title:
Superconductor/ferromagnet heterostructures exhibit potential for
  significant reduction of hysteretic losses

abstract:
  First experimental observations of the ferromagnetic shielding effect in
high-Tc superconducting coated conductors were carried out. Experimental
results were compared to simulations calling upon finite-element calculations
based on the H-formulation of Maxwell equations to model superconducting strips
with ferromagnetic shields. Samples of copper-stabilized coated conductors were
electroplated with nickel shields and afterwards characterized. Both externally
applied oscillating transverse magnetic fields as well as transport currents
were studied. Having observed promising gains with respect to the reduction of
ac losses in both cases, we further investigated the potential of ferromagnetic
shielding. The numerical model was able to reproduce and also predict
experimental results very well and will serve as an indispensable tool to
determine the potential of soft ferromagnetic materials to significantly reduce
hysteretic losses.


title: Detectability of small-scale magnetic fields in early-type stars

abstract:
  Strong, globally-organized magnetic fields are found for a small fraction of
O, B, and A stars. At the same time, many theoretical and indirect
observational studies suggested ubiquitous presence of weak localized magnetic
fields at the surfaces of massive stars. However, no direct detections of such
fields have been reported yet. We have carried out the first comprehensive
theoretical investigation of the spectropolarimetric observational signatures
of the structured magnetic fields. These calculations are applied to interpret
null results of the recent magnetic surveys of massive stars. The intensity and
circular polarization spectra of early-type stars are simulated using detailed
polarized radiative transfer calculations with LTE model atmospheres. Similar
to observational analyses, the mean Stokes I and V line profiles are obtained
by applying a multi-line averaging technique. Different spectropolarimetric
observables are examined for multiple realizations of randomly distributed
radial magnetic field spots with different spatial scales. We characterize the
amplitude of the circular polarization profiles and the mean longitudinal
magnetic field as a function of magnetic spot sizes. The dependence of these
observables on the effective temperature, projected rotational velocity, and
inclination angle is also investigated. Using results of the recently completed
Magnetism in Massive Stars (MiMeS) survey, we derive upper limits on the
small-scale magnetic fields compatible with the MiMeS non-detections. According
to our simulations, existing spectropolarimetric observations of sharp-lined
massive stars rule out the presence of the small-scale fields stronger than
50-250 G, depending on the typical spot sizes. For broad-lined stars, the
observations constrain such fields to be below approximately 1 kG.


title: A Posteriori Transit Probabilities

abstract:
  Typically, when estimating the prior transit probability, one assumes a
uniform distribution for the cosine of the inclination angle i of the
companion's orbit, which yields the familiar estimate of ~R_*/a. However, the
posterior transit probability depends not only on the prior probability
distribution of i but also on the prior probability distribution of the
companion mass M_c. In general, the posterior can be larger or smaller than the
prior transit probability. We derive analytic expressions for the posterior
transit probability assuming a power-law form for the distribution of true
masses with exponent alpha. For low transit probabilities, these probabilities
reduce to a constant multiplicative factor of the corresponding prior transit
probability. The prior and posterior probabilities are equal for alpha = -1,
whereas the posterior transit probability is ~1.5 times larger and ~4/pi larger
for for alpha = -3 and alpha = -2, but is less than the prior for alpha >= 0,
and can be arbitrarily small for alpha > 1. We also calculate the posterior
transit probability in different mass regimes for two physically-motivated mass
distributions of companions around Sun-like stars, finding that the posterior
is likely higher for Super-Earths, Neptunes and Super-Jupiters. We therefore
suggest that companions with minimum masses in these regimes might be
better-than-expected targets for transit follow-up, and we identify promising
targets from RV-detected planets in the literature.


title: Cosmic Clocks

abstract:
  In a perturbed Universe, comoving tracers on a two-dimensional surface of
constant observed redshift are at different proper time since the Big Bang. For
tracers whose age is known independently, one can measure these perturbations
of the proper time. Examples of such sources include cosmic events which only
happen during a short period of cosmic history, as well as evolving standard
candles and standard rulers. In this paper we derive a general gauge-invariant
linear expression for this perturbation in terms of space-time perturbations.
As an example, we show that the observed temperature perturbations of the
cosmic microwave background (CMB) on large scales are exactly given by these
proper time perturbations. Together with the six ruler perturbations derived in
Schmidt and Jeong (2012), this completes the set of independent observables
which can be measured with standard rulers and candles.


title:
The 300km/s stellar stream near Segue 1: Insights From high-resolution
  spectroscopy of its brightest star

abstract:
  We present a chemical abundance analysis of 300S-1, the brightest likely
member star of the 300 km/s stream near the faint satellite galaxy Segue 1.
From a high-resolution Magellan/MIKE spectrum we determine a metallicity of
[Fe/H] = -1.46 +- 0.05 +- 0.23 (random and systematic uncertainties) for star
300S-1, and find an abundance pattern similar to typical halo stars at this
metallicity. Comparing our stellar parameters to theoretical isochrones, we
estimate a distance of 18 +- 7 kpc. Both the metallicity and distance estimates
are in good agreement with what can be inferred from comparing the SDSS
photometric data of the stream stars to globular cluster sequences. While
several other structures overlap with the stream in this part of the sky, the
combination of kinematic, chemical and distance information makes it unlikely
that these stars are associated with either the Segue 1 galaxy, the Sagittarius
stream or the Orphan stream. Streams with halo-like abundance signatures, such
as the 300 km/s stream, present another observational piece for understanding
the accretion history of the Galactic halo.


title:
Spontaneous emissions and thermalization of cold bosons in optical
  lattices

abstract:
  We study the thermalization of excitations generated by spontaneous emission
events for cold bosons in an optical lattice. Computing the dynamics described
by the many-body master equation, we characterize equilibration timescales in
different parameter regimes. For simple observables, we find regimes in which
the system relaxes rapidly to values in agreement with a thermal distribution,
and others where thermalization does not occur on typical experimental
timescales. Because spontaneous emissions lead effectively to a local quantum
quench, this behavior is strongly dependent on the low-energy spectrum of the
Hamiltonian, and undergoes a qualitative change at the Mott
Insulator-superfluid transition point. These results have important
implications for the understanding of thermalization after localized quenches
in isolated quantum gases, as well as the characterization of heating in
experiments.


title:
The second ULX transient in M31: Chandra, HST and XMM observations, and
  evidence for an extended corona

abstract:
  XMM J004243.6+412519 is a transient X-ray source in M31, first discovered
2012 January 15. Different approaches to fitting the brightest follow-up
observation gave luminosities 1.3--2.5E+39 erg/s, making it the second
ultraluminous X-ray source (ULX) in M31, with a probable black hole accretor.
These different models represent different scenarios for the corona: optically
thick and compact, or optically thin and extended. We obtained Chandra ACIS and
{\em HST} ACS observations of this object as part of our transient monitoring
program, and also observed it serendipitously in a 120 ks XMM-Newton
observation. We identify an optical counterpart at J2000 position 00:42:43.70
+41:25:18.54; its F435W (~ B band) magnitude was 25.97+/-0.03 in the 2012 March
7 observation, and >28.4 at the 4 sigma level during the 2012 September 7
observation, indicating a low mass donor. We created two alternative
lightcurves, using the different corona scenarios, finding linear decay for the
compact corona and exponential decay for the extended corona; linear decay
implies a disk that is >5 magnitudes brighter than we observed. We therefore
favor the extended corona scenario, but caution that there is no statistical
preference for this model in the X-ray spectra alone. Using two empirical
relations between the X-ray to optical ratio and the orbital period, we
estimate a period of ~9--30 hr; this period is consistent with that of the
first ULX in M31 (18 +5 -6 hr).


title:
Observation of HCN hyperfine line anomalies towards low- and high-mass
  star-forming cores

abstract:
  HCN is becoming a popular choice of molecule for studying star formation in
both low- and high-mass regions and for other astrophysical sources from comets
to high-redshift galaxies. However, a major and often overlooked difficulty
with HCN is that it can exhibit non-local thermodynamic equilibrium (non-LTE)
behaviour in its hyperfine line structure. Individual hyperfine lines can be
strongly boosted or suppressed. In low-mass star-forming cloud observations,
this could possibly lead to large errors in the calculation of opacity and
excitation temperature, while in massive star-forming clouds, where the
hyperfine lines are blended due to turbulent broadening, errors will arise in
infall measurements that are based on the separation of the peaks in a
self-absorbed profile. The underlying line shape cannot be known for certain if
hyperfine anomalies are present. We present a first observational investigation
of these anomalies across a range of conditions and transitions by carrying out
a survey of low-mass starless cores (in Taurus & Ophiuchus) and high-mass
protostellar objects (in the G333 giant molecular cloud) using hydrogen cyanide
(HCN) J=1-0 and J=3-2 emission lines. We quantify the degree of anomaly in
these two rotational levels by considering ratios of individual hyperfine lines
compared to LTE values. We find that all the cores observed show some degree of
anomaly while many of the lines are severely anomalous. We conclude that HCN
hyperfine anomalies are common in both lines in both low-mass and high-mass
protostellar objects, and we discuss the differing hypotheses for the
generation of the anomalies. In light of the results, we favour a line overlap
effect for the origins of the anomalies. We discuss the implications for the
use of HCN as a dynamical tracer and suggest in particular that the J=1-0,
F=0-1 hyperfine line should be avoided in quantitative calculations.


title: Duality-symmetric actions for non-Abelian tensor fields

abstract:
  We construct the duality-symmetric actions for a large class of
six-dimensional models describing hierarchies of non-Abelian scalar, vector and
tensor fields related to each other by first-order (self-)duality equations
that follow from these actions. In particular, this construction provides a
Lorentz invariant action for non-Abelian self-dual tensor fields. The class of
models includes the bosonic sectors of the 6d (1,0) superconformal models of
interacting non-Abelian self-dual tensor, vector, and hypermultiplets.


title:
Evolution of Star Formation in the UKIDSS Ultra Deep Survey Field - I.
  Luminosity Functions and Cosmic Star Formation Rate out to z=1.6

abstract:
  We present new results on the cosmic star formation history in the SXDS-UDS
field out to z=1.6. We compile narrow-band data from the Subaru Telescope and
the Visible and Infrared Survey Telescope for Astronomy (VISTA) in conjunction
with broad-band data from the SXDS and UDS, to make a selection of 5725
emission-line galaxies in 12 redshift slices, spanning 10 Gyr of cosmic time.
We determine photometric redshifts for the sample using 11-band photometry, and
use a spectroscopically confirmed subset to fine tune the resultant redshift
distribution. We use the maximum-likelihood technique to determine luminosity
functions in each redshift slice and model the selection effects inherent in
any narrow-band selection statistically, to obviate the retrospective
corrections ordinarily required. The deep narrow-band data are sensitive to
very low star formation rates (SFRs), and allow an accurate evaluation of the
faint end slope of the Schechter function, alpha. We find that alpha is
particularly sensitive to the assumed faintest broadband magnitude of a galaxy
capable of hosting an emission line, and propose that this limit should be
empirically motivated. For this analysis we base our threshold on the limiting
observed equivalent widths of emission lines in the local Universe. We compute
the characteristic SFR of galaxies in each redshift slice, and the integrated
SFR density, rho_{SFR}. We find our results to be in good agreement with the
literature and parametrize the evolution of the SFR density as rho_{SFR}
proportional to (1 + z)^{4.58} confirming a steep decline in star formation
activity since z = 1.6.


title: On the Dynamics of Non-Relativistic Flavor-Mixed Particles

abstract:
  Evolution of a system of interacting non-relativistic quantum flavor-mixed
particles is considered both theoretically and numerically. It was shown that
collisions of mixed particles not only scatter them elastically, but can also
change their mass eigenstates thus affecting particles' flavor composition and
kinetic energy. The mass eigenstate conversions and elastic scattering are
related but different processes, hence the conversion $S$-matrix elements can
be arbitrarily large even when the elastic scattering $S$-matrix elements
vanish. The conversions are efficient when the mass eigenstates are
well-separated in space but suppressed if their wave-packets overlap; the
suppression is most severe for mass-degenerate eigenstates in flat space-time.
The mass eigenstate conversions can lead to an interesting process, called
`quantum evaporation,' in which mixed particles, initially confined deep inside
a gravitational potential well and scattering only off each other, can escape
from it without extra energy supply leaving nothing behind inside the potential
at $t\to \infty$. Implications for the cosmic neutrino background and the
two-component dark matter model are discussed and a prediction for the direct
detection dark matter experiments is made.


title: Cosmological Simulations of Multi-Component Cold Dark Matter

abstract:
  The nature of dark matter is unknown. A number of dark matter candidates are
quantum flavor-mixed particles but this property has never been accounted for
in cosmology. Here we explore this possibility from the first principles via
extensive $N$-body cosmological simulations and demonstrate that the
two-component dark matter model agrees with observational data at all scales.
Substantial reduction of substructure and flattening of density profiles in the
centers of dark matter halos found in simulations can simultaneously resolve
several outstanding puzzles of modern cosmology. The model shares the "why
now?" fine-tuning caveat pertinent to all self-interacting models. Predictions
for direct and indirect detection dark matter experiments are made.


title:
Spot the difference. Impact of different selection criteria on observed
  properties of passive galaxies in zCOSMOS 20-k sample

abstract:
  We present the analysis of photometric, spectroscopic, and morphological
properties for differently selected samples of passive galaxies up to z=1
extracted from the zCOSMOS-20k spectroscopic survey. This analysis intends to
explore the dependence of galaxy properties on the selection criterion adopted,
study the degree of contamination due to star-forming outliers, and provide a
comparison between different commonly used selection criteria. We extracted
from the zCOSMOS-20k catalog six different samples of passive galaxies, based
on morphology, optical colors, specific star-formation rate, a best fit to the
observed spectral energy distribution, and a criterion that combines
morphological, spectroscopic, and photometric information. The morphological
sample has the higher percentage of contamination in colors, specific star
formation rate and presence of emission lines, while the red & passive ETGs
sample is the purest, with properties mostly compatible with no star formation
activity; however, it is also the less economic criterion in terms of
information used. The best performing among the other criteria are the red SED
and the quiescent ones, providing a percentage of contamination only slightly
higher than the red & passive ETGs criterion (on average of a factor of ~2) but
with absolute values of the properties of contaminants still compatible with a
red, passively evolving population. We also provided two revised definitions of
early type galaxies based on restframe color-color and color-mass criteria,
that better reproduce the observed bimodalities. The analysis of the number
densities shows evidences of mass-assembly downsizing, with galaxies at
10.25<log(M/Msun)<10.75 increasing their number by a factor ~2-4 from z=0.6 to
z=0.2, by a factor ~2-3 from z=1 to z=0.2 at 10.75<log(M/Msun)<11, and by only
~10-50% from z=1 to z=0.2 at 11<log(M/Msun)<11.5.


title: Non-symmetric finite networks: the two-point resistance

abstract:
  An explicit formula for the resistance between two nodes in a network with a
non-symmetric Laplacian matrix L is obtained. This is of great advantage e.g.
in electronic circuit fault analysis, where non-linear systems have to be
solved repeatedly. Analysis time can be greatly reduced by utilization of the
obtained formula. The presented approach is based on the "mutual orthogonality"
of the full system of left and right-hand eigenvectors of a diagonalizable
matrix L. Some examples are given that demonstrate the accuracy of the approach
on circuit networks.


title: Statistical mechanics of the lattice sphere packing problem

abstract:
  We present an efficient Monte Carlo method for the lattice sphere packing
problem in d dimensions. We use this method to numerically discover de novo the
densest lattice sphere packing in dimensions 9 through 20. Our method goes
beyond previous methods not only in exploring higher dimensions but also in
shedding light on the statistical mechanics underlying the problem in question.
We observe evidence of a phase transition in the thermodynamic limit
$d\to\infty$. In the dimensions explored in the present work, the results are
consistent with a first-order crystallization transition, but leave open the
possibility that a glass transition is manifested in higher dimensions.

categories: cond-mat.stat-mech math-ph math.MG math.MP


title:
Spherically-symmetric model stellar atmospheres and limb darkening I:
  limb-darkening laws, gravity-darkening coefficients and angular diameter
  corrections for red giant stars

abstract:
  Model stellar atmospheres are fundamental tools for understanding stellar
observations from interferometry, microlensing, eclipsing binaries and
planetary transits. However, the calculations also include assumptions, such as
the geometry of the model. We use intensity profiles computed for both
plane-parallel and spherically symmetric model atmospheres to determine fitting
coefficients in the BVRIHK, CoRot and Kepler wavebands for limb darkening using
several different fitting laws, for gravity-darkening and for interferometric
angular diameter corrections. Comparing predicted variables for each geometry,
we find that the spherically symmetric model geometry leads to different
predictions for surface gravities log g < 3. In particular, the most commonly
used limb-darkening laws produce poor fits to the intensity profiles of
spherically symmetric model atmospheres, which indicates the need for more
sophisticated laws. Angular diameter corrections for spherically symmetric
models range from 0.67 to 1, compared to the much smaller range from 0.95 to 1
for plane-parallel models.


title: Generic method for bijections between blossoming trees and planar maps

abstract:
  This article presents a unified bijective scheme between planar maps and
blossoming trees, where a blossoming tree is defined as a spanning tree of the
map decorated with some dangling half-edges that enable to reconstruct its
faces. Our method generalizes a previous construction of Bernardi by loosening
its conditions of applications so as to include annular maps, that is maps
embedded in the plane with a root face different from the outer face.
  The bijective construction presented here relies deeply on the theory of
\alpha-orientations introduced by Felsner, and in particular on the existence
of minimal and accessible orientations. Since most of the families of maps can
be characterized by such orientations, our generic bijective method is proved
to capture as special cases all previously known bijections involving
blossoming trees: for example Eulerian maps, m-Eulerian maps, non separable
maps and simple triangulations and quadrangulations of a k-gon. Moreover, it
also permits to obtain new bijective constructions for bipolar orientations and
d-angulations of girth d of a k-gon.
  As for applications, each specialization of the construction translates into
enumerative by-products, either via a closed formula or via a recursive
computational scheme. Besides, for every family of maps described in the paper,
the construction can be implemented in linear time. It yields thus an effective
way to encode and generate planar maps.
  In a recent work, Bernardi and Fusy introduced another unified bijective
scheme, we adopt here a different strategy which allows us to capture different
bijections. These two approaches should be seen as two complementary ways of
unifying bijections between planar maps and decorated trees.


title: Natural Supersymmetry and Implications for Higgs physics

abstract:
  We re-analyze the LHC bounds on light third generation squarks in Natural
Supersymmetry, where the sparticles have masses inversely proportional to their
leading-log contributions to the electroweak symmetry breaking scale. Higgsinos
are the lightest supersymmetric particles; top and bottom squarks are the
next-to-lightest sparticles that decay into both neutral and charged Higgsinos
with well-defined branching ratios determined by Yukawa couplings and
kinematics. The Higgsinos are nearly degenerate in mass, once the bino and wino
masses are taken to their natural (heavy) values. We consider three scenarios
for the stop and sbottom masses: (I) $\tilde{t}_R$ is light, (II) $\tilde{t}_L$
and $\tilde{b}_L$ are light, and (III) $\tilde{t}_R$, $\tilde{t}_L$, and
$\tilde{b}_L$ are light. Dedicated stop searches are currently sensitive to
Scenarios II and III, but not Scenario I. Sbottom-motivated searches ($2 b +
\rm{MET}$) impact both squark flavors due to $\tilde{t} \ra b \charp_1$ as well
as $\tilde{b} \ra b \neut_{1,2}$, constraining Scenarios I and III with
somewhat weaker constraints on Scenario II. The totality of these searches
yield relatively strong constraints on Natural Supersymmetry. Two regions that
remain are: (1) the "compressed wedge", where $(m_{\tilde{q}} -
|\mu|)/m_{\tilde{q}} \ll 1$, and (2) the "kinematic limit" region, where
$m_{\tilde{q}} \gsim 600-750 GeV, at the kinematic limit of the LHC searches.
We calculate the correlated predictions for Higgs physics, demonstrating that
these regions lead to distinct predictions for the lightest Higgs couplings
that are separable with $\simeq 10% measurements. We show that these
conclusions remain largely unchanged once the MSSM is extended to the NMSSM in
order to naturally obtain a large enough mass for the lightest Higgs boson
consistent with LHC data.


title:
Enumerations of lozenge tilings, lattice paths, and perfect matchings
  and the weak Lefschetz property

abstract:
  MacMahon enumerated the plane partitions in an $a \times b \times c$ box.
These are in bijection to lozenge tilings of a hexagon, to certain perfect
matchings, and to families of non-intersecting lattice paths. In this work we
consider more general regions, called triangular regions, and establish signed
versions of the latter three bijections. Indeed, we use perfect matchings and
families of non-intersecting lattice paths to define two signs of a lozenge
tiling. A combinatorial argument involving a new method, called resolution of a
puncture, then shows that the signs are in fact equivalent. This provides in
particular two different determinantal enumerations of these families. These
results are then applied to study the weak Lefschetz property of Artinian
quotients by monomial ideals of a three-dimensional polynomial ring. We
establish sufficient conditions guaranteeing the weak Lefschetz property as
well as the semistability of the syzygy bundle of the ideal, classify the type
two algebras with the weak Lefschetz property, and study monomial almost
complete intersections in depth. Furthermore, we develop a general method that
often associates to an algebra that fails the weak Lefschetz property a toric
surface that satisfies a Laplace equation. We also present examples of toric
varieties that satisfy arbitrarily many Laplace equations. Our combinatorial
methods allow us to address the dependence on the characteristic of the base
field for many of our results.


title:
Holographic Measurements of Anisotropic Three-Dimensional Diffusion of
  Colloidal Clusters

abstract:
  We measure all nonzero elements of the three-dimensional (3D) diffusion
tensor D for clusters of colloidal spheres to a precision of 1% or better using
digital holographic microscopy. We study both dimers and triangular trimers of
spheres, for which no analytical calculations of the diffusion tensor exist. We
observe anisotropic rotational and translational diffusion arising from the
asymmetries of the clusters. In the case of the three-particle triangular
cluster, we also detect a small but statistically significant difference in the
rotational diffusion about the two in-plane axes. We attribute this difference
to weak breaking of threefold rotational symmetry due to a small amount of
particle polydispersity. Our experimental measurements agree well with
numerical calculations and show how diffusion constants can be measured under
conditions relevant to colloidal self-assembly, where theoretical and even
numerical prediction is difficult.


title: Entanglement sampling and applications

abstract:
  A natural measure for the amount of quantum information that a physical
system E holds about another system A = A_1,...,A_n is given by the min-entropy
Hmin(A|E). Specifically, the min-entropy measures the amount of entanglement
between E and A, and is the relevant measure when analyzing a wide variety of
problems ranging from randomness extraction in quantum cryptography, decoupling
used in channel coding, to physical processes such as thermalization or the
thermodynamic work cost (or gain) of erasing a quantum system. As such, it is a
central question to determine the behaviour of the min-entropy after some
process M is applied to the system A. Here we introduce a new generic tool
relating the resulting min-entropy to the original one, and apply it to several
settings of interest, including sampling of subsystems and measuring in a
randomly chosen basis. The sampling results lead to new upper bounds on quantum
random access codes, and imply the existence of "local decouplers". The results
on random measurements yield new high-order entropic uncertainty relations with
which we prove the optimality of cryptographic schemes in the bounded quantum
storage model.


title:
Magnetic excitations in stripe-ordered La$_{1.875}$Ba$_{0.125}$CuO$_4$
  studied using resonant inelastic x-ray scattering

abstract:
  The charge and spin correlations in La$_{1.875}$Ba$_{0.125}$CuO$_4$ (LBCO
1/8) are studied using Cu $L_3$ edge resonant inelastic x-ray scattering
(RIXS). The static charge order (CO) is observed at a wavevector of $(0.24,0)$
and its charge nature confirmed by measuring the dependence of this peak on the
incident x-ray polarization. The paramagnon excitation in LBCO 1/8 is then
measured as it disperses through the CO wavevector. Within the experimental
uncertainty no changes are observed in the paramagnon due to the static CO, and
the paramagnon seems to be similar to that measured in other cuprates, which
have no static CO. Given that the stripe correlation modulates both the charge
and spin degrees of freedom, it is likely that subtle changes do occur in the
paramagnon due to CO. Consequently, we propose that future RIXS measurements,
realized with higher energy resolution and sensitivity, should be performed to
test for these effects.


title: Meta-Analysis of Gene Level Association Tests

abstract:
  The vast majority of connections between complex disease and common genetic
variants were identified through meta-analysis, a powerful approach that
enables large samples sizes while protecting against common artifacts due to
population structure, repeated small sample analyses, and/or limitations with
sharing individual level data. As the focus of genetic association studies
shifts to rare variants, genes and other functional units are becoming the unit
of analysis. Here, we propose and evaluate new approaches for meta-analysis of
rare variant association. We show that our approach retains useful features of
single variant meta-analytic approaches and demonstrate its utility in a study
of blood lipid levels in ~18,500 individuals genotyped with exome arrays.


title: New Alignment Methods for Discriminative Book Summarization

abstract:
  We consider the unsupervised alignment of the full text of a book with a
human-written summary. This presents challenges not seen in other text
alignment problems, including a disparity in length and, consequent to this, a
violation of the expectation that individual words and phrases should align,
since large passages and chapters can be distilled into a single summary
phrase. We present two new methods, based on hidden Markov models, specifically
targeted to this problem, and demonstrate gains on an extractive book
summarization task. While there is still much room for improvement,
unsupervised alignment holds intrinsic value in offering insight into what
features of a book are deemed worthy of summarization.


title: Timescale for equilibration of N/Z gradients in dinuclear systems

abstract:
  Equilibration of N/Z in binary breakup of an excited and transiently deformed
projectile-like fragment (PLF*), produced in peripheral collisions of 64Zn +
27Al, 64Zn, 209Bi at E/A = 45 MeV, is examined. The composition of emitted
light fragments (3<=Z<=6) changes with the decay angle of the PLF*. The most
neutron-rich fragments observed are associated with a small rotation angle. A
clear target dependence is observed with the largest initial N/Z correlated
with the heavy, neutron-rich target. Using the rotation angle as a clock, we
deduce that N/Z equilibration persists for times as long as 3-4 zs (1zs = 1 x
10^-21 s = 300 fm/c). The rate of N/Z equilibration is found to depend on the
initial neutron gradient within the PLF*.


title: Diagonal Limit for Conformal Blocks in d Dimensions

abstract:
  Conformal blocks in any number of dimensions depend on two variables z, zbar.
Here we study their restrictions to the special "diagonal" kinematics z = zbar,
previously found useful as a starting point for the conformal bootstrap
analysis. We show that conformal blocks on the diagonal satisfy ordinary
differential equations, third-order for spin zero and fourth-order for the
general case. These ODEs determine the blocks uniquely and lead to an efficient
numerical evaluation algorithm. For equal external operator dimensions, we find
closed-form solutions in terms of finite sums of 3F2 functions.


title:
Accretion of gas onto gap-opening planets and circumplanetary flow
  structure in magnetized turbulent disks

abstract:
  We have performed three-dimensional magneto-hydrodynamical simulations of
stellar accretion disks, using the PLUTO code, and studied the accretion of gas
onto a Jupiter-mass planet and the structure of the circumplanetary gas flow
after opening a gap in the disk. We compare our results with simulations of
laminar, yet viscous disks with different levels of an $\alpha$-type viscosity.
In all cases, we find that the accretion flow across the surface of the Hill
sphere of the planet is not spherically or azimuthally symmetric, and is
predominantly restricted to the mid-plane region of the disk. Even in the
turbulent case, we find no significant vertical flow of mass into the Hill
sphere. The outer parts of the circumplanetary disk are shown to rotate
significantly below Keplerian speed, independent of viscosity, while the
circumplanetary disk density (therefore the angular momentum) increases with
viscosity. For a simulation of a magnetized turbulent disk, where the global
averaged alpha stress is $\alpha_{MHD}=10^{-3}$, we find the accretion rate
onto the planet to be $\dot{M}\approx 2\times10^{-6}M_{J}yr^{-1}$ for a gap
surface density of $12 g cm^{-2}$. This is about a third of the accretion rate
obtained in a laminar viscous simulation with equivalent $\alpha$ parameter.


title:
Enhanced violation of a Leggett-Garg inequality under nonequilibrium
  thermal conditions

abstract:
  We investigate both analytically and numerically violations of a Leggett-Garg
inequality (LGI) for a composite quantum system in contact with two separate
reservoirs at different temperatures. Remarkably we find that LGI violations
can be enhanced when a heat current is established at low temperatures in a
steady-state regime. Based on a Kraus operator decomposition of the non-unitary
evolution for a system formed by two interacting spins or quantum bits, we
provide analytical support for power law relations between dissipation strength
and mean temperature in the borderlines separating parameter regions where
non-equilibrium conditions affect differently the maximal LGI violation.
Furthermore, a correspondence between spatial and temporal correlation
inequalities is shown to persist even in such nonequilibrium thermal settings.


title: AMS02 results support the secondary origin of cosmic ray positrons

abstract:
  We show that the recent AMS02 positron fraction measurement is consistent
with a secondary origin for positrons, and does not require additional primary
sources such as pulsars or dark matter. The measured positron fraction at high
energy saturates the previously predicted upper bound for secondary production
(Katz et al 2009), obtained by neglecting radiative losses. This coincidence,
which will be further tested by upcoming AMS02 data at higher energy, is a
compelling indication for a secondary source. Within the secondary model the
AMS02 data imply a cosmic ray propagation time in the Galaxy of < Myr and an
average traversed interstellar matter density of order 1/cc, comparable to the
density of the Milky Way gaseous disk, at a rigidity of 300 GV.


title: Population III Stars and Remnants in High Redshift Galaxies

abstract:
  Recent simulations of Population III star formation have suggested that some
fraction form in binary systems, in addition to having a characteristic mass of
tens of solar masses. The deaths of metal-free stars result in the initial
chemical enrichment of the universe and the production of the first
stellar-mass black holes. Here we present a cosmological adaptive mesh
refinement simulation of an overdense region that forms a few 10^9 Msun dark
matter halos and over 13,000 Population III stars by redshift 15. We find that
most halos do not form Population III stars until they reach Mvir ~ 10^7 Msun
because this biased region is quickly enriched from both Population III and
galaxies, which also produce high levels of ultraviolet radiation that suppress
H2 formation. Nevertheless, Population III stars continue to form, albeit in
more massive halos, at a rate of ~ 10^{-4} Msun yr^{-1} Mpc^{-3} at redshift
15. The most massive starless halo has a mass of 7 x 10^7 Msun, which could
host massive black hole formation through the direct gaseous collapse scenario.
We show that the multiplicity of the Population III remnants grows with halo
mass above 10^8 Msun, culminating in 50 remnants located in 10^9 Msun halos on
average. This has implications that high mass X-ray binaries and intermediate
mass black holes that originate from metal-free stars may be abundant in
high-redshift galaxies.


title:
Parrondo's paradox and superactivation of classical and quantum capacity
  of communication channels with memory

abstract:
  There exist memoryless zero-capacity quantum channels that when used jointly
result in the channel with positive capacity. This phenomenon is called
superactivation. Making use of Parrondo's paradox, we exhibit examples of
superactivation-like effect for the capacity of classical communication
channels as well as quantum and private capacity of quantum channels with
memory. There are several ingredients necessary for superactivation of quantum
capacity to occur in memoryless case. The first one is the requirement for the
quantum channels which are amenable for superactivation to come from two
distinct families - binding entanglement channels and erasure channels. The
second one is the ability to utilize inputs which are entangled across the uses
of the channels. Our construction uses a single family of erasure channels with
classical memory to achieve the same superactivation-like effect for quantum
capacity without any of the ingredients above.


title:
Classical and Quantum Algorithms for Testing Equivalence of Group
  Extensions

abstract:
  While efficient algorithms are known for solving many important problems
related to groups, no efficient algorithm is known for determining whether two
arbitrary groups are isomorphic. The particular case of 2-nilpotent groups, a
special type of central extension, is widely believed to contain the essential
hard cases. However, looking specifically at central extensions, the natural
formulation of being "the same" is not isomorphism but rather "equivalence,"
which requires an isomorphism to preserves the structure of the extension. In
this paper, we show that equivalence of central extensions can be computed
efficiently on a classical computer when the groups are small enough to be
given by their multiplication tables. However, in the model of black box
groups, which allows the groups to be much larger, we show that equivalence can
be computed efficiently on a quantum computer but not a classical one (under
common complexity assumptions). Our quantum algorithm demonstrates a new
application of the hidden subgroup problem for general abelian groups.


title: Spin-Torque Generation in Topological-Insulator-Based Heterostructures

abstract:
  Heterostructures utilizing topological insulators exhibit a remarkable
spin-torque efficiency. However, the exact origin of the strong torque, in
particular whether it stems from the spin-momentum locking of the topological
surface states or rather from spin-Hall physics of the topological-insulator
bulk remains unclear. Here, we explore a mechanism of spin-torque generation
purely based on the topological surface states. We consider
topological-insulator-based bilayers involving ferromagnetic metal (TI/FM) and
magnetically doped topological insulators (TI/mdTI), respectively. By ascribing
the key theoretical differences between the two setups to location and number
of active surface states, we describe both setups within the same framework of
spin diffusion of the non-equilibrium spin density of the topological surface
states. For the TI/FM bilayer, we find large spin-torque efficiencies of
roughly equal magnitude for both in-plane and out-of-plane spin torques. For
the TI/mdTI bilayer, we elucidate the dominance of the spin-transfer-like
torque. However, we cannot explain the orders of magnitude enhancement
reported. Nevertheless, our model gives an intuitive picture of spin-torque
generation in topological-insulator-based bilayers and provides theoretical
constraints on spin-torque generation due to topological surface states.


title: Absolute Calibration of a Large-diameter Light Source

abstract:
  A method of absolute calibration for large aperture optical systems is
presented, using the example of the Pierre Auger Observatory fluorescence
detectors. A 2.5 m diameter light source illuminated by an ultra--violet light
emitting diode is calibrated with an overall uncertainty of 2.1 % at a
wavelength of 365 nm.


title: Optimal Noise Adding Mechanisms for Approximate Differential Privacy

abstract:
  We study the (nearly) optimal mechanisms in $(\epsilon,\delta)$-approximate
differential privacy for integer-valued query functions and vector-valued
(histogram-like) query functions under a utility-maximization/cost-minimization
framework. We characterize the tradeoff between $\epsilon$ and $\delta$ in
utility and privacy analysis for histogram-like query functions ($\ell^1$
sensitivity), and show that the $(\epsilon,\delta)$-differential privacy is a
framework not much more general than the $(\epsilon,0)$-differential privacy
and $(0,\delta)$-differential privacy in the context of $\ell^1$ and $\ell^2$
cost functions, i.e., minimum expected noise magnitude and noise power. In the
same context of $\ell^1$ and $\ell^2$ cost functions, we show the
near-optimality of uniform noise mechanism and discrete Laplacian mechanism in
the high privacy regime (as $(\epsilon,\delta) \to (0,0)$). We conclude that in
$(\epsilon,\delta)$-differential privacy, the optimal noise magnitude and noise
power are $\Theta(\min(\frac{1}{\epsilon},\frac{1}{\delta}))$ and
$\Theta(\min(\frac{1}{\epsilon^2},\frac{1}{\delta^2}))$, respectively, in the
high privacy regime.


title: Immersions in highly edge connected graphs

abstract:
  We consider the problem of how much edge connectivity is necessary to force a
graph G to contain a fixed graph H as an immersion. We show that if the maximum
degree in H is D, then all the examples of D-edge connected graphs which do not
contain H as a weak immersion must have a tree-like decomposition called a
tree-cut decomposition of bounded width. If we consider strong immersions, then
it is easy to see that there are arbitrarily highly edge connected graphs which
do not contain a fixed clique K_t as a strong immersion. We give a structure
theorem which roughly characterizes those highly edge connected graphs which do
not contain K_t as a strong immersion.


title: Counting common perpendicular arcs in negative curvature

abstract:
  Let $D^-$ and $D^+$ be properly immersed closed locally convex subsets of a
Riemannian manifold with pinched negative sectional curvature. Using mixing
properties of the geodesic flow, we give an asymptotic formula as $t\to+\infty$
for the number of common perpendiculars of length at most $t$ from $D^-$ to
$D^+$, counted with multiplicities, and we prove the equidistribution in the
outer and inner unit normal bundles of $D^-$ and $D^+$ of the tangent vectors
at the endpoints of the common perpendiculars. When the manifold is compact
with exponential decay of correlations or arithmetic with finite volume, we
give an error term for the asymptotic. As an application, we give an asymptotic
formula for the number of connected components of the domain of discontinuity
of Kleinian groups as their diameter goes to $0$.


title:
On the location of the zero-free half-plane of a random Epstein zeta
  function

abstract:
  In this note we study, for a random lattice L of large dimension n, the
supremum of the real parts of the zeros of the Epstein zeta function E_n(L,s)
and prove that this random variable has a limit distribution, which we give
explicitly. This limit distribution is studied in some detail; in particular we
give an explicit formula for its distribution function.


title:
Invariants of pure 2-dimensional sheaves inside threefolds and modular
  forms

abstract:
  Motivated by S-duality modularity conjectures in string theory, we study the
Donaldson-Thomas type invariants of pure 2-dimensional sheaves inside a
nonsingular threefold X in three different situations:
  (1). X is a K3 fibration over a curve. We study the Donaldson-Thomas
invariants of the 2 dimensional Gieseker stable sheaves in X supported on the
fibers. Analogous to the Gromov-Witten theory formula established in the work
of Maulik-Pandharipande, we express these invariants in terms of the Euler
characteristic of the Hilbert scheme of points on the K3 surface and the
Noether-Lefschetz numbers of the fibration, and prove that the invariants have
modular properties.
  (2). X is the total space of the canonical bundle of P^2. We study the
generalized Donaldson-Thomas invariants defined by Joyce-Song of the moduli
spaces of the 2-dimensional Gieseker semistable sheaves on X with first Chern
class equal to k times the class of the zero section of X. When k=1,2 or 3, and
semistability implies stability, we express the invariants in terms of known
modular forms. We prove a combinatorial formula for the invariants when k=2 in
the presence of the strictly semistable sheaves, and verify the BPS integrality
conjecture of Joyce-Song in some cases.
  (3). (Joint with Richard Thomas) X is a Calabi-Yau threefold and L is a
sufficiently positive line bundle. We define new invariants counting a
restricted class of 2-dimensional torsion sheaves, enumerating pairs (Z,H) in X
where H is a member of the linear system |L| and Z is a 1-dimensional subscheme
of H. The associated sheaf is the ideal sheaf of Z in H, pushed forward to X
and considered as a certain Joyce-Song pair in the derived category of X. We
express these invariants in terms of the MNOP invariants of X.


title: The paucity of globular clusters around the field elliptical NGC 7507

abstract:
  Context: There is strong evidence that globular cluster systems (GCSs) of
massive galaxies are largely assembled by infall/accretion processes.
Therefore, we expect the GCSs of isolated elliptical galaxies to be poor.
Alhough not completely isolated, NGC 7507 is a massive field elliptical galaxy
with an apparently very low dark matter content. Aims: We determine the
richness, the colour distribution, and the structural properties of the GCS of
NGC 7507. Methods: We perform wide-field Washington photometry with data
obtained with the MOSAIC II camera at the 4m-Blanco telescope, CTIO. Results:
The GCS is very poor with S_N ~ 0.6. We identify three subpopulations with
peaks at (C-T1) colours of 1.21, 1.42, and 1.72. The bluest population may
represent the old, metal-poor component. This interpretation is supported by
its shallow density profile. The red population is more concentrated,
resembling the galaxy light. The intermediate-colour population is strongly
peaked in colour and we interpret this population as the signature of a
starburst, whose age depends on the metallicity, but should be quite old, since
no signatures of a merger are identifiable. In addition, we find a main
sequence in the stellar foreground population, which we attribute to the
Sagittarius dwarf tidal stream. Conclusions: The extraordinarily poor GCS of
NGC 7507, a massive elliptical galaxy, is an illustration of how important the
environmental conditions are for producing rich GCSs.


title:
Non-perturbative interpretation of the Bloch vector's path beyond
  rotating wave approximation

abstract:
  The Bloch vector's path of a two-level system exposed to a monochromatic
field exhibits, in the regime of strong coupling, complex corkscrew
trajectories. By considering the infinitesimal evolution of the two-level
system when the field is treated as a classical object, we show that the Bloch
vector's rotation speed oscillates between zero and twice the rotation speed
predicted by the rotating wave approximation. Cusps appear when the rotation
speed vanishes. We prove analytically that in correspondence to cusps the
curvature of the Bloch vector's path diverges. On the other hand, numerical
data show that the curvature is very large even for a quantum field in the deep
quantum regime with mean number of photons $\bar{n}\lesssim 1$. We finally
compute numerically the typical error size in a quantum gate when the terms
beyond rotating wave approximation are neglected.


title:
Limits on the dependence of the fine-structure constant on gravitational
  potential from white-dwarf spectra

abstract:
  We propose a new probe of the dependence of the fine structure constant,
alpha, on a strong gravitational field using metal lines in the spectra of
white dwarf stars. Comparison of laboratory spectra with far-UV astronomical
spectra from the white dwarf star G191-B2B recorded by the Hubble Space
Telescope Imaging Spectrograph gives limits on the fractional variation of
alpha of (Delta alpha/alpha)=(4.2 +- 1.6)x10^(-5) and (-6.1 +- 5.8)x10^(-5)
from Fe V and Ni V spectra, respectively, at a dimensionless gravitational
potential relative to Earth of (Delta phi) ~ 5x10^(-5). With better
determinations of the laboratory wavelengths of the lines employed these
results could be improved by up to two orders of magnitude.

categories: astro-ph.CO gr-qc hep-th physics.atom-ph


title:
Extremal Trajectories and Maxwell Strata in Sub-Riemannian Problem on
  Group of Motions of Pseudo Euclidean Plane

abstract:
  We consider the sub-Riemannian length minimization problem on the group of
motions of pseudo Euclidean plane that form the special hyperbolic group SH(2).
The system comprises of left invariant vector fields with 2-dimensional linear
control input and energy cost functional. We apply the Pontryagin Maximum
Principle to obtain the extremal control input and the sub-Riemannian
geodesics. A change of coordinates transforms the vertical subsystem of the
normal Hamiltonian system into the mathematical pendulum. In suitable elliptic
coordinates the vertical and the horizontal subsystems are integrated such that
the resulting extremal trajectories are parametrized by the Jacobi elliptic
functions. Qualitative analysis reveals that the projections of normal extremal
trajectories on the xy-plane have cusps and inflection points. The vertical
subsystem being a generalized pendulum admits reflection symmetries that are
used to obtain a characterization of the Maxwell strata.


title:
Bayesian method for the analysis of the dust emission in the
  Far-Infrared and Submillimeter

abstract:
  We present a method, based on Bayesian statistics, to fit the dust emission
parameters in the far-infrared and submillimeter wavelengths. The method
estimates the dust temperature and spectral emissivity index, plus their
relationship, taking into account properly the statistical and systematic
uncertainties. We test it on three sets of simulated sources detectable by the
Herschel Space Observatory in the PACS and SPIRE spectral bands (70-500
micron), spanning over a wide range of dust temperatures. The simulated
observations are a one-component Interstellar Medium, and two two-component
sources, both warm (HII regions) and cold (cold clumps). We first define a
procedure to identify the better model, then we recover the parameters of the
model and measure their physical correlations by means of a Monte Carlo Markov
Chain algorithm adopting multi-variate Gaussian priors. In this process we
assess the reliability of the model recovery, and of parameters estimation. We
conclude that the model and parameters are properly recovered only under
certain circumstances, and that false models may be derived in some case. We
applied the method to a set of 91 starless cold clumps in an inter-arm region
of the Galactic Plane with low star formation activity, observed by Herschel in
the Hi-GAL survey. Our results are consistent with a temperature independent
spectral index.


title: Specific heat of apple at different moisture contents and temperatures

abstract:
  This work discusses results of experimental investigations of the specific
heat, $C$, of apple in a wide interval of moisture contents ($W=0-0.9$) and
temperatures ($T = 283-363$ K). The obtained data reveal the important role of
the bound water in determination of $C(W,T)$ behaviour. The additive model for
description of $C(W)$ dependence in the moisture range of $0.1<W<1.0$ was
applied, where the apple was considered as a mixture of water and hydrated
apple material (water plasticised apple) with specific heat $C_h$. The
difference between $C_h$ and specific heat of dry apple, $\Delta Cb=C_h-C_d$,
was proposed as a measure of the excess contribution of bound water to the
specific heat. The estimated amounts of bound water $W_b$ were comparable with
the monolayer moisture content in apple. The analytical equation was proposed
for approximation of $C(W,T)$ dependencies in the studied intervals of moisture
content and temperature.


title:
Spatially homogeneous ferromagnetism below the enhanced Curie
  temperature in EuO_{1-x} thin films

abstract:
  We have used low energy implanted muons as a volume sensitive probe of the
magnetic properties of EuO_{1-x} thin films. We find that static and
homogeneous magnetic order persists up to the elevated T_C in the doped samples
and the muon signal displays the double dome feature also observed in the
sample magnetization. Our results appear incompatible with either the magnetic
phase separation or bound magnetic polaron descriptions previously suggested to
explain the elevated T_C, but are compatible with an RKKY-like interaction
mediating magnetic interactions above 69 K.


title:
Compatible quantum correlations: on extension problems for Werner and
  isotropic states

abstract:
  We investigate some basic scenarios in which a given set of bipartite quantum
states may consistently arise as the set of reduced states of a global
N-partite quantum state. Intuitively, we say that the multipartite state
"joins" the underlying correlations. Determining whether, for a given set of
states and a given joining structure, a compatible N-partite quantum state
exists is known as the quantum marginal problem. We restrict to bipartite
reduced states that belong to the paradigmatic classes of Werner and isotropic
states in d dimensions, and focus on two specific versions of the quantum
marginal problem which we find to be tractable. The first is Alice-Bob,
Alice-Charlie joining, with both pairs being in a Werner or isotropic state.
The second is m-n sharability of a Werner state across N subsystems, which may
be seen as a variant of the N-representability problem to the case where
subsystems are partitioned into two groupings of m and n parties, respectively.
By exploiting the symmetry properties that each class of states enjoys, we
determine necessary and sufficient conditions for three-party joinability and
1-n sharability for arbitrary d. Our results explicitly show that although
entanglement is required for sharing limitations to emerge, correlations beyond
entanglement generally suffice to restrict joinability, and not all unentangled
states necessarily obey the same limitations. The relationship between
joinability and quantum cloning as well as implications for the joinability of
arbitrary bipartite states are discussed.


title:
Towards an Author-Topic-Term-Model Visualization of 100 Years of German
  Sociological Society Proceedings

abstract:
  Author co-citation studies employ factor analysis to reduce high-dimensional
co-citation matrices to low-dimensional and possibly interpretable factors, but
these studies do not use any information from the text bodies of publications.
We hypothesise that term frequencies may yield useful information for
scientometric analysis. In our work we ask if word features in combination with
Bayesian analysis allow well-founded science mapping studies. This work goes
back to the roots of Mosteller and Wallace's (1964) statistical text analysis
using word frequency features and a Bayesian inference approach, tough with
different goals. To answer our research question we (i) introduce a new data
set on which the experiments are carried out, (ii) describe the Bayesian model
employed for inference and (iii) present first results of the analysis.


title: Speckle Noise Reduction in Medical Ultrasound Images

abstract:
  Ultrasound imaging is an incontestable vital tool for diagnosis, it provides
in non-invasive manner the internal structure of the body to detect eventually
diseases or abnormalities tissues. Unfortunately, the presence of speckle noise
in these images affects edges and fine details which limit the contrast
resolution and make diagnostic more difficult. In this paper, we propose a
denoising approach which combines logarithmic transformation and a non linear
diffusion tensor. Since speckle noise is multiplicative and nonwhite process,
the logarithmic transformation is a reasonable choice to convert
signaldependent or pure multiplicative noise to an additive one. The key idea
from using diffusion tensor is to adapt the flow diffusion towards the local
orientation by applying anisotropic diffusion along the coherent structure
direction of interesting features in the image. To illustrate the effective
performance of our algorithm, we present some experimental results on
synthetically and real echographic images.


title:
Some results on general quadratic reflected BSDEs driven by a continous
  martingale

abstract:
  We study the well-posedness of general reflected BSDEs driven by a continuous
martingale, when the coefficient f of the driver has at most quadratic growth
in the control variable Z, with a bounded terminal condition and a lower
obstacle which is bounded above. We obtain the basic results in this setting :
comparison and uniqueness, existence, stability. For the comparison theorem and
the special comparison theorem for reflected BSDEs (which allows one to compare
the increasing processes of two solutions), we give intrinsic proofs which do
not rely on the comparison theorem for standard BSDEs. This allows to obtain
the special comparison theorem under minimal assumptions. We obtain existence
by using the fixed point theorem and then a series of perturbations, first in
the case where f is Lipschitz in the primary variable Y, and then in the case
where f can have slightly-superlinear growth and the case where f is monotonous
in Y with arbitrary growth. We also obtain a local Lipschitz estimate in BMO
for the martingale part of the solution.


title: The most powerful particles in the Universe: a cosmic smash

abstract:
  This year we are celebrating 101 years since the discovery of cosmic rays.
They are whizzing all around the Universe, and they occur at very different
energies, including the highest particle energies that exist. However, theory
predicts an abrupt suppression (a "cutoff") above a specific huge energy. This
is difficult to verify, the measurements are controversial, but it provides a
unique opportunity to probe established concepts of physics - like Lorentz
Invariance - under extreme conditions. If the observations will ultimately
contradict this "cutoff", this could require a fundamental pillar of physics to
be revised.

categories: physics.hist-ph astro-ph.HE hep-ph physics.pop-ph


title:
Sparsest Cut on Bounded Treewidth Graphs: Algorithms and Hardness
  Results

abstract:
  We give a 2-approximation algorithm for Non-Uniform Sparsest Cut that runs in
time $n^{O(k)}$, where $k$ is the treewidth of the graph. This improves on the
previous $2^{2^k}$-approximation in time $\poly(n) 2^{O(k)}$ due to
Chlamt\'a\v{c} et al.
  To complement this algorithm, we show the following hardness results: If the
Non-Uniform Sparsest Cut problem has a $\rho$-approximation for series-parallel
graphs (where $\rho \geq 1$), then the Max Cut problem has an algorithm with
approximation factor arbitrarily close to $1/\rho$. Hence, even for such
restricted graphs (which have treewidth 2), the Sparsest Cut problem is NP-hard
to approximate better than $17/16 - \epsilon$ for $\epsilon > 0$; assuming the
Unique Games Conjecture the hardness becomes $1/\alpha_{GW} - \epsilon$. For
graphs with large (but constant) treewidth, we show a hardness result of $2 -
\epsilon$ assuming the Unique Games Conjecture.
  Our algorithm rounds a linear program based on (a subset of) the
Sherali-Adams lift of the standard Sparsest Cut LP. We show that even for
treewidth-2 graphs, the LP has an integrality gap close to 2 even after
polynomially many rounds of Sherali-Adams. Hence our approach cannot be
improved even on such restricted graphs without using a stronger relaxation.


title: Uniform sup-norm bounds on average for cusp forms of higher weights

abstract:
  Let $\Gamma\subseteq\mathrm{PSL}_{2}(\mathbb{R})$ be a Fuchsian subgroup of
the first kind acting on the upper half-plane $\mathbb{H}$. Consider the
$d$-dimensional space of cusp forms $\mathcal{S}_{k}^{\Gamma}$ of weight $2k$
for $\Gamma$, and let $\{f_{1},\ldots,f_{d}\}$ be an orthonormal basis of
$\mathcal{S}_{k}^{\Gamma}$ with respect to the Petersson inner product. In this
paper we show that the sup-norm of the quantity
$S_{k}^{\Gamma}(z):=\sum_{j=1}^{d}| f_{j}(z)|^{2}\,\mathrm{Im}(z)^{2k}$ is
bounded as $O_{\Gamma}(k)$ in the cocompact setting, and as
$O_{\Gamma}(k^{3/2})$ in the cofinite case, where the implied constants depend
solely on $\Gamma$. We also show that the implied constants are uniform if
$\Gamma$ is replaced by a subgroup of finite index.


title: Phonons in Twisted Bilayer Graphene

abstract:
  We theoretically investigated phonon dispersion in AA-stacked, AB-stacked and
twisted bilayer graphene with various rotation angles. The calculations were
performed using the Born-von-Karman model for the intra-layer atomic
interactions and the Lennard-Jones potential for the inter-layer interactions.
It was found that the stacking order affects the out-of-plane acoustic phonon
modes the most. The difference in the phonon densities of states in the twisted
bilayer graphene and in AA- or AB-stacked bilayer graphene appears in the
phonon frequencies range 90 - 110 1/cm. Twisting bilayer graphene leads to
emergence of new phonon branches - termed entangled phonons - which originate
from mixing of phonon modes from different high-symmetry directions in the
Brillouin zone. The frequencies of the entangled phonon depend strongly on the
rotation angle and can be used for non-contact identification of the twist
angles in graphene samples. The obtained results and tabulated frequencies of
phonons in twisted bilayer graphene are important for interpretation of
experimental Raman data and determining thermal conductivity of these materials
systems.


title: A 5-Engel associative algebra whose group of units is not 5-Engel

abstract:
  Let R be an associative ring with unity and let [R] and U(R) denote the
associated Lie ring (with [a,b]=ab-ba) and the group of units of R,
respectively. In 1983 Gupta and Levin proved that if [R] is a nilpotent Lie
ring of class c then U(R) is a nilpotent group of class at most c. The aim of
the present note is to show that, in general, a similar statement does not hold
if [R] is n-Engel. We construct an algebra R over a field of characteristic
different from 2 and 3 such that the Lie algebra [R] is 5-Engel but U(R) is not
a 5-Engel group.


title: Exit densities of Super--Brownian motion as extreme X-harmonic functions

abstract:
  Let $X$ be a super-Brownian motion (SBM) defined on a domain $E\subset R^n$
and $(X_D)$ be its exit measures indexed by sub-domains of $E$. The
relationship between the equation $1/2 \Delta u=2 u^2$ and Super-Brownian
motion (SBM) is analogous to the relationship between Brownian motion and the
Laplace's equation, and substantial progress has been made on the study of the
solutions of this semi-linear p.d.e. exploring this analogy. An area that
remains to be explored is Martin boundary theory. Martin boundary in the
semi-linear case is defined as the convex set of extreme $X$-harmonic functions
which are functions on the space of finite measures supported in a domain $E$
of $R^d$ and characterized by a mean value property with respect to the
Super-Brownian law. So far no probabilistic construction of Martin boundary is
known.
  In this paper, we consider a bounded smooth domain $D$, and we investigate
exit densities of SBM, a certain family of $X$ harmonic functions, $H^{\nu}$,
indexed by finite measures $\nu$ on $\partial{D}$, These densities were first
introduced by E.B. Dynkin and also identified by T.Salisbury and D. Sezer as
the extended X-harmonic functions corresponding to conditioning SBM on its exit
measure $X_D$ being equal to $\nu$. $H^{\nu}(\mu)$ can be thought as the
analogue of the Poisson kernel for Brownian motion. It is well known that
Poisson kernel for a smooth domain $D$ is equivalent to the so called Martin
kernel, the class of extreme harmonic functions for $D$. We show that a similar
result is true for Super-Brownian motion as well, that is $H^{\nu}$ is extreme
for almost all $\nu$ with respect to a certain measure.


title: Statistical Physics of Evolutionary Trajectories on Fitness Landscapes

abstract:
  Random walks on multidimensional nonlinear landscapes are of interest in many
areas of science and engineering. In particular, properties of adaptive
trajectories on fitness landscapes determine population fates and thus play a
central role in evolutionary theory. The topography of fitness landscapes and
its effect on evolutionary dynamics have been extensively studied in the
literature. We will survey the current research knowledge in this field,
focusing on a recently developed systematic approach to characterizing path
lengths, mean first-passage times, and other statistics of the path ensemble.
This approach, based on general techniques from statistical physics, is
applicable to landscapes of arbitrary complexity and structure. It is
especially well-suited to quantifying the diversity of stochastic trajectories
and repeatability of evolutionary events. We demonstrate this methodology using
a biophysical model of protein evolution that describes how proteins maintain
stability while evolving new functions.


title: Subdiffraction-limited quantum imaging within a living cell

abstract:
  We report both sub-diffraction-limited quantum metrology and quantum enhanced
spatial resolution for the first time in a biological context. Nanoparticles
are tracked with quantum correlated light as they diffuse through an extended
region of a living cell in a quantum enhanced photonic force microscope. This
allows spatial structure within the cell to be mapped at length scales down to
10 nm. Control experiments in water show a 14% resolution enhancement compared
to experiments with coherent light. Our results confirm the longstanding
prediction that quantum correlated light can enhance spatial resolution at the
nanoscale and in biology. Combined with state-of-the-art quantum light sources,
this technique provides a path towards an order of magnitude improvement in
resolution over similar classical imaging techniques.


title:
Automatic Calibration Method of Voxel Size for Cone-beam 3D-CT Scanning
  System

abstract:
  For cone-beam three-dimensional computed tomography (3D-CT) scanning system,
voxel size is an important indicator to guarantee the accuracy of data analysis
and feature measurement based on 3D-CT images. Meanwhile, the voxel size
changes with the movement of the rotary table along X-ray direction. In order
to realize the automatic calibration of the voxel size, a new
easily-implemented method is proposed. According to this method, several
projections of a spherical phantom are captured at different imaging positions
and the corresponding voxel size values are calculated by non-linear least
square fitting. Through these interpolation values, a linear equation is
obtained, which reflects the relationship between the rotary table displacement
distance from its nominal zero position and the voxel size. Finally, the linear
equation is imported into the calibration module of the 3D-CT scanning system,
and when the rotary table is moving along X-ray direction, the accurate value
of the voxel size is dynamically exported. The experimental results prove that
this method meets the requirements of the actual CT scanning system, and has
virtues of easy implementation and high accuracy


title: Exact functors on perverse coherent sheaves

abstract:
  Inspired by symplectic geometry and a microlocal characterizations of
perverse (constructible) sheaves we consider an alternative definition of
perverse coherent sheaves. We show that a coherent sheaf is perverse if and
only if $R\Gamma_Z(\mathcal{F})$ is concentrated in degree 0 for special
subvarieties Z of X. These subvarieties Z are analogs of Lagrangians in the
symplectic case.


title:
Dynamical relations in the system of two objects with internal degrees
  of freedom

abstract:
  A system of $N$ interacting objects with internal degrees of freedom is
considered. Derivation of system of equations for the description of two
interacting objects with spin is given. Relations between the parameters
describing subsystems and the parameters describing the system as a whole are
obtained. In particular, relation between energies of subsystems and energy of
system is found, on the basis of which the assumption is made that energy of
subsystem should be oscillatory functions of time, so that interaction between
objects is reduced to permanent energy exchange


title:
UVUDF: Ultraviolet Imaging of the Hubble Ultradeep Field with Wide-field
  Camera 3

abstract:
  We present an overview of a 90-orbit Hubble Space Telescope treasury program
to obtain near ultraviolet imaging of the Hubble Ultra Deep Field using the
Wide Field Camera 3 UVIS detector with the F225W, F275W, and F336W filters.
This survey is designed to: (i) Investigate the episode of peak star formation
activity in galaxies at 1<z<2.5; (ii) Probe the evolution of massive galaxies
by resolving sub-galactic units (clumps); (iii) Examine the escape fraction of
ionizing radiation from galaxies at z~2-3; (iv) Greatly improve the reliability
of photometric redshift estimates; and (v) Measure the star formation rate
efficiency of neutral atomic-dominated hydrogen gas at z~1-3. In this overview
paper, we describe the survey details and data reduction challenges, including
both the necessity of specialized calibrations and the effects of charge
transfer inefficiency. We provide a stark demonstration of the effects of
charge transfer inefficiency on resultant data products, which when
uncorrected, result in uncertain photometry, elongation of morphology in the
readout direction, and loss of faint sources far from the readout. We agree
with the STScI recommendation that future UVIS observations that require very
sensitive measurements use the instrument's capability to add background light
through a "post-flash". Preliminary results on number counts of UV-selected
galaxies and morphology of galaxies at z~1 are presented. We find that the
number density of UV dropouts at redshifts 1.7, 2.1, and 2.7 is largely
consistent with the number predicted by published luminosity functions. We also
confirm that the image mosaics have sufficient sensitivity and resolution to
support the analysis of the evolution of star-forming clumps, reaching 28-29th
magnitude depth at 5 sigma in a 0.2 arcsecond radius aperture depending on
filter and observing epoch.


title: A realisation of the quantum linear superalgebra

abstract:
  We reconstruct the quantum enveloping superalgebra ${\bf
U}(\mathfrak{gl}_{m|n})$ over $\mathbb Q(v)$ via (finite dimensional) quantum
Schur superalgebras. In particular, we obtain a new basis containing the
standard generators of ${\bf U}(\mathfrak{gl}_{m|n})$ and explicit
multiplication formulas between the generators and an arbitrary basis element.


title: A Differential Equations Approach to Optimizing Regret Trade-offs

abstract:
  We consider the classical question of predicting binary sequences and study
the {\em optimal} algorithms for obtaining the best possible regret and payoff
functions for this problem. The question turns out to be also equivalent to the
problem of optimal trade-offs between the regrets of two experts in an "experts
problem", studied before by \cite{kearns-regret}. While, say, a regret of
$\Theta(\sqrt{T})$ is known, we argue that it important to ask what is the
provably optimal algorithm for this problem --- both because it leads to
natural algorithms, as well as because regret is in fact often comparable in
magnitude to the final payoffs and hence is a non-negligible term.
  In the basic setting, the result essentially follows from a classical result
of Cover from '65. Here instead, we focus on another standard setting, of
time-discounted payoffs, where the final "stopping time" is not specified. We
exhibit an explicit characterization of the optimal regret for this setting.
  To obtain our main result, we show that the optimal payoff functions have to
satisfy the Hermite differential equation, and hence are given by the solutions
to this equation. It turns out that characterization of the payoff function is
qualitatively different from the classical (non-discounted) setting, and,
namely, there's essentially a unique optimal solution.


title: A unified geometric treatment of material defects

abstract:
  A unified theory of material defects, incorporating both the smooth and the
singular descriptions, is presented based upon the theory of currents of
Georges de Rham. The fundamental geometric entity of discourse is assumed to be
represented by a single differential form or current, whose boundary is
identified with the defect itself. The possibility of defining a less
restrictive dislocation structure is explored in terms of a plausible weak
formulation of the theorem of Frobenius. Several examples are presented and
discussed.


title: A new collective mode in YBCO observed by time-domain reflectometry

abstract:
  We report the observation of coherent oscillations associated with charge
density wave (CDW) order in the underdoped cuprate superconductor YBa2Cu3O6+x
by time-resolved optical reflectivity. Oscillations with frequency 1.87 THz
onset at approximately 105 K and 130 K for dopings of x = 0.67 (ortho-VIII) and
x = 0.75 (ortho-III), respectively. Upon cooling below the superconducting
critical temperature (T_c), the oscillation amplitude is enhanced, the phase
shifts by \pi, and the frequency softens by \delta \nu / \nu~7%. A
bi-quadratically coupled Landau-Ginzburg model qualitatively describes this
behavior as arising from competition between superconducting and CDW orders.


title: Demonstration of the Double Penning Trap Technique with a Single Proton

abstract:
  Spin flips of a single proton were driven in a Penning trap with a
homogeneous magnetic field. For the spin-state analysis the proton was
transported into a second Penning trap with a superimposed magnetic bottle, and
the continuous Stern-Gerlach effect was applied. This first demonstration of
the double Penning trap technique with a single proton suggests that the
antiproton magnetic moment measurement can potentially be improved by three
orders of magnitude or more.


title: One-Pass AUC Optimization

abstract:
  AUC is an important performance measure and many algorithms have been devoted
to AUC optimization, mostly by minimizing a surrogate convex loss on a training
data set. In this work, we focus on one-pass AUC optimization that requires
only going through the training data once without storing the entire training
dataset, where conventional online learning algorithms cannot be applied
directly because AUC is measured by a sum of losses defined over pairs of
instances from different classes. We develop a regression-based algorithm which
only needs to maintain the first and second order statistics of training data
in memory, resulting a storage requirement independent from the size of
training data. To efficiently handle high dimensional data, we develop a
randomized algorithm that approximates the covariance matrices by low rank
matrices. We verify, both theoretically and empirically, the effectiveness of
the proposed algorithm.


title:
Spin Wave Excitation in Magnetic Insulator Thin Films by Spin-Transfer
  Torque

abstract:
  We describe excitation of dipole-exchange spin waves in insulating magnetic
thin films by spin current injection at the surface of the film. An easy-axis
magnetic surface anisotropy can induce a non-chiral surface spin wave mode with
penetration depth inversely proportional to the strength of the surface
anisotropy, which strongly reduces the critical current and enhances the
excitation power. The importance of the interface spin wave modes on the
excitation spectrum is reduced by spin pumping, which depends on the quality of
the interface as expressed by the spin mixing conductance.


title:
Filon-Clenshaw-Curtis rules for a class of highly-oscillatory integrals
  with logarithmic singularities

abstract:
  In this work we propose and analyse a numerical method for computing a family
of highly oscillatory integrals with logarithmic singularities. For these
quadrature rules we derive error estimates in terms of $N$, the number of
nodes, $k$ the rate of oscillations and a Sobolev-like regularity of the
function. We prove that that the method is not only robust but the error even
decreases, for fixed $N$, as $k$ increases. Practical issues about the
implementation of the rule are also covered in this paper by: (a) writing down
ready-to-implement algorithms; (b) analysing the numerical stability of the
computations and (c) estimating the overall computational cost. We finish by
showing some numerical experiments which illustrate the theoretical results
presented in this paper.


title:
The Domination Number of Generalized Petersen Graphs with a Faulty
  Vertex

abstract:
  In this paper, we investigate the domination number of generalized Petersen
graphs P(n, 2) when there is a faulty vertex. Denote by $\gamma(P(n,2))$ the
domination number of P(n,2) and $\gamma(P_f(n,2))$ the domination number of
P(n,2) with a faulty vertex $u_f$. We show that
$\gamma(P_f(n,2))=\gamma(P(n,2))-1$ when $n=5k+1$ or $5k+2$ and
$\gamma(P_f(n,2))=\gamma(P(n,2))$ for the other cases.


title: Folded Graphene Nanoribbons with Single and Double Closed Edges

abstract:
  Graphene nanoribbon folds with single and double closed edges are studied
using density functional theory methods. Van der Waals dispersive interactions
are included via semi-empirical pairwise optimized potential. The geometrical
phases of the single and double folded ribbons are obtained. The electronic
structure in terms of energy needed for the folding process, van der Waals
contribution, energy band gaps, and bandstructures are also calculated. The
results are interpreted in terms of peculiarities of the structures and
dispersion interactions. It is shown that significant modifications in the
electronic structure can be achieved as a result of folding.


title:
First-principles Investigations on Polytypes of BaTiO3: Hybrid
  Calculations and Pressure Dependences

abstract:
  We report our first-principles investigations on three polytypes of BaTiO3
(BTO): a paraelectric phase with cubic Pm-3m structure and two ferroelectric
(FE) phases with tetragonal P4mm and rhombohedral R3m structures. We compared
the structural and the electrical properties of BTO obtained by using various
approaches: e.g., the Hartree-Fock (HF) theory, the density functional theory
(DFT) with the local density approximation (LDA) or with the two generalized
gradient approximations (two GGAs: PWGGA and PBE), and three hybrid functionals
of the HF and the DFT (B3LYP, B3PW, and PBE0). For the P4mm structure, the two
GGAs and the hybrid functionals reproduced the cell volumes, but slightly
overestimated the c/a ratio. The hybrid functionals provided accurate
predictions for the experimental energy gaps, but slightly underestimated the
experimental dielectric constants. The calculated dielectric constants were
inversely proportional to the c/a ratios for the P4mm structure (or the cH/aH
ratio for the R3m structure), irrespective of the functional choice. Also, the
over-estimated polarization could be ascribed to a super-tetragonality in the
GGA/hybrid functionals. The pressure dependences for the cell parameters,
fractional atomic displacements, energy gaps, dielectric constants, and FE
polarizations were calculated by using the B3PW hybrid functional. As pressure
was increased, the polarization decreased monotonically until it reached zero
at a critical pressure of ~ 20 GPa for both the P4mm and the R3m structures.
Anomalous behaviors were also observed in the atomic movements and the
polarizations for the P4mm structure: (Omitted due to length..) Such behaviors
of the polarizations, together with super-tetragonality/super-trigonality, are
discussed.


title:
Ab-initio studies on the phonons of BaTiO3 polytypes: pressure
  dependences with a hybrid functional

abstract:
  We report the first principles investigations on the phonons of three
polytypes of BaTiO3 (BTO): paraelectric (PE) cubic Pm-3m and two ferroelectric
(FE) phases, tetragonal P4mm and rhombohedral R3m. The phonon frequencies
calculated using various exchange-correlation functionals, including density
functional theory, Hartree-Fock approximation, and their hybrids were reviewed.
The pressure-induced interplays between the modes form individual phases were
explored by calculating the phonon modes as a function of pressure, P from -15
to 230 GPa. The pressure-sensitive modes of the FE phases showed softening and
converged to the modes of the PE phase at pressures below ~ 10 GPa. These
results on the FE phases can be interpreted as phonon-precursors for a change
in symmetry from low- to high-symmetry and partly as a theoretical explanation
for the pressure-induced mode-coupling behaviors reported by Sood et al. [Phys.
Rev. B 51, 8892 (1995)]. As pressure is applied further beyond ~ 50 GPa to the
cubic PE phase, the lowest F1u mode softens again and diverges into two
separate modes of tetragonal FE P4mm at above ~ 150 GPa. These phonon-branching
behaviors at high pressures provide a clear re-confirmation of the re-entrant
ferroelectricity predicted in [Phys. Rev. Lett. 95, 196804 (2005); Phys. Rev. B
74, 180101 (2006); ibid. 85, 054108 (2012)]. The high-pressure-re-entrant FE
polarization was not found in the rhombohedral structure. Instead, the
centosymmetric R-3m phase was favored at above ~ 30 GPa. The phonon modes
calculated for the phonon-propagation vectors in the high-symmetry directions
show that the Pm-3m phase exhibits polar instability at the \Gamma point and
non-polar instability at the X, M, and R points under high pressure.


title: Robust pole placement with Moore's algorithm

abstract:
  We consider the classic problem of pole placement by state feedback. We adapt
the Moore eigenstructure assignment algorithm to obtain a novel parametric form
for the pole-placing gain matrix, and introduce an unconstrained nonlinear
optimization algorithm to obtain a gain matrix that will deliver robust pole
placement. Numerical experiments indicate the algorithm's performance compares
favorably against several other notable robust pole placement methods from the
literature.


title: Granular association rules for multi-valued data

abstract:
  Granular association rule is a new approach to reveal patterns hide in
many-to-many relationships of relational databases. Different types of data
such as nominal, numeric and multi-valued ones should be dealt with in the
process of rule mining. In this paper, we study multi-valued data and develop
techniques to filter out strong however uninteresting rules. An example of such
rule might be "male students rate movies released in 1990s that are NOT
thriller." This kind of rules, called negative granular association rules,
often overwhelms positive ones which are more useful. To address this issue, we
filter out negative granules such as "NOT thriller" in the process of granule
generation. In this way, only positive granular association rules are generated
and strong ones are mined. Experimental results on the movielens data set
indicate that most rules are negative, and our technique is effective to filter
them out.


title: Cold-start recommendation through granular association rules

abstract:
  Recommender systems are popular in e-commerce as they suggest items of
interest to users. Researchers have addressed the cold-start problem where
either the user or the item is new. However, the situation with both new user
and new item has seldom been considered. In this paper, we propose a cold-start
recommendation approach to this situation based on granular association rules.
Specifically, we provide a means for describing users and items through
information granules, a means for generating association rules between users
and items, and a means for recommending items to users using these rules.
Experiments are undertaken on a publicly available dataset MovieLens. Results
indicate that rule sets perform similarly on the training and the testing sets,
and the appropriate setting of granule is essential to the application of
granular association rules.


title:
Soft Modes and Local Structural Transitions in Pb-free
  Ba(Ti0.8Zr0.2)O3-x(Ba0.7Ca0.3)TiO3 (x = 0.5): Pressure- and
  Temperature-dependent Raman Studies

abstract:
  We report our Raman studies of a new lead-free relaxor ferroelectrics,
Ba0.85Ca0.15Ti0.9Zr0.1O3 (BCTZO). The Raman modes of BCTZO are compared with
those of BaTi0.8Zr0.2O3 (BTZO), and BaTiO3 (BTO). Also, they are compared with
the eigenmodes of BTO calculated by using an ab-initio quantum-mechanical
frozen-phonon method. The sharp mode at 321 cm-1 of BTO, reported as a coupled
mode showing an interference effect, becomes progressively broader in BTZO and
BCTZO. This behavior, together with a broadening of the 527-cm-1 mode, suggests
that the mode-coupling is weakened in BTZO and BCTZO. The structural
transitions of BCTZO were investigated as functions of pressure at pressures
below 20 GPa and of temperature at temperatures below 600 K. Three
characteristic pressure-induced transitions, on each at 2.5, 5.0, and 13.0 GPa,
were found. The transitions are suggested by the drastic changes in phonon
modes (two softening modes, one each at ~ 300 and ~ 530 cm-1) and by the
transformation of the intensity profile. A temperature-induced transition was
found at a Curie temperature of ~ 380 K, where the average structure changes
from tetragonal to cubic. It is accompanied by a softening mode at ~ 530 cm-1.
The phonon spectrum of BCTZO suggests that its local environment is close to
that of BTZO. However, the characteristic pressures of BCTZO are close to those
of BTO. The sequence of pressure-induced transitions in both BCTZO and BTZO
illustrate rich interplay between the long-range averaged structure and the
short-range local order such that four distinguishable phases are suggested:
tetragonal, locally ordered but compensated cubic, disordered cubic, and ideal
cubic. We found that the critical pressures are plausibly related to the
average crystal lattice.


title:
Finite difference method for the arbitrary potential in two dimensions:
  application to double/triple quantum dots

abstract:
  A finite difference method (FDM) applicable to a two dimensional (2D) quantum
dot was developed as a non-conventional approach to the theoretical
understandings of quantum devices. This method can be applied to a realistic
potential with an arbitrary shape. Using this method, the Hamiltonian in a
tri-diagonal matrix could be obtained from any 2D potential, and the
Hamiltonian could be diagonalized numerically for the eigenvalues. The
legitimacy of this method was first checked by comparing the results with a
finite round well with the analytic solutions. Two truncated harmonic wells
were examined as a realistic model potential for lateral double quantum dots
(DQDs) and for triple quantum dots (TQDs). The successful applications of the
2D FDM were observed with the entanglements in the DQDs. The level-splitting
and anticrossing behaviors of the DQDs could be obtained by varying the
distance between the dots and by introducing asymmetry in the well-depths. The
2D FDM results for linear/triangular TQDs were compared with the tight binding
approximations.


title:
Unique Perfect Phylogeny Characterizations via Uniquely Representable
  Chordal Graphs

abstract:
  The perfect phylogeny problem is a classic problem in computational biology,
where we seek an unrooted phylogeny that is compatible with a set of
qualitative characters. Such a tree exists precisely when an intersection graph
associated with the character set, called the partition intersection graph, can
be triangulated using a restricted set of fill edges. Semple and Steel used the
partition intersection graph to characterize when a character set has a unique
perfect phylogeny. Bordewich, Huber, and Semple showed how to use the partition
intersection graph to find a maximum compatible set of characters. In this
paper, we build on these results, characterizing when a unique perfect
phylogeny exists for a subset of partial characters. Our characterization is
stated in terms of minimal triangulations of the partition intersection graph
that are uniquely representable, also known as ur-chordal graphs. Our
characterization is motivated by the structure of ur-chordal graphs, and the
fact that the block structure of minimal triangulations is mirrored in the
graph that has been triangulated.


abstract:
  This paper proposes a CLT for linear spectral statistics of random matrix
$S^{-1}T$ for a general non-negative definite and {\bf non-random} Hermitian
matrix $T$.


title:
Determination of the Local Symmetry and the Multiferroic-ferromagnetic
  Crossover in Ni3-xCoxV2O8 by using Raman Scattering Spectroscopy

abstract:
  Comprehensive vibrational studies on the multiferroic-to-normal-ferromagnetic
crossover in isostructural Ni3-xCoxV2O8 (NCVO, x = 0 - 3.0) are performed using
Raman scattering spectroscopy. The systematically red-shifted phonon modes are
discussed in terms of the mode Gr\"uneisen parameters, and are interpreted as a
chemical pressure effect. In addition, we present evidence that the local
symmetry is broken in the multiferroic phase.


title:
A simple and efficient numerical method for computing the dynamics of
  rotating Bose-Einstein condensates via a rotating Lagrangian coordinate

abstract:
  We propose a simple, efficient and accurate numerical method for simulating
the dynamics of rotating Bose-Einstein condensates (BECs) in a rotational frame
with/without a long-range dipole-dipole interaction. We begin with the
three-dimensional (3D) Gross-Pitaevskii equation (GPE) with an angular momentum
rotation term and/or long-range dipole-dipole interaction, state the
two-dimensional (2D) GPE obtained from the 3D GPE via dimension reduction under
anisotropic external potential and review some dynamical laws related to the 2D
and 3D GPE. By introducing a rotating Lagrangian coordinate system, the
original GPEs are re-formulated to GPEs without the angular momentum rotation
which is replaced by a time-dependent potential in the new coordinate system.
We then cast the conserved quantities and dynamical laws in the new rotating
Lagrangian coordinates. Based on the new formulation of the GPE for rotating
BECs in the rotating Lagrangian coordinates, a time-splitting spectral method
is presented for computing the dynamics of rotating BECs. The new numerical
method is explicit, simple to implement, unconditionally stable and very
efficient in computation. It is spectral order accurate in space and
second-order accurate in time, and conserves the mass in the discrete level.
Extensive numerical results are reported to demonstrate the efficiency and
accuracy of the new numerical method. Finally, the numerical method is applied
to test the dynamical laws of rotating BECs such as the dynamics of condensate
width, angular momentum expectation and center-of-mass, and to investigate
numerically the dynamics and interaction of quantized vortex lattices in
rotating BECs without/with the long-range dipole-dipole interaction.


title: Hyperbolic Geometry and Homotopic Homeomorphisms of Surfaces

abstract:
  The Epstein-Baer theory of curve isotopies is basic to the remarkable theorem
that homotopic homeomorphisms of surfaces are isotopic. The groundbreaking work
of R. Baer was carried out on closed, orientable surfaces and extended by D. B.
A. Epstein to arbitrary surfaces, compact or not, with or without boundary and
orientable or not. We give a new method of deducing the theorem about homotopic
homeomorphisms from the results about homotopic curves via the hyperbolic
geometry of surfaces. This works on all but 13 surfaces where ad hoc proofs are
needed.


title: Enzyme-Based Logic: OR Gate with Double-Sigmoid Filter Response

abstract:
  The first realization of a biomolecular OR gate function with double-sigmoid
response (sigmoid in both inputs) is reported. Two chemical inputs activate the
enzymatic gate processes resulting in the output signal: chromogen oxidation,
which occurs when either one of the inputs or both are present (corresponding
to the OR binary function), and can be optically detected. High-quality gate
functioning in handling of sources of noise is enabled by "filtering" involving
pH control with an added buffer. The resulting gate response is sigmoid in both
inputs when proper system parameters are chosen, and the gate properties are
theoretically analyzed within a model devised to evaluate its noise-handling
properties.


title:
Scaling of the Kondo zero bias peak in a hole quantum dot at finite
  temperatures

abstract:
  We have measured the zero bias peak in differential conductance in a hole
quantum dot. We have scaled the experimental data with applied bias and
compared to real time renormalization group calculations of the differential
conductance as a function of source-drain bias in the limit of zero temperature
and at finite temperatures. The experimental data show deviations from the T=0
calculations at low bias, but are in very good agreement with the finite T
calculations. The Kondo temperature T_K extracted from the data using T=0
calculations, and from the peak width at 2/3 maximum, is significantly higher
than that obtained from finite T calculations.


title: Corresponding states for mesostructure and dynamics of supercooled water

abstract:
  Water famously expands upon freezing, foreshadowed by a negative coefficient
of expansion of the liquid at temperatures close to its freezing temperature.
These behaviors, and many others, reflect the energetic preference for local
tetrahedral arrangements of water molecules and entropic effects that oppose
it. Here, we provide theoretical analysis of mesoscopic implications of this
competition, both equilibrium and non-equilibrium, including mediation by
interfaces. With general scaling arguments bolstered by simulation results, and
with reduced units that elucidate corresponding states, we derive a phase
diagram for bulk and confined water and water-like materials. For water itself,
the corresponding states cover the temperature range of 150 K to 300 K and the
pressure range of 1 bar to 2 kbar. In this regime, there are two reversible
condensed phases - ice and liquid. Out of equilibrium, there is irreversible
polyamorphism, i.e., more than one glass phase, reflecting dynamical arrest of
coarsening ice. Temperature-time plots are derived to characterize time scales
of the different phases and explain contrasting dynamical behaviors of
different water-like systems.


title: Mixing, entropy and competition

abstract:
  Non-traditional thermodynamics, applied to random behaviour associated with
turbulence, mixing and competition, is reviewed and analysed. Competitive
mixing represents a general framework for the study of generic properties of
competitive systems and can be used to model a wide class of non-equilibrium
phenomena ranging from turbulent premixed flames and invasion waves to complex
competitive systems. We demonstrate consistency of the general principles of
competition with thermodynamic description, review and analyse the related
entropy concepts and introduce the corresponding competitive H-theorem. A
competitive system can be characterised by a thermodynamic quantity -
competitive potential --- which determines the likely direction of evolution of
the system. Contested resources tend to move between systems from lower to
higher values of the competitive potential. There is, however, an important
difference between conventional thermodynamics and competitive thermodynamics.
While conventional thermodynamics is constrained by its zeroth law and is
fundamentally transitive, the transitivity of competitive thermodynamics
depends on the transitivity of the competition rules. Intransitivities are
common in the real world and are responsible for complex behaviour in
competitive systems.
  This work follows the ideas and methods that are originated in analysis of
turbulent combustion but reviews a much broader scope of issues linked to
mixing and competition, including thermodynamic characterisation of complex
competitive systems with self-organisation. The approach presented here is
interdisciplinary and is addressed to a general educated reader, while the
mathematical details can be found in the Appendices.


title: Results on D+-->lv and Ds+-->lv decays at Charm factory

abstract:
  In this article, we reviewed the results on D+-->lv and Ds+-->lv decays at
Charm factory.


title:
Functional and Parametric Estimation in a Semi- and Nonparametric Model
  with Application to Mass-Spectrometry Data

abstract:
  Motivated by modeling and analysis of mass-spectrometry data, a semi- and
nonparametric model is proposed that consists of a linear parametric component
for individual location and scale and a nonparametric regression function for
the common shape. A multi-step approach is developed that simultaneously
estimates the parametric components and the nonparametric function. Under
certain regularity conditions, it is shown that the resulting estimators is
consistent and asymptotic normal for the parametric part and achieve the
optimal rate of convergence for the nonparametric part when the bandwidth is
suitably chosen. Simulation results are presented to demonstrate the
effectiveness and finite-sample performance of the method. The method is also
applied to a SELDI-TOF mass spectrometry data set from a study of liver cancer
patients.