title: New Prospects for Higgs Compositeness in h -> Z gamma

abstract:
  We discuss novel effects in the phenomenology of a light Higgs boson within
the context of composite models. We show that large modifications may arise in
the decay of a composite Nambu-Goldstone boson Higgs to a photon and a Z boson,
h -> Z gamma. These can be generated by the exchange of massive composite
states of a strong sector that breaks a left-right symmetry, which we show to
be the sole symmetry structure responsible for governing the size of these new
effects in the absence of Goldstone-breaking interactions. In this paper we
consider corrections to the decay h -> Z gamma obtained either by integrating
out vectors at tree level, or by integrating out vector-like fermions at loop
level. In each case, the pertinent operators that are generated are
parametrically enhanced relative to other interactions that arise at loop level
in the Standard Model such as h -> gg and h -> gamma gamma. Thus we emphasize
that the effects of interest here provide a unique possibility to probe the
dynamics underlying electroweak symmetry breaking, and do not depend on any
contrivance stemming from carefully chosen spectra. The effects we discuss
naturally lead to concerns of compatibility with precision electroweak
measurements, and we show with relevant computations that these corrections can
be kept well under control in our general parameter space.


title: Rotor-routing and spanning trees on planar graphs

abstract:
  The sandpile group Pic^0(G) of a finite graph G is a discrete analogue of the
Jacobian of a Riemann surface which was rediscovered several times in the
contexts of arithmetic geometry, self-organized criticality, random walks, and
algorithms. Given a ribbon graph G, Holroyd et al. used the "rotor-routing"
model to define a free and transitive action of Pic^0(G) on the set of spanning
trees of G. However, their construction depends a priori on a choice of
basepoint vertex. Ellenberg asked whether this action does in fact depend on
the choice of basepoint. We answer this question by proving that the action of
Pic^0(G) is independent of the basepoint if and only if G is a planar ribbon
graph.


title: NMSSM with Gravitino Dark Matter to be tested at LHC

abstract:
  We present a solution to the gravitino problem, which arises in the NMSSM,
allowing for sparticle spectra from ordinary gravity-mediated supersymmetry
breaking with weak-scale gravitino dark matter. The coupling, which links the
singlet to the MSSM sector, enhances the tree-level Higgs mass, providing an
attractive explanation why the observed Higgs boson is so heavy. The same
coupling induces very efficient pair-annihilation processes of the neutralino
NLSP. Its relic abundance can be sufficiently suppressed to satisfy the strong
constraints on late decaying relics from primordial nucleosynthesis -- even for
very long neutralino lifetimes. The striking prediction of this scenario is the
detection of a pseudoscalar Higgs boson in the search for top-top resonances at
LHC-14, rendering it completely testable.


title: Simplified Models for Dark Matter Interacting with Quarks

abstract:
  We investigate simplified models in which dark matter particles, taken to be
either Dirac or Majorana fermions, couple to quarks via colored mediators. We
determine bounds from colliders and direct detection experiments, and show how
the interplay of the two leads to a complementary view of this class of dark
matter models. Forecasts for future searches in light of the current
constraints are presented.


title: The \HI column density power spectrum of six nearby spiral galaxies

abstract:
  We propose a method to determine the power spectrum of \HI column density
fluctuations using radio-interferometric observations of 21-cm emission from
the ISM of galaxies. We have used this to estimate the power spectra of six
nearly face on nearby spiral galaxies. Earlier work has shown that these power
spectra are well fitted by power laws with slopes around -1.6 across
length-scales $\sim 1 \, {\rm kpc}$ to $\sim 10 \, {\rm kpc}$, the amplitude
however was undetermined. In the present work we have determined the amplitude
of the \HI column density power spectrum. We find that the \HI column density
$N_{\rm HI}$ expressed in units of $10^{20} \, {\rm cm}^{-2}$ has mean square
fluctuations in the range $\sim 0.03$ to $\sim 20$. The amplitude of the power
spectrum is found to be tightly correlated with the \HI mass fraction of the
galaxies. The physical process responsible for these scale-invariant
fluctuations is, however, at present not known.


title:
Probing the IGM-galaxy connection at z<0.5 II. New insights into the
  galaxy environments of OVI absorbers in PKS 0405-123

abstract:
  We present new absorption-line analysis and new galaxy survey data obtained
for the field around PKS0405-123 at z=0.57. Combining previously known OVI
absorbers with new identifications in the higher S/N UV spectra obtained with
COS, we have established a sample of 7 OVI absorbers and 12 individual
components at z=0.0918-0.495 along the sightline toward PKS0405-123. We
complement the available UV absorption spectra with galaxy survey data that
reach 100% completeness at projected distances rho<200 kpc of the quasar
sightline for galaxies as faint as 0.1L* (0.2L*) out to redshifts of z=0.35
(z=0.5). The high level of completeness achieved at faint magnitudes by our
survey reveals that OVI absorbers are closely associated with gas-rich
environments containing at least one low-mass, emission-line galaxy. An
intriguing exception is a strong OVI system at z=0.183 that does not have a
galaxy found at rho<4 Mpc, and our survey rules out the presence of any
galaxies of L>0.04L* at rho<250 kpc and any galaxies of L>0.3L* at rho<1 Mpc.
We further examine the galactic environments of OVI absorbers and those
"Lya-only" absorbers with HI column density log N(HI)>13.6 and no detectable
OVI absorption features. The Lya-only absorbers serve as a control sample in
seeking the discriminating galactic features that result in the observed OVI
absorbing gas at large galactic radii. We find a clear distinction in the
radial profiles of mean galaxy surface brightness around different absorbers.
Specifically, OVI absorbers are found to reside in regions of higher mean
surface brightness at rho<500 kpc (+5 mag Mpc^-2 relative to the background),
while only a mild increase in galaxy surface brightness is seen at small rho
around Lya-only absorbers (+2 mag Mpc^-2). The additional insights gained from
our deep galaxy survey demonstrates the need to probe to low luminosities to
better understand absorbing systems.


title:
The Stellar Halos of Massive Elliptical Galaxies II: Detailed Abundance
  Ratios at Large Radius

abstract:
  We study the radial dependence in stellar populations of 33 nearby early-type
galaxies with central stellar velocity dispersions sigma* > 150 km/s. We
measure stellar population properties in composite spectra, and use ratios of
these composites to highlight the largest spectral changes as a function of
radius. Based on stellar population modeling, the typical star at 2 R_e is old
(~10 Gyr), relatively metal poor ([Fe/H] -0.5), and alpha-enhanced
([Mg/Fe]~0.3). The stars were made rapidly at z~1.5-2 in shallow potential
wells. Declining radial gradients in [C/Fe], which follow [Fe/H], also arise
from rapid star formation timescales due to declining carbon yields from
low-metallicity massive stars. In contrast, [N/Fe] remains high at large
radius. Stars at large radius have different abundance ratio patterns from
stars in the center of any present-day galaxy, but are similar to Milky Way
thick disk stars. Our observations are thus consistent with a picture in which
the stellar outskirts are built up through minor mergers with disky galaxies
whose star formation is truncated early (z~1.5-2).


title: Negative mass

abstract:
  Some physical aspects of negative mass are examined. Several unusual
properties, such as the ability of negative mass to penetrate any armor, are
analyzed. Other surprising effects include the bizarre system of negative mass
chasing positive pass, naked singularities and the violation of cosmic
censorship, wormholes, and quantum mechanical results as well. In addition, a
brief look into the implications for strings is given.


title: Strongly correlated bosons and fermions in optical lattices

abstract:
  These lectures are an introduction to the physics of strongly correlated
fermions and bosons. They are specially targeted for the experimental
realizations that have been provided by cold atomic gases in optical lattices.


title:
A glance at the host galaxy of high-redshift quasars using strong damped
  Lyman-alpha systems as coronagraphs

abstract:
  We searched quasar spectra from the SDSS-III Baryon Oscillation Spectroscopic
Survey (BOSS) for the rare occurrences where a strong damped Lyman-alpha
absorber (DLA) blocks the Broad Line Region emission from the quasar and acts
as a natural coronagraph to reveal narrow Ly\alpha\ emission from the host
galaxy. We define a statistical sample of 31 DLAs in Data Release 9 (DR9) with
log N(HI) > 21.3 cm^-2 located at less than 1500 km s^-1 from the quasar
redshift. In 25% (8) of these DLAs, a strong narrow Ly\alpha\ emission line is
observed with flux ~25 x 10^-17 erg s^-1 cm^-2 on average. For DLAs without
this feature in their troughs, the average 3-\sigma\ upper limit is < 0.8 x
10^-17 erg s^-1 cm^-2. Our statistical sample is nearly 2.5 times larger than
the anticipated number of intervening DLAs in DR9 within 1500 km s^-1 of the
quasar redshift. We also define a sample of 26 DLAs from DR9 and DR10 with
narrow Ly\alpha\ emission detected and no limit on the HI column density to
better characterize properties of the host galaxy emission. Analyzing the
statistical sample, we do not find substantial differences in the kinematics,
metals, or reddening for the two populations with and without emission
detected. The highly symmetric narrow Ly\alpha\ emission line profile centered
in the HI trough indicates that the emitting region is separate from the
absorber. The luminosity of the narrow Ly\alpha\ emission peaks is intermediate
between that of Lyman-alpha emitters and radio galaxies, implying that the
Ly\alpha\ emission is predominantly due to ionizing radiation from the AGN.
Galaxies neighboring the quasar host are likely responsible for the majority (>
75%) of these DLAs, with only a minority (< 25%) arising from HI clouds located
in the AGN host galaxy.


title:
Dipolar Poisson-Boltzmann Approach to Ionic Solutions: A Mean Field and
  Loop Expansion Analysis

abstract:
  We study the variation of the dielectric response of ionic aqueous solutions
as function of their ionic strength. The effect of salt on the dielectric
constant appears through the coupling between ions and dipolar water molecules.
On a mean-field level, we account for any internal charge distribution of
particles. The dipolar degrees of freedom are added to the ionic ones and
result in a generalization of the Poisson-Boltzmann (PB) equation called the
Dipolar PB (DPB). By looking at the DPB equation around a fixed point-like ion,
a closed-form formula for the dielectric constant is obtained. We express the
dielectric constant using the "hydration length" that characterizes the
hydration shell of dipoles around ions, and thus the strength of the dielectric
decrement. The DPB equation is then examined for three additional cases:
mixture of solvents, polarizable medium and ions of finite size. Employing
field-theoretical methods we expand the Gibbs free-energy to first order in a
loop expansion and calculate self-consistently the dielectric constant. For
pure water, the dipolar fluctuations represent an important correction to the
mean-field value and good agreement with the water dielectric constant is
obtained. For ionic solutions we predict analytically the dielectric decrement
that depends on the ionic strength in a non-linear way. Our prediction fits
rather well a large range of concentrations for different salts using only one
fit parameter related to the size of ions and dipoles. A linear dependence of
the dielectric constant on the salt concentration is observed at low salinity,
and a noticeable deviation from linearity can be seen for ionic strength above
1\,M, in agreement with experiments.


title: Corner states of topological fullerenes

abstract:
  The unusual electronic properties of the quantum spin Hall or Chern insulator
become manifest in the form of robust edge states when samples with boundaries
are studied. In this work, we ask if and how the topologically non-trivial
electronic structure of these two-dimensional systems can be passed on to their
zero-dimensional relatives, namely fullerenes or other closed-cage molecules.
To address this question, we study Haldane's honeycomb lattice model on
polyhedral nano-surfaces. We find that for sufficiently large surfaces
characteristic corner states appear for parameters for which the planar model
displays a quantized Hall effect. In the electronic structure, these corner
states show up as in-gap modes which are well separated from the
quasi-continuum of states. We discuss the role of finite size effects and how
the coupling between the corner states lifts the degeneracy in a characteristic
way determined by the combined Berry phases which leads to an effective
magnetic monopole of charge 2 at the center of the nano-surface. Experimental
implications for fullerenes in the large spin-orbit regime are also pointed
out.


title:
American options with gradual exercise under proportional transaction
  costs

abstract:
  American options in a multi-asset market model with proportional transaction
costs are studied in the case when the holder of an option is able to exercise
it gradually at a so-called mixed (randomised) stopping time. The introduction
of gradual exercise leads to tighter bounds on the option price when compared
to the case studied in the existing literature, where the standard assumption
is that the option can only be exercised instantly at an ordinary stopping
time. Algorithmic constructions for the bid and ask prices and the associated
superhedging strategies and optimal mixed stoping times for an American option
with gradual exercise are developed and implemented, and dual representations
are established.


title: Diamond Magnetometry of Superconducting Thin Films

abstract:
  In recent years diamond magnetometers based on the nitrogen-vacancy (NV)
center have been of considerable interest for magnetometry applications at the
nanoscale. An interesting application which is well suited for NV centers is
the study of nanoscale magnetic phenomena in superconducting materials. We
employ the magnetic sensitivity of NV centers in diamond to interrogate the
magnetic properties of a thin-layer yttrium barium copper oxide (YBCO)
superconductor. Using fluorescence-microscopy methods and samples integrated
with an NV sensor on a microchip, we measure the temperature of phase
transition in the layer to be 70.0(2) K, and the penetration field of vortices
to be 46(4) G. We observe the pinning of the vortices in the layer at 65 K, and
estimate their density after cooling the sample in a ~ 10 G field to be 0.45(1)
\mu m^{-2}. These measurements are done with a 10 nm thick NV layer, so that
high spatial resolution may be enabled in the future. Based on these results,
we anticipate that this magnetometer could be useful for imaging the structure
and dynamics of vortices. As an outlook, we present a fabrication method for a
superconductor chip designed for this purpose.


title: Induction in Algebra: a First Case Study

abstract:
  Many a concrete theorem of abstract algebra admits a short and elegant proof
by contradiction but with Zorn's Lemma (ZL). A few of these theorems have
recently turned out to follow in a direct and elementary way from the Principle
of Open Induction distinguished by Raoult. The ideal objects characteristic of
any invocation of ZL are eliminated, and it is made possible to pass from
classical to intuitionistic logic. If the theorem has finite input data, then a
finite partial order carries the required instance of induction, which thus is
constructively provable. A typical example is the well-known theorem "every
nonconstant coefficient of an invertible polynomial is nilpotent".


title: Constructing Double Magma with Commutation Operations

abstract:
  A double magma is a nonempty set with two binary operations satisfying the
interchange law. We call a double magma proper if the two operations are
distinct and commutative if the operations are commutative. A double semigroup
is a double magma for which both operations are associative. Given a group G we
define a double magma (G,*,#) with the commutator operations x * y = [x,y] (=
x^-1y^-1xy) and x # y = [y,x]. We show that (G,*,#) is a double magma if and
only if G satisfies the commutator laws [x,y;x,z]=1 and [w,x;y,z]^2 = 1. Note
that the first law defines the variety of 3-metabelian groups. If both these
laws hold in G, (G,*,#) is proper if and only if G contains a commutator whose
square is nontrivial. B.H. Neumann has given an example of such a group which
is not metabelian; thus the associated double magma is proper and produces an
example with some complexity. The double magma (G,*,#) is a double semigroup if
and only if G is nilpotent of class 2. In this case, (G,*,#) is a proper double
semigroup if and only if G contains a commutator whose square is nontrivial. We
construct a specific example letting G be the dihedral group of order 16. In
addition we comment on a similar construction for rings using Lie commutators.


title: On the character varieties of finitely generated groups

abstract:
  We establish three results dealing with the character varieties of finitely
generated groups. The first two are concerned with the behavior of $\dim
X_n(\Gamma)$ as a function of $n$, and the third addresses the problem of
realizing a $\mathbb{Q}$-defined complex affine algebraic variety as a
character variety.


title:
One-Pot Multi-component Synthesis of 1,4-Dihydropyridine Derivatives in
  Biocompatible Deep Eutectic Solvents

abstract:
  An efficient protocol for the synthesis of differently substituted 1,
4-dihydropyridines in deep eutectic solvents under solvent-free conditions is
reported herewith. Excellent yields of the resultant products have been
obtained. Recyclability studies have also been performed for deep eutectic
solvents with very little loss in activity up to five recycles.


title:
A Super-Fast Distributed Algorithm for Bipartite Metric Facility
  Location

abstract:
  The \textit{facility location} problem consists of a set of
\textit{facilities} $\mathcal{F}$, a set of \textit{clients} $\mathcal{C}$, an
\textit{opening cost} $f_i$ associated with each facility $x_i$, and a
\textit{connection cost} $D(x_i,y_j)$ between each facility $x_i$ and client
$y_j$. The goal is to find a subset of facilities to \textit{open}, and to
connect each client to an open facility, so as to minimize the total facility
opening costs plus connection costs. This paper presents the first
expected-sub-logarithmic-round distributed O(1)-approximation algorithm in the
$\mathcal{CONGEST}$ model for the \textit{metric} facility location problem on
the complete bipartite network with parts $\mathcal{F}$ and $\mathcal{C}$. Our
algorithm has an expected running time of $O((\log \log n)^3)$ rounds, where $n
= |\mathcal{F}| + |\mathcal{C}|$. This result can be viewed as a continuation
of our recent work (ICALP 2012) in which we presented the first
sub-logarithmic-round distributed O(1)-approximation algorithm for metric
facility location on a \textit{clique} network. The bipartite setting presents
several new challenges not present in the problem on a clique network. We
present two new techniques to overcome these challenges. (i) In order to deal
with the problem of not being able to choose appropriate probabilities (due to
lack of adequate knowledge), we design an algorithm that performs a random walk
over a probability space and analyze the progress our algorithm makes as the
random walk proceeds. (ii) In order to deal with a problem of quickly
disseminating a collection of messages, possibly containing many duplicates,
over the bipartite network, we design a probabilistic hashing scheme that
delivers all of the messages in expected-$O(\log \log n)$ rounds.


title: Invariant scalar product on extended Poincare algebra

abstract:
  Two methods can be used to calculate explicitly the Killing form on the Lie
algebras. The first one is a direct calculation of the traces of the generators
in a matrix representation of the algebra, and the second one is the usage of
the group invariance of the scalar product. We use both methods in our
calculation of the scalar product on the extended Poincare algebra in order to
have a cross check of our results. The algebra is infinite-dimensional and
requires careful treatment of the infinities. The scalar product on the
extended algebra found by both methods coincides and the important conclusion
which follows is that Poincare generators are orthogonal to the gauge
generators.


title: B(eo)W(u)LF: Facilitating recurrence analysis on multi-level language

abstract:
  Discourse analysis may seek to characterize not only the overall composition
of a given text but also the dynamic patterns within the data. This technical
report introduces a data format intended to facilitate multi-level
investigations, which we call the by-word long-form or B(eo)W(u)LF. Inspired by
the long-form data format required for mixed-effects modeling, B(eo)W(u)LF
structures linguistic data into an expanded matrix encoding any number of
researchers-specified markers, making it ideal for recurrence-based analyses.
While we do not necessarily claim to be the first to use methods along these
lines, we have created a series of tools utilizing Python and MATLAB to enable
such discourse analyses and demonstrate them using 319 lines of the Old English
epic poem, Beowulf, translated into modern English.


title: Wafer bonding solution to epitaxial graphene - silicon integration

abstract:
  The development of graphene electronics requires the integration of graphene
devices with Si-CMOS technology. Most strategies involve the transfer of
graphene sheets onto silicon, with the inherent difficulties of clean transfer
and subsequent graphene nano-patterning that degrades considerably the
electronic mobility of nanopatterned graphene. Epitaxial graphene (EG) by
contrast is grown on an essentially perfect crystalline (semi-insulating)
surface, and graphene nanostructures with exceptional properties have been
realized by a selective growth process on tailored SiC surface that requires no
graphene patterning. However, the temperatures required in this structured
growth process are too high for silicon technology. Here we demonstrate a new
graphene to Si integration strategy, with a bonded and interconnected compact
double-wafer structure. Using silicon-on-insulator technology (SOI) a thin
monocrystalline silicon layer ready for CMOS processing is applied on top of
epitaxial graphene on SiC. The parallel Si and graphene platforms are
interconnected by metal vias. This method inspired by the industrial
development of 3d hyper-integration stacking thin-film electronic devices
preserves the advantages of epitaxial graphene and enables the full spectrum of
CMOS processing.


title: Positroids and non-crossing partitions

abstract:
  We investigate the role that non-crossing partitions play in the study of
positroids, a class of matroids introduced by Postnikov. We prove that every
positroid can be constructed uniquely by choosing a non-crossing partition on
the ground set, and then freely placing the structure of a connected positroid
on each of the blocks of the partition. This structural result yields several
combinatorial facts about positroids. We show that the face poset of a
positroid polytope embeds in a poset of weighted non-crossing partitions. We
enumerate connected positroids, and show how they arise naturally in free
probability. Finally, we prove that the probability that a positroid on [n] is
connected equals 1/e^2 asymptotically.


title:
WLS R\&D for the Detection of Noble Gas Scintillation at LBL: seeing the
  light from neutrinos, to dark matter, to double beta decay

abstract:
  Radiation detectors with noble gasses as the active medium are becoming
increasingly common in experimental programs searching for physics beyond the
standard model. Nearly all of these experiments rely to some degree on
collecting scintillation light from noble gasses. The VUV wavelengths
associated with noble gas scintillation mean that most of these experiments use
a fluorescent material to shift the direct scintillation light into the visible
or near UV band. We present an overview of the R&D program at LBL related to
noble gas detectors for neutrino physics, double beta decay, and dark matter.
This program ranges from precise measurements of the fluorescence behavior of
wavelength shifting films, to the prototyping of large are VUV sensitive light
guides for multi-kiloton detectors.

categories: physics.ins-det hep-ex nucl-ex physics.optics


title:
Ab initio many-body calculations of nucleon-4He scattering with
  three-nucleon forces

abstract:
  We extend the ab initio no-core shell model/resonating-group method to
include three-nucleon (3N) interactions for the description of nucleon-nucleus
collisions. We outline the formalism, give algebraic expressions for the
3N-force integration kernels, and discuss computational aspects of two
alternative implementations. The extended theoretical framework is then applied
to nucleon-4He scattering using similarity-renormalization-group (SRG) evolved
nucleon-nucleon plus three-nucleon potentials derived from chiral effective
field theory. We analyze the convergence properties of the calculated phase
shifts and explore their dependence upon the SRG evolution parameter. We
include up to six excited states of the 4He target and find significant effects
from the inclusion of the chiral 3N force, e.g., it enhances the spin-orbit
splitting between the 3/2- and 1/2- resonances and leads to an improved
agreement with the phase shifts obtained from an accurate R-matrix analysis of
the five-nucleon experimental data. We find remarkably good agreement with
measured differential cross sections at various energies, while analyzing
powers manifest larger deviations from experiment for certain energies and
angles.


title: Intersection local times, loop soups and permanental Wick powers

abstract:
  Several stochastic processes related to transient L\'evy processes with
potential densities $u(x,y)=u(y-x)$, that need not be symmetric nor bounded on
the diagonal, are defined and studied.
  They are real valued processes on a space of measures $V$ endowed with a
metric $d$. Sufficient conditions are obtained for the continuity of these
processes on $(V,d)$. The processes include $n$-fold self-intersection local
times of transient L\'evy processes and permanental chaoses, which are `loop
soup $n$-fold self-intersection local times' constructed from the loop soup of
the L\'evy process. Loop soups are also used to define permanental Wick powers,
which generalizes standard Wick powers, a class of $n$-th order Gaussian
chaoses. Dynkin type isomorphism theorems are obtained that relate the various
processes.
  Poisson chaos processes are defined and permanental Wick powers are shown to
have a Poisson chaos decomposition. Additional properties of Poisson chaos
processes are studied and a martingale extension is obtained for many of the
processes described above.


title: Galileon Duality

abstract:
  We show that every Galileon theory admits a dual formulation as a Galileon
theory with new operator coefficients. In n dimensions a free scalar field in
Minkowski spacetime is dual to a (n+1)-th order Galileon theory which exhibits
the Vainshtein mechanism when coupled to sources and superluminal propagation
even on-shell. This demonstrates that superluminal propagation is compatible
with an analytic S-matrix and causality. For point sources, the duality
interchanges the strongly coupled Vainshtein regime with the weakly coupled
asymptotic regime. The duality is made manifest in the context of the
decoupling limit of bigravity, but is independent of this.


title: Grouping Normal Type Ia Supernovae by UV to Optical Color Differences

abstract:
  Observations of many SNe Ia with the UVOT instrument on the Swift satellite
has revealed that there exists order to the differences in the UV-OPT colors of
normal SNe. We examine UV-OPT color curves for 25 SNe Ia, dividing them into 4
groups, finding that ~1/3 of these SNe Ia have bluer UV-OPT colors than the
larger group, with these "NUV-blue" SNe Ia 0.4 mag bluer than the "NUV-red" SNe
Ia in u-v. Another group of events feature colors similar to NUV-red SNe Ia in
the u-v to uvw1-v colors, but similar to the NUV-blue SNe Ia in the uvm2-v
color. We name these events "MUV-blue". The last group initially has colors
similar to NUV-red SNe Ia, but with color curves that feature more modest
changes than the larger NUV-red group. These "irregular" events are comprised
of all the NUV-red events with the broadest optical peaks, which leads us to
consider this minor group a subset of the NUV-red group. When so separated and
the accounting is made for the rapid time evolution of the UV-OPT colors, we
find that the scatter in two NUV-OPT colors, u-v & uvw1-v, is at the level of
the scatter in b-v. This finding is promising for extending the cosmological
utilization of SNe Ia into the NUV. We generate spectrophotometry of SNe Ia
that have been observed with HST and argue that there is a fundamental spectral
difference in the 2900-3500A wavelength range, a range suggested to be
dominated by absorption from iron-peak elements. The NUV-blue SNe Ia feature
less NUV absorption than the NUV-red SNe Ia. We show that all the NUV-blue SNe
Ia in this sample have also featured evidence of unburned carbon in optical
spectra, whereas only one NUV-red SN Ia features that absorption line. Every
NUV-blue event also exhibits a low gradient of the SiII 6355A absorption
feature, but many NUV-red events also exhibit a low gradient, perhaps
suggestive that NUV-blue events are a subset of the larger LVG group.


title: The energy identity for a sequence of Yang-Mills {\alpha}-connections

abstract:
  We prove that the Yang-Mills $\alpha$-functional satisfies the Palais-Smale
condition. This guarantees the existence of critical points, which are called
Yang-Mills $\alpha$-connections. It was shown by Hong, Tian and Yin in [10] (to
appear in Comm. Math. Helv.) that as $\alpha \to 1$, a sequence of Yang-Mills
$\alpha$-connections converges to a Yang-Mills connection away from finitely
many points. We prove an energy identity for such a sequence of Yang-Mills
$\alpha$-connections. As an application, we also prove an energy identity for
the Yang-Mills flow at the maximal existence time.


title: Stochastic Models Predict User Behavior in Social Media

abstract:
  User response to contributed content in online social media depends on many
factors. These include how the site lays out new content, how frequently the
user visits the site, how many friends the user follows, how active these
friends are, as well as how interesting or useful the content is to the user.
We present a stochastic modeling framework that relates a user's behavior to
details of the site's user interface and user activity and describe a procedure
for estimating model parameters from available data. We apply the model to
study discussions of controversial topics on Twitter, specifically, to predict
how followers of an advocate for a topic respond to the advocate's posts. We
show that a model of user behavior that explicitly accounts for a user
transitioning through a series of states before responding to an advocate's
post better predicts response than models that fail to take these states into
account. We demonstrate other benefits of stochastic models, such as their
ability to identify users who are highly interested in advocate's posts.


title: Heat kernel for flat generalized Laplacians with anisotropic scaling

abstract:
  We calculate the closed analytic form of the solution of heat kernel equation
for the anisotropic generalizations of flat Laplacian. We consider a UV as well
as UV/IR interpolating generalizations. In all cases, the result can be
expressed in terms of Fox-Wright psi-functions. We perform different
consistency checks, analytically reproducing some of the previous numerical or
qualitative results, such as spectral dimension flow. Our study should be
considered as a first step towards the construction of a heat kernel for curved
Ho\v{r}ava-Lifshitz geometries, which is an essential ingredient in the
spectral action approach to the construction of the Ho\v{r}ava-Lifshitz
gravity.


title: Vacuum energy in Kerr-AdS black holes

abstract:
  We compute the vacuum energy for Kerr black holes with anti-de Sitter (AdS)
asymptotics in dimensions $5\leq D\leq 9$ with all rotation parameters. The
calculations are carried out employing an alternative regularization scheme for
asymptotically AdS gravity, which considers supplementing the bulk action with
counterterms which are a given polynomial in the extrinsic and intrinsic
curvatures of the boundary (also known as Kounterterms). The Kerr-Schild form
of the rotating solutions enables us to identify the vacuum energy as coming
from the part of the metric that corresponds to global AdS spacetime written in
oblate spheroidal coordinates. We find that the zero-point energy for
higher-dimensional Kerr-AdS reduces to the one of Schwarzschild-AdS black hole
when all the rotation parameters are equal to each other, fact that is
well-known in five dimensions. We also sketch a compact expression for the
vacuum energy formula in terms of asymptotic quantities that might be useful to
extend the computations to higher odd dimensions.


title:
Measurement of the differential cross section of photon plus jet
  production in ppbar collisions at sqrt{s}=1.96 TeV

abstract:
  We study the process of associated photon and jet production, p+pbar -->
photon + jet + X, using 8.7 fb^-1 of integrated luminosity collected by the D0
detector at the Fermilab Tevatron Collider at a center-of-mass energy
sqrt{s}=1.96 TeV. Photons are reconstructed with rapidity |y^gamma| <1.0 or
1.5<|y^{gamma}| < 2.5 and transverse momentum pT^gamma GeV. The highest-p_T jet
is required to be in one of four rapidity regions up to |y^{jet}|< 3.2. For
each rapidity configuration we measure the differential cross sections in
pT_gamma separately for events with the same sign (y^{gamma} y^{jet}}>0) and
opposite sign (y^{gamma} y^{jet}<=0) of photon and jet rapidities. We compare
the measured triple differential cross sections, d^3 sigma / d pT_gamma
y^{gamma} y^{jet}, to next-to-leading order (NLO) perturbative QCD calculations
using different sets of parton distribution functions and to predictions from
the SHERPA and PYTHIA Monte Carlo event generators. The NLO calculations are
found to be in general agreement with the data, but do not describe all
kinematic regions.


title:
The Carbon Cycle as the Main Determinant of Glacial-Interglacial
  Transitions

abstract:
  An intriguing problem in climate science is the existence of Earth's glacial
cycles. We show that it is possible to generate these periodic changes in
climate by means of the Earth's carbon cycle as the main determinant factor.
The carbon exchange between the Ocean, the Continent and the Atmosphere is
modeled by means of a tridimensional Lotka-Volterra system and the resulting
atmospheric carbon cycle is used as the unique radiative forcing mechanism. It
is shown that the carbon dioxide (CO$_{2}$) and temperature anomaly curves,
which are thus obtained, have the same first-order structure as the 100 kyr
glacial--interglacial cycles depicted by the Vostok ice core data, reproducing
the asymmetries of rapid heating--slow cooling, and short interglacial--long
glacial ages.


title: The Upscattering of Ultracold Neutrons from the polymer $[C_6 H_{12}]_n$

abstract:
  It is generally accepted that the main cause of ultracold neutron (UCN)
losses in storage traps is the upscattering to the thermal energy range by
hydrogen adsorbed on the surface of the trap walls. However, the data on which
this conclusion is based are poor and contradictory. Here, we report a
measurement, performed at the Los Alamos National Laboratory UCN source, of the
average energy of the flux of upscattered neutrons after the interaction of UCN
with hydrogen bound in semicrystalline polymer PMP (tradename TPX),
[C$_{6}$H$_{12}$]$_n$. Our analysis, performed with the MCNP code based on the
application of the neutron scattering law to UCN upscattered by bound hydrogen
in semicrystalline polyethylene, [C$_{2}$H$_{4}$]$_n$, leads us to a flux
average energy value of 26$\pm3$ meV in contradiction with previously reported
experimental values of 10 to 13 meV and in agreement with the theoretical
models of neutron heating implemented in the MCNP code.


title:
Strong microwave absorption observed in dielectric La1.5Sr0.5NiO4
  nanoparticles

abstract:
  La$_{1.5}$Sr$_{0.5}$NiO$_4$ is well known to have a colossal dielectric
constant ($\varepsilon_R>10^7$). The La$_{1.5}$Sr$_{0.5}$NiO$_4$ nanoparticle
powder was prepared by a combinational method of solid state reaction and
high-energy ball milling. Magnetic measurements show that the material has a
very small magnetic moment and paramagnetic characteristic at room temperature.
The mixture of the nanoparticle powder (40% vol.) and paraffin (60% vol.)
coated in the form of flat layers of different thicknesses ($t$) exhibits
strong microwave absorption resonances in the 4-18 GHz range. The reflection
loss ($RL$) decreases with $t$ and reaches down to -36.7 dB for $t=3.0$ mm. The
impedance matching ($|Z|=Z_0=377$ $\Omega$), rather than the phase matching
mechanism, is found responsible for the resonance observed in the samples with
$1<t\leq3.0$ mm. Further increase of the thickness leads to $|Z|>Z_0$ at all
frequencies and a reduced absorption. The influence of non-metal backing is
also discussed. Our observation suggests that La$_{1.5}$Sr$_{0.5}$NiO$_4$
nanoparticles could be used as good fillers for high performance radar
absorbing material.


title: Spin ladders and quantum simulators for Luttinger liquids

abstract:
  Magnetic insulators have proven to be usable as quantum simulators for
itinerant interacting quantum systems. In particular the compound
(C$_{5}$H$_{12}$N)$_{2}$CuBr$_{4}$ (short (Hpip)$_{2}$CuBr$_{4}$) was shown to
be a remarkable realization of a Tomonaga-Luttinger liquid (TLL) and allowed to
quantitatively test the TLL theory. Substitution weakly disorders this class of
compounds and allows thus to use them to tackle questions pertaining to the
effect of disorder in TLL as well, such as the formation of the Bose glass. As
a first step in this direction we present in this paper a study of the
properties of the related (Hpip)$_{2}$CuCl$_{4}$ compound. We determine the
exchange couplings and compute the temperature and magnetic field dependence of
the specific heat, using a finite temperature Density Matrix Renormalization
group (DMRG) procedure. Comparison with the measured specific heat at zero
magnetic field confirms the exchange parameters and Hamiltonian for the
(Hpip)$_{2}$CuCl$_{4}$ compound, giving the basis needed to start studying the
disorder effects.


title:
MOJAVE. X. Parsec-Scale Jet Orientation Variations and Superluminal
  Motion in AGN

abstract:
  We describe the parsec-scale kinematics of 200 AGN jets based on 15 GHz VLBA
data obtained between 1994 Aug 31 and 2011 May 1. We present new VLBA 15 GHz
images of these and 59 additional AGN from the MOJAVE and 2 cm Survey programs.
Nearly all of the 60 most heavily observed jets show significant changes in
their innermost position angle over a 12 to 16 year interval, ranging from 10
deg to 150 deg on the sky, corresponding to intrinsic variations of ~0.5 deg to
~2 deg. The BL Lac jets show smaller variations than quasars. Roughly half of
the heavily observed jets show systematic position angle trends with time, and
20 show indications of oscillatory behavior. The time spans of the data sets
are too short compared to the fitted periods (5 to 12 y), however, to reliably
establish periodicity. The rapid changes and large jumps in position angle seen
in many cases suggest that the superluminal AGN jet features occupy only a
portion of the entire jet cross section, and may be energized portions of thin
instability structures within the jet. We have derived vector proper motions
for 887 moving features in 200 jets having at least five VLBA epochs. For 557
well-sampled features, there are sufficient data to additionally study possible
accelerations. We find that the moving features are generally non-ballistic,
with 70% of the well-sampled features showing either significant accelerations
or non-radial motions. Inward motions are rare (2% of all features), are slow
(<0.1 mas per y), are more prevalent in BL Lac jets, and are typically found
within 1 mas of the unresolved core feature. There is a general trend of
increasing apparent speed with distance down the jet for both radio galaxies
and BL Lac objects. In most jets, the speeds of the features cluster around a
characteristic value, yet there is a considerable dispersion in the
distribution. (abridged)


title:
Electron Spin Resonance in Quasi-One-Dimensional Quantum
  Antiferromagnets: Relevance of Weak Interchain Interactions

abstract:
  We discuss universal features on the electron spin resonance (ESR) of a
temperature-induced Tomonaga-Luttinger liquid phase in a wide class of weakly
coupled $S=1/2$ antiferromagnetic spin chains such as spin ladders, spin tubes
and three-dimensionally coupled spin chains. We show that the ESR linewidth of
various coupled chains increases with lowering temperature while the linewidth
of a single spin chain is typically proportional to temperature. This
broadening with lowering temperature is attributed to anisotropic interchain
interactions and has been indeed observed in several kinds of three-dimensional
(3D) magnets of weakly coupled spin chains above the 3D ordering temperature.
We demonstrate that our theory can account for anomalous behaviors of the
linewidths in an $S=1/2$ four-leg spin tube compound Cu$_2$Cl$_4 \cdot
$H$_8$C$_4$SO$_2$ (abbreviated to Sul-Cu$_2$Cl$_4$) and a three-dimensionally
coupled $S=1/2$ spin chain compound CuCl$_2\cdot 2$NC$_5$H$_5$.


title: Adjoint groups of $p$-nil rings and $p$-group automorphisms

abstract:
  We introduce a class of rings, namely the class of left or right $p$-nil
rings, for which the adjoint groups behave regularly. Every $p$-ring is close
to being left or right $p$-nil in the sense that it contains a large ideal
belonging to this class. Also their adjoint groups occur naturally as groups of
automorphisms of $p$-groups. These facts and some of their applications are
investigated in this paper.


title: Anomalous soft photon production from the induced currents in Dirac sea

abstract:
  The propagation of a high energy quark disturbs the confining QCD vacuum
inducing the currents in Dirac sea. Since quarks possess electric charge, these
induced vacuum quark currents act as a source of soft photon radiation. This
can lead to the enhancement of the soft photon production above the
expectations based on the charged hadron yields and the Low theorem. We
illustrate the phenomenon by using the exactly soluble 1+1 dimensional massless
Abelian gauge model that shares with QCD all of the ingredients involved in
this mechanism: confinement, chiral symmetry breaking, axial anomaly, and the
periodic $\theta$-vacuum. We show that the propagating quark throughout the
process of hadronization induces in the vacuum charged transition currents that
lead to a strong resonant enhancement of the soft photon yield; the Low theorem
however remains accurate in the limit of very soft momenta. We then construct
on the basis of our result a simple phenomenological model and apply it to the
soft photon production in the fragmentation of jets produced in $Z^0$ decays.
We find a qualitative agreement with the recent result from the DELPHI
Collaboration.


title:
Identification time-delayed fractional order chaos with functional
  extrema model via differential evolution

abstract:
  In this paper, a novel inversion mechanism of functional extrema model via
the differential evolution algorithms(DE), is proposed to exactly identify
time-delays fractional order chaos systems. With the functional extrema model,
the unknown time-delays, systematic parameters and fractional-orders of the
fractional chaos, are converted into independent variables of a non-negative
multiple modal functions' minimization, as a particular case of the functional
extrema model's minimization. And the objective of the model is to find their
optimal combinations by DE in the predefined intervals, such that the objective
functional is minimized. Simulations are done to identify two classical
time-delayed fractional chaos, Logistic and Chen system, both in cases with
noise and without. The experiments' results show that the proposed inversion
mechanism for time-delay fractional-order chaotic systems is a successful
methods, with the advantages of high precision and robustness.


title: Radio pulsar activity and the crustal Hall drift

abstract:
  Models of pulsar radio emission that are based on an inner accelerating
region require the existence of very strong and small scale surface magnetic
field structures at or near the canonical polar cap. The aim of this paper is
to identify a mechanism that creates such field structures and maintains them
over a pulsar's lifetime. The likely physical process that can create the
required 'magnetic spots' is the Hall drift occurring in the crust of a neutron
star. It is demonstrated, that the Hall drift can produce small scale strong
surface magnetic field anomalies (spots) on timescales of $10^4$ years by means
of non-linear interaction between poloidal and toroidal components of the
subsurface magnetic field. These anomalies are characterized by strengths of
about $10^{14}$ G and curvature radii of field lines of about $10^6$ cm, both
of which are fundamental for generation of observable radio emission.


title: Learning interactions through hierarchical group-lasso regularization

abstract:
  We introduce a method for learning pairwise interactions in a manner that
satisfies strong hierarchy: whenever an interaction is estimated to be nonzero,
both its associated main effects are also included in the model. We motivate
our approach by modeling pairwise interactions for categorical variables with
arbitrary numbers of levels, and then show how we can accommodate continuous
variables and mixtures thereof. Our approach allows us to dispense with
explicitly applying constraints on the main effects and interactions for
identifiability, which results in interpretable interaction models. We compare
our method with existing approaches on both simulated and real data, including
a genome wide association study, all using our R package glinternet.


title: Beukers-like proofs of irrationality for $\zeta{(2)}$ and $\zeta{(3)}$

abstract:
  In this note, I develop step-by-step proofs of irrationality for
$\,\zeta{(2)}\,$ and $\,\zeta{(3)}$. Though the proofs follow closely those
based upon unit square integrals proposed originally by Beukers, I introduce
some modifications which certainly will be useful for those interested in
understanding this kind of proof and/or trying to extend it to higher zeta
values, Catalan's constant, or other related numbers.


title: Gowers norms for singular measures

abstract:
  Gowers introduced the notion of uniformity norm $\|f\|_{U^k(G)}$ of a bounded
function $f:G\rightarrow\mathbb{R}$ on an abelian group $G$ in order to provide
a Fourier-theoretic proof of Szemeredi's Theorem, that is, that a subset of the
integers of positive upper density contains arbitrarily long arithmetic
progressions. Since then, Gowers norms have found a number of other uses, both
within and outside of Additive Combinatorics. The $U^k$ norm is defined in
terms of an operator $\triangle^k : L^{\infty}(G)\mapsto L^{\infty} (G^{k+1})$.
  In this paper, we introduce an analogue of the object $\triangle^k f$ when
$f$ is a singular measure on the torus $\mathbb{T}^d$, and similarly an object
$\|\mu\|_{U^k}$. We provide criteria for $\triangle^k \mu$ to exist, which
turns out to be equivalent to finiteness of $\||\mu|\|_{U^k}$, and show that
when $\mu$ is absolutely continuous with density $f$, then the objects which we
have introduced are reduced to the standard $\triangle^kf$ and
$\|f\|_{U^k(\mathbb{T})}$. We further introduce a higher-order inner product
between measures of finite $U^k$ norm and prove a Gowers-Cauchy-Schwarz
inequality for this inner product.


title:
Forward and backward helicity scattering coefficients for systems with
  discrete rotational symmetry

abstract:
  The forward and backward scattering off linear systems with discrete
rotational symmetries R_z (2{\pi} /n) with n $\ge$ 3 are shown to be restricted
by symmetry reasons. Along the symmetry axis, forward scattering can only be
helicity preserving and backward scattering can only be helicity flipping.
These restrictions do not exist for n < 3. If, in addition to the n $\ge$ 3
discrete rotational symmetry, the system has duality symmetry (obeys the
helicity conservation law), it will exhibit zero backscattering. The results
pinpoint the underlying symmetry reasons for some notable scattering properties
of R_z (2{\pi} /4) symmetric systems that have been reported in the
metamaterials and radar literature. Applications to planar metamaterials and
solar cells are briefly discussed.


title: Operator algebras with contractive approximate identities, III

abstract:
  We continue our study of operator algebras with contractive approximate
identities (cais). In earlier papers we have introduced and studied a new
notion of positivity in operator algebras, with an eye to extending certain
$C^*$-algebraic results and theories to more general algebras. In the first
part of this paper we do a more systematic development of this positivity and
its associated ordering, proving many foundational facts. In much of this it is
not necessary that the algebra have an approximate identity. In the second part
we study interesting examples of operator algebras with cais, which in
particular answer questions raised in previous papers in this series. Indeed
the present work solves almost all of the open questions raised in these
papers. Many of our results apply immediately to function algebras, but we will
not take the time to point these out, although most of these applications seem
new.


title: New models for two real scalar fields and their kinklike solutions

abstract:
  In this work we study the presence of kinks in models described by two real
scalar fields in bi-dimensional space-time. We generate new two-field models,
constructed from distinct but important one-field models, and we solve them
with techniques that we introduce in the current work. We illustrate the
results with several examples of current interest to high energy physics.


title:
Adaptive and Iterative Multi-Branch MMSE Decision Feedback Detection
  Algorithms for MIMO Systems

abstract:
  In this work, decision feedback (DF) detection algorithms based on multiple
processing branches for multi-input multi-output (MIMO) spatial multiplexing
systems are proposed. The proposed detector employs multiple cancellation
branches with receive filters that are obtained from a common matrix inverse
and achieves a performance close to the maximum likelihood detector (MLD).
Constrained minimum mean-squared error (MMSE) receive filters designed with
constraints on the shape and magnitude of the feedback filters for the
multi-branch MMSE DF (MB-MMSE-DF) receivers are presented. An adaptive
implementation of the proposed MB-MMSE-DF detector is developed along with a
recursive least squares-type algorithm for estimating the parameters of the
receive filters when the channel is time-varying. A soft-output version of the
MB-MMSE-DF detector is also proposed as a component of an iterative detection
and decoding receiver structure. A computational complexity analysis shows that
the MB-MMSE-DF detector does not require a significant additional complexity
over the conventional MMSE-DF detector, whereas a diversity analysis discusses
the diversity order achieved by the MB-MMSE-DF detector. Simulation results
show that the MB-MMSE-DF detector achieves a performance superior to existing
suboptimal detectors and close to the MLD, while requiring significantly lower
complexity.


title: Polymer-disordered liquid crystals: Susceptibility to electric field

abstract:
  When nematic liquid crystals are embedded in random polymer networks, the
disordered environment disrupts the long-range order, producing a glassy state.
If an electric field is applied, it induces large and fairly
temperature-independent orientational order. To understand the experiments, we
simulate a liquid crystal in a disordered polymer network, visualize the domain
structure, and calculate the response to a field. Furthermore, using an
Imry-Ma-like approach we predict the domain size and estimate the field-induced
order. The simulations and analytic results agree with each other, and suggest
how the materials can be optimized for electro-optic applications.


title:
On the mass assembly of low-mass galaxies in hydrodynamical simulations
  of structure formation

abstract:
  Cosmological hydrodynamical simulations are studied in order to analyse
generic trends for the stellar, baryonic and halo mass assembly of low-mass
galaxies (M_* < 3 x 10^10 M_sun) as a function of their present halo mass, in
the context of the Lambda-CDM scenario and common subgrid physics schemes. We
obtain that smaller galaxies exhibit higher specific star formation rates and
higher gas fractions. Although these trends are in rough agreement with
observations, the absolute values of these quantities tend to be lower than
observed ones since z~2. The simulated galaxy stellar mass fraction increases
with halo mass, consistently with semi-empirical inferences. However, the
predicted correlation between them shows negligible variations up to high z,
while these inferences seem to indicate some evolution. The hot gas mass in z=0
halos is higher than the central galaxy mass by a factor of ~1-1.5 and this
factor increases up to ~5-7 at z~2 for the smallest galaxies. The stellar,
baryonic and halo evolutionary tracks of simulated galaxies show that smaller
galaxies tend to delay their baryonic and stellar mass assembly with respect to
the halo one. The Supernova feedback treatment included in this model plays a
key role on this behaviour albeit the trend is still weaker than the one
inferred from observations. At z>2, the overall properties of simulated
galaxies are not in large disagreement with those derived from observations.


title: Coulomb interaction and valley-orbit coupling in Si quantum dots

abstract:
  The valley-orbit coupling in a few-electron Si quantum dot is expected to be
a function of its occupation number N. We study the spectrum of multivalley Si
quantum dots for 2 <= N <= 4, showing that, counterintuitively,
electron-electron interaction effects on the valley-orbit coupling are
negligible. For N=2 they are suppressed by valley interference, for N=3 they
vanish due to spinor overlaps, and for N = 4 they cancel between different
pairs of electrons. To corroborate our theoretical findings, we examine the
experimental energy spectrum of a few-electron metal-oxide-semiconductor
quantum dot. The measured spin-valley state filling sequence in a magnetic
field reveals that the valley-orbit coupling is definitively unaffected by the
occupation number.


title: Size bias for one and all

abstract:
  Size bias occurs famously in waiting-time paradoxes, undesirably in sampling
schemes, and unexpectedly in connection with Stein's method, tightness,
analysis of the lognormal distribution, Skorohod embedding, infinite
divisibility, and number theory. In this paper we review the basics and survey
some of these unexpected connections.


title: On positivity and roots in operator algebras

abstract:
  In earlier papers the second author and Charles Read have introduced and
studied a new notion of positivity for operator algebras, with an eye to
extending certain C*-algebraic results and theories to more general algebras.
The present paper consists of complements to some facts in the just mentioned
papers, concerning this notion of positivity. For example we prove a result on
the numerical range of products of the roots of commuting operators with
numerical range in a sector.


title: Some experimental tests of Tomonaga-Luttinger liquids

abstract:
  The Tomonaga-Luttinger-Liquid (TLL) has been the cornerstone of our
understanding of the properties of one dimensional systems. This universal set
of properties plays in one dimension, the same role than Fermi liquid plays for
the higher dimensional metals. I will give in these notes an overview of some
of the experimental tests that were made to probe such TLL physics. In
particular I will detail some of the recent experiments that were made in spin
systems and which provided remarkable quantitative tests of the TLL physics.


title:
A relative information approach to financial time series analysis using
  binary $N$-grams dictionaries

abstract:
  Here we present a novel approach to statistical analysis of financial time
series. The approach is based on $n$-grams frequency dictionaries derived from
the quantized market data. Such dictionaries are studied by evaluating their
information capacity using relative entropy. A specific quantization of
(originally continuous) financial data is considered: so called binary
quantization. Possible applications of the proposed technique include market
event study with the $n$-grams of higher information value. The finite length
of the input data presents certain computational and theoretical challenges
discussed in the paper. also, some other versions of a quantization are
discussed.


title:
Strain effects on the spin-orbit induced band structure splittings in
  monolayer MoS2 and graphene

abstract:
  The strain effects on the spin-orbit induced splitting of the valence band
maximum and conduction band minimum in monolayer MoS2 and the gap in graphene
are calculated using first-principles calculations. The dependence of these
splittings on the various symmetry types of strain is described by means of an
effective Hamiltonian based on the method of invariants and the parameters in
the model are extracted by fitting to the theory. These splittings are related
to acoustic phonon deformation potentials, or electron-phonon coupling matrix
elements which enter the spin-dependent scattering theory of conduction in
these materials.


title: Tachyon Perturbation on Two Dimensional Black Hole

abstract:
  We study the geometry of the two dimensional string theoretic black hole
under tachyonic perturbations. These perturbations are restricted to affect
only the metric and the dilaton, while other string theoretic excitations (like
the axion) are ignored. The metric and linearized dilaton perturbations are
determined to lowest non-trivial order of the tachyonic hair in the presence of
back reaction. We evaluate the Kretschmann scalar and argue that the horizon
does not become singular in the presence of tachyon perturbations (to the order
of our consideration). A closed-form solution of the allowed tachyon field and
that of the allowed tachyon potential emerges as a requirement of
self-consistency of our solution.


title:
Precision Measurements of Temperature and Chemical Potential of Quantum
  Gases

abstract:
  We investigate the sensitivity with which the temperature and the chemical
potential characterizing quantum gases can be measured. We calculate the
corresponding quantum Fisher information matrices for both fermionic and
bosonic gases. For the latter, particular attention is devoted to the situation
close to the Bose-Einstein condensation transition, which we examine not only
for the standard scenario in three dimensions, but also for generalized
condensation in lower dimensions, where the bosons condense in a subspace of
Hilbert space instead of a unique ground state, as well as condensation at
fixed volume or fixed pressure. We show that Bose Einstein condensation can
lead to sub-shot noise sensitivity for the measurement of the chemical
potential. We also examine the influence of interactions on the sensitivity in
three different models, and show that mean-field and contact interactions
deteriorate the sensitivity but only slightly for experimentally accessible
weak interactions.


title: On the $q$-log-convexity conjecture of Sun

abstract:
  In his study of Ramanujan-Sato type series for $1/\pi$, Sun introduced a
sequence of polynomials $S_n(q)$ as given by
$$S_n(q)=\sum\limits_{k=0}^n{n\choose k}{2k\choose k}{2(n-k)\choose n-k}q^k,$$
and he conjectured that the polynomials $S_n(q)$ are $q$-log-convex. By
imitating a result of Liu and Wang on generating new $q$-log-convex sequences
of polynomials from old ones, we obtain a sufficient condition for determining
the $q$-log-convexity of self-reciprocal polynomials. Based on this criterion,
we then give an affirmative answer to Sun's conjecture.


title: H-infinity Optimal Approximation for Causal Spline Interpolation

abstract:
  In this paper, we give a causal solution to the problem of spline
interpolation using H-infinity optimal approximation. Generally speaking,
spline interpolation requires filtering the whole sampled data, the past and
the future, to reconstruct the inter-sample values. This leads to non-causality
of the filter, and this becomes a critical issue for real-time applications.
Our objective here is to derive a causal system which approximates spline
interpolation by H-infinity optimization for the filter. The advantage of
H-infinity optimization is that it can address uncertainty in the input signals
to be interpolated in design, and hence the optimized system has robustness
property against signal uncertainty. We give a closed-form solution to the
H-infinity optimization in the case of the cubic splines. For higher-order
splines, the optimal filter can be effectively solved by a numerical
computation. We also show that the optimal FIR (Finite Impulse Response) filter
can be designed by an LMI (Linear Matrix Inequality), which can also be
effectively solved numerically. A design example is presented to illustrate the
result.


title:
Diagnosis of a New Neutral Gauge Boson at the LHC and ILC for Snowmass
  2013

abstract:
  A U(1)' or Z' is generic in many scenarios of physics beyond the Standard
Model, such as string theory compactifications, GUTs, extra-dimensions,
compositeness, dynamical electroweak symmetry breaking, dark-sector models,
etc. We study the potential of probing a TeV-scale Z' with electroweak
couplings in future experiments. In particular, we focus on two scenarios: (1)
If a Z' is discovered at the LHC, what is the potential of measuring its mass
and width and to distinguish between benchmark models utilizing various
observables, especially asymmetries, at a high luminosity LHC and the ILC. (2)
If the Z' is not accessible as a clear resonance signal, what is the exclusion
reach at the ILC.


title: Revisiting SWJ2000.6+3210 : A persistent Be X-ray pulsar ?

abstract:
  We present a detailed timing and spectral analysis of the Be X-ray binary
SWJ2000.6+3210 discovered by the BAT Galactic plane survey. Two Suzaku
observations of the source made at six months interval, reveal pulsations at ~
890s for both observations with a much weaker pulse fraction in the second one.
Pulsations are clearly seen in the energy band of 0.3-10 keV of XIS for both
observations and at high energies up to 40 keV for the second observation. The
broad band X-ray spectrum is consistent with a powerlaw and high energy cutoff
model along with a hot blackbody component. No change in spectral parameters is
detected between the observations. We have also analyzed several short
observations of the source with Swift/XRT and detected only a few percent
variation in flux around a mean value of 3:5 *10^{-11} erg cm^{-2} s^{-1}. The
results indicates that SWJ2000.6+3210 is a member of persistent Be X-ray
binaries which have the same broad characteristics as this source.


title:
Detailed analysis of the Bi-O pockets problem in
  $Bi_2Sr_2Ca_2Cu_3O_{10}$

abstract:
  The Bi-O pockets problem, namely, the appearance in theoretical ab initio
calculations of the electronic band structure of Bi-cuprates of a pocket of
states at the Fermi energy ($E_F$) that is attributed to states belonging to
the Bi-O plane is an issue that still calls for more study. The Bi-O pockets
are in contradiction with experiments. We have investigated the possible
reasons for the disagreement. We checked that by using the experimental lattice
and internal parameters without any optimization procedure, the Bi-O pockets do
not appear at $E_F$ in agreement with experiment. Nevertheless, as pointed out
by R. Kouba et al. [{\em Phys. Rev. B} {\bf 60}, 9321 (1999)] optimization is
compulsory to a band structure calculation that will describe appropriately the
electronic properties. But starting with the experimental parameters a further
optimization procedure previous to the actual ab initio calculation leads to
the Bi-O pockets. Doping with 25% of Pb they disappear. From the several
configurations that we have considered, we found two very simple ways in which
the Bi-O pockets disappear without avoiding an optimization procedure previous
to the calculation and without including a doping of any kind. In this paper,
we report the effect of the slight displacement of the oxygen atom associated
to the Sr-plane (O3) in the electronic properties of $Bi_2Sr_2Ca_2Cu_3O_{10}$
(Bi-2223) with tetragonal structure ($I4/mmm$) using the Local Density
Approximation (LDA). The slight displacement is performed after the system has
been optimized. We determined the intervals of the O3 atomic positions for
which calculations of the band structures show that the Bi-O bands emerge
towards higher energies in agreement with the experimental results, thereby
solving the Bi-O pockets problem (continue).


title: Discrete Extremal Length and Cube Tilings in Finite Dimensions

abstract:
  Extremal length is a conformal invariant that transfers naturally to the
discrete setting, giving square tilings as a natural combinatorial analog of
conformal mappings. Recent work by S. Hersonsky has explored generalizing these
ideas to three-dimensional cube tilings. The connections between discrete
extremal length and cube tilings survive the dimension jump, but a condition
called the triple intersection property is needed to generalize existence
arguments. We show that this condition is too strong to realize a tiling, thus
showing that discrete conformal mappings are far more limited in dimension
three, mirroring the classical phenomenon. We also generalize results about
discrete extremal length beyond dimension three and introduce some necessary
conditions for cube tilings.


title:
On the detection and tracking of space debris using the Murchison
  Widefield Array. I. Simulations and test observations demonstrate feasibility

abstract:
  The Murchison Widefield Array (MWA) is a new low frequency interferomeric
radio telescope. The MWA is the low frequency precursor to the Square Kilometre
Array (SKA) and is the first of three SKA precursors to be operational,
supporting a varied science mission ranging from the attempted detection of the
Epoch of Reionisation to the monitoring of solar flares and space weather. We
explore the possibility that the MWA can be used for the purposes of Space
Situational Awareness (SSA). In particular we propose that the MWA can be used
as an element of a passive radar facility operating in the frequency range 87.5
- 108 MHz (the commercial FM broadcast band). In this scenario the MWA can be
considered the receiving element in a bi-static radar configuration, with FM
broadcast stations serving as non-cooperative transmitters. The FM broadcasts
propagate into space, are reflected off debris in Earth orbit, and are received
at the MWA. The imaging capabilities of the MWA can be used to simultaneously
detect multiple pieces of space debris, image their positions on the sky as a
function of time, and provide tracking data that can be used to determine
orbital parameters. Such a capability would be a valuable addition to
Australian and global SSA assets, in terms of southern and eastern hemispheric
coverage. We provide a feasibility assessment of this proposal, based on simple
calculations and electromagnetic simulations that shows the detection of
sub-metre size debris should be possible (debris radius of >0.5 m to ~1000 km
altitude). We also present a proof-of-concept set of observations that
demonstrate the feasibility of the proposal, based on the detection and
tracking of the International Space Station via reflected FM broadcast signals
originating in south-west Western Australia. These observations broadly
validate our calculations and simulations.


title:
H-infinity Design of Periodically Nonuniform Interpolation and
  Decimation for Non-Band-Limited Signals

abstract:
  In this paper, we consider signal interpolation of discrete-time signals
which are decimated nonuniformly. A conventional interpolation method is based
on the sampling theorem, and the resulting system consists of an ideal filter
with complex-valued coefficients. While the conventional method assumes band
limitation of signals, we propose a new method by sampled-data H-infinity
optimization. By this method, we can remove the band-limiting assumption and
the optimal filter can be with real-valued coefficients. Moreover, we show that
without band-limited assumption, there can be the optimal decimation patterns
among ones with the same ratio. By examples, we show the effectiveness of our
method.


title: A Modification on the Ivanenko-Landau-K\"ahler Equation

abstract:
  In this paper, we illustrated one scenario to modify the
Ivanenko-Landau-K\"ahler equation. Since Ivanenko and Landau introduced the
equation in 1928, the equation has been regarded as having a certain role as a
fermion in particular in the discrete Lattice. Also, although it correctly is
formulated as an alternative classical field equation by the Ideal projection
for the Dirac equation in the Minkowski space-time, so does it only in that
flat geometry. I. M. Benn and R. W. Tucker in 1985 and Yu. N. Obukhov and S. N.
Solodukhin in 1994 suggested two resolutions respectively. They modified the
equation in order for it to make senses as an alternative for the Dirac
equation in the general space-time. This paper advances a still another
approach, however in the Minkowski space yet, as the first stage toward the
generalization. Two ingredients for the modifications are essential. One is the
restriction of the space of anti-symmetric tensor field to only its
subalgebras, not to its Ideals. The other is the modification on the mass term
for the equation to mean the eigenvalue problem generating physical states. The
Vector U(1) and the Axial U(1) symmetries built in the modified equation are
described.


title:
Exploring Boolean and Non-Boolean Computing Applications of Spin Torque
  Devices

abstract:
  In this paper we discuss the potential of emerging spintorque devices for
computing applications. Recent proposals for spinbased computing schemes may be
differentiated as all-spin vs. hybrid, programmable vs. fixed, and, Boolean vs.
non-Boolean. All spin logic-styles may offer high area-density due to small
form-factor of nano-magnetic devices. However, circuit and system-level design
techniques need to be explored that leverage the specific spin-device
characteristics to achieve energy-efficiency, performance and reliability
comparable to those of CMOS. The non-volatility of nanomagnets can be exploited
in the design of energy and area-efficient programmable logic. In such
logic-styles, spin-devices may play the dual-role of computing as well as
memory-elements that provide field-programmability. Spin-based threshold logic
design is presented as an example (dynamic resisitve threshold logic and
magnetic threshold logic). Emerging spintronic phenomena may lead to ultralow-
voltage, current-mode, spin-torque switches that can offer attractive computing
capabilities, beyond digital switches. Such devices may be suitable for
non-Boolean data-processing applications which involve analog processing.
Integration of such spin-torque devices with charge-based devices like CMOS and
resistive memory can lead to highly energy-efficient information processing
hardware for applications like pattern-matching, neuromorphic-computing,
image-processing and data-conversion. Towards the end, we discuss the
possibility of applying emerging spin-torque switches in the design of
energy-efficient global interconnects, for future chip multiprocessors.


title: On the renormalization of the Gibbons-Hawking boundary term

abstract:
  The bulk (Einstein-Hilbert) and boundary (Gibbons-Hawking) terms in the
gravitational action are generally renormalized differently when integrating
out quantum fluctuations. The former is affected by nonminimal couplings, while
the latter is affected by boundary conditions. We use the heat kernel method to
analyze this behavior for a nonminimally coupled scalar field, the Maxwell
field, and the graviton field. Allowing for Robin boundary conditions, we
examine in which cases the renormalization preserves the ratio of boundary and
bulk terms required for the effective action to possess a stationary point. The
implications for field theory and black hole entropy computations are
discussed.


title: Closed-Loop Beam Alignment for Massive MIMO Channel Estimation

abstract:
  Training sequences are designed to probe wireless channels in order to obtain
channel state information for block-fading channels. Optimal training sounds
the channel using orthogonal beamforming vectors to find an estimate that
optimizes some cost function, such as mean square error. As the number of
transmit antennas increases, however, the training overhead becomes
significant. This creates a need for alternative channel estimation schemes for
increasingly large transmit arrays. In this work, we relax the orthogonal
restriction on sounding vectors. The use of a feedback channel after each
forward channel use during training enables closed-loop sounding vector design.
A misalignment cost function is introduced, which provides a metric to
sequentially design sounding vectors. In turn, the structure of the sounding
vectors aligns the transmit beamformer with the true channel direction, thereby
increasing beamforming gain. This beam alignment scheme for massive MIMO is
shown to improve beamforming gain over conventional orthogonal training for a
MISO channel.


title:
Multivalued backward doubly stochastic differential equations with time
  delayed coefficients

abstract:
  In this paper, we deal with a class of multivalued backward doubly stochastic
differential equations with time delayed coefficients. Based on a slight
extension of the existence and uniqueness of solutions for backward doubly
stochastic differential equations with time delayed coefficients, we establish
the existence and uniqueness of solutions for these equations by means of
Yosida approximation.


title:
High-Performance, High-Index-Contrast Chalcogenide Glass Photonics on
  Silicon and Unconventional Non-planar Substrates

abstract:
  This paper reports a versatile, roll-to-roll and backend compatible technique
for the fabrication of high-index-contrast photonic structures on both silicon
and plastic substrates. The fabrication technique combines low-temperature
chalcogenide glass film deposition and resist-free single-step thermal
nanoimprint to process low-loss (1.6 dB/cm), sub-micron single-mode waveguides
with a smooth surface finish using simple contact photolithography. Using this
approach, the first chalcogenide glass micro-ring resonators are fabricated by
thermal nanoimprint. The devices exhibit an ultra-high quality-factor of
400,000 near 1550 nm wavelength, which represents the highest value reported in
chalcogenide glass micro-ring resonators. Furthermore, sub-micron nanoimprint
of chalcogenide glass films on non-planar plastic substrates is demonstrated,
which establishes the method as a facile route for monolithic fabrication of
high-index-contrast devices on a wide array of unconventional substrates.


title: Split general quasi-variational inequality problem

abstract:
  In this paper, we introduce a split general quasi-variational inequality
problem which is a natural extension of split variational inequality problem,
quasi-variational and variational inequality problems in Hilbert spaces. Using
projection method, we propose an iterative algorithm for the split general
quasi-variational inequality problem and discuss some its special cases.
Further, we discuss the convergence criteria of these iterative algorithms. The
results presented in this paper generalize, unify and improve the previously
known many results for the quasi-variational and variational inequality
problems.


title:
Memory, Bias and Correlations in Bidirectional Transport of Molecular
  Motor-driven Cargoes

abstract:
  Molecular motors are specialized proteins which perform active, directed
transport of cellular cargoes on cytoskeletal filaments. In many cases, cargo
motion powered by motor proteins is found to be bidirectional, and may be
viewed as a biased random walk with fast unidirectional runs interspersed with
slow `tug-of-war' states. The statistical properties of this walk are not known
in detail, and here, we study memory and bias, as well as directional
correlations between successive runs in bidirectional transport. We show, based
on a study of the direction reversal probabilities of the cargo using a purely
stochastic (tug-of-war) model, that bidirectional motion of cellular cargoes
is, in general, a correlated random walk. In particular, while the motion of a
cargo driven by two oppositely pulling motors is a Markovian random walk,
memory of direction appears when multiple motors haul the cargo in one or both
directions. In the latter case, the Markovian nature of the underlying single
motor processes is hidden by internal transitions between degenerate run and
pause states of the cargo. Interestingly, memory is found to be a non-monotonic
function of the number of motors. Stochastic numerical simulations of the
tug-of-war model support our mathematical results and extend them to
biologically relevant situations.


title: The Hopf structure of some dual operator algebras

abstract:
  We study the Hopf structure of a class of dual operator algebras
corresponding to certain semigroups. This class of algebras arises in dilation
theory, and includes the noncommutative analytic Toeplitz algebra and the
multiplier algebra of the Drury-Arveson space, which correspond to the free
semigroup and the free commutative semigroup respectively. The preduals of the
algebras in this class naturally form Hopf (convolution) algebras. The original
algebras and their preduals form (non-self-adjoint) dual Hopf algebras in the
sense of Effros and Ruan. We study these algebras from this perspective, and
obtain a number of results about their structure.


title:
Copious Amounts of Hot and Cold Dust Orbiting the Main Sequence A-type
  Stars HD 131488 and HD 121191

abstract:
  We report two new dramatically dusty main sequence stars: HD 131488 (A1V) and
HD 121191 (A8V). HD 131488 is found to have substantial amounts of dust in its
terrestrial planet zone (L_IR/L_bol~4x10^-3), cooler dust further out in its
planetary system, and an unusual mid-infrared spectral feature. HD 121191 shows
terrestrial planet zone dust (L_IR/L_bol~2.3x10^-3), hints of cooler dust, and
shares the unusual mid-infrared spectral shape identified in HD 131488. These
two stars belong to sub-groups of the Scorpius-Centaurus OB association and
have ages of ~10 Myr. HD 131488 and HD 121191 are the dustiest main sequence
A-type stars currently known. Early-type stars that host substantial inner
planetary system dust are thus far found only within the age range of 5-20 Myr.


title:
The Formation of Population III Stars in Gas Accretion Stage: Effects of
  Magnetic Fields

abstract:
  The formation of Population III stars is investigated using resistive
magnetohydrodynamic simulations. Starting from a magnetized primordial
prestellar cloud, we calculate the cloud evolution several hundreds of years
after first protostar formation, resolving the protostellar radius. When the
natal minihalo field strength is weaker than B \lesssim 10^-13 (n/1 cm^-3)^-2/3
G (n is the hydrogen number density), magnetic effects can be ignored. In this
case, fragmentation occurs frequently and a stellar cluster forms, in which
stellar mergers and mass exchange between protostars contribute to the mass
growth of these protostars. During the early gas accretion phase, the most
massive protostar remains near the cloud centre, whereas some of the less
massive protostars are ejected. The magnetic field significantly affects
Population III star formation when B_amb \gtrsim 10^-12 (n/1 cm^-3)^-2/3 G. In
this case, because the angular momentum around the protostar is effectively
transferred by both magnetic braking and protostellar jets, the gas falls
directly onto the protostar without forming a disk, and only a single massive
star forms. In addition, a massive binary stellar system appears when B_amb
\sim 10^-12 (n/1cm^-3)^-2/3 G. Therefore, the magnetic field determines the end
result of the formation process (cluster, binary or single star) for Population
III stars. Moreover, no persistent circumstellar disk appears around the
protostar regardless of the magnetic field strength, which may influence the
further evolution of Population III stars.


title:
Rigorous analysis of highly tunable cylindrical Transverse Magnetic mode
  re-entrant cavities

abstract:
  Cylindrical re-entrant cavities are unique three-dimensional structures that
resonate with their electric and magnetic fields in separate parts of the
cavity. To further understand these devices, we undertake rigorous analysis of
the properties of the resonance using in-house developed Finite Element Method
(FEM) software capable of dealing with small gap structures of extreme aspect
ratio. Comparisons between the FEM method and experiments are consistent and we
illustrate where predictions using established lumped element models work well
and where they are limited. With the aid of the modeling we design a highly
tunable cavity that can be tuned from 2 GHz to 22 GHz just by inserting a post
into a fixed dimensioned cylindrical cavity. We show this is possible as the
mode structure transforms from a re-entrant mode during the tuning process to a
standard cylindrical Transverse Magnetic (TM) mode.


title: Photometrically Triggered Keck Spectroscopy of Fermi BL Lac Objects

abstract:
  We report on Keck spectra of ten Fermi blazars. J0622+3326, previously
unobserved, is shown to be a flat-spectrum radio quasar at redshift z=1.062.
The others are known BL Lac-type objects that have resisted previous attempts
to secure redshifts. Using a photometric monitoring campaign with the 0.76 m
Katzman Automatic Imaging Telescope at Lick Observatory, we identified epochs
when the relativistic jet emission was fainter than usual, thus triggering the
Keck spectroscopy. This strategy gives improved sensitivity to stars and
ionized gas in the host galaxy, thereby providing improved redshift constraints
for seven of these sources.


title:
A (7/2)-Approximation Algorithm for Guarding Orthogonal Art Galleries
  with Sliding Cameras

abstract:
  Consider a sliding camera that travels back and forth along an orthogonal
line segment $s$ inside an orthogonal polygon $P$ with $n$ vertices. The camera
can see a point $p$ inside $P$ if and only if there exists a line segment
containing $p$ that crosses $s$ at a right angle and is completely contained in
$P$. In the minimum sliding cameras (MSC) problem, the objective is to guard
$P$ with the minimum number of sliding cameras. In this paper, we give an
$O(n^{5/2})$-time $(7/2)$-approximation algorithm to the MSC problem on any
simple orthogonal polygon with $n$ vertices, answering a question posed by Katz
and Morgenstern (2011). To the best of our knowledge, this is the first
constant-factor approximation algorithm for this problem.


title:
Decoherence of quantum gates based on Aharonov-Anandan phases in a
  multistep scheme

abstract:
  We study quantum decoherence of single-qubit and two-qubit Aharonov-Anandan
(AA) geometric phase gates realized in a multistep scheme. Each AA gate is also
compared with the dynamical phase gate performing the same unitary
transformation within the same time period and coupled with the same
environment, which is modeled as harmonic oscillators. It is found that the
fidelities and the entanglement protection of the AA phase gates are enhanced
by the states being superpositions of different eigenstates of the
environmental coupling, and the noncommutativity between the qubit interaction
and the environmental coupling.


title:
Continuous phase transition from N\'eel state to Z_2 spin liquid state
  on a square lattice

abstract:
  Recent numerical studies of the $J_1$-$J_2$ model on a square lattice suggest
a possible continuous phase transition between the N\'eel state and a gapped
spin-liquid state with Z$_2$ topological order. We show that such a phase
transition can be realized through two steps: First bring the N\'eel state to
the U(1) deconfined quantum critical point, which has been studied in the
context of N\'eel -- valence bond solid (VBS) state phase transition. Then
condense the spinon pair -- skyrmion/antiskyrmion bound state, which carries
both gauge charge and flux of the U(1) gauge field emerging at the deconfined
quantum critical point. We also propose a Schwinger boson projective wave
function to realize such a Z$_2$ spin liquid state and find that it has a
relatively low variational energy ($-0.4893J_1$/site) for the $J_1$-$J_2$ model
at $J_2=0.5J_1$. The spin liquid state we obtain breaks the fourfold rotational
symmetry of the square lattice and therefore is a nematic spin liquid state.
This direct continuous phase transition from the N\'eel state to a spin liquid
state may be realized in the $J_1$-$J_2$ model, or the anisotropic
$J_{1x}$-$J_{1y}$-$J_2$ model.


title:
Observation of a charged charmoniumlike structure in $e^+e^- \to (D^{*}
  \bar{D}^{*})^{\pm} \pi^\mp$ at $\sqrt{s}=4.26$GeV

abstract:
  We study the process $e^+e^- \to (D^{*} \bar{D}^{*})^{\pm} \pi^\mp$ at a
center-of-mass energy of 4.26GeV using a 827pb$^{-1}$ data sample obtained with
the BESIII detector at the Beijing Electron Positron Collider. Based on a
partial reconstruction technique, the Born cross section is measured to be
$(137\pm9\pm15)$pb. We observe a structure near the $(D^{*} \bar{D}^{*})^{\pm}$
threshold in the $\pi^\mp$ recoil mass spectrum, which we denote as the
$Z^{\pm}_c(4025)$. The measured mass and width of the structure are
$(4026.3\pm2.6\pm3.7)$MeV/c$^2$ and $(24.8\pm5.6\pm7.7)$MeV, respectively. Its
production ratio $\frac{\sigma(e^+e^-\to Z^{\pm}_c(4025)\pi^\mp \to (D^{*}
\bar{D}^{*})^{\pm} \pi^\mp)}{\sigma(e^+e^-\to (D^{*} \bar{D}^{*})^{\pm}
\pi^\mp)}$ is determined to be $0.65\pm0.09\pm0.06$. The first uncertainties
are statistical and the second are systematic.


title:
The Circumnuclear Star Formation Environment of NGC 6946: Br-gamma and
  H2 Results from Keck Integral Field Spectroscopy

abstract:
  We present a 3-dimensional data cube of the K band continuum and the
Br-gamma, H2 S(0) and S(1) lines within the central 18.5" x 13.8" (520 pc x 390
pc) region of NGC 6946. Data were obtained using OSIRIS, a near-infrared
Integral Field Unit at Keck Observatory, with Laser Guide Star Adaptive Optics.
The 0.3" resolution allows us to investigate the stellar bulge and the forming
star clusters in the nuclear region on 10 parsec scales. We detect giant HII
regions associated with massive young star clusters in the nuclear spiral/ring
(R ~ 30pc) and in the principal shocks along the nuclear bar. Comparisons of
the Br-gamma fluxes with Pa-alpha line emission and radio continuum indicate
A_K ~ 3, A_V ~ 25 for the nuclear star forming regions. The most luminous HII
regions are restricted to within 70pc of the center, despite the presence of
high gas columns at larger radii (R ~ 200pc). H2 emission is restricted to
clouds within R ~ 60pc of the center, and in this sense resembles the
distribution of the HCN line emission. We propose that gas-assisted migration
of the young star clusters is contributing to the buildup of the nuclear bar
and nuclear star cluster (R < 30pc) in this galaxy.


title:
An efficient ant based qos aware intelligent temporally ordered routing
  algorithm for manets

abstract:
  A Mobile Ad hoc network (MANET) is a self configurable network connected by
wireless links. This type of network is only suitable for temporary
communication links as it is infrastructure-less and there is no centralised
control. Providing QoS aware routing is a challenging task in this type of
network due to dynamic topology and limited resources. The main purpose of QoS
aware routing is to find a feasible path from source to destination which will
satisfy two or more end to end QoS constrains. Therefore, the task of designing
an efficient routing algorithm which will satisfy all the quality of service
requirements and be robust and adaptive is considered as a highly challenging
problem. In this work we have designed a new efficient and energy aware
multipath routing algorithm based on ACO framework, inspired by the behaviours
of biological ants. Basically by considering QoS constraints and artificial
ants we have designed an intelligent version of classical Temporally Ordered
Routing Algorithm (TORA) which will increase network lifetime and decrease
packet loss and average end to end delay that makes this algorithm suitable for
real time and multimedia applications.


title:
Controllable optical bistability based on photons and phonons in a
  two-mode optomechanical system

abstract:
  We explore theoretically the bistable behavior of intracavity photon number
in a two-mode cavity optomechanical system, where two cavity modes are coupled
to a common mechanical resonator. When the two cavity modes are driven by two
pump laser beams, respectively, we find that the optical bistability can be
controlled by tuning the power and frequency of the pump beams. The common
interaction to a mechanical mode enables one to control the bistable behavior
in one cavity by adjusting the pump laser beam driving another cavity. We also
show that both branches of optical bistability at photon numbers below unity
can be observed in this two-mode optomechanical system. This phenomenon can
find potential applications in controllable optical switch.


title:
Maximum-likelihood estimation for diffusion processes via closed-form
  density expansions

abstract:
  This paper proposes a widely applicable method of approximate
maximum-likelihood estimation for multivariate diffusion process from
discretely sampled data. A closed-form asymptotic expansion for transition
density is proposed and accompanied by an algorithm containing only basic and
explicit calculations for delivering any arbitrary order of the expansion. The
likelihood function is thus approximated explicitly and employed in statistical
estimation. The performance of our method is demonstrated by Monte Carlo
simulations from implementing several examples, which represent a wide range of
commonly used diffusion models. The convergence related to the expansion and
the estimation method are theoretically justified using the theory of Watanabe
[Ann. Probab. 15 (1987) 1-39] and Yoshida [J. Japan Statist. Soc. 22 (1992)
139-159] on analysis of the generalized random variables under some standard
sufficient conditions.


title:
Inadmissibility of the best equivariant predictive density in the
  unknown variance case

abstract:
  In this work, we are concerned with the estimation of the predictive density
of a Gaussian random vector where both the mean and the variance are unknown.
In such a context, we prove the inadmissibility of the best equivariant
predictive density under the Kullback-Leibler risk in a nonasymptotic
framework. Our result stands whatever the dimension d of the vector is, even
when d<=2, which can be somewhat surprising compared to the known variance
setting. We also propose a class of priors leading to a Bayesian predictive
density that dominates the best equivariant one. Throughout the article, we
give several elements that we believe are useful for establishing the parallel
between the prediction and the estimation problems, as it was done in the known
variance framework.


title: AIC, Cp and estimators of loss for elliptically symmetric distributions

abstract:
  In this article, we develop a modern perspective on Akaike's Information
Criterion and Mallows' Cp for model selection. Despite the diff erences in
their respective motivation, they are equivalent in the special case of
Gaussian linear regression. In this case they are also equivalent to a third
criterion, an unbiased estimator of the quadratic prediction loss, derived from
loss estimation theory. Our first contribution is to provide an explicit link
between loss estimation and model selection through a new oracle inequality. We
then show that the form of the unbiased estimator of the quadratic prediction
loss under a Gaussian assumption still holds under a more general
distributional assumption, the family of spherically symmetric distributions.
One of the features of our results is that our criterion does not rely on the
speci ficity of the distribution, but only on its spherical symmetry. Also this
family of laws o ffers some dependence property between the observations, a
case not often studied.


title:
Building non commutative spacetimes at the Planck length for Friedmann
  flat cosmologies

abstract:
  We propose physically motivated spacetime uncertainty relations (STUR) for
flat Friedmann-Lema\^{i}tre cosmologies. We show that the physical features of
these STUR crucially depend on whether a particle horizon is present or not. In
particular, when this is the case we deduce the existence of a maximal value
for the Hubble rate (or equivalently for the matter density), thus providing an
indication that quantum effects may rule out a pointlike big bang singularity.
Finally, we costruct a concrete realisation of the corresponding quantum
Friedmann spacetime in terms of operators on a Hilbert space.


title: Large distortion dimension reduction using random variable

abstract:
  Consider a random matrix $H:\mathbb{R}^n\longrightarrow\mathbb{R}^m$. Let
$D\geq2$ and let $\{W_l\}_{l=1}^{p}$ be a set of $k$-dimensional affine
subspaces of $\mathbb{R}^n$. We ask what is the probability that for all $1\leq
l\leq p$ and $x,y\in W_l$, \[
  \|x-y\|_2\leq\|Hx-Hy\|_2\leq D\|x-y\|_2. \] We show that for
$m=O\big(k+\frac{\ln{p}}{\ln{D}}\big)$ and a variety of different classes of
random matrices $H$, which include the class of Gaussian matrices, existence is
assured and the probability is very high. The estimate on $m$ is tight in terms
of $k,p,D$.


title: HI Absorption Toward HII Regions at Small Galactic Longitudes

abstract:
  We make a comprehensive study of HI absorption toward HII regions located
within Galactic longitudes less than 10 degrees. Structures in the extreme
inner Galaxy are traced using the longitude-velocity space distribution of this
absorption. We find significant HI absorption associated with the Near and Far
3kpc Arms, the Connecting Arm, Banias Clump 1 and the H I Tilted Disk. We also
constrain the line of sight distances to HII regions, by using HI absorption
spectra together with the HII region velocities measured by radio recombination
lines.


title:
Intrinsic Solar System decoupling of a scalar-tensor theory with a
  universal coupling between the scalar field and the matter Lagrangian

abstract:
  In this communication, we present a class of Brans-Dicke-like theories with a
universal coupling between the scalar field and the matter Lagrangian. We show
this class of theories naturally exhibits a decoupling mechanism between the
scalar field and matter. As a consequence, this coupling leads to almost the
same phenomenology as general relativity in the Solar System: the trajectories
of massive bodies and the light propagation differ from general relativity only
at the second post-Newtonian order. Deviations from general relativity are
beyond present detection capabilities. However, this class of theories predicts
a deviation of the gravitational redshift at a level detectable by the future
ACES and STE/QUEST missions.


title: Network-based multivariate gene-set testing

abstract:
  The identification of predefined groups of genes ("gene-sets") which are
differentially expressed between two conditions ("gene-set analysis", or GSA)
is a very popular analysis in bioinformatics. GSA incorporates biological
knowledge by aggregating over genes that are believed to be functionally
related. This can enhance statistical power over analyses that consider only
one gene at a time. However, currently available GSA approaches are all based
on univariate two-sample comparison of single genes. This means that they
cannot test for differences in covariance structure between the two conditions.
Yet interplay between genes is a central aspect of biological investigation and
it is likely that such interplay may differ between conditions. This paper
proposes a novel approach for gene-set analysis that allows for truly
multivariate hypotheses, in particular differences in gene-gene networks
between conditions. Testing hypotheses concerning networks is challenging due
the nature of the underlying estimation problem. Our starting point is a
recent, general approach for high-dimensional two-sample testing. We refine the
approach and show how it can be used to perform multivariate, network-based
gene-set testing. We validate the approach in simulated examples and show
results using high-throughput data from several studies in cancer biology.