotropic X-ray luminosity of at
least 4 x 10^{39} erg/s. Our results suggest that Holmberg II X-1 is powered by
a black hole of M_BH \geq 25 M_sun, that is inferred to be accreting at a high
Eddington rate with intermittent radio activity.


title: Anisotropic magneto-thermal transport and Spin-Seebeck effect

abstract:
  The angular dependence of the thermal transport in insulating or conducting
ferromagnets is derived on the basis of the Onsager reciprocity relations
applied to a magnetic system. It is shown that the angular dependence of the
temperature gradient takes the same form as that of the anisotropic
magnetoresistance, including anomalous and planar Hall contributions. The
measured thermocouple generated between the extremities of the non-magnetic
electrode in thermal contact to the ferromagnet follows this same angular
dependence. The sign and amplitude of the magneto-voltaic signal is controlled
by the difference of the Seebeck coefficients of the thermocouple.


title:
Numerical study of impeller-driven von Karman flows via a volume
  penalization method

abstract:
  The von Karman flow apparatus produces a highly turbulent flow inside a
cylinder vessel driven by two counter-rotating impellers. Over more than two
decades, this experiment has become a very classic turbulence tool, studied for
a wide range of physical systems by many groups, with incompressible flow,
compressible flow, for magnetohydrodynamics and dynamo studies inside liquid
metal, for particle tracking purposes, and recently with turbulent super-fluid
helium. We present a direct numerical simulation (DNS) version the von Karman
flow, forced by two rotating impellers. The cylinder geometry and the rotating
objects are modelled via a penalization method and implemented in a massive
parallel pseudo-spectral Navier-Stokes solver. We choose a special
configuration (TM28) of the impellers to be able to compare with set of water
experiments well documented. But our good comparison results implied, that our
numerical modelling could also be applied to many physical systems and
configurations driven by the von Karman flow. The decomposition into poloidal,
toroidal components and the mean velocity fields from our simulations are in
agreement with experimental results. We analyzed also the flow structure close
to the impeller blades and found different vortex topologies.


title: The Sloan Digital Sky Survey quasar catalog: tenth data release

abstract:
  We present the Data Release 10 Quasar (DR10Q) catalog from the Baryon
Oscillation Spectroscopic Survey (BOSS) of the Sloan Digital Sky Survey III.
The catalog includes all BOSS objects that were targeted as quasar candidates
during the first 2.5 years of the survey and that are confirmed as quasars via
visual inspection of the spectra. The catalog also includes known quasars
(mostly from SDSS-I and II) that were reobserved by BOSS. The catalog contains
166,583 quasars (74,454 are new discoveries since SDSS-DR9) detected over 6,373
deg$^{2}$ with robust identification and redshift measured by a combination of
principal component eigenspectra. The number of quasars with $z>2.15$ (117,668)
is $\sim$5 times greater than the number of $z>2.15$ quasars known prior to
BOSS. Redshifts and FWHMs are provided for the strongest emission lines (CIV,
CIII, MgII). The catalog identifies 16,461 broad absorption line quasars and
gives their characteristics. For each object, the catalog presents five-band
(u, g, r, i, z) CCD-based photometry with typical accuracy of 0.03 mag and
information on the optical morphology and selection method. The catalog also
contains X-ray, ultraviolet, near-infrared, and radio emission properties of
the quasars, when available, from other large-area surveys. The calibrated
digital spectra cover the wavelength region 3,600-10,500\AA\ at a spectral
resolution in the range 1,300$<$R$<$2,500; the spectra can be retrieved from
the SDSS Catalog Archive Server. We also provide a supplemental list of an
additional 2,376 quasars that have been identified among the galaxy targets of
the SDSS-III/BOSS.


title: On stopping Fock-space processes

abstract:
  We consider the theory of stopping bounded processes within the framework of
Hudson--Parthasarathy quantum stochastic calculus, for both identity and vacuum
adaptedness. This provides significant new insight into Coquio's method of
stopping (J. Funct. Anal. 238:149-180, 2006). Vacuum adaptedness is required to
express certain quantum stochastic representations, and many results, including
the proof of the optional-sampling theorem, take a more natural form.


title:
Supercontinuum and ultra-short pulse generation from nonlinear Thomson
  and Compton scattering

abstract:
  Nonlinear Thomson and Compton processes, in which energetic electrons collide
with an intense optical pulse, are investigated in the framework of classical
and quantum electrodynamics. Spectral modulations of the emitted radiation,
appearing as either oscillatory or pulsating structures, are observed and
explained. It is shown that both processes generate a bandwidth radiation
spanning the range of few MeV, which occurs in a small cone along the
propagation direction of the colliding electrons. Most importantly, these broad
bandwidth structures are temporarily coherent which proves that Thomson and
Compton processes lead to generation of a supercontinuum. It is demonstrated
that the radiation from the supercontinuum can be synthesized into zeptosecond
(possibly even yoctosecond) pulses. Thus, confirming that Thomson and Compton
scattering can be used as novel sources of an ultra-short radiation, opening
routes to new physical domains for strong laser physics.

categories: hep-ph physics.acc-ph physics.atom-ph physics.optics physics.plasm-ph


title: Simple closed geodesics on most Alexandrov surfaces

abstract:
  We study the existence of simple closed geodesics on most (in the sense of
Baire category) Alexandrov surfaces with curvature bounded below, compact and
without boundary. We show that it depends on both the curvature bound and the
topology of the surfaces.


title:
Tunneling Electroresistance Induced by Interfacial Phase Transitions in
  Ultrathin Oxide Heterostructures

abstract:
  The ferroelectric (FE) control of electronic transport is one of the emerging
technologies in oxide heterostructures. Many previous studies in FE tunnel
junctions (FTJs) exploited solely the differences in the electrostatic
potential across the FTJs that are induced by changes in the FE polarization
direction. Here, we show that in practice the junction current ratios between
the two polarization states can be further enhanced by the electrostatic
modification in the correlated electron oxide electrodes, and that FTJs with
nanometer thin layers can effectively produce a considerably large
electroresistance ratio at room temperature. To understand these surprising
results, we employed an additional control parameter, which is related to the
crossing of electronic and magnetic phase boundaries of the correlated electron
oxide. The FE-induced phase modulation at the heterointerface ultimately
results in an enhanced electroresistance effect. Our study highlights that the
strong coupling between degrees of freedom across heterointerfaces could yield
versatile and novel applications in oxide electronics.


title:
Performance measures for single-degree-of-freedom energy harvesters
  under stochastic excitation

abstract:
  We develop performance criteria for the objective comparison of different
classes of single-degree-of-freedom oscillators under stochastic excitation.
For each family of oscillators, these objective criteria take into account the
maximum possible energy harvested for a given response level, which is a
quantity that is directly connected to the size of the harvesting
configuration. We prove that the derived criteria are invariant with respect to
magnitude or temporal rescaling of the input spectrum and they depend only on
the relative distribution of energy across different harmonics of the
excitation. We then compare three different classes of linear and nonlinear
oscillators and using stochastic analysis tools we illustrate that in all cases
of excitation spectra (monochromatic, broadband, white-noise) the optimal
performance of all designs cannot exceed the performance of the linear design.
Subsequently, we study the robustness of this optimal performance to small
perturbations of the input spectrum and illustrate the advantages of nonlinear
designs relative to linear ones.


title:
An Argument for Weakly-Magnetized, Slowly-Rotating Progenitors of Long
  Gamma-Ray Bursts

abstract:
  Using binary evolution with Case-C mass transfer, the spins of several black
holes (BHs) in X$-$ray binaries (XBs) have been predicted and confirmed (three
cases) by observations. The rotational energy of these BHs is sufficient to
power up long gamma$-$ray bursts and hypernovae (GRBs/HNe) and still leave a
Kerr BH behind. However, strong magnetic fields and/or dynamo effects in the
interior of such stars deplete their cores from angular momentum preventing the
formation of collapsars. Thus, even though binaries can produce Kerr BHs, most
of their rotation is acquired from the stellar mantle, with a long delay
between BH formation and spin up. Such binaries would not form GRBs. We study
whether the conditions required to produce GRBs can be met by the progenitors
of such BHs. Tidal-synchronization and Alfv\'en timescales are compared for
magnetic fields of different intensities threading He stars. A search is made
for a magnetic field range which allows tidal spin up all the way in to the
stellar core but prevents its slow down during differential rotation phases.
The energetics for producing a strong magnetic field during core collapse,
which may allow for a GRB central engine, are also estimated. An
observationally-reasonable choice of parameters is found ($B \lesssim10^2$ G
threading a slowly-rotating He star) which allows Fe cores to retain
substantial angular momentum. Thus, the Case-C-mass-transfer binary channel is
capable of explaining long GRBs. However, the progenitors must have low initial
spin and low internal magnetic field throughout their H-burning and He-burning
phases.


title:
A Direct Stellar Metallicity Determination in the Disk of the Maser
  Galaxy NGC4258

abstract:
  We present the first direct determination of a stellar metallicity in the
spiral galaxy NGC4258 (D=7.6 Mpc) based on the quantitative analysis of a
low-resolution (~5 AE) Keck LRIS spectrum of a blue supergiant star located in
its disk. A determination of stellar metallicity in this galaxy is important
for the absolute calibration of the Cepheid Period-Luminosity relation as an
anchor for the extragalactic distance scale and for a better characterization
of its dependence as a function of abundance. We find a value 0.2 dex lower
than solar metallicity at a galactocentric distance of 8.7 kpc, in agreement
with recent HII region studies using the weak forbidden auroral oxygen line at
4363 AE. We determine the effective stellar temperature, gravity, luminosity
and line-of-sight extinction of the blue supergiant being studied. We show that
it fits well on the flux-weighted gravity--luminosity relation (FGLR),
strengthening the potential of this method as a new extragalactic distance
indicator.


title: Dirac structures on nilmanifolds and coexistence of fluxes

abstract:
  We study some aspects of the generalized geometry of nilmanifolds and examine
to which extent different types of fluxes can coexist on them. Nilmanifolds
constitute a class of homogeneous spaces which are interesting in string
compactifications with fluxes since they carry geometric flux by construction.
They are generalized Calabi-Yau spaces and therefore simple examples of
generalized geometry at work. We identify and classify Dirac structures on
nilmanifolds, which are maximally isotropic subbundles closed under the Courant
bracket. In the presence of non-vanishing fluxes, these structures are twisted
and closed under appropriate extensions of the Courant bracket. Twisted Dirac
structures on a nilmanifold may carry multiple coexistent fluxes of any type.
We also show how dual Dirac structures combine to Courant algebroids and work
out an explicit example where all types of generalized fluxes coexist. These
results may be useful in the context of general flux compactifications in
string theory.


title:
Kinematic analysis of a sample of X-ray luminous distant galaxy
  clusters. The $L_X$ - $\sigma_v$ relation in the $z>0.6$ universe

abstract:
  Observations and cosmological simulations show galaxy clusters as a family of
nearly self-similar objects with properties that can be described by scaling
relations as a function of e.g. mass and time. Here we study the scaling
relations between the galaxy velocity dispersion and X-ray quantities like
X-ray bolometric luminosity and temperature in galaxy clusters at high
redshifts (0.64 $\leq$ z $\leq$ 1.46). We also compare our results with the
similar study of the local HIFLUGCS sample. For the analysis, we use a set of
15 distant galaxy clusters extracted from the literature plus a sample of 10
newly discovered clusters selected in X-rays by the \XMM Distant Cluster
Project (XDCP) with more than 10 confirmed spectroscopic members per cluster.
We also study the evolution of this scaling relation by comparing the high
redshift results with the data from the local HIFLUGCS sample. We also
investigated the $L_X - T_X$ and the $\sigma_v - T_X$ relations for the 15
clusters in the literature sample. We report the results of the X-ray and
kinematic analysis of 10 newly detected high redshift clusters and provide
their spectroscopic and kinematic details. For the entire, distant sample we
find a slope fully consistent with the one typical of local clusters, albeit
with a large associated uncertainty. The study on the evolution of the
amplitude reveals a positive offset if the self-similar evolution is neglected,
hence possibly indicating the need for including evolutionary effects. However,
the $L_X - T_X$ relation is found to be in good agreement with the local
relation without any significant redshift evolution. Finally, the $\sigma_v -
T_X$ relation appears to slightly deviate from the theoretical expectation that
galaxies and gas particles have a similar specific kinetic energy. However, the
associated uncertainty is currently too large for making any conclusive
statement in this regard.


title: What obscures low X-ray-scattering active galactic nuclei?

abstract:
  X-ray surveys have revealed a new class of active galactic nuclei (AGN) with
a very low observed fraction of scattered soft X-rays, f_scat < 0.5%. Based on
X-ray modeling these "X-ray new-type", or low observed X-ray scattering
(hereafter:"low-scattering") sources have been interpreted as deeply-buried AGN
with a high covering factor of gas. In this paper we address the questions
whether the host galaxies of low-scattering AGN may contribute to the observed
X-ray properties, and whether we can find any direct evidence for high covering
factors from the infrared (IR) emission. We find that X-ray low-scattering AGN
are preferentially hosted by highly-inclined galaxies or merger systems as
compared to other Seyfert galaxies, increasing the likelihood that the
line-of-sight toward the AGN intersects with high columns of host-galactic gas
and dust. Moreover, while a detailed analysis of the IR emission of
low-scattering AGN ESO 103-G35 remains inconclusive, we do not find any
indication of systematically higher dust covering factors in a sample of
low-scattering AGN based on their IR emission. For ESO 103-G35, we constrained
the temperature, mass and location of the IR emitting dust which is consistent
with expectations for the dusty torus. However, a deep silicate absorption
feature probably from much cooler dust suggests an additional screen absorber
on larger scales within the host galaxy. Taking these findings together, we
propose that the low f_scat observed in low-scattering AGN is not necessarily
the result of circumnuclear dust but could originate from interference of
host-galactic gas with a column density of the order of 10^22 cm^-2 with the
line-of-sight. We discuss implications of this hypothesis for X-ray models,
high-ionization emission lines, and observed star-formation activity in these
objects.


title: Young Stellar Objects close to Sgr A*

abstract:
  We aim at modelling small groups of young stars such as IRS 13N, 0.1 pc away
from Sgr A*, which is suggested to contain a few embedded massive young stellar
objects. We perform hydrodynamical simulations to follow the evolution of
molecular clumps orbiting about a $4\times10^6 ~ M_{\odot}$ black hole, to
constrain the formation and the physical conditions of such groups. We find
that, the strong compression due to the black hole along the orbital radius
vector of clumps evolving on highly eccentric orbits causes the clumps
densities to increase to higher than the tidal density of Sgr A*, and required
for star formation. This suggests that the tidal compression from the black
hole could support star formation. Additionally, we speculate that the infrared
excess source G2/DSO approaching Sgr A* on a highly eccentric orbit could be
associated with a dust enshrouded star that may have been formed recently
through the mechanism supported by our models.


title:
Holographic Spontaneous Parity Breaking and Emergent Hall Viscosity and
  Angular Momentum

abstract:
  We study the spontaneous parity breaking and generating of Hall viscosity and
angular momentum in holographic p+ip model, which can describe strongly-coupled
chiral superfluid states in many quantum systems. The dual gravity theory, an
SU(2) gauge field minimally coupled to Einstein gravity, is parity-invariant
but allows a black hole solution with vector hair corresponding to a
parity-broken superfluid state. We show that this state possesses a
non-vanishing parity-odd transport coefficient -- Hall viscosity -- and an
angular momentum density. We first develop an analytic method to solve this
model near the critical regime and to take back-reactions into account. Then we
solve the equation for the tensor mode fluctuations and obtain the expression
for Hall viscosity via Kubo formula. We also show that a non-vanishing angular
momentum density can be obtained through the vector mode fluctuations and the
corresponding boundary action. We give analytic results of both Hall viscosity
and angular momentum density near the critical regime in terms of physical
parameters. The near-critical behavior of Hall viscosity is different from that
obtained from a gravitational Chern-Simons model. We find that the magnitude of
Hall viscosity to angular momentum density ratio is numerically consistent with
being equal to 1/2 at large SU(2) coupling corresponding to the probe limit, in
agreement with previous results obtained for various quantum fluid systems and
from effective theory approaches. In addition, we find the shear viscosity to
entropy density ratio remains above the universal bound.


title: Supersymmetric Janus Solutions in Four Dimensions

abstract:
  We use maximal gauged supergravity in four dimensions to construct the
gravity dual of a class of supersymmetric conformal interfaces in the theory on
the world-volume of multiple M2-branes. We study three classes of examples in
which the $(1+1)$-dimensional defects preserve $(4,4)$, $(0,2)$ or $(0,1)$
supersymmetry. Many of the solutions have the maximally supersymmetric $AdS_4$
vacuum dual to the $\mathcal{N}=8$ ABJM theory on both sides of the interface.
We also find new special classes of solutions including one that interpolates
between the maximally supersymmetric vacuum and a conformal fixed point with
$\mathcal{N}=1$ supersymmetry and $G_2$ global symmetry. We find another
solution that interpolates between two distinct conformal fixed points with
$\mathcal{N}=1$ supersymmetry and $G_2$ global symmetry. In eleven dimensions,
this $G_2$ to $G_2$ solution corresponds to a domain wall across which a
magnetic flux reverses orientation.


title:
Lagrangian or Eulerian; Real or Fourier? Not All Approaches to
  Large-Scale Structure Are Created Equal

abstract:
  We present a pedagogical systematic investigation of the accuracy of Eulerian
and Lagrangian perturbation theories of large-scale structure. We show that
significant differences exist between them especially when trying to model the
Baryon Acoustic Oscillations (BAO). We find that the best available model of
the BAO in real space is the Zel'dovich Approximation (ZA), giving an accuracy
of <~3% at redshift of z=0 in modelling the matter 2-pt function around the
acoustic peak. All corrections to the ZA around the BAO scale are perfectly
perturbative in real space. Any attempt to achieve better precision requires
calibrating the theory to simulations because of the need to renormalize those
corrections. In contrast, theories which do not fully preserve the ZA as their
solution, receive O(1) corrections around the acoustic peak in real space at
z=0, and are thus of suspicious convergence at low redshift around the BAO. As
an example, we find that a similar accuracy of 3% for the acoustic peak is
achieved by Eulerian Standard Perturbation Theory (SPT) at linear order only at
z~4. Thus even when SPT is perturbative, one needs to include loop corrections
for z<~4 in real space. In Fourier space, all models perform similarly, and are
controlled by the overdensity amplitude, thus recovering standard results.
However, that comes at a price. Real space cleanly separates the BAO signal
from non-linear dynamics. In contrast, Fourier space mixes signal from short
mildly non-linear scales with the linear signal from the BAO to the level that
non-linear contributions from short scales dominate. Therefore, one has little
hope in constructing a systematic theory for the BAO in Fourier space.


title:
Fluctuations of imbalanced fermionic superfluids in two dimensions
  induce continuous quantum phase transitions and non-Fermi liquid behavior

abstract:
  We study the nature of superfluid pairing in imbalanced Fermi mixtures in two
spatial dimensions. We present evidence that the combined effect of Fermi
surface mismatch and order parameter fluctuations of the superfluid condensate
can lead to continuous quantum phase transitions from a normal Fermi mixture to
an intermediate Sarma-Liu-Wilczek superfluid with two gapless Fermi surfaces --
even when mean-field theory (incorrectly) predicts a first order transition to
a phase-separated "Bardeen-Cooper-Schrieffer plus excess fermions" ground
state. We propose a mechanism for non-Fermi liquid behavior from repeated
scattering processes between the two Fermi surfaces and fluctuating Cooper
pairs. Prospects for experimental observation with ultracold atoms are
discussed.


title:
The role of leading twist operators in the Regge and Lorentzian OPE
  limits

abstract:
  We study two kinematical limits, the Regge limit and the Lorentzian OPE
limit, of the four-point function of the stress-tensor multiplet in Super
Yang-Mills at weak coupling. We explain how both kinematical limits are
controlled by the leading twist operators. We use the known expression of the
four-point function up to three loops, to extract the pomeron residue at
next-to-leading order. Using this data and the known form of pomeron spin up to
next-to-leading order, we predict the behaviour of the four-point function in
the Regge limit at higher loops. Specifically, we determine the leading log
behaviour at any loop order and the next-to-leading log at four loops. Finally,
we check the consistency of our results with conformal Regge theory. This leads
us to predict the behaviour around $J=1$ of the OPE coefficient of the spin $J$
leading twist operator in the OPE of two chiral primary operators.


title: The Formation of the Wide Asynchronous Binary Asteroid Population

abstract:
  We propose and analyze a new mechanism for the formation of the wide
asynchronous binary population. These binary asteroids have wide semi-major
axes relative to most near-Earth and Main Belt asteroid systems. Confirmed
members have rapidly rotating primaries and satellites that are not tidally
locked. Previously suggested formation mechanisms from impact ejecta, planetary
flybys and directly from rotational fission events cannot satisfy all of the
observations. The newly hypothesized mechanism works as follows: (i) these
systems are formed from rotational fission, (ii) their satellites are tidally
locked, (iii) their orbits are expanded by the BYORP effect, (iv) their
satellites de-synchronize due to the adiabatic invariance between the libration
of the secondary and the mutual orbit, and (v) the secondary avoids
resynchronization due to the the YORP effect. This seemingly complex chain of
events is a natural pathway for binaries with satellites that have particular
shapes, which define the BYORP effect torque that acts on the system. After
detailing the theory, we analyze each of the wide asynchronous binary members
and candidates to assess their most likely formation mechanism. Finally, we
suggest possible future observations to check and constrain our hypothesis.


title: Throat quantization of the Schwarzschild-Tangherlini(-AdS) Black Hole

abstract:
  Adopting the throat quantization pioneered by Louko and M\"akel\"a, we derive
the mass and area spectra for the Schwarzschild-Tangherlini black hole and its
anti-de~Sitter (AdS) generalization in arbitrary dimensions. We obtain exact
spectra in three special cases: the three-dimensional BTZ black hole, toroidal
black holes in any dimension, and five-dimensional
Schwarzshild-Tangherlini(-AdS) black holes. For the remaining cases the spectra
are obtained for large mass using the WKB approximation. For asymptotically
flat black holes, the area/entropy has an equally spaced spectrum, as expected
from previous work. In the asymptotically AdS case on the other hand, it is the
mass spectrum that is equally spaced. Our exact results for the BTZ black hole
with Dirichlet and Neumann boundary conditions are consistent with the spacing
of the spectra of the corresponding operators in the dual CFT.


title: Two-Color Theory with Novel Infrared Behavior

abstract:
  Using lattice simulations, we study the infrared behavior of a particularly
interesting SU(2) gauge theory, with six massless Dirac fermions in the
fundamental representation. We compute the running gauge coupling derived
non-perturbatively from the Schrodinger functional of the theory, finding no
evidence for an infrared fixed point up through gauge couplings of order 20.
This implies that the theory either is governed in the infrared by a fixed
point of considerable strength, unseen so far in non-supersymmetric gauge
theories, or breaks its global chiral symmetries producing a large number of
composite Nambu-Goldstone bosons relative to the number of underlying degrees
of freedom. Thus either of these phases exhibits novel behavior.


title:
The full electroweak Standard Model prediction for (g-2) of the muon and
  improvements on the MSSM prediction

abstract:
  Recent progress on the (g-2)_\mu prediction is presented. In the SM, the
Higgs-boson mass dependent contributions have been evaluated exactly up to the
two-loop level and consistently combined with leading three-loop effects. Thus,
the currently most accurate value including a detailed error analysis for the
SM electroweak contributions has been obtained. The SUSY two-loop corrections
from fermion/sfermion-loop insertions have been computed; they are generally
large and logarithmically enhanced for heavy squarks.


title:
Intermediate co-t-structures, two-term silting objects, tau-tilting
  modules, and torsion classes

abstract:
  If (A,B) and (A',B') are co-t-structures of a triangulated category, then
(A',B') is called intermediate if A \subseteq A' \subseteq \Sigma A. Our main
results show that intermediate co-t-structures are in bijection with two-term
silting subcategories, and also with support tau-tilting subcategories under
some assumptions. We also show that support tau-tilting subcategories are in
bijection with certain finitely generated torsion classes. These generalise
results by Adachi, Iyama, and Reiten.


title: Symmetry Breaking in d-Dimensional Self-gravitating Systems

abstract:
  Systems with long-range interactions, such as self-gravitating clusters and
magnetically confined plasmas, do not relax to the usual Boltzmann-Gibbs
thermodynamic equilibrium, but become trapped in quasi-stationary states (QSS)
the life time of which diverges with the number of particles. The QSS are
characterized by the lack of ergodicity which can result in a symmetry broken
QSS starting from a spherically symmetric particle distribution. We will
present a theory which allows us to quantitatively predict the instability
threshold for spontaneous symmetry breaking for a class of d-dimensional
self-gravitating systems.


title:
The top induced backgrounds to Higgs production in the WW -> llvv decay
  channel at NLO in QCD

abstract:
  We present the complete NLO contributions to the pp -> e^+ v_e mu^- vbar_m b
bbar + X process in the four flavour scheme, i.e. with massive b quarks, and
its contribution to the H -> WW -> llvv measurement in the 1-jet bin at the
LHC. This background process includes top pair, single top and non-top
quark-resonant contributions. The uncertainty at NLO from renormalisation and
factorisation scale dependence is about +30% -20%. We show that the NLO
corrections are relatively small, and that separating this background in top
pair, Wt and b-quark associated llvv is a fair approximation.


title: Multitask Diffusion Adaptation over Networks

abstract:
  Adaptive networks are suitable for decentralized inference tasks, e.g., to
monitor complex natural phenomena. Recent research works have intensively
studied distributed optimization problems in the case where the nodes have to
estimate a single optimum parameter vector collaboratively. However, there are
many important applications that are multitask-oriented in the sense that there
are multiple optimum parameter vectors to be inferred simultaneously, in a
collaborative manner, over the area covered by the network. In this paper, we
employ diffusion strategies to develop distributed algorithms that address
multitask problems by minimizing an appropriate mean-square error criterion
with $\ell_2$-regularization. The stability and convergence of the algorithm in
the mean and in the mean-square sense is analyzed. Simulations are conducted to
verify the theoretical findings, and to illustrate how the distributed strategy
can be used in several useful applications related to spectral sensing, target
localization, and hyperspectral data unmixing.


title: Efficient Decoders for Qudit Topological Codes

abstract:
  Qudit toric codes are a natural higher-dimensional generalization of the
well-studied qubit toric code. However standard methods for error correction of
the qubit toric code are not applicable to them. Novel decoders are needed. In
this paper we introduce two renormalization group decoders for qudit codes and
analyze their error correction thresholds and efficiency. The first decoder is
a generalization of a "hard-decisions" decoder due to Bravyi and Haah
[arXiv:1112.3252]. We modify this decoder to overcome a percolation effect
which limits its threshold performance for high dimensions. The second decoder
is a generalization of a "soft-decisions" decoder due to Poulin and
Duclos-Cianci [Phys. Rev. Lett. 104, 050504 (2010)], with a small cell size to
optimize the efficiency of implementation in the high dimensional case. In each
case, we estimate thresholds for the uncorrelated bit-flip error model and
provide a comparative analysis of the performance of both these approaches to
error correction of qudit toric codes.


title:
Hubble Space Telescope Pre-Perihelion ACS/WFC Imaging Polarimetry of
  Comet ISON (C/2012 S1) at 3.81 AU

abstract:
  We present polarization images of Comet ISON (C/2012 S1) taken with the
Hubble Space Telescope (HST) on UTC 2013 May 8 (rh = 3.81 AU, Delta = 4.34 AU),
when the phase angle was alpha = 12.16 degrees. This phase angle is
approximately centered in the negative polarization branch for cometary dust.
The region beyond 1000 km from the nucleus shows a negative polarization
amplitude of p% -1.6%. Within 1000 km of the nucleus, the polarization position
angle rotates to be approximately perpendicular to the scattering plane, with
an amplitude p% +2.5%. Such positive polarization has been observed previously
as a characteristic feature of cometary jets, and we show that Comet ISON does
indeed harbor a jet-like feature. These HST observations of Comet ISON
represent the first visible light, imaging polarimetry with sub-arcsecond
spatial resolution of a Nearly Isotropic Comet (NIC) beyond 3.8 AU from the Sun
at a small phase angle. The observations provide an early glimpse of the
properties of the cometary dust preserved in this Oort-cloud comet.


title: QFT, RG, and all that, for mathematicians, in eleven pages

abstract:
  We present a quick introduction to quantum field theory and Wilson's theory
of the renormalization group from the point of view of mathematical analysis.
The presentation is geared primarily towards a probability theory, harmonic
analysis and dynamical systems theory audience.


title:
Mis-Modelling in Gravitational Wave Astronomy: The Trouble With
  Templates

abstract:
  Waveform templates are a powerful tool for extracting and characterizing
gravitational wave signals, acting as highly restrictive priors on the signal
morphologies that allow us to extract weak events buried deep in the
instrumental noise. The templates map the waveform shapes to physical
parameters, thus allowing us to produce posterior probability distributions for
these parameters. However, there are attendant dangers in using highly
restrictive signal priors. If strong field gravity is not accurately described
by General Relativity (GR), then using GR templates may result in fundamental
bias in the recovered parameters, or even worse, a complete failure to detect
signals. Here we study such dangers, concentrating on three distinct
possibilities. First, we show that there exist modified theories compatible
with all existing tests that would fail to be detected by the LIGO/Virgo
network using searches based on GR templates, but which would be detected using
a one parameter post-Einsteinian extension. Second, we study modified theories
that produce departures from GR that turn on suddenly at a critical frequency,
producing waveforms that do not naively fit into the simplest parameterized
post-Einsteinian (ppE) scheme. We show that even the simplest ppE templates are
still capable of picking up these strange signals and diagnosing a departure
from GR. Third, we study whether using inspiral-only ppE waveforms for signals
that include merger and ringdown can lead to problems in misidentifying a GR
departure. We present an easy technique that allows us to self-consistently
identify the inspiral portion of the signal, and thus remove these potential
biases, allowing GR tests to be performed on higher mass signals that merge
within the detector band. We close by studying a parameterized waveform model
that may allow us to test GR using the full inspiral-merger-ringdown signal.


title: Alliances and related parameters in graphs

abstract:
  In this paper, we show that several graph parameters are known in different
areas under completely different names. More specifically, our observations
connect signed domination, monopolies, $\alpha$-domination,
$\alpha$-independence, positive influence domination, and a parameter
associated to fast information propagation in networks to parameters related to
various notions of global $r$-alliances in graphs. We also propose a new
framework, called (global) $(D,O)$-alliances, not only in order to characterize
various known variants of alliance and domination parameters, but also to
suggest a unifying framework for the study of alliances and domination.
Finally, we also give a survey on the mentioned graph parameters, indicating
how results transfer due to our observations.


title: Query Interface Integrator For Domain Specific Hidden Web

abstract:
  Web is title admittance today mainly relies on search engines. A large amount
of data is hidden in the databases behind the search interfaces referred to as
Hidden web, which needs to be indexed so in order to serve user query. In this
paper database and data mining techniques are used for query interface
integration. The query interface must resemble the look and feel of local
interface as much as possible despite being automatically generated without
human support.This technique keeps the related documents in the same domain so
that searching of documents becomes more efficient in terms of time complexity.


title:
Stellar Diameters and Temperatures IV. Predicting Stellar Angular
  Diameters

abstract:
  The number of stellar angular diameter measurements has greatly increased
over the past few years due to innovations and developments in the field of
long baseline optical interferometry (LBOI). We use a collection of
high-precision angular diameter measurements for nearby, main-sequence stars to
develop empirical relations that allow the prediction of stellar angular sizes
as a function of observed photometric color. These relations are presented for
a combination of 48 broad-band color indices. We empirically show for the first
time a dependence on metallicity to these relations using Johnson $(B-V)$ and
Sloan $(g-r)$ colors. Our relations are capable of predicting diameters with a
random error of less than 5% and represent the most robust and empirical
determinations to stellar angular sizes to date.


title: Dissipation and Rheology of Sheared Soft-Core Frictionless Disks

abstract:
  We use numerical simulations to investigate the effect of different
dissipative models on the shearing rheology of massive soft-core frictionless
disks in two dimensions. We show that the presence of Newtonian (overdamped) vs
Bagnoldian (inertial) rheology is related to the formation of large connected
clusters of disks, and that sharp transitions may exist between the two as
system parameters vary. In the limit of strongly inelastic collisions, we find
that rheological curves collapse to a well-defined limit when plotted against
an appropriate dimensionless strain rate.


title:
Local Spin-density Approximation Exchange-correlation Free-energy
  Functional

abstract:
  An accurate analytical parametrization for the exchange-correlation free
energy of the homogeneous electron gas, including interpolation for partial
spin-polarization, is derived via thermodynamic analysis of recent restricted
path integral Monte-Carlo (RPIMC) data. This parametrization constitutes the
local spin density approximation (LSDA) for the exchange-correlation functional
in density functional theory. The new finite-temperature LSDA reproduces the
RPIMC data well, satisfies the correct high-density and low- and high-$T$
asymptotic limits, and is well-behaved beyond the range of the RPIMC data,
suggestive of broad utility.


title: On the Structure of Bispecial Sturmian Words

abstract:
  A balanced word is one in which any two factors of the same length contain
the same number of each letter of the alphabet up to one. Finite binary
balanced words are called Sturmian words. A Sturmian word is bispecial if it
can be extended to the left and to the right with both letters remaining a
Sturmian word. There is a deep relation between bispecial Sturmian words and
Christoffel words, that are the digital approximations of Euclidean segments in
the plane. In 1997, J. Berstel and A. de Luca proved that \emph{palindromic}
bispecial Sturmian words are precisely the maximal internal factors of
\emph{primitive} Christoffel words. We extend this result by showing that
bispecial Sturmian words are precisely the maximal internal factors of
\emph{all} Christoffel words. Our characterization allows us to give an
enumerative formula for bispecial Sturmian words. We also investigate the
minimal forbidden words for the language of Sturmian words.


title: The covariance of almost-primes in $\mathbb{F}_q[T]$

abstract:
  We estimate the covariance in counts of almost-primes in $\mathbb{F}_q[T]$,
weighted by higher-order von Mangoldt functions. The answer takes a pleasant
algebraic form. This generalizes recent work of Keating and Rudnick that
estimates the variance of primes, and makes use, as theirs, of a recent
equidistribution result of Katz.
  In an appendix we prove some related identities for random matrix statistics,
which allows us to give a quick proof of a $2\times2$ ratio theorem for the
characteristic polynomial of the unitary group. We additionally identify
arithmetic functions whose statistics mimic those of hook Schur functions.


title: On the Rationality of the Appearance of Consciousness

abstract: This paper has been withdrawn by the author(s)


title:
Convergence of pointed non-compact metric measure spaces and stability
  of Ricci curvature bounds and heat flows

abstract:
  Aim of this paper is to discuss convergence of pointed metric measure spaces
in absence of any compactness condition. We propose various definitions, show
that all of them are equivalent and that for doubling spaces these are also
equivalent to the well known measured-Gromov-Hausdorff convergence. Then we
show that the curvature conditions $CD(K,\infty)$ and $RCD(K,\infty)$ are
stable under this notion of convergence and that the heat flow passes to the
limit as well, both in the Wasserstein and in the $L^2$-framework. We also
prove the variational convergence of Cheeger energies in the naturally adapted
$\Gamma$-Mosco sense and the convergence of the spectra of the Laplacian in the
case of spaces either uniformly bounded or satisfying the $RCD(K,\infty)$
condition with $K>0$. When applied to Riemannian manifolds, our results allow
for sequences with diverging dimensions.


title:
Influence of the degree of decoupling of graphene on the properties of
  transition metal adatoms

abstract:
  We investigate the adsorption sites of $3d$ transition metal (TM) adatoms by
means of low-temperature scanning tunneling microscopy and spectroscopy. Co and
Ni adatoms were adsorbed on two types of graphene on SiC(0001), i.e. pristine
epitaxial monolayer graphene (MLG) and quasi-free-standing monolayer graphene
(QFMLG). In the case of QFMLG, two stable adsorption sites are identified,
while in the case of MLG, only one adsorption site is observed. Our
experimental results reveal the decoupling efficiency as a crucial parameter
for determining the adsorption site as well as the electronic properties of
$3d$ transition metal atoms on graphene. Furthermore, we show that Co atoms
adsorbed on QFMLG are strong scattering potentials for Dirac fermions and cause
intervalley scattering in their vicinity.


title: Chiral $d$-wave Superconductivity in SrPtAs

abstract:
  Recent $\mu$SR measurements on SrPtAs revealed time-reversal-symmetry
breaking with the onset of superconductivity [Biswas et al., Phys. Rev. B 87,
180503(R) (2013)], suggesting an unconventional superconducting state. We
investigate this possibility via functional renormalization group and find a
chiral $(d+\mathrm{i}d)$-wave order parameter favored by the multiband
fermiology and hexagonal symmetry of SrPtAs. This $(d+\mathrm{i}d)$-wave state
exhibits significant gap anisotropies as well as gap differences on the
different bands, but only has point nodes on one of the bands at the Brillouin
zone corners. We study the topological characteristics of this superconducting
phase, which features Majorana-Weyl nodes in the bulk, protected surface
states, and an associated thermal Hall response. The lack of extended nodes and
the spontaneously broken time-reversal symmetry of the $(d+\mathrm{i}d)$-wave
state are in agreement with the $\mu$SR experiments. Our theoretical findings
together with the experimental evidence thus suggests that SrPtAs is the first
example of chiral $d$-wave superconductivity.


title: Charge transfer satellites in x-ray spectra of transition metal oxides

abstract:
  Strongly correlated materials such as transition metal oxides (TMOs) often
exhibit large satellites in their x-ray photoemission (XPS) and x-ray
absorption spectra (XAS). These satellites arise from localized charge-transfer
(CT) excitations that accompany the sudden creation of a core hole. Here we use
a two-step approach to treat such excitations in a localized system embedded in
a condensed system and coupled to a photoelectron. The total XAS is then given
by a convolution of a spectral function representing the localized excitations
and the XAS of the extended system. The local system is modeled roughly in
terms of a simple three-level model, leading to a double-pole approximation for
the spectral function that represents dynamically weighted contributions from
the dominant neutral and charge-transfer excitations. This method is
implemented using a resolvent approach, with potentials, radial wave-functions
and matrix elements from the real-space Green's function code FEFF, and
parameters fitted to XPS experiments. Representative calculations for several
TMOs are found to be in reasonable agreement with experiment.


title:
Black hole solution in third order Lovelock gravity has no Gauss-Bonnet
  limit

abstract:
  We revisit the spherically symmetric third order Lovelock black hole solution
in 7-dimensions. We show that the general solution for the metric function does
not admit the Gauss-Bonnet (GB) limit. This is not expected due to the linear
superposition of the second (GB) and third order Lovelock Lagrangians in the
general action. It is found that the two branches of the GB solutions are
indeed the limit of the other two complex solutions of the field equations in
the third order Lovelock gravity. These two complex solutions could not be
accepted as the solutions of the Einstein's field equations which are supposed
to be real values function on entire real r- axis. A new solution which is only
valid if the third order Lovelock parameter is small is introduced which can be
considered as the natural extension of the general relativity (GR) to the third
order Lovelock modified theory of gravity. We also generalize the discussion to
the higher dimensional third order Lovelock gravity coupled to the matter
sources with cosmological constant.


title: Einstein's equivalence principle in cosmology

abstract:
  We study physical consequences of the Einstein equivalence principle (EEP)
for a Hubble observer in FLRW universe. We introduce the local inertial
coordinates with the help of a special conformal transformation. The local
inertial metric is Minkowski-flat and materialized by a congruence of time-like
geodesics of static observers. The static observers are equipped with the ideal
clocks measuring the proper time that is synchronized with the clocks of the
Hubble observer. The local inertial metric is used for physical measurements of
spacetime intervals with the ideal clocks and rulers. The special conformal
transformation preserves null geodesics but does not keep invariant time-like
geodesics. Moreover, it makes the rate of the local time coordinate dependent
on velocity of the particle which makes impossible to rich the uniform
parameterization of the world lines of static observers and light geodesics
with a single parameter - they differ by the conformal factor of FLRW metric.
It tells us that the metric on the light cone is not Minkowski-flat but depends
on the scale factor of FLRW universe and it can be interpreted as a weak
violation of EEP for photons. The importance of this violation for
gravitational physics is that some of local experiments conducted with
freely-propagating electromagnetic waves may be sensitive to the Hubble
expansion. We show that the Hubble constant H can be measured within the solar
system by means of high-precision spacecraft Doppler tracking as a blue shift
of frequency of radio waves circulating in the Earth-spacecraft radio link. We
also analyze the behavior of the standing wave in a microwave resonator and
show that the standing wave is insensitive to the Hubble expansion.


title:
$^3$He impurities and mass transport through solid $^4$He: a universal
  temperature dependence and flux extinction

abstract:
  The flux, $F$, carried by solid $^4$He in the range $25.6 - 26.3$ bar rises
with falling temperature and at a temperature $T_d$ the flux decreases toward
zero. We study $F$ as a function of $^3$He impurity concentration, $\chi$. At
temperatures above $T_d$ the flux has an unexpected universal temperature
dependence and the flux terminates in a narrow window near a characteristic
temperature $T_h \approx$ 610 mK, which is independent of $\chi$. We find that
$T_d$ is an increasing function of increasing $\chi$. We document that the
extinction of the flux at $T_d$ is prompt and precipitous, with the transition
complete within a few mK. Comparison of our ($T_d, \chi$) results with a
calculated phase separation line suggests that the extinction of the flux is
related to phase separation.


title:
Hodge polynomials of the SL(2,C)-character variety of an elliptic curve
  with two marked points

abstract:
  We compute the Hodge polynomials for the moduli space of representations of
an elliptic curve with two marked points into SL(2,C). When we fix the
conjugacy classes of the representations around the marked points to be
diagonal and of modulus one, the character variety is diffeomorphic to the
moduli space of strongly parabolic Higgs bundles, whose Betti numbers are
known. In that case we can recover some of the Hodge numbers of the character
variety. We extend this result to the moduli space of doubly periodic
instantons.


title: Senescent Ground Tree Rewrite Systems

abstract:
  Ground Tree Rewrite Systems with State are known to have an undecidable
control state reachability problem. Taking inspiration from the recent
introduction of scope-bounded multi-stack pushdown systems, we define Senescent
Ground Tree Rewrite Systems. These are a restriction of ground tree rewrite
systems with state such that nodes of the tree may no longer be rewritten after
having witnessed an a priori fixed number of control state changes. As well as
generalising scope-bounded multi-stack pushdown systems, we show --- via
reductions to and from reset Petri-nets --- that these systems have an
Ackermann-complete control state reachability problem. However, reachability of
a regular set of trees remains undecidable.


title: SU(3) flavour breaking and baryon structure

abstract:
  We present results from the QCDSF/UKQCD collaboration for hyperon
electromagnetic form factors and axial charges obtained from simulations using
Nf=2+1 flavours of O(a)-improved Wilson fermions. We also consider matrix
elements relevant for hyperon semileptonic decays. We find flavour-breaking
effects in hyperon magnetic moments which are consistent with experiment, while
our results for the connected quark spin content indicates that quarks
contribute more to the spin of the Xi baryon than they do to the proton.


title: Thermodynamics of a Photon Gas in Nonlinear Electrodynamics

abstract:
  In this paper we analyze the thermodynamic properties of a photon gas under
the influence of a background electromagnetic field in the context of any
nonlinear electrodynamics. Neglecting the self-interaction of photons, we
obtain a general expression for the grand canonical potential. Particularizing
for the case when the background field is uniform, we determine the pressure
and the energy density for the photon gas. Although the pressure and the energy
density change when compared with the standard case, the relationship between
them remains unaltered, namely $\rho=3p$. Finally, we apply the developed
formulation to the cases of Heisenberg-Euler and Born-Infeld nonlinear
electrodynamics. For the Heisenberg-Euler case, we show that our formalism
recover the results obtained with the $2$-loop thermal effective action
approach.


title:
Phase structure and Hosotani mechanism in QCD-like theory with compact
  dimensions

abstract:
  We investigated the phase diagram of $SU(3)$ gauge theory in four dimension
with one compact dimension by using the perturbative one-loop effective
potential. Effects of the adjoint and fundamental fermions are investigated and
then the rich phase structure in the quark-mass and compact-size scale is
realized. Our results are qualitatively consistent with the recent lattice
calculation and clearly show that the lattice calculation can be understood
from the Hosotani mechanism. Moreover, we show the result obtained by using the
flavor twisted boundary condition for fundamental fermion which does not break
the $Z_3$ symmetry, explicitly.


title: Hysteresis Can Grant Fitness in Stochastically Varying Environment

abstract:
  Hysteresis and bet-hedging (random choice of phenotypes) are two different
observations typically linked with multiplicity of phenotypes in biological
systems. Hysteresis can be viewed as form of the system's persistent memory of
past environmental conditions, while bet-hedging is a diversification strategy
not necessarily associated with any memory. It has been shown that bet-hedging
can increase population growth when phenotype adjusts its switching probability
in response to environmental inputs. Although memory and hysteresis have been
used to generate environment dependent phenotype switching probabilities, their
exact connection to bet-hedging have remained unclear. In this work, using a
simple model that takes into account phenotype switching as well as lag phase
in the population growth occurring after the phenotype switching, it is shown
that memory and hysteresis emerge naturally and are firmly linked to
bet-hedging as organisms attempt to optimize their population growth rate. The
optimal ``magnitude'' of hysteresis is explained to be associated with
stochastic resonance where the characteristic time between subsequent phenotype
switching events is linked to the lag phase delay. Furthermore, hysteretic
switching strategy is shown not to confer any additional population growth
advantage if the environment varies periodically in a deterministic fashion.
This suggests that, while bet-hedging may evolve under some conditions even in
deterministic environments, memory and hysteresis is probably the result of
environmental uncertainty in the presence of lag phase in the switching of
phenotypes.


title: Counting elliptic curves with prescribed torsion

abstract:
  Mazur's theorem states that there are exactly 15 possibilities for the
torsion subgroup of an elliptic curve over the rational numbers. We determine
how often each of these groups actually occurs. Precisely, if $G$ is one of
these 15 groups, we show that the number of elliptic curves up to height $X$
whose torsion subgroup is isomorphic to $G$ is on the order of $X^{1/d}$, for
some number $d=d(G)$ which we compute.


title:
Calibrated birth-death phylogenetic time-tree priors for Bayesian
  inference

abstract:
  Here we introduce a general class of multiple calibration birth-death tree
priors for use in Bayesian phylogenetic inference. All tree priors in this
class separate ancestral node heights into a set of "calibrated nodes" and
"uncalibrated nodes" such that the marginal distribution of the calibrated
nodes is user-specified whereas the density ratio of the birth-death prior is
retained for trees with equal values for the calibrated nodes. We describe two
formulations, one in which the calibration information informs the prior on
ranked tree topologies, through the (conditional) prior, and the other which
factorizes the prior on divergence times and ranked topologies, thus allowing
uniform, or any arbitrary prior distribution on ranked topologies. While the
first of these formulations has some attractive properties the algorithm we
present for computing its prior density is computationally intensive. On the
other hand, the second formulation is always computationally efficient. We
demonstrate the utility of the new class of multiple-calibration tree priors
using both small simulations and a real-world analysis and compare the results
to existing schemes. The two new calibrated tree priors described in this paper
offer greater flexibility and control of prior specification in calibrated
time-tree inference and divergence time dating, and will remove the need for
indirect approaches to the assessment of the combined effect of calibration
densities and tree process priors in Bayesian phylogenetic inference.


title:
Simultaneous Greedy Analysis Pursuit for Compressive Sensing of
  Multi-Channel ECG Signals

abstract:
  This paper addresses compressive sensing for multi-channel ECG. Compared to
the traditional sparse signal recovery approach which decomposes the signal
into the product of a dictionary and a sparse vector, the recently developed
cosparse approach exploits sparsity of the product of an analysis matrix and
the original signal. We apply the cosparse Greedy Analysis Pursuit (GAP)
algorithm for compressive sensing of ECG signals. Moreover, to reduce
processing time, classical signal-channel GAP is generalized to the
multi-channel GAP algorithm, which simultaneously reconstructs multiple signals
with similar support. Numerical experiments show that the proposed method
outperforms the classical sparse multi-channel greedy algorithms in terms of
accuracy and the single-channel cosparse approach in terms of processing speed.


title: Travelling Waves in Hall-MHD and the Ion-Acoustic Shock Structure

abstract:
  Hall-MHD is a mixed hyperbolic-parabolic partial differential equation that
describes the dynamics of an ideal two fluid plasma with massless electrons. We
study the only shock wave family that exists in this system (the other
discontinuities being contact discontinuities and not shocks). We study planar
travelling wave solutions and we find solutions with discontinuities in the
hydrodynamic variables, which arise due to the presence of real characteristics
in Hall-MHD. We introduce a small viscosity into the equations and use the
method of matched asymptotic expansions to show that solutions with a
discontinuity satisfying the Rankine-Hugoniot conditions and also an entropy
condition have continuous shock structures. The lowest order inner equations
reduce to the compressible Navier-Stokes equations, plus an equation which
implies the constancy of the magnetic field inside the shock structure. We are
able to show that the current is discontinuous across the shock, even as the
magnetic field is continuous, and that the lowest order outer equations, which
are the equations for travelling waves in inviscid Hall-MHD, are exactly
integrable. We show that the inner and outer solutions match, which allows us
to construct a family of uniformly valid continuous composite solutions that
become discontinuous when the diffusivity vanishes.


title: Robust Compressed Sensing Under Matrix Uncertainties

abstract:
  Compressed sensing (CS) shows that a signal having a sparse or compressible
representation can be recovered from a small set of linear measurements. In
classical CS theory, the sampling matrix and representation matrix are assumed
to be known exactly in advance. However, uncertainties exist due to sampling
distortion, finite grids of the parameter space of dictionary, etc. In this
paper, we take a generalized sparse signal model, which simultaneously
considers the sampling and representation matrix uncertainties. Based on the
new signal model, a new optimization model for robust sparse signal
reconstruction is proposed. This optimization model can be deduced with
stochastic robust approximation analysis. Both convex relaxation and greedy
algorithms are used to solve the optimization problem. For the convex
relaxation method, a sufficient condition for recovery by convex relaxation is
given; For the greedy algorithm, it is realized by the introduction of a
pre-processing of the sensing matrix and the measurements. In numerical
experiments, both simulated data and real-life ECG data based results show that
the proposed method has a better performance than the current methods.

categories: cs.IT cs.CV math.IT math.RT stat.AP stat.ML


title:
Asymptotic Improvement of the Gilbert-Varshamov Bound on the Size of
  Permutation Codes

abstract:
  Given positive integers $n$ and $d$, let $M(n,d)$ denote the maximum size of
a permutation code of length $n$ and minimum Hamming distance $d$. The
Gilbert-Varshamov bound asserts that $M(n,d) \geq n!/V(n,d-1)$ where $V(n,d)$
is the volume of a Hamming sphere of radius $d$ in $\S_n$.
  Recently, Gao, Yang, and Ge showed that this bound can be improved by a
factor $\Omega(\log n)$, when $d$ is fixed and $n \to \infty$. Herein, we
consider the situation where the ratio $d/n$ is fixed and improve the
Gilbert-Varshamov bound by a factor that is \emph{linear in $n$}. That is, we
show that if $d/n < 0.5$, then $$ M(n,d)\geq cn\,\frac{n!}{V(n,d-1)} $$ where
$c$ is a positive constant that depends only on $d/n$. To establish this
result, we follow the method of Jiang and Vardy. Namely, we recast the problem
of bounding $M(n,d)$ into a graph-theoretic framework and prove that the
resulting graph is locally sparse.


title: On the system $f(nx)$ and probabilistic number theory

abstract:
  Let $f: {\mathbb R}\to {\mathbb R}$ be a measurable function satisfying
\begin{equation*} f(x+1)=f(x), \qquad \int_0^1 f(x)\, dx=0, \qquad \int_0^1
f^2(x)\, dx<\infty. \end{equation*} The asymptotic properties of series $\sum
c_k f(kx)$ have been studied extensively in the literature and turned out to
be, in general, quite different from those of the trigonometric system. As the
theory shows, the behavior of such series is determined by a combination of
analytic, probabilistic and number theoretic effects, resulting in highly
interesting phenomena not encountered in classical harmonic analysis. In this
paper we survey some recent results in the field and prove asymptotic results
for the system $\{f(nx), n\ge 1\}$ in the case when the function $f$ is not
square integrable.


title: On the law of the iterated logarithm for permuted lacunary sequences

abstract:
  It is known that for any smooth periodic function $f$ the sequence
$(f(2^kx))_{k\ge 1}$ behaves like a sequence of i.i.d.\ random variables, for
example, it satisfies the central limit theorem and the law of the iterated
logarithm. Recently Fukuyama showed that permuting $(f(2^kx))_{k\ge 1}$ can
ruin the validity of the law of the iterated logarithm, a very surprising
result. In this paper we present an optimal condition on $(n_k)_{k\ge 1}$,
formulated in terms of the number of solutions of certain Diophantine
equations, which ensures the validity of the law of the iterated logarithm for
any permutation of the sequence $(f(n_k x))_{k \geq 1}$. A similar result is
proved for the discrepancy of the sequence $(\{n_k x\})_{k \geq 1}$, where $\{
\cdot \}$ denotes fractional part.


title:
Fundamentals of Cavity-Enhanced Polarimetry for Parity-Nonconserving
  Optical Rotation Measurements: Application to Xe, Hg and I

abstract:
  We present the theoretical basis of a cavity-enhanced polarimetric scheme for
the measurement of parity-nonconserving (PNC) optical rotation. We discuss the
possibility of detecting PNC optical rotation in accessible transitions in
metastable Xe and Hg, and ground state I. In particular, the physics of the PNC
optical rotation is presented, and we explore the lineshape effects on the
expected PNC optical rotation signals. Furthermore, we present an analysis of
the eigenpolarizations of the cavity-enhanced polarimeter, which is necessary
for understanding the measurement procedure and the ability of employing robust
background subtraction procedures using two novel signal reversals. Using
recent atomic structure theoretical calculations, we present simulations of the
PNC optical rotation signals for all proposed transitions, assuming a range of
experimentally feasible parameters. Finally, the possibility of performing
sensitive measurements of the nuclear-spin-dependent PNC effects is
investigated, for the odd-neutron nuclei $^{129}$Xe and $^{199}$Hg, and the
odd-proton nucleus $^{127}$I.


title: Relativistic mean field plus exact pairing approach to open shell nuclei

abstract:
  Background: Pairing correlations play a critical role in determining numerous
properties of open-shell nuclei. Traditionally, they are included in a
mean-field description of atomic nuclei through the approximate
Bardeen-Cooper-Schrieffer or Hartree-Fock-Bogoliubov formalism. Purpose: We
propose a new hybrid ''relativistic-mean-field-plus-pairing'' approach in which
pairing is treated exactly so the number of particles is conserved. To verify
the reliability of the formalism, we apply it to the study of both ground-state
properties and isoscalar monopole excitations of the Tin isotopes. Methods:
Accurately-calibrated relativistic mean-field models supplemented by an exact
treatment of pairing correlations are used to compute ground-state observables
along the isotopic chain in Tin. In turn, ground-state densities are used as
input to the calculation of giant monopole resonances through a
constrained-relativistic approach. Results: We compute a variety of
ground-state observables sensitive to pairing correlations as well as the
evolution of giant monopole energies along the isotopic chain in Tin. Whereas
ground-state properties are consistent with experiment, we find that pairing
correlations have a minor effect on the giant monopole energies. Conclusions: A
new mean-field-plus-pairing approach is introduced to compute properties of
open-shell nuclei. The formalism provides an efficient and powerful alternative
to the computation of both ground-state properties and monopole energies of
open-shell nuclei. We find ground-state properties to be well reproduced in
this approach. However, as many have concluded before us, we find that pairing
correlations are unlikely to provide an answer to the question of ''why is Tin
so soft?''


title: On permutations of lacunary series

abstract:
  It is a well known fact that for periodic measurable $f$ and rapidly
increasing $(n_k)_{k \geq 1}$ the sequence $(f(n_kx))_{k\ge 1}$ behaves like a
sequence of independent, identically distributed random variables. For example,
if $f$ is a periodic Lipschitz function, then $(f(2^kx))_{k\ge 1}$ satisfies
the central limit theorem, the law of the iterated logarithm and several
further limit theorems for i.i.d.\ random variables. Since an i.i.d.\ sequence
remains i.i.d.\ after any permutation of its terms, it is natural to expect
that the asymptotic properties of lacunary series are also
permutation-invariant. Recently, however, Fukuyama (2009) showed that a
rearrangement of the sequence $(f(2^kx))_{k\ge 1}$ can change substantially its
asymptotic behavior, a very surprising result. The purpose of the present paper
is to investigate this interesting phenomenon in detail and to give necessary
and sufficient criteria for the permutation-invariance of the CLT and LIL for
$f(n_kx)$.


title: The K-theory of filtered deformations of graded polynomial algebras

abstract:
  Recent discoveries make it possible to compute the K-theory of certain rings
from their cyclic homology and certain versions of their cdh-cohomology. We
extend the work of G. Corti\~nas et al. who calculated the K-theory of, in
addition to many other varieties, cones over smooth varieties, or equivalently
the K-theory of homogeneous polynomial rings. We focus on specific examples of
polynomial rings, which happen to be filtered deformations of homogeneous
polynomial rings. Along the way, as a secondary result, we will develop a
method for computing the periodic cyclic homology of a singular variety as well
as the negative cyclic homology when the cyclic homology of that variety is
known. Finally, we will apply these methods to extend the results of Michler
who computed the cyclic homology of hypersurfaces with isolated singularities.


title:
The semiclassical zeta function for geodesic flows on negatively curved
  manifolds

abstract:
  We consider the semi-classical (or Gutzwiller-Voros) zeta function for
$C^\infty$ contact Anosov flows. Analyzing the spectrum of transfer operators
associated to the flow, we prove, for any $\tau>0$, that its zeros are
contained in the union of the $\tau$-neighborhood of the imaginary axis,
$|\Re(s)|<\tau$, and the region $\Re(s)<-\chi_0+\tau$, up to finitely many
exceptions, where $\chi_0>0$ is the hyperbolicity exponent of the flow. Further
we show that the zeros in the neighborhood of the imaginary axis satisfy an
analogue of the Weyl law.


title:
On the asymptotic behavior of complex earthquakes and Teichm\"{u}ller
  disks

abstract:
  Given a hyperbolic surface and a simple closed geodesic on it, complex-twists
along the curve produce a holomorphic family of deformations in Teichm\"{u}ller
space, degenerating to the Riemann surface where it is pinched. We show there
is a corresponding Teichm\"{u}ller disk such that the two are strongly
asymptotic, in the Teichm\"{u}ller metric, around the noded Riemann surface. We
establish a similar comparison with plumbing deformations that open the node.


title: Dynamic Package Interfaces - Extended Version

abstract:
  A hallmark of object-oriented programming is the ability to perform
computation through a set of interacting objects. A common manifestation of
this style is the notion of a package, which groups a set of commonly used
classes together. A challenge in using a package is to ensure that a client
follows the implicit protocol of the package when calling its methods.
Violations of the protocol can cause a runtime error or latent invariant
violations. These protocols can extend across different, potentially
unboundedly many, objects, and are specified informally in the documentation.
As a result, ensuring that a client does not violate the protocol is hard.
  We introduce dynamic package interfaces (DPI), a formalism to explicitly
capture the protocol of a package. The DPI of a package is a finite set of
rules that together specify how any set of interacting objects of the package
can evolve through method calls and under what conditions an error can happen.
We have developed a dynamic tool that automatically computes an approximation
of the DPI of a package, given a set of abstraction predicates. A key property
of DPI is that the unbounded number of configurations of objects of a package
are summarized finitely in an abstract domain. This uses the observation that
many packages behave monotonically: the semantics of a method call over a
configuration does not essentially change if more objects are added to the
configuration. We have exploited monotonicity and have devised heuristics to
obtain succinct yet general DPIs. We have used our tool to compute DPIs for
several commonly used Java packages with complex protocols, such as JDBC,
HashSet, and ArrayList.


title:
Gap Structure of the Hofstadter System of Interacting Dirac Fermions in
  Graphene

abstract:
  The effects of mutual Coulomb interactions between Dirac fermions in
monolayer graphene on the Hofstadter energy spectrum have been studied. Our
studies indicate that the effects of the interaction depend strongly on the
amplitude of the periodic potential. For large amplitudes the interaction
effects are small and the properties of the system are primarily determined by
the periodic potential but for small amplitudes the interaction greatly
influences the band gap. The signature of the interaction effects in the
Hofstadter system can be probed through magnetization where the Coulomb effects
are dominant for small amplitudes of the periodic potential.


title:
Influence on superconductivity in the parity mixing superconductor
  Li2T3B(T:Pt,Pd) by non-magnetic impurity and defect doping

abstract:
  Superconductors with noncentrosymmetric crystal structures such as
Li2T3B(T:Pd,Pt) have been the focus of in-depth research with their parity
mixing nature. In this study, we focused our research on non-magnetic impurity
effect in Li2T3B (T: Pd, Pt). The nature of the pair breaking by non-magnetic
impurity in the parity mixing superconducting state is still unclear. We
prepared different quality samples of Li2Pd3B and Li2Pt3B by changing
conditions in synthesizing, and sample qualities were estimated by residual
resistivity. Spin singlet dominant superconductor Li2Pd3B exhibits the weak Tc
suppression attributed by nonmagnetic impurity and defects, while Hc2 (0) value
increased. This behavior is similar in ordinary s-wave superconductor. On the
other hand, for the spin triplet dominant superconductor Li2Pt3B, it was
suggested that the Cooper pair was broken and superconducting gap was decreased
by non-magnetic impurities and defects. Li2Pt3B is similar to unconventional
superconducting state.


title:
Search for supersymmetry in pp collisions at sqrt(s) = 8 TeV in events
  with a single lepton, large jet multiplicity, and multiple b jets

abstract:
  Results are reported from a search for supersymmetry in pp collisions at a
center-of-mass energy of 8 TeV, based on events with a single isolated lepton
(electron or muon) and multiple jets, at least two of which are identified as b
jets. The data sample corresponds to an integrated luminosity of 19.3 inverse
femtobarns recorded by the CMS experiment at the LHC in 2012. The search is
motivated by supersymmetric models that involve strong-production processes and
cascade decays of new particles. The resulting final states contain multiple
jets as well as missing transverse momentum from weakly interacting particles.
The event yields, observed across several kinematic regions, are consistent
with the expectations from standard model processes. The results are
interpreted in the context of simplified supersymmetric scenarios with pair
production of gluinos, where each gluino decays to a top quark-antiquark pair
and the lightest neutralino. For the case of decays via virtual top squarks,
gluinos with a mass smaller than 1.26 TeV are excluded for low neutralino
masses.


title:
On the output of nonlinear systems excited by discrete prolate
  spheroidal sequences

abstract:
  The discrete prolate spheroidal sequences (DPSSs) - a set of optimally
bandlimited sequences with unique properties - are important to applications in
both science and engineering. In this work, properties of nonlinear system
response due to DPSS excitation are reported. In particular, this output is
shown to be approximately orthogonal after passing through a nonlinear,
multiple-input multiple-output system with memory under quite general
conditions. This work quantifies these conditions in terms of constraints upon
the higher-order generalized transfer functions characterizing the Volterra
expansion of a MIMO system, the Volterra order of the system, and the DPSS
bandwidth parameter W and time-bandwidth parameter NW. The approximate system
output orthogonality allows multiple input, multiple-output parameter
identification of edge structure in interconnected nonlinear systems using
simultaneous, DPSS excitation. This narrowband method of system identification
is particularly appealing when compared to classical broadband system
excitation in sensitive, neural engineering applications involving electrical
stimulation of multiple brain regions. Through the comparison of inner-product
and kernel-based narrowband detectors, the utility of this work is demonstrated
when identifying narrowband system response of a third-order Volterra system
from noisy observations.


title: Geometrical perspective on quantum states and quantum computation

abstract:
  We interpret quantum computing as a geometric evolution process by
reformulating finite quantum systems via Connes' noncommutative geometry. In
this formulation, quantum states are represented as noncommutative connections,
while gauge transformations on the connections play a role of unitary quantum
operations. Thereby, a geometrical model for quantum computation is presented,
which is equivalent to the quantum circuit model. This result shows a geometric
way of realizing quantum computing and as such, provides an alternative
proposal of building a quantum computer.


title: A note on the metrizability of spaces

abstract:
  With the blessing of hind sight we consider the problem of metrizability and
show that the classical Bing-Nagata-Smirnov Theorem and a more recent result of
Flagg give complementary answers to the metrization problem, that are in a
sense dual to each other.


title: Polar Coding for Fading Channels: Binary and Exponential Channel Cases

abstract:
  This work presents a polar coding scheme for fading channels, focusing
primarily on fading binary symmetric and additive exponential noise channels.
For fading binary symmetric channels, a hierarchical coding scheme is
presented, utilizing polar coding both over channel uses and over fading
blocks. The receiver uses its channel state information (CSI) to distinguish
states, thus constructing an overlay erasure channel over the underlying fading
channels. By using this scheme, the capacity of a fading binary symmetric
channel is achieved without CSI at the transmitter. Noting that a fading AWGN
channel with BPSK modulation and demodulation corresponds to a fading binary
symmetric channel, this result covers a fairly large set of practically
relevant channel settings.
  For fading additive exponential noise channels, expansion coding is used in
conjunction to polar codes. Expansion coding transforms the continuous-valued
channel to multiple (independent) discrete-valued ones. For each level after
expansion, the approach described previously for fading binary symmetric
channels is used. Both theoretical analysis and numerical results are
presented, showing that the proposed coding scheme approaches the capacity in
the high SNR regime. Overall, utilizing polar codes in this (hierarchical)
fashion enables coding without CSI at the transmitter, while approaching the
capacity with low complexity.


title: Detector and Event Visualization with SketchUp at the CMS Experiment

abstract:
  We have created 3D models of the CMS detector and particle collision events
in SketchUp, a 3D modelling program. SketchUp provides a Ruby API which we use
to interface with the CMS Detector Description to create 3D models of the CMS
detector. With the Ruby API, we also have created an interface to the
JSON-based event format used for the iSpy event display to create 3D models of
CMS events. These models have many applications related to 3D representation of
the CMS detector and events. Figures produced based on these models were used
in conference presentations, journal publications, technical design reports for
the detector upgrades, art projects, outreach programs, and other
presentations.


title:
A statistical study of gaseous environment of Spitzer interstellar
  bubbles

abstract:
  The expansion of interstellar bubbles is suggested to be an important
mechanism of triggering material accumulation and star formation. In this work,
we study the gaseous environment of a large sample of bubbles, aiming to
explore the possible evidence of triggered gas accumulation and star formation
in a statistical sense. By cross-matching 6124 Spitzer bubbles from the Milky
Way Project (MWP) and more than 2500 Galactic HII regions, we obtain the
velocity information for 818 MWP bubbles. To study the gaseous environment of
the interstellar bubbles and get rid of the projection effect as much as
possible, we constrain the velocity difference between the bubbles and the
13CO(1-0) emission extracted from the Galactic Ring Survey (GRS). Three
methods: the mean azimuthally averaged radial profile of 13CO emission, the
surface number density of molecular clumps, and the angular cross-correlation
function of MWP bubbles and the GRS molecular clumps are adopted. Significant
over density of molecular gas is found to be close to the bubble rims. 60
percent of the studied bubbles were found to have associated molecular clumps.
By comparing the clump-associated and the clump-unassociated MWP bubbles, we
reveal that the bubbles in associations tend to be larger and thicker in
physical sizes. We speculate that some of the bubble-associated clumps result
from the expansion of bubbles. The fraction of the molecular clumps associated
with the MWP bubbles is estimated to be about 20 percent after considering the
projection effect. For the bubble-clump complexes, we found that the bubbles in
the complexes with associated massive young stellar object(s) (MYSO(s)) have
larger physical sizes, hence the complexes tend to be older. We propose that an
evolutionary sequence might exist between the relative younger
MYSO-unassociated bubble-clump complexes and the MYSO-associated complexes.


title: Minimum Supersymmetric Standard Model on the Noncommutative Geometry

abstract:
  We have obtained the supersymmetric extension of spectral triple which
specify a noncommutative geometry(NCG). We assume that the functional space H
constitutes of wave functions of matter fields and their superpartners included
in the minimum supersymmetric standard model(MSSM). We introduce the internal
fluctuations to the Dirac operator on the manifold as well as on the finite
space by elements of the algebra A in the triple. So, we obtain not only the
vector supermultiplets which meditate SU(3)xSU(2)xU(1)_Y gauge degrees of
freedom but also Higgs supermultiplets which appear in MSSM on the same
standpoint. Accoding to the supersymmetric version of the spectral action
principle, we calculate the square of the fluctuated total Dirac operator and
verify that the Seeley-DeWitt coeffients give the correct action of MSSM. We
also verify that the relation between coupling constants of $SU(3)$,$SU(2)$ and
$U(1)_Y$ is same as that of SU(5) unification theory.


title: Dynamical energy transfer in ac driven quantum systems

abstract:
  We analyze the time-dependent energy and heat flows in a resonant level
coupled to a fermionic continuum. The level is periodically forced with an
external power source that supplies energy into the system. Based on the
tunneling Hamiltonian approach and scattering theory, we discuss the different
contributions to the total energy flux. We then derive the appropriate
expression for the dynamical dissipation, in accordance with the fundamental
principles of thermodynamics. Remarkably, we find that the dissipated heat can
be expressed as a Joule law with a universal resistance that is constant at all
times.


title:
Structural phase transition induced by van Hove singularity in 5d
  transition metal compound IrTe2

abstract:
  Comprehensive studies of the electronic states of Ir 5d and Te 5p have been
performed to elucidate the origin of the structural phase transition in IrTe2
by combining angle-resolved photoemission spectroscopy and resonant inelastic
X-ray scattering. While no considerable changes are observed in the
configuration of the Ir 5d electronic states across the transition, indicating
that the Ir 5d orbitals are not involved in the transition, we reveal a van
Hove singularity at the Fermi level (EF) related to the Te px+py orbitals,
which is removed from EF at low temperatures. The wavevector connecting the
adjacent saddle points is consistent with the in-plane projection of the
superstructure modulation wavevector. These results can be qualitatively
understood with the Rice-Scott "saddle-point" mechanism, while effects of the
lattice distortions need to be additionally involved.


title:
A Framework of Constructions of Minimal Storage Regenerating Codes with
  the Optimal Access/Update Property

abstract:
  In this paper, we present a generic framework for constructing systematic
minimum storage regenerating codes with two parity nodes based on the invariant
subspace technique. Codes constructed in our framework not only contain some
best known codes as special cases, but also include some new codes with key
properties such as the optimal access property and the optimal update property.
In particular, for a given storage capacity of an individual node, one of the
new codes has the largest number of systematic nodes and two of the new codes
have the largest number of systematic nodes with the optimal update property.


title:
A Priori Estimates of the Degenerate Monge-Ampere Equation on Kahler
  Manifolds of Nonnegative Bisectional Curvature

abstract:
  The regularity theory of the degenerate complex Monge-Amp\`{e}re equation is
studied. The equation is considered on a closed compact K\"{a}hler manifold
$(M,g)$ with nonnegative orthogonal bisectional curvature of dimension $m$.
Given a solution $\phi$ of the degenerate complex Monge-Amp\`{e}re equation
$\det(g_{i \bar{j}} + \phi_{i \bar{j}}) = f \det(g_{i \bar{j}})$, it is shown
that the Laplacian of $\phi$ can be controlled by a constant depending on
$(M,g)$, $\sup f$, and $\inf_M \Delta f^{1/(m-1)}$.


title: Mid-Infrared Imaging of the Bipolar Planetary Nebula M2-9 from SOFIA

abstract:
  We have imaged the bipolar planetary nebula M2-9 using SOFIA's FORCAST
instrument in six wavelength bands between 6.6 and 37.1 $\mu m$. A bright
central point source, unresolved with SOFIA's $\sim$ 4${''}$-to-5${''}$ beam,
is seen at each wavelength, and the extended bipolar lobes are clearly seen at
19.7 $\mu m$ and beyond. The photometry between 10 and 25 $\mu m$ is well fit
by the emission predicted from a stratified disk seen at large inclination, as
has been proposed for this source by Lykou et al and by Smith and Gehrz. The
principal new results in this paper relate to the distribution and properties
of the dust that emits the infrared radiation. In particular, a considerable
fraction of this material is spread uniformly through the lobes, although the
dust density does increase at the sharp outer edge seen in higher resolution
optical images of M2-9. The dust grain population in the lobes shows that small
($<$ 0.1 $\mu m$) and large ($>$ 1 $\mu m$) particles appear to be present in
roughly equal amounts by mass. We suggest that collisional processing within
the bipolar outflow plays an important role in establishing the particle size
distribution.


title: Wilson loops and Riemann theta functions II

abstract:
  In this paper we extend and simplify previous results regarding the
computation of Euclidean Wilson loops in the context of the AdS/CFT
correspondence, or, equivalently, the problem of finding minimal area surfaces
in hyperbolic space (Euclidean AdS3). If the Wilson loop is given by a boundary
curve X(s) we define, using the integrable properties of the system, a family
of curves X(lambda,s) depending on a complex parameter lambda known as the
spectral parameter. This family has remarkable properties. As a function of
lambda, X(lambda,s) has cuts and therefore is appropriately defined on a
hyperelliptic Riemann surface, namely it determines the spectral curve of the
problem. Moreover, X(lambda,s) has an essential singularity at the origin
lambda=0. The coefficients of the expansion of X(lambda,s) around lambda=0,
when appropriately integrated along the curve give the area of the
corresponding minimal area surface.
  Furthermore we show that the same construction allows the computation of
certain surfaces with one or more boundaries corresponding to Wilson loop
correlators. We extend the area formula for that case and give some concrete
examples. As the main example we consider a surface ending on two concentric
circles and show how the boundary circles can be deformed by introducing extra
cuts in the spectral curve.


title: A pre-order principle and set-valued Ekeland variational principle

abstract:
  We establish a pre-order principle. From the principle, we obtain a very
general set-valued Ekeland variational principle, where the objective function
is a set-valued map taking values in a quasi ordered linear space and the
perturbation contains a family of set-valued maps satisfying certain property.
From this general set-valued Ekeland variational principle, we deduce a number
of particular versions of set-valued Ekeland variational principle, which
include many known Ekeland variational principles, their improvements and some
new results.


title:
Distributed Painting by a Swarm of Robots with Unlimited Sensing
  Capabilities and Its Simulation

abstract:
  This paper presents a distributed painting algorithm for painting a priori
known rectangular region by swarm of autonomous mobile robots. We assume that
the region is obstacle free and of rectangular in shape. The basic approach is
to divide the region into some cells, and to let each robot to paint one of
these cells. Assignment of different cells to the robots is done by ranking the
robots according to their relative positions. In this algorithm, the robots
follow the basic Wait-Observe-Compute-Move model together with the synchronous
timing model. This paper also presents a simulation of the proposed algorithm.
The simulation is performed using the Player/Stage Robotic Simulator on Ubuntu
10.04 (Lucid Lynx) platform.