title: Terrestrial Planet Formation at Home and Abroad

abstract:
  We review the state of the field of terrestrial planet formation with the
goal of understanding the formation of the inner Solar System and low-mass
exoplanets. We review the dynamics and timescales of accretion from
planetesimals to planetary embryos and from embryos to terrestrial planets. We
discuss radial mixing and water delivery, planetary spins and the importance of
parameters regarding the disk and embryo properties. Next, we connect accretion
models to exoplanets. We first explain why the observed hot Super Earths
probably formed by in situ accretion or inward migration. We show how
terrestrial planet formation is altered in systems with gas giants by the
mechanisms of giant planet migration and dynamical instabilities. Standard
models of terrestrial accretion fail to reproduce the inner Solar System. The
"Grand Tack" model solves this problem using ideas first developed to explain
the giant exoplanets. Finally, we discuss whether most terrestrial planet
systems form in the same way as ours, and highlight the key ingredients missing
in the current generation of simulations.


title: Bar slowdown and the distribution of dark matter in barred galaxies

abstract:
  `Conspiracy' between the dark and the baryonic mater prohibits an unambiguous
decomposition of disc galaxy rotation curves into the corresponding components.
Several methods have been proposed to counter this difficulty, but their
results are widely discrepant. In this paper, I revisit one of these methods,
which relies on the relation between the halo density and the decrease of the
bar pattern speed. The latter is routinely characterised by the ratio ${\cal
R}$ of the corotation radius $R_{CR}$ to the bar length $L_b$, ${\cal
R}=R_{CR}/L_b$. I use a set of $N$-body+SPH simulations, including sub-grid
physics, whose initial conditions cover a range of gas fractions and halo
shapes. The models, by construction, have roughly the same azimuthally averaged
circular velocity curve and halo density and they are all submaximal, i.e.
according to previous works they are expected to have all roughly the same
${\cal
  R}$ value, well outside the fast bar range (1.2 $\pm$ 0.2). Contrary to these
expectations, however, these simulations end up having widely different ${\cal
R}$ values, either within the fast bar range, or well outside it. This shows
that the ${\cal R}$ value can not constrain the halo density, nor determine
whether galactic discs are maximal or submaximal. I argue that this is true
even for early type discs (S0s and Sas).


title:
Transient jet formation and state transitions from large-scale magnetic
  reconnection in black hole accretion discs

abstract:
  Magnetically arrested accretion discs (MADs), where the magnetic pressure in
the inner disc is dynamically important, provide an alternative mechanism for
regulating accretion to what is commonly assumed in black hole systems. We show
that a global magnetic field inversion in the MAD state can destroy the jet,
significantly increase the accretion rate, and move the effective inner disc
edge in to the marginally stable orbit. Reconnection of the MAD field in the
inner radii launches a new type of transient outflow containing hot plasma
generated by magnetic dissipation. This transient outflow can be as powerful as
the steady magnetically-dominated Blandford-Znajek jet in the MAD state. The
field inversion qualitatively describes many of the observational features
associated with the high luminosity hard to soft state transition in black hole
X-ray binaries: the jet line, the transient ballistic jet, and the drop in rms
variability. These results demonstrate that the magnetic field configuration
can influence the accretion state directly, and hence the magnetic field
structure is an important second parameter in explaining observations of
accreting black holes across the mass and luminosity scales.


title: IIA supergravity and M-theory on manifolds with SU(4) structure

abstract:
  We give the general form of supersymmetric backgrounds with two real
supercharges of M-theory and type IIA supergravity (with non-zero Romans mass
in general) of the form $\mathbb{R}^{1,d} \times \M_8$, d=1,2, on
eight-dimensional manifolds with SU(4) structure. We point out a subtlety in
the integrability theorems for low-dimensional supersymmetric
compactifications. As a special case we examine Calabi-Yau flux vacua and we
show that unbroken supersymmetry does not in general require the four-form flux
to be (2,2) or primitive. Our results could be used to construct novel
higher-dimensional analogues of the Klebanov-Strassler geometry. In the case of
M-theory large-volume Calabi-Yau flux vacua our results are in agreement with
partial supersymmetry breaking in three-dimensional N=2 supergravity.
Alternatively, the conditions for supersymmetry can be expressed in terms of a
real `superpotential' in accordance with three-dimensional N=1 supergravity. We
present explicit examples of M-theory flux vacua on K3 \times K3, which however
do not appear to possess F-theory duals with four-dimensional Poincar\'e
invariance.


title:
Bethe Ansatz for Yangian Invariants: Towards Super Yang-Mills Scattering
  Amplitudes

abstract:
  We propose that Baxter's Z-invariant six-vertex model at the rational gl(2)
point on a planar but in general not rectangular lattice provides a way to
study Yangian invariants. These are identified with eigenfunctions of certain
monodromies of an auxiliary inhomogeneous spin chain. As a consequence they are
special solutions to the eigenvalue problem of the associated transfer matrix.
Excitingly, this allows to construct them using Bethe ansatz techniques.
Conceptually, our construction generalizes to general (super) Lie algebras and
general representations. Here we present the explicit form of sample invariants
for totally symmetric, finite-dimensional representations of gl(n) in terms of
oscillator algebras. In particular, we discuss invariants of three- and
four-site monodromies that can be understood respectively as intertwiners of
the bootstrap and Yang-Baxter equation. We state a set of functional relations
significant for these representations of the Yangian and discuss their
solutions in terms of Bethe roots. They arrange themselves into exact strings
in the complex plane. In addition, it is shown that the sample invariants can
be expressed analogously to Grassmannian integrals. This aspect is closely
related to a recent on-shell formulation of scattering amplitudes in planar N=4
super Yang-Mills theory.

categories: math-ph cond-mat.stat-mech hep-th math.MP nlin.SI


title:
Star formation in the cluster CLG0218.3-0510 at z=1.62 and its
  large-scale environment: the infrared perspective

abstract:
  The galaxy cluster CLG0218.3-0510 at z=1.62 is one of the most distant galaxy
clusters known, with a rich muti-wavelength data set that confirms a mature
galaxy population already in place. Using very deep, wide area (20x20 Mpc)
imaging by Spitzer/MIPS at 24um, in conjunction with Herschel 5-band imaging
from 100-500um, we investigate the dust-obscured, star-formation properties in
the cluster and its associated large scale environment. Our galaxy sample of
693 galaxies at z=1.62 detected at 24um (10 spectroscopic and 683 photo-z)
includes both cluster galaxies (i.e. within r <1 Mpc projected clustercentric
radius) and field galaxies, defined as the region beyond a radius of 3 Mpc. The
star-formation rates (SFRs) derived from the measured infrared luminosity range
from 18 to 2500 Ms/yr, with a median of 55 Ms/yr, over the entire radial range
(10 Mpc). The cluster brightest FIR galaxy, taken as the centre of the galaxy
system, is vigorously forming stars at a rate of 256$\pm$70 Ms/yr, and the
total cluster SFR enclosed in a circle of 1 Mpc is 1161$\pm$96 Ms/yr. We
estimate a dust extinction of about 3 magnitudes by comparing the SFRs derived
from [OII] luminosity with the ones computed from the 24um fluxes. We find that
the in-falling region (1-3 Mpc) is special: there is a significant decrement
(3.5x) of passive relative to star-forming galaxies in this region, and the
total SFR of the galaxies located in this region is lower (130 Ms/yr/Mpc2) than
anywhere in the cluster or field, regardless of their stellar mass. In a
complementary approach we compute the local galaxy density, Sigma5, and find no
trend between SFR and Sigma5. However, we measure an excess of star-forming
galaxies in the cluster relative to the field by a factor 1.7, that lends
support to a reversal of the SF-density relation in CLG0218.


title:
Gate count estimates for performing quantum chemistry on small quantum
  computers

abstract:
  As quantum computing technology improves and quantum computers with a small
but non-trivial number of N > 100 qubits appear feasible in the near future the
question of possible applications of small quantum computers gains importance.
One frequently mentioned application is Feynman's original proposal of
simulating quantum systems, and in particular the electronic structure of
molecules and materials. In this paper, we analyze the computational
requirements for one of the standard algorithms to perform quantum chemistry on
a quantum computer. We focus on the quantum resources required to find the
ground state of a molecule twice as large as what current classical computers
can solve exactly. We find that while such a problem requires about a ten-fold
increase in the number of qubits over current technology, the required increase
in the number of gates that can be coherently executed is many orders of
magnitude larger. This suggests that for quantum computation to become useful
for quantum chemistry problems, drastic algorithmic improvements will be
needed.


title: BTZ Black Hole Entropy and the Turaev-Viro model

abstract:
  We show the explicit agreement between the derivation of the
Bekenstein-Hawking entropy of a Euclidean BTZ black hole from the point of view
of spin foam models and canonical quantization. This is done by considering a
graph observable (corresponding to the black hole horizon) in the Turaev-Viro
state sum model, and then analytically continuing the resulting partition
function to negative values of the cosmological constant.


title:
The LOFT mission: new perspectives in the research field of (accreting)
  compact objects

abstract:
  LOFT, the Large Observatory For X-ray Timing, is one of five ESA M3 candidate
missions. It will address the Cosmic Vision theme: "Matter under Extreme
Conditions". By coupling for the first time a huge collecting area for the
detection of X-ray photons with CCD-quality spectral resolution (15 times
bigger in area than any previously flown X-ray instrument and >100 times bigger
for spectroscopy than any similar-resolution instrument), the instruments
on-board LOFT have been designed to (i) determine the properties of ultradense
matter by reconstructing its Equation of State through neutron star mass and
radius measurements of unprecedented accuracy; (ii) measure General Relativity
effects in the strong field regime in the stationary spacetimes of neutron
stars and black holes of all masses down to a few gravitational radii. Besides
the above two themes, LOFT's observations will be devoted to "observatory
science", providing new insights in a number of research fields in high energy
astrophysics (e.g. Gamma-ray Bursts). The assessment study phase of LOFT, which
ended in September 2013, demonstrated that the mission is low risk and the
required Technology Readiness Level can be easily reached in time for a launch
by the end of 2022.


title: Multiphoton signatures of goldstini at the LHC

abstract:
  We study models of gauge mediated SUSY breaking with more than one hidden
sector. In these models the neutralino sector of the MSSM is supplemented with
additional light neutral fermions, the nearly massless gravitino and the
massive pseudo-goldstini. For the case where the Bino is the lightest ordinary
SUSY particle, its preferred decay is to a photon and the heaviest
pseudo-goldstino, which generically cascades down to lighter pseudo-goldstini,
or to the gravitino, in association with photons. This gives rise to
multiphoton plus missing energy signatures at the LHC. We investigate in detail
simplified models where the SUSY spectrum consists of the right-handed
sleptons, a Bino-like neutralino, the pseudo-goldstini and the gravitino. We
compare against existing LHC searches and show that the sensitivity to our
models could be significantly improved by relaxing the kinematic cuts and
requiring additional final state particles. We propose inclusive searches in
the final state with at least three photons plus missing energy and in the
final state with at least two photons plus two leptons plus missing energy, the
former being sensitive to any production mode and the latter being optimized
for slepton pair production. We show that they could lead to an observation (or
strong constraints) already with the data set from LHC Run I, and present
prospects for LHC Run II.


title:
Mergers as triggers for nuclear activity: A near-IR study of the close
  environment of AGN in the VISTA-VIDEO survey

abstract:
  There is an ongoing debate concerning the driver of nuclear activity in
galaxies, with AGN either being triggered by major or minor galactic mergers
or, alternatively, through secular processes like cooling gas accretion and/or
formation of bars. We investigate the close environment of active galaxies
selected in the X-ray, the radio, and the mid-IR. We utilise the first data
release of the new near-IR VISTA Deep Extragalactic Observations (VIDEO) survey
of the XMM-Large Scale Structure (LSS) field. We use two measures of
environment density, namely counts within a given aperture and a finite
redshift slice (pseudo-3D density) and closest neighbour density measures
${\Sigma}_{2}$ and ${\Sigma}_{5}$. We select both AGN and control samples,
matching them in redshift and apparent Ks-band magnitude. We find that AGN are
found in a range of environments, with a subset of the AGN samples residing in
over-dense environments. Seyfert-like X-ray AGN and flat-spectrum radio-AGN are
found to inhabit significantly over-dense environments compared to their
control sample. The relation between over-densities and AGN luminosity does not
however reveal any positive correlation. Given the absence of an environment
density-AGN luminosity relation,we find no support for a scheme where high
luminosity AGN are preferentially triggered by mergers. On the contrary, we
find that AGN likely trace over dense environments at high redshift due to the
fact that they inhabit the most massive galaxies, rather than being an AGN.


title: The Pressure of the Star Forming ISM in Cosmological Simulations

abstract:
  We examine the pressure of the star-forming interstellar medium (ISM) of
Milky-Way sized disk galaxies using fully cosmological SPH+N-body, high
resolution simulations. These simulations include explicit treatment of
metal-line cooling in addition to dust and self-shielding, $\mathrm{H_{2}}$
based star formation. The 4 simulated halos have masses ranging from a few
times $10^{10}$ to nearly $10^{12}$ solar masses. Using a kinematic
decomposition of these galaxies into present-day bulge and disk components, we
find that the typical pressure of the star-forming ISM in the present-day bulge
is higher than that in the present-day disk by an order of magnitude. We also
find that pressure of the star-forming ISM at high redshift is on average,
higher than ISM pressures at low redshift. This explains the why the bulge
forms at higher pressures: the disk assembles at lower redshift, when the ISM
is lower pressure and the bulge forms at high redshift, when the ISM is at
higher pressure. If ISM pressure and IMF variation are tied together as
suggested in studies like \cite{Conroy2012}, these results could indicate a
time-dependent IMF in Milky-Way like systems, as well as a different IMF in the
bulge and the disk.


title: Remote Filters and Discretely Generated Spaces

abstract:
  Alas, Junqueira and Wilson asked whether there is a discretely generated
locally compact space whose one point compactification is not discretely
generated and gave a consistent example using CH. Their construction uses a
remote filter in $\omega\times{}^{\omega}2$ with a base of order type
$\omega_1$ when ordered modulo compact subsets. In this paper we study the
existence and preservation (under forcing extension) of similar types of
filters, mainly using small uncountable cardinals. With these results we show
that the CH example can be constructed in more general situations.


title:
Chemically-exfoliated single-layer MoS$_2$ : stability, lattice dynamics
  and catalytic adsorption from first principles

abstract:
  Chemically and mechanically exfoliated MoS$_2$ single-layer samples have
substantially different properties. While mechanically exfoliated single-layers
are mono-phase (1H polytype with Mo in trigonal prismatic coordination), the
chemically exfoliated samples show coexistence of three different phases, 1H,
1T (Mo in octahedral coordination) and 1T$^{'}$ (a distorted $2\times 1$
1T-superstructure). By using first-principles calculations, we investigate the
energetics and the dynamical stability of the three phases. We show that the 1H
phase is the most stable one, while the metallic 1T phase, strongly unstable,
undergoes a phase transition towards a metastable and insulating 1T$^{'}$
structure composed of separated zig-zag chains. We calculate electronic
structure, phonon dispersion, Raman frequencies and intensities for the
1T$^{'}$ structure. We provide a microscopical description of the J$_1$, J$_2$
and J$_3$ Raman features first detected more then $20$ years ago, but
unexplained up to now. Finally, we show that H adsorbates, that are naturally
present at the end of the chemical exfoliation process, stabilize the
1T$^{\prime}$ over the 1H one.


title:
Generalized Taylor-Duffy Method for Efficient Evaluation of Galerkin
  Integrals in Boundary-Element Method Computations

abstract:
  We present a generic technique, automated by computer-algebra systems and
available as open-source software \cite{scuff-em}, for efficient numerical
evaluation of a large family of singular and nonsingular 4-dimensional
integrals over triangle-product domains, such as those arising in the
boundary-element method (BEM) of computational electromagnetism. To date,
practical implementation of BEM solvers has often required the aggregation of
multiple disparate integral-evaluation schemes to treat all of the distinct
types of integrals needed for a given BEM formulation; in contrast, our
technique allows many different types of integrals to be handled by the
\emph{same} algorithm and the same code implementation. Our method is a
significant generalization of the Taylor--Duffy approach
\cite{Taylor2003,Duffy1982}, which was originally presented for just a single
type of integrand; in addition to generalizing this technique to a broad class
of integrands, we also achieve a significant improvement in its efficiency by
showing how the \emph{dimension} of the final numerical integral may often be
reduced by one. In particular, if $n$ is the number of common vertices between
the two triangles, in many cases we can reduce the dimension of the integral
from $4-n$ to $3-n$, obtaining a closed-form analytical result for $n=3$ (the
common-triangle case).


title: A Whitney map onto the Long Arc

abstract:
  In a recent paper, Garc\'{\i}a-Velazquez has extended the notion of Whitney
map to include maps with non-metrizable codomain and left open the question of
whether there is a continuum that admits such a Whitney map. In this paper, we
consider two examples of hereditarily indecomposable, chainable continua of
weight $\omega_1$ constructed by Michel Smith; we show that one of them admits
a Whitney function onto the long arc and the other admits no Whitney maps at
all.


title: Wijsman hyperspaces of non-separable metric spaces

abstract:
  Given a metric space $\langle X,\rho \rangle$, consider its hyperspace of
closed sets $CL(X)$ with the Wijsman topology $\tau_{W(\rho)}$. It is known
that $\langle{CL(X),\tau_{W(\rho)}}\rangle$ is metrizable if and only if $X$ is
separable and it is an open question by Di Maio and Meccariello whether this is
equivalent to $\langle{CL(X),\tau_{W(\rho)}}\rangle$ being normal. In this
paper we prove that if the weight of $X$ is a regular uncountable cardinal and
$X$ is locally separable, then $\langle{CL(X),\tau_{W(\rho)}}\rangle$ is not
normal. We also solve some questions by Cao, Junnilla and Moors regarding
isolated points in Wijsman hyperspaces.


title:
Swapping Variables for High-Dimensional Sparse Regression with
  Correlated Measurements

abstract:
  We consider the high-dimensional sparse linear regression problem of
accurately estimating a sparse vector using a small number of linear
measurements that are contaminated by noise. It is well known that the standard
cadre of computationally tractable sparse regression algorithms---such as the
Lasso, Orthogonal Matching Pursuit (OMP), and their extensions---perform poorly
when the measurement matrix contains highly correlated columns. To address this
shortcoming, we develop a simple greedy algorithm, called SWAP, that
iteratively swaps variables until convergence. SWAP is surprisingly effective
in handling measurement matrices with high correlations. In fact, we prove that
SWAP outputs the true support, the locations of the non-zero entries in the
sparse vector, under a relatively mild condition on the measurement matrix.
Furthermore, we show that SWAP can be used to boost the performance of any
sparse regression algorithm. We empirically demonstrate the advantages of SWAP
by comparing it with several state-of-the-art sparse regression algorithms.


title: The MICE Grand Challenge Lightcone Simulation I: Dark matter clustering

abstract:
  We present a new N-body simulation from the MICE collaboration, the MICE
Grand Challenge (MICE-GC), containing about 70 billion dark-matter particles in
a (3 Gpc/h)^3 comoving volume. Given its large volume and fine spatial
resolution, spanning over 5 orders of magnitude in dynamic range, it allows an
accurate modeling of the growth of structure in the universe from the linear
through the highly non-linear regime of gravitational clustering. We validate
the dark-matter simulation outputs using 3D and 2D clustering statistics, and
discuss mass-resolution effects in the non-linear regime by comparing to
previous simulations and the latest numerical fits. We show that the MICE-GC
run allows for a measurement of the BAO feature with percent level accuracy and
compare it to state-of-the-art theoretical models. We also use sub-arcmin
resolution pixelized 2D maps of the dark-matter counts in the lightcone to make
tomographic analyses in real and redshift space. Our analysis shows the
simulation reproduces the Kaiser effect on large scales, whereas we find a
significant suppression of power on non-linear scales relative to the real
space clustering. We complete our validation by presenting an analysis of the
3-point correlation function in this and previous MICE simulations, finding
further evidence for mass-resolution effects. This is the first of a series of
three papers in which we present the MICE-GC simulation, along with a wide and
deep mock galaxy catalog built from it. This mock is made publicly available
through a dedicated webportal, http://cosmohub.pic.es.


title: Focus-focus singularities in classical mechanics

abstract:
  In this paper the local singularities of integrable Hamiltonian systems with
two degrees of freedom are studied. The topological obstruction to the
existence of focus-focus singularity with given complexity was found. It has
been showed that only simple focus-focus singularities can appear in a typical
mechanical system. The model examples of mechanical systems with complex
focus-focus singularity are given.


title: Heaps and unpointed stable homotopy theory

abstract:
  In this paper, we show how certain ``stability phenomena'' in unpointed model
categories provide the sets of homotopy classes with the structure of abelian
heaps, i.e. abelian groups without a choice of a zero. In contrast with the
classical situation of stable (pointed) model categories, these sets can be
empty.


title:
The failure of DFT-based computations for a stepped-substrate-supported
  correlated Co wire

abstract:
  Density functional theory (DFT) has been immensely successful in its ability
to predict physical properties, and, in particular, structures of condensed
matter systems. Here, however, we show that DFT qualitatively fails to predict
the dimerized structural phase for a monatomic Co wire that is self-assembled
on a vicinal, i.e. stepped, Cu(111) substrate. To elucidate the nature of this
failure, we compute the energetics of a Co chain on a Cu surface, step, notch,
and embedded in bulk. The results demonstrate that increasing Co coordination
extinguishes the dimerization, indicating that the failure of DFT for Co on the
Cu step arises from excessive hybridization, which both weakens the
ferromagnetic correlations that drive the dimerization and increases the
bonding that opposes dimerization. Additionally, we show that including local
interactions via DFT+U or DFT+DMFT does not restore the dimerization for the
step-substrate supported wire, though the Co wire does dimerize in DFT+DMFT for
the isolated vacuum case. This system can serve as a benchmark for future
electronic structure methods.


title: Tunable Spin Qubit Coupling Mediated by a Multi-Electron Quantum Dot

abstract:
  We present an approach for entangling electron spin qubits localized on
spatially separated impurity atoms or quantum dots via a multi-electron,
two-level quantum dot. The effective exchange interaction mediated by the dot
can be understood as the simplest manifestation of
Ruderman-Kittel-Kasuya-Yosida exchange, and can be manipulated through gate
voltage control of level splittings and tunneling amplitudes within the system.
This provides both a high degree of tuneability and a means for realizing
high-fidelity two-qubit gates between spatially separated spins, yielding an
experimentally accessible method of coupling donor electron spins in silicon
via a hybrid impurity-dot system.


title:
How soon after a zero-temperature quench is the fate of the Ising model
  sealed?

abstract:
  We study the transient between a fully disordered initial condition and a
percolating structure in the low-temperature non-conserved order parameter
dynamics of the bi-dimensional Ising model. We show that a stable structure of
spanning clusters establishes at a time $t_p \simeq L^{\alpha_p}$. Our
numerical results yield $\alpha_p=0.50(2)$ for the square and kagome,
$\alpha_p=0.33(2)$ for the triangular and $\alpha_p=0.38(5)$ for the bowtie-a
lattices.We generalise the dynamic scaling hypothesis to take into account this
new time-scale. We discuss the implications of these results for other
non-equilibrium processes.


title:
Interstellar Absorption Lines in the Direction of the Cataclysmic
  Variable SS Cygni

abstract:
  We present an analysis of interstellar absorption lines in high-resolution
optical echelle spectra of SS Cyg obtained during an outburst in 2013 June and
in archival Hubble Space Telescope and Far Ultraviolet Spectroscopic Explorer
data. The Ca II K and Na I D lines toward SS Cyg are compared with those toward
nearby B and A stars in an effort to place constraints on the distance to SS
Cyg. We find that the distance constraints are not very robust from this method
due to the rather slow increase in neutral gas column density with distance and
the scatter in the column densities from one sight line to another. However,
the optical absorption-line measurements allow us to derive a precise estimate
for the line-of-sight reddening of E(B-V) = 0.020+/-0.005 mag. Furthermore, our
analysis of the absorption lines of O I, Si II, P II, and Fe II seen in the UV
spectra yields an estimate of the H I column density and depletion strength in
this direction.


title: On the number of non-congruent lattice tetrahedra

abstract:
  We prove that there are "many" non-congruent tetrahedra in the truncated
lattice $[0,q]^3\cap \mathbb{Z}^3$.


title: The Keplerian orbit of G2

abstract:
  We give an update of the observations and analysis of G2 - the gaseous red
emission-line object that is on a very eccentric orbit around the Galaxy's
central black hole and predicted to come within 2400 Rs in early 2014. During
2013, the laser guide star adaptive optics systems on the W. M. Keck I and II
telescopes were used to obtain three epochs of spectroscopy and imaging at the
highest spatial resolution currently possible in the near-IR. The updated
orbital solution derived from radial velocities in addition to Br-Gamma line
astrometry is consistent with our earlier estimates. Strikingly, even ~6 months
before pericenter passage there is no perceptible deviation from a Keplerian
orbit. We furthermore show that a proposed "tail" of G2 is likely not
associated with it but is rather an independent gas structure. We also show
that G2 does not seem to be unique, since several red emission-line objects can
be found in the central arcsecond. Taken together, it seems more likely that G2
is ultimately stellar in nature, although there is clearly gas associated with
it.


title: Lattice Input on the Inclusive $\tau$ Decay $V_{us}$ Puzzle

abstract:
  Recent analyses of flavor-breaking hadronic-$\tau$-decay-based sum rules
produce values of $\vert V_{us}\vert$ $\sim 3\sigma$ low compared to 3-family
unitarity expectations. An unresolved systematic issue is the significant
variation in $\vert V_{us}\vert$ produced by different prescriptions for
treating the slowly converging $D=2$ OPE series. We investigate the reliability
of these prescriptions using lattice data for various flavor-breaking
correlators and show the fixed-scale prescription is clearly preferred.
Preliminary updates of the conventional $\tau$-based, and related mixed
$\tau$-electroproduction-data-based, sum rule analyses incorporating B-factory
results for low-multiplicity strange $\tau$ decay mode distributions are then
performed. Use of the preferred FOPT $D=2$ OPE prescription is shown to
significantly reduce the discrepancy between 3-family unitarity expectations
and the sum rule results.


title:
Sampling and Reconstruction in Different Subspaces by Using Oblique
  Projections

abstract:
  We introduce a new method for the reconstruction of a function from linear
measurements by means of oblique projections. The space spanned by the
measurement vectors may be different from the subspace in which the function is
reconstructed. This method is a variation of the generalized sampling of Adcock
and Hansen. In many cases the use of suitable oblique projections yield a
better quasi-optimality constants than in generalized sampling.


title: Upper semicomputable sumtests for lower semicomputable semimeasures

abstract:
  A sumtest for a discrete semimeasure $P$ is a function $f$ mapping bitstrings
to non-negative rational numbers such that \[
  \sum P(x)f(x) \le 1 \,.
  \] Sumtests are the discrete analogue of Martin-L\"of tests. The behavior of
sumtests for computable $P$ seems well understood, but for some applications
lower semicomputable $P$ seem more appropriate. In the case of tests for
independence, it is natural to consider upper semicomputable tests (see
[B.Bauwens and S.Terwijn, Theory of Computing Systems 48.2 (2011): 247-268]).
  In this paper, we characterize upper semicomputable sumtests relative to any
lower semicomputable semimeasures using Kolmogorov complexity. It is studied to
what extend such tests are pathological: can upper semicomputable sumtests for
$m(x)$ be large? It is shown that the logarithm of such tests does not exceed
$\log |x| + O(\log^{(2)} |x|)$ (where $|x|$ denotes the length of $x$ and
$\log^{(2)} = \log\log$) and that this bound is tight, i.e. there is a test
whose logarithm exceeds $\log |x| - O(\log^{(2)} |x|$) infinitely often.
Finally, it is shown that for each such test $e$ the mutual information of a
string with the Halting problem is at least $\log e(x)-O(1)$; thus $e$ can only
be large for ``exotic'' strings.


title: Programming Protocol-Independent Packet Processors

abstract:
  P4 is a high-level language for programming protocol-independent packet
processors. P4 works in conjunction with SDN control protocols like OpenFlow.
In its current form, OpenFlow explicitly specifies protocol headers on which it
operates. This set has grown from 12 to 41 fields in a few years, increasing
the complexity of the specification while still not providing the flexibility
to add new headers. In this paper we propose P4 as a strawman proposal for how
OpenFlow should evolve in the future. We have three goals: (1)
Reconfigurability in the field: Programmers should be able to change the way
switches process packets once they are deployed. (2) Protocol independence:
Switches should not be tied to any specific network protocols. (3) Target
independence: Programmers should be able to describe packet-processing
functionality independently of the specifics of the underlying hardware. As an
example, we describe how to use P4 to configure a switch to add a new
hierarchical label.


title:
Propagation of non-classical states of light through one-dimensional
  photonic lattices

abstract:
  We study the propagation of non-classical light through arrays of coupled
linear photonic waveguides and introduce some sets of refractive indices and
coupling parameters that provide a closed form propagator in terms of
orthogonal polynomials. We present propagation examples of non-classical states
of light: single photon, coherent state, path-entangled state and two-mode
squeezed vacuum impinging into two-waveguide couplers and a photonic lattice
producing coherent transport.


title: Cartan class of Invariant forms on Lie groups

abstract:
  We are interested in the class, in the Elie Cartan sense, of left invariant
forms on a Lie group. We construct the class of Lie algebras provided with a
contact form and classify the frobeniusian Lie algebras up to a contraction. We
also study forms which are invariant by a subgroup. We show that the simple
group SL(2n,R) which doesn't admit left invariant contact form, yet admits a
contact form which is invariant by a maximal compact subgroup. We determine
also Pfaffian forms on the Heisenberg $3$-dimensional group invariant by a
subgroup and obtain the Transport Equation.


title:
Giant topological Hall effect in strained Fe$_{0.7}$Co$_{0.3}$Si
  epilayers

abstract:
  The coupling of electron spin to real-space magnetic textures leads to a
variety of interesting magnetotransport effects. The skyrmionic spin textures
often found in chiral B20-lattice magnets give rise, via real-space Berry
phases, to the topological Hall effect, but it is typically rather small. Here,
B20-ordered Fe$_{0.7}$Co$_{0.3}$Si epilayers display a giant topological Hall
effect due to the combination of three favourable properties: they have a high
spin-polarisation, a large ordinary Hall coefficient, and dense chiral spin
textures. The topological Hall resistivity is as large as 820 n$\Omega$cm at
helium temperatures. Moreover, we observed a drop in the longitudinal
resistivity of 100 n$\Omega$cm at low temperatures in the same field range,
suggesting that it is also of topological origin. That such strong effects can
be found in material grown in thin film form on commercial silicon wafer bodes
well for skyrmion-based spintronics.


title: Pair Creation of Rotating Black Holes

abstract:
  An exact and regular solution, describing a couple of charged and spinning
black holes, is generated in an external electromagnetic field, via Ernst
technique, in Einstein-Maxwell gravity. A wormhole instantonic solution
interpolating between the two black holes is constructed to discuss, at the
semi-classical level, the quantum process of creation rate, in an external
magnetic field, of this charged and spinning black hole pair.


title: On the path separation number of graphs

abstract:
  A path separator of a graph $G$ is a set of paths
$\mathcal{P}=\{P_1,\ldots,P_t\}$ such that for every pair of edges $e,f\in
E(G)$, there exist paths $P_e,P_f\in\mathcal{P}$ such that $e\in E(P_e)$,
$f\not\in E(P_e)$, $e\not\in E(P_f)$ and $f\in E(P_f)$. The path separation
number of $G$, denoted ${\rm psn}(G)$, is the smallest number of paths in a
path separator. We shall estimate the path separation number of several graph
families, including complete graphs, random graph, the hypercube, and discuss
general graphs as well.


title: Book embeddings of Reeb graphs

abstract:
  Let $X$ be a simplicial complex with a piecewise linear function
$f:X\to\mathbb{R}$. The Reeb graph $Reeb(f,X)$ is the quotient of $X$, where we
collapse each connected component of $f^{-1}(t)$ to a single point. Let the
nodes of $Reeb(f,X)$ be all homologically critical points where any homology of
the corresponding component of the level set $f^{-1}(t)$ changes. Then we can
label every arc of $Reeb(f,X)$ with the Betti numbers
$(\beta_1,\beta_2,\dots,\beta_d)$ of the corresponding $d$-dimensional
component of a level set. The homology labels give more information about the
original complex $X$ than the classical Reeb graph. We describe a canonical
embedding of a Reeb graph into a multi-page book (a star cross a line) and give
a unique linear code of this book embedding.


title:
Entanglement propagation and typicality of measurements in the quantum
  Kac ring

abstract:
  We study the time evolution of entanglement in a quantum version of the Kac
ring. Our model consists of two spin chains and quantum gates instead of the
classical markers. The gates take one qubit from each ring at a time as an
input and entangle them. Subsequently, one ring is rotated. This protocol
creates non-trivial entanglement between the two rings, which we measure by the
entanglement entropy. The features of the entanglement evolution can best be
understood by using knowledge about the behavior of an ensemble of classical
Kac rings. For instance, the recurrence time of this quantum many-body system
is twice the length of the chain and "thermalization" only occurs on time
scales much smaller than the dimension of the Hilbert space. The model thus
elucidates the relation between distribution of measurement results in quantum
and classical systems: While in classical systems repeated measurements are
performed over an ensemble of systems, the corresponding result is obtained by
measuring the same quantum system prepared in an appropriate superposition
repeatedly.


title:
On the Capacity Region of Broadcast Packet Erasure Relay Networks With
  Feedback

abstract:
  We derive a new outer bound on the capacity region of broadcast traffic in
multiple input broadcast packet erasure channels with feedback, and extend this
outer bound to packet erasure relay networks with feedback. We show the
tightness of the outer bound for various classes of networks. An important
engineering implication of this work is that for network coding schemes for
parallel broadcast channels, the `xor' packets should be sent over correlated
broadcast subchannels.


title:
p-Type Zinc Oxide Spinels: Application to Transparent Conductors and
  Spintronics

abstract:
  We report on the electronic and optical properties of two theoretically
predicted stable spinel compounds of the form ZnB2O4, where B = Ni or Cu;
neither compound has been previously synthesized, so we compare them to the
previously studied p-type ZnCo2O4 spinel. These new materials exhibit spin
polarization that is ideal for spintronics applications, and broad conductivity
maxima near the valence band edge that facilitate p-type dopability. We show
that 3d electrons on the octahedrally coordinated Zn atom fall deep within the
valence band and do not contribute significantly to the electronic structure of
the material, while the O 2p and tetrahedrally coordinated B 3d electrons
hybridize broadly in the shallow valence states, resulting in increasing
curvature (i.e., decreased electron effective mass) of valence bands near the
band edge. In particular, ZnCu2O4 exhibits high electrical conductivities near
the valence band edge that, at sigma = 2 x 10^4 S/cm, are twice the maximum
found for ZnCo2O4, a previously synthesized compound in this class of
materials. This material also exhibits ferromagnetism in all of its most stable
structures, which makes it a good candidate for further study as a dilute
magnetic semiconductor.


title:
The flattening of the concentration-mass relation towards low halo
  masses and its implications for the annihilation signal boost

abstract:
  In the standard Cold Dark Matter (CDM) theory for understanding the formation
of structure in the universe, there exists a tight connection between the
properties of dark matter (DM) haloes, and their formation epochs. Such
relation can be expressed in terms of a single key parameter, namely the halo
concentration. In this work, we examine the median concentration-mass relation,
c(M), at present time, over more than 20 orders of magnitude in halo mass,
i.e., from tiny Earth-mass microhalos up to galaxy clusters. The c(M) model
proposed by Prada et al. (2012), which links the halo concentration with the
r.m.s. amplitude of matter linear fluctuations, describes remarkably well all
the available N-body simulation data down to ~10^(-6) Msun microhalos. A clear
fattening of the halo concentration-mass relation towards smaller masses is
observed, that excludes the commonly adopted power-law c(M) models, and stands
as a natural prediction for the CDM paradigm. We provide a parametrization for
the c(M) relation that works accurately for all halo masses. This feature in
the c(M) relation at low masses has decisive consequences e.g. for gamma-ray DM
searches, as it implies more modest boosts of the DM annihilation flux due to
substructure, i.e., ~35 for galaxy clusters and ~15 for galaxies like our own,
as compared to those huge values adopted in the literature that rely on such
power-law c(M) extrapolations. We provide a parametrization of the boosts that
can be safely used for dwarfs to galaxy cluster-size halos.


title: The OLYMPUS Experiment

abstract:
  The OLYMPUS experiment was designed to measure the ratio between the
positron-proton and electron-proton elastic scattering cross sections, with the
goal of determining the contribution of two-photon exchange to the elastic
cross section. Two-photon exchange might resolve the discrepancy between
measurements of the proton form factor ratio, $\mu_p G^p_E/G^p_M$, made using
polarization techniques and those made in unpolarized experiments. OLYMPUS
operated on the DORIS storage ring at DESY, alternating between 2.01~GeV
electron and positron beams incident on an internal hydrogen gas target. The
experiment used a toroidal magnetic spectrometer instrumented with drift
chambers and time-of-flight detectors to measure rates for elastic scattering
over the polar angular range of approximately $25^\circ$--$75^\circ$. Symmetric
M{\o}ller/Bhabha calorimeters at $1.29^\circ$ and telescopes of GEM and MWPC
detectors at $12^\circ$ served as luminosity monitors. A total luminosity of
approximately 4.5~fb$^{-1}$ was collected over two running periods in 2012.
This paper provides details on the accelerator, target, detectors, and
operation of the experiment.


title:
Quenched Large Deviations for Multiscale Diffusion Processes in Random
  Environments

abstract:
  We consider multiple time scales systems of stochastic differential equations
with small noise in random environments. We prove a quenched large deviations
principle with explicit characterization of the action functional. The random
medium is assumed to be stationary and ergodic. In the course of the proof we
also prove related quenched ergodic theorems for controlled diffusion processes
in random environments that are of independent interest. The proof relies
entirely on probabilistic arguments, allowing to obtain detailed information on
how the rare event occurs. We derive a control, equivalently a change of
measure, that leads to the large deviations lower bound. This information on
the change of measure can motivate the design of asymptotically efficient Monte
Carlo importance sampling schemes for multiscale systems in random
environments.


title: A fast and light stream cipher for smartphones

abstract:
  We present a stream cipher based on a chaotic dynamical system. Using a
chaotic trajectory sampled under certain rules in order to avoid any attempt to
reconstruct the original one, we create a binary pseudo-random keystream that
can only be exactly reproduced by someone that has fully knowledge of the
communication system parameters formed by a transmitter and a receiver and
sharing the same initial conditions. The plaintext is XORed with the keystream
creating the ciphertext, the encrypted message. This keystream passes the NISTs
randomness test and has been implemented in a videoconference App for
smartphones, in order to show the fast and light nature of the proposed
encryption system.


title: Impact of regularization on Spectral Clustering

abstract:
  The performance of spectral clustering can be considerably improved via
regularization, as demonstrated empirically in Amini et. al (2012). Here, we
provide an attempt at quantifying this improvement through theoretical
analysis. Under the stochastic block model (SBM), and its extensions, previous
results on spectral clustering relied on the minimum degree of the graph being
sufficiently large for its good performance. By examining the scenario where
the regularization parameter $\tau$ is large we show that the minimum degree
assumption can potentially be removed. As a special case, for an SBM with two
blocks, the results require the maximum degree to be large (grow faster than
$\log n$) as opposed to the minimum degree.
  More importantly, we show the usefulness of regularization in situations
where not all nodes belong to well-defined clusters. Our results rely on a
`bias-variance'-like trade-off that arises from understanding the concentration
of the sample Laplacian and the eigen gap as a function of the regularization
parameter. As a byproduct of our bounds, we propose a data-driven technique
\textit{DKest} (standing for estimated Davis-Kahan bounds) for choosing the
regularization parameter. This technique is shown to work well through
simulations and on a real data set.


title: Complex scalar field dark matter on galactic scales

abstract:
  The nature of the cosmological dark matter remains elusive. Recent studies
have advocated the possibility that dark matter could be composed of
ultra-light, self-interacting bosons, forming a Bose-Einstein condensate in the
very early Universe. We consider models which are charged under a global
U(1)-symmetry such that the dark matter number is conserved. It can then be
described as a classical complex scalar field which evolves in an expanding
Universe. We present a brief review on the bounds on the model parameters from
cosmological and galactic observations, along with the properties of galactic
halos which result from such a dark matter candidate.


title:
Signatures of superconductivity and pseudogap formation in
  non-equilibrium nodal quasiparticles revealed by ultrafast angle-resolved
  photoemission

abstract:
  We use time- and angle-resolved photoemission to measure the nodal
non-equilibrium electronic states in various dopings of
Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$. We find that the initial pump-induced
transient signal of these ungapped states is strongly affected by the onset of
the superconducting gap at $T_c$, superconducting pairing fluctuations at
$T_p$, and the pseudogap at $T^*$. Moreover, $T_p$ marks a suggestive threshold
in the fluence-dependent transient signal, with the appearance of a critical
fluence below $T_p$ that corresponds to the energy required to break apart all
Cooper pairs. These results challenge the notion of a nodal-antinodal dichotomy
in cuprate superconductors by establishing a new link between nodal
quasiparticles and the cuprate phase diagram.


title: The Solar Neighborhood XXXII. The Hydrogen Burning Limit

abstract:
  We construct a Hertzsprung-Russell diagram for the stellar/substellar
boundary based on a sample of 63 objects ranging in spectral type from M6V to
L4. We report newly observed VRI photometry for all 63 objects and new
trigonometric parallaxes for 37 objects. The remaining 26 objects have
trigonometric parallaxes from the literature. We combine our optical photometry
and trigonometric parallaxes with 2MASS and WISE photometry and employ a novel
SED fitting algorithm to determine effective temperatures, bolometric
luminosities, and radii. Our uncertainties range from ~20K to ~150K in
temperature, ~0.01 to ~0.06 in log(L/Ls}) and 3% to 10% in radius. We check our
methodology by comparing our calculated radii to radii directly measured via
long baseline optical interferometry. We find evidence for the local minimum in
the radius-temperature and radius-luminosity trends that signals the end of the
stellar main sequence and the start of the brown dwarf sequence at T ~ 2075K,
log(L/Ls)~ -3.9, and (R/Rs) ~ 0.086. The existence of this local minimum is
predicted by evolutionary models, but at temperatures ~400K cooler. The minimum
radius happens near the locus of 2MASS J0523-1403, an L2.5 dwarf with V-K=9.42.
We make qualitative arguments as to why the effects of the recent revision in
solar abundances accounts for the discrepancy between our findings and the
evolutionary models. We also report new color-absolute magnitude relations for
optical and infrared colors useful for estimating photometric distances. We
study the optical variability of all 63 targets and find an overall variability
fraction of 36^{+9}_{-7}% at a threshold of 15 milli-magnitudes in the I band,
in agreement with previous studies.


title: Curriculum Learning for Handwritten Text Line Recognition

abstract:
  Recurrent Neural Networks (RNN) have recently achieved the best performance
in off-line Handwriting Text Recognition. At the same time, learning RNN by
gradient descent leads to slow convergence, and training times are particularly
long when the training database consists of full lines of text. In this paper,
we propose an easy way to accelerate stochastic gradient descent in this
set-up, and in the general context of learning to recognize sequences. The
principle is called Curriculum Learning, or shaping. The idea is to first learn
to recognize short sequences before training on all available training
sequences. Experiments on three different handwritten text databases (Rimes,
IAM, OpenHaRT) show that a simple implementation of this strategy can
significantly speed up the training of RNN for Text Recognition, and even
significantly improve performance in some cases.


title:
Divalent Rydberg atoms in optical lattices: intensity landscape and
  magic trapping

abstract:
  We develop a theoretical understanding of trapping divalent Rydberg atoms in
optical lattices. Because the size of the Rydberg electron cloud can be
comparable to the scale of spatial variations of laser intensity, we pay
special attention to averaging optical fields over the atomic wavefunctions.
Optical potential is proportional to the ac Stark polarizability. We find that
in the independent particle approximation for the valence electrons, this
polarizability breaks into two contributions: the singly ionized core
polarizability and the contribution from the Rydberg electron. Unlike the
usually employed free electron polarizability, the Rydberg contribution depends
both on laser intensity profile and the rotational symmetry of the total
electronic wavefunction. We focus on the $J=0$ Rydberg states of Sr and
evaluate the dynamic polarizabilities of the 5s$n$s($^1S_0$) and
5s$n$p($^3P_0$) Rydberg states. We specifically choose Sr atom for its optical
lattice clock applications. We find that there are several magic wavelengths in
the infrared region of the spectrum at which the differential Stark shift
between the clock states (5s$^2$($^1S_0$) and 5s5p($^3P_0$)) and the $J=0$
Rydberg states, 5s$n$s($^1S_0$) and 5s$n$p($^3P_0$), vanishes. We tabulate
these wavelengths as a function of the principal quantum number $n$ of the
Rydberg electron. We find that because the contribution to the total
polarizability from the Rydberg electron vanishes at short wavelengths, magic
wavelengths below $\sim$1000 nm are ``universal" as they do not depend on the
principal quantum number $n$.


title: Topology and Volume Effects in Quantum Gravity: Wheeler-DeWitt Theory

abstract:
  We consider the quantization of space-times which can possess different
topologies within a symmetry reduced version of Wheeler-DeWitt theory. The
quantum states are defined from a natural decomposition as an outer-product of
a topological state, dictating the topology of the two-surfaces of the
space-time, and a geometric state, which controls the geometry and is comprised
of solutions to the Wheeler-DeWitt constraints. Within this symmetry reduced
theory an eigenvalue equation is derived for the two-volume of spacetime, which
for spherical topology is fixed to a value of $4\pi$. However, for the other
topologies it is found that the spectrum can be \emph{discrete} and hence the
universe, if in one of these other topological states, may only possess certain
possible values for the two-volume, whereas classically all values are allowed.
We analyze this result in the context of pure gravity (black holes).


title:
Approximate message-passing with spatially coupled structured operators,
  with applications to compressed sensing and sparse superposition codes

abstract:
  We study the behavior of Approximate Message-Passing, a solver for linear
sparse estimation problems such as compressed sensing, when the i.i.d matrices
-for which it has been specifically designed- are replaced by structured
operators, such as Fourier and Hadamard ones. We show empirically that after
proper randomization, the structure of the operators does not significantly
affect the performances of the solver. Furthermore, for some specially designed
spatially coupled operators, this allows a computationally fast and memory
efficient reconstruction in compressed sensing up to the
information-theoretical limit. We also show how this approach can be applied to
sparse superposition codes, allowing the Approximate Message-Passing decoder to
perform at large rates for moderate block length.


title: The Photon Propagator in Light-Shell Gauge

abstract:
  We derive the photon propagator in light-shell gauge, which was first
introduced in the context of light-shell effective theory.


title: $A_1$ weights on $\R$, an alternative approach

abstract:
  We will prove that if $\phi$ belongs to the class $A_1(\R)$ with constant
$c\ge1$ then the decreasing rearrangement of $\phi$, belongs to the same class
with constant not more than $c$. We also find for such $\phi$ the exact best
possible range of those $p>1$ for which $\phi\in L^p$. In this way we provide
alternative proofs of the results that appear in \cite{1}.


title: Dual coordinate solvers for large-scale structural SVMs

abstract:
  This manuscript describes a method for training linear SVMs (including binary
SVMs, SVM regression, and structural SVMs) from large, out-of-core training
datasets. Current strategies for large-scale learning fall into one of two
camps; batch algorithms which solve the learning problem given a finite
datasets, and online algorithms which can process out-of-core datasets. The
former typically requires datasets small enough to fit in memory. The latter is
often phrased as a stochastic optimization problem; such algorithms enjoy
strong theoretical properties but often require manual tuned annealing
schedules, and may converge slowly for problems with large output spaces (e.g.,
structural SVMs). We discuss an algorithm for an "intermediate" regime in which
the data is too large to fit in memory, but the active constraints (support
vectors) are small enough to remain in memory. In this case, one can design
rather efficient learning algorithms that are as stable as batch algorithms,
but capable of processing out-of-core datasets. We have developed such a
MATLAB-based solver and used it to train a collection of recognition systems
for articulated pose estimation, facial analysis, 3D object recognition, and
action classification, all with publicly-available code. This writeup describes
the solver in detail.


title:
A sharp integral Hardy type inequality and applications to Muckenhoupt
  weights on $\R$

abstract:
  We prove a generalization of a Hardy type inequality for negative exponents
valid for non-negative functions defined on $(0,1]$. As an application we find
the exact best possible range of $p$ such that $1<p\le q$ such that any
non-decreasing $\phi$ which satisfies the Muckenhoupt $A_q$ condition with
constant $c$ upon all open subintervals of $(0,1]$ should additionally satisfy
the $A_p$ condition for another possibly real constant $c'$. The result have
been treated in \cite{9} based on \cite{1}, but we give in this paper an
alternative proof which relies on the above mentioned inequality.


title: Strichartz estimates for wave equation with inverse square potential

abstract:
  In this paper, we study the Strichartz-type estimates of the solution for the
linear wave equation with inverse square potential. Assuming the initial data
possesses additional angular regularity, especially the radial initial data,
the range of admissible pairs is improved. As an application, we show the
global well-posedness of the semi-linear wave equation with inverse-square
potential $\partial_t^2 u-\Delta u+\frac{a}{|x|^2}u=\pm|u|^{p-1}u$ for power
$p$ being in some regime when the initial data are radial. This result extends
the well-posedness result in Planchon, Stalker, and Tahvildar-Zadeh.


title: Nuclear energy density optimization: Shell structure

abstract:
  Nuclear density functional theory is the only microscopical theory that can
be applied throughout the entire nuclear landscape. Its key ingredient is the
energy density functional. In this work, we propose a new parameterization
UNEDF2 of the Skyrme energy density functional. The functional optimization is
carried out using the POUNDerS optimization algorithm within the framework of
the Skyrme Hartree-Fock-Bogoliubov theory. Compared to the previous
parameterization UNEDF1, restrictions on the tensor term of the energy density
have been lifted, yielding a very general form of the energy density functional
up to second order in derivatives of the one-body density matrix. In order to
impose constraints on all the parameters of the functional, selected data on
single-particle splittings in spherical doubly-magic nuclei have been included
into the experimental dataset. The agreement with both bulk and spectroscopic
nuclear properties achieved by the resulting UNEDF2 parameterization is
comparable with UNEDF1. While there is a small improvement on single-particle
spectra and binding energies of closed shell nuclei, the reproduction of
fission barriers and fission isomer excitation energies has degraded. As
compared to previous UNEDF parameterizations, the parameter confidence interval
for UNEDF2 is narrower. In particular, our results overlap well with those
obtained in previous systematic studies of the spin-orbit and tensor terms.
UNEDF2 can be viewed as an all-around Skyrme EDF that performs reasonably well
for both global nuclear properties and shell structure. However, after adding
new data aiming to better constrain the nuclear functional, its quality has
improved only marginally. These results suggest that the standard Skyrme energy
density has reached its limits and significant changes to the form of the
functional are needed.


title:
Image cloning beyond diffraction based on coherent population trapping
  in a hot Rubidium vapor

abstract:
  Following the recent theoretical predictions given in a paper [PRA 88, 013810
(2013)], we reported on an experimental realization of an image cloning beyond
usual diffraction through coherent population trapping (CPT) effect in a hot
rubidium vapor. In our experiment, an alphabet image was transferred from a
coupling field to a probe field based on the CPT effect. Furthermore, we
demonstrated that the cloned probe field carrying the image transmitted without
usual diffraction. To our best knowledge, there is no any such an experimental
report about images cloning beyond diffraction. We believe this mechanism based
on CPT definitely has important applications in image metrology, image
processing and biological imaging.


title:
The MMP for deformations of Hilbert schemes of points on the projective
  plane

abstract:
  We study the birational geometry of deformations of Hilbert schemes of points
on the projective plane P2. We complete the picture in the paper of Daniele
Arcara, Aaron Bertram, Izzet Coskun and Jack Huizenga by giving an explicit
correspondence between the stable base locus walls on the Neron-Severi space
and the actual walls on the Bridgeland stability space. We show that the
birational geometry of a deformed Hilb P2 is different from that of Hilb P2.


title: Studies of exotic hadrons by high-energy exclusive reactions

abstract:
  We investigate the possibility of clarifying internal structure of exotic
hadrons by high-energy exclusive reactions. In particular, the
constituent-counting rule could be used for determining the internal
configuration in large-angle exclusive scattering. As an example, we show the
cross section pi^- + p -> K^0 + Lambda(1405) in comparison with the one for the
ground-state Lambda production pi^- + p -> K^0 + Lambda. The counting rule
indicates that the cross section scales as s^8 dsigma /dt=constant if
Lambda(1405) is an ordinary three-quark baryon, whereas it is s^{10} dsigma
/dt=constant if Lambda(1405) is a five-quark baryon. Here, s and t are
Mandelstam variables. Such experiments could be possible at J-PARC, LEP, JLab,
CERN-COMPASS, and other high-energy facilities.


title: Lazy Cops and Robbers played on Graphs

abstract:
  We consider a variant of the game of Cops and Robbers, called Lazy Cops and
Robbers, where at most one cop can move in any round. We investigate the
analogue of the cop number for this game, which we call the lazy cop number.
Lazy Cops and Robbers was recently introduced by Offner and Ojakian, who
provided asymptotic upper and lower bounds on the lazy cop number of the
hypercube. By investigating expansion properties, we provide asymptotically
almost sure bounds on the lazy cop number of binomial random graphs
$\mathcal{G}(n,p)$ for a wide range of $p=p(n)$. By coupling the probabilistic
method with a potential function argument, we also improve on the existing
lower bounds for the lazy cop number of hypercubes. Finally, we provide an
upper bound for the lazy cop number of graphs with genus $g$ by using the
Gilbert-Hutchinson-Tarjan separator theorem.


title: Supersolidity of a dipolar Fermi gas in a cubic optical lattice

abstract:
  We study the phase diagram of a dipolar fermi gas at half-filling in a cubic
optical lattice with dipole moments aligned along the z-axis. The anisotropic
dipole-dipole interaction leads to the competition between pz-wave superfluid
and nematic charge-density-wave (CDW) orders at low temperatures. We find that
the superfluid phase survives with weak interactions and the CDW phase
dominates with strong interactions. In between, the supersolid phase appears as
a balance between superfluid and CDW orders. The superfluid density is
anisotropic in the supersolid and superfluid phases. In the CDW phase, there is
a semimetal to insulator transition with increase of the interaction strength.
Experimental implications are discussed.


title:
Particle Swarm Optimization of Information-Content Weighting of Symbolic
  Aggregate Approximation

abstract:
  Bio-inspired optimization algorithms have been gaining more popularity
recently. One of the most important of these algorithms is particle swarm
optimization (PSO). PSO is based on the collective intelligence of a swam of
particles. Each particle explores a part of the search space looking for the
optimal position and adjusts its position according to two factors; the first
is its own experience and the second is the collective experience of the whole
swarm. PSO has been successfully used to solve many optimization problems. In
this work we use PSO to improve the performance of a well-known representation
method of time series data which is the symbolic aggregate approximation (SAX).
As with other time series representation methods, SAX results in loss of
information when applied to represent time series. In this paper we use PSO to
propose a new minimum distance WMD for SAX to remedy this problem. Unlike the
original minimum distance, the new distance sets different weights to different
segments of the time series according to their information content. This
weighted minimum distance enhances the performance of SAX as we show through
experiments using different time series datasets.


title: On the maximum order of graphs embedded in surfaces

abstract:
  The maximum number of vertices in a graph of maximum degree $\Delta\ge 3$ and
fixed diameter $k\ge 2$ is upper bounded by $(1+o(1))(\Delta-1)^{k}$. If we
restrict our graphs to certain classes, better upper bounds are known. For
instance, for the class of trees there is an upper bound of
$(2+o(1))(\Delta-1)^{\lfloor k/2\rfloor}$ for a fixed $k$. The main result of
this paper is that graphs embedded in surfaces of bounded Euler genus $g$
behave like trees, in the sense that, for large $\Delta$, such graphs have
orders bounded from above by \[begin{cases} c(g+1)(\Delta-1)^{\lfloor
k/2\rfloor} & \text{if $k$ is even} c(g^{3/2}+1)(\Delta-1)^{\lfloor k/2\rfloor}
& \text{if $k$ is odd}, \{cases}\] where $c$ is an absolute constant. This
result represents a qualitative improvement over all previous results, even for
planar graphs of odd diameter $k$. With respect to lower bounds, we construct
graphs of Euler genus $g$, odd diameter $k$, and order
$c(\sqrt{g}+1)(\Delta-1)^{\lfloor k/2\rfloor}$ for some absolute constant
$c>0$. Our results answer in the negative a question of Miller and
\v{S}ir\'a\v{n} (2005).


title:
Determining the stability and activation energy of Si acceptors in
  AlGaAs using quantum interference in an open hole quantum dot

abstract:
  We fabricated an etched hole quantum dot in a Si-doped (311)A AlGaAs/GaAs
heterostructure to study disorder effects via magnetoconductance fluctuations
(MCF) at millikelvin temperatures. Recent experiments in electron quantum dots
have shown that the MCF is sensitive to the disorder potential created by
remote ionised impurities. We utilize this to study the temporal/thermal
stability of Si acceptors in p-type AlGaAs/GaAs heterostructures. In
particular, we use a surface gate to cause charge migration between Si acceptor
sites at T = 40 mK, and detect the ensuing changes in the disorder potential
using the MCF. We show that Si acceptors are metastable at T = 40 mK and that
raising the device to a temperature T = 4.2 K and returning to T = 40 mK is
sufficient to produce complete decorrelation of the MCF. The same decorrelation
occurs at T ~ 165 K for electron quantum dots; by comparing with the known trap
energy for Si DX centers, we estimate that the shallow acceptor traps in our
heterostructures have an activation energy EA ~ 3 meV. Our method can be used
to study charge noise and dopant stability towards optimisation of
semiconductor materials and devices.


title: Beating the Generator-Enumeration Bound for $p$-Group Isomorphism

abstract:
  We consider the group isomorphism problem: given two finite groups G and H
specified by their multiplication tables, decide if G cong H. For several
decades, the n^(log_p n + O(1)) generator-enumeration bound (where p is the
smallest prime dividing the order of the group) has been the best worst-case
result for general groups. In this work, we show the first improvement over the
generator-enumeration bound for p-groups, which are believed to be the hard
case of the group isomorphism problem. We start by giving a Turing reduction
from group isomorphism to n^((1 / 2) log_p n + O(1)) instances of p-group
composition-series isomorphism. By showing a Karp reduction from p-group
composition-series isomorphism to testing isomorphism of graphs of degree at
most p + O(1) and applying algorithms for testing isomorphism of graphs of
bounded degree, we obtain an n^(O(p)) time algorithm for p-group
composition-series isomorphism. Combining these two results yields an algorithm
for p-group isomorphism that takes at most n^((1 / 2) log_p n + O(p)) time.
This algorithm is faster than generator-enumeration when p is small and slower
when p is large. Choosing the faster algorithm based on p and n yields an upper
bound of n^((1 / 2 + o(1)) log n) for p-group isomorphism.


title: Joint Energy and Spectrum Cooperation for Cellular Communication Systems

abstract:
  Powered by renewable energy sources, cellular communication systems usually
have different wireless traffic loads and available resources over time. To
match their traffics, it is beneficial for two neighboring systems to cooperate
in resource sharing when one is excessive in one resource (e.g., spectrum),
while the other is sufficient in another (e.g., energy). In this paper, we
propose a joint energy and spectrum cooperation scheme between different
cellular systems to reduce their operational costs. When the two systems are
fully cooperative in nature (e.g., belonging to the same entity), we formulate
the cooperation problem as a convex optimization problem to minimize their
weighted sum cost and obtain the optimal solution in closed form. We also study
another partially cooperative scenario where the two systems have their own
interests. We show that the two systems seek for partial cooperation as long as
they find inter-system complementarity between the energy and spectrum
resources. Under the partial cooperation conditions, we propose a distributed
algorithm for the two systems to gradually and simultaneously reduce their
costs from the non-cooperative benchmark to the Pareto optimum. This
distributed algorithm also has proportional fair cost reduction by reducing
each system's cost proportionally over iterations. Finally, we provide
numerical results to validate the convergence of the distributed algorithm to
the Pareto optimality and compare the centralized and distributed cost
reduction approaches for fully and partially cooperative scenarios.


title:
Observation of well-defined quasi-particle over a wide energy range in
  quasi-2D system

abstract:
  We report the observation by angle-resolved photoemission spectroscopy
measurements of a highly anisotropic Dirac-cone structure in high quality
SrMnBi2 crystals. We reveal a well-defined sharp quasi-particle, linearly
dispersive with $v_{F_1}/v_{F_2}\sim$ 5--6, forming a hole-like anisotropic
Dirac-cone. The density of states for the cone remains linear up to as high as
~650 meV of binding energy. The scattering rate of the quasi-particle (QP)
increases linearly as function of binding energy, indicating a non-Fermi-Liquid
behavior. Our results suggest the existence of a dilute two-dimensional
electron gas system in this three-dimensional material.


title:
A multi-dimensional SRBM: Geometric views of its product form stationary
  distribution

abstract:
  We present a geometric interpretation of a product form stationary
distribution for a $d$-dimensional semimartingale reflecting Brownian motion
(SRBM) that lives in the nonnegative orthant. The $d$-dimensional SRBM data can
be equivalently specified by $d+1$ geometric objects: an ellipse and $d$ rays.
Using these geometric objects, we establish necessary and sufficient conditions
for characterizing product form stationary distribution. The key idea in the
characterization is that we decompose the $d$-dimensional problem to
$\frac{1}{2}d(d-1)$ two-dimensional SRBMs, each of which is determined by an
ellipse and two rays. This characterization contrasts with the algebraic
condition of [14]. A $d$-station tandem queue example is presented to
illustrate how the product form can be obtained using our characterization.
Drawing the two-dimensional results in [1,7], we discuss potential optimal
paths for a variational problem associated with the three-station tandem queue.
Except Appendix D, the rest of this paper is almost identical to the QUESTA
paper with the same title.


title:
Quantitative chemical tagging, stellar ages and the chemo-dynamical
  evolution of the Galactic disc

abstract:
  The early science results from the new generation of high-resolution stellar
spectroscopic surveys, such as GALAH and the Gaia-ESO survey, will represent
major milestones in the quest to chemically tag the Galaxy. Yet this technique
to reconstruct dispersed coeval stellar groups has remained largely untested
until recently. We build on previous work that developed an empirical chemical
tagging probability function, which describes the likelihood that two field
stars are conatal, that is, they were formed in the same cluster environment.
In this work we perform the first ever blind chemical tagging experiment, i.e.,
tagging stars with no known or otherwise discernable associations, on a sample
of 714 disc field stars with a number of high quality high resolution
homogeneous metal abundance measurements. We present evidence that chemical
tagging of field stars does identify coeval groups of stars, yet these groups
may not represent distinct formation sites, e.g. as in dissolved open clusters,
as previously thought. Our results point to several important conclusions,
among them that group finding will be limited strictly to chemical abundance
space, e.g. stellar ages, kinematics, colors, temperature and surface gravity
do not enhance the detectability of groups. We also demonstrate that in
addition to its role in probing the chemical enrichment and kinematic history
of the Galactic disc, chemical tagging represents a powerful new stellar age
determination technique.


title:
Towards Normalizing the Edit Distance Using a Genetic Algorithms Based
  Scheme

abstract:
  The normalized edit distance is one of the distances derived from the edit
distance. It is useful in some applications because it takes into account the
lengths of the two strings compared. The normalized edit distance is not
defined in terms of edit operations but rather in terms of the edit path. In
this paper we propose a new derivative of the edit distance that also takes
into consideration the lengths of the two strings, but the new distance is
related directly to the edit distance. The particularity of the new distance is
that it uses the genetic algorithms to set the values of the parameters it
uses. We conduct experiments to test the new distance and we obtain promising
results.


title: GoSam @ LHC: algorithms and applications to Higgs production

abstract:
  We elaborate on GoSam, a code-writer for automated one-loop calculations.
After recalling its main features, we present a selection of phenomenological
results recently obtained, giving relevance at the evaluation of NLO QCD
corrections to the production of a Higgs boson in association with jets and
heavy quarks.


title: On compact exceptional objects in derived module categories

abstract:
  Let $A$ be a finite dimensional algebra and $D^b(A)$ be the bounded derived
category of finitely generated left $A$-modules. In this paper we consider
lengths of compact exceptional objects in $D^b(A)$, proving a sufficient
condition such that these lengths are bounded by the number of isomorphism
classes of simple $A$-modules. Moreover, we show that algebras satisfying this
condition is bounded derived simple.


title:
Optimal Error Rates for Interactive Coding II: Efficiency and List
  Decoding

abstract:
  We study coding schemes for error correction in interactive communications.
Such interactive coding schemes simulate any $n$-round interactive protocol
using $N$ rounds over an adversarial channel that corrupts up to $\rho N$
transmissions. Important performance measures for a coding scheme are its
maximum tolerable error rate $\rho$, communication complexity $N$, and
computational complexity.
  We give the first coding scheme for the standard setting which performs
optimally in all three measures: Our randomized non-adaptive coding scheme has
a near-linear computational complexity and tolerates any error rate $\delta <
1/4$ with a linear $N = \Theta(n)$ communication complexity. This improves over
prior results which each performed well in two of these measures.
  We also give results for other settings of interest, namely, the first
computationally and communication efficient schemes that tolerate $\rho <
\frac{2}{7}$ adaptively, $\rho < \frac{1}{3}$ if only one party is required to
decode, and $\rho < \frac{1}{2}$ if list decoding is allowed. These are the
optimal tolerable error rates for the respective settings. These coding schemes
also have near linear computational and communication complexity.
  These results are obtained via two techniques: We give a general black-box
reduction which reduces unique decoding, in various settings, to list decoding.
We also show how to boost the computational and communication efficiency of any
list decoder to become near linear.


title:
Optimal Error Rates for Interactive Coding I: Adaptivity and Other
  Settings

abstract:
  We consider the task of interactive communication in the presence of
adversarial errors and present tight bounds on the tolerable error-rates in a
number of different settings.
  Most significantly, we explore adaptive interactive communication where the
communicating parties decide who should speak next based on the history of the
interaction. Braverman and Rao [STOC'11] show that non-adaptively one can code
for any constant error rate below 1/4 but not more. They asked whether this
bound could be improved using adaptivity. We answer this open question in the
affirmative (with a slightly different collection of resources): Our adaptive
coding scheme tolerates any error rate below 2/7 and we show that tolerating a
higher error rate is impossible. We also show that in the setting of Franklin
et al. [CRYPTO'13], where parties share randomness not known to the adversary,
adaptivity increases the tolerable error rate from 1/2 to 2/3. For
list-decodable interactive communications, where each party outputs a constant
size list of possible outcomes, the tight tolerable error rate is 1/2.
  Our negative results hold even if the communication and computation are
unbounded, whereas for our positive results communication and computation are
polynomially bounded. Most prior work considered coding schemes with linear
amount of communication, while allowing unbounded computations. We argue that
studying tolerable error rates in this relaxed context helps to identify a
setting's intrinsic optimal error rate. We set forward a strong working
hypothesis which stipulates that for any setting the maximum tolerable error
rate is independent of many computational and communication complexity
measures. We believe this hypothesis to be a powerful guideline for the design
of simple, natural, and efficient coding schemes and for understanding the
(im)possibilities of coding for interactive communications.


title:
Ribosome profiling reveals post-transcriptional buffering of divergent
  gene expression in yeast

abstract:
  Understanding the patterns and causes of phenotypic divergence is a central
goal in evolutionary biology. Much work has shown that mRNA abundance is highly
variable between closely related species. However, the extent and mechanisms of
post-transcriptional gene regulatory evolution are largely unknown. Here we
used ribosome profiling to compare transcript abundance and translation
efficiency in two closely related yeast species (S. cerevisiae and S.
paradoxus). By comparing translation regulatory divergence to interspecies
differences in mRNA sequence features, we show that differences in transcript
leaders and codon bias substantially contribute to divergent translation.
Globally, we find that translation regulatory divergence often buffers
species-differences in mRNA abundance, such that ribosome occupancy is more
conserved than transcript abundance. We used allele-specific ribosome profiling
in interspecies hybrids to compare the relative contributions of cis- and
trans-regulatory divergence to species differences in mRNA abundance and
translation efficiency. The mode of gene regulatory divergence differs for
these processes, as trans-regulatory changes play a greater role in divergent
mRNA abundance than in divergent translation efficiency. Strikingly, most genes
with aberrant transcript abundance in F1 hybrids (either over- or
under-expressed compared to both parent species) did not exhibit aberrant
ribosome occupancy. Our results show that interspecies differences in
translation contribute substantially to the evolution of gene expression.
Compensatory differences in transcript abundance and translation efficiency may
increase the robustness of gene regulation.


title: Matrix-Monotonic Optimization for MIMO Systems

abstract:
  For MIMO systems, due to the deployment of multiple antennas at both the
transmitter and the receiver, the design variables e.g., precoders, equalizers,
training sequences, etc. are usually matrices. It is well known that matrix
operations are usually more complicated compared to their vector counterparts.
In order to overcome the high complexity resulting from matrix variables, in
this paper we investigate a class of elegant multi-objective optimization
problems, namely matrix-monotonic optimization problems (MMOPs). In our work,
various representative MIMO optimization problems are unified into a framework
of matrix-monotonic optimization, which includes linear transceiver design,
nonlinear transceiver design, training sequence design, radar waveform
optimization, the corresponding robust design and so on as its special cases.
Then exploiting the framework of matrix-monotonic optimization the optimal
structures of the considered matrix variables can be derived first. Based on
the optimal structure, the matrix-variate optimization problems can be greatly
simplified into the ones with only vector variables. In particular, the
dimension of the new vector variable is equal to the minimum number of columns
and rows of the original matrix variable. Finally, we also extend our work to
some more general cases with multiple matrix variables.


title:
Asymptotic solution of the diffusion equation in slender impermeable
  tubes of revolution. I. The leading-term approximation

abstract:
  The anisotropic 3D equation describing the pointlike particles diffusion in
slender impermeable tubes of revolution with cross section smoothly depending
on the longitudial coordinate is the object of our study. We use singular
perturbations approach to find the rigorous asymptotic expression for the local
particles concentration as an expansion in the ratio of the characteristic
transversal and longitudial diffusion relaxation times. The corresponding
leading-term approximation is a generalization of well-known Fick-Jacobs
approximation. This result allowed us to delineate the conditions on temporal
and spatial scales under which the Fick-Jacobs approximation is valid. A
striking analogy between solution of our problem and the method of inner-outer
expansions for low Knudsen numbers gas kinetic theory is established. With the
aid of this analogy we clarify the physical and mathematical meaning of the
obtained results.


title: Sphere-plate Casimir interaction in (D+1)-dimensional spacetime

abstract:
  In this paper, we derive the formula for the Casimir interaction energy
between a sphere and a plate in $(D+1)$-dimensional Minkowski spacetime. It is
assumed that the scalar field satisfies the Dirichlet or Neumann boundary
conditions on the sphere and the plate. As in the $D=3$ case, the formula is of
TGTG type. One of our main contributions is deriving the translation matrices
which express the change of bases between plane waves and spherical waves for
general $D$. Using orthogonality of Gegenbauer polynomials, it turns out that
the final TGTG formula for the Casimir interaction energy can be simplified to
one that is similar to the $D=3$ case. To illustrate the application of the
formula, both large separation and small separation asymptotic behaviors of the
Casimir interaction energy are computed. The large separation leading term is
proportional to $L^{-D+1}$ if the sphere is imposed with Dirichlet boundary
condition, and to $L^{-D-1}$ if the sphere is imposed with Neumann boundary
condition, where $L$ is distance from the center of the sphere to the plane.
For the small separation asymptotic behavior, it is shown that the leading term
is equal to the one obtained using proximity force approximation. The
next-to-leading order term is also computed using perturbation method. It is
shown that when the space dimension $D$ is larger than 5, the next-to-leading
order has sign opposite to the leading order term. Moreover, the ratio of the
next-to-leading order term to the leading order term is linear in $D$,
indicating a larger correction at higher dimensions.


title: HOMFLY polynomial from a generalized Yang-Yang function

abstract:
  Starting from the free field realization of Kac-Moody Lie algebra, we define
a generalized Yang-Yang function. Then for the Lie algebra of type $A_{n}$, we
derive braiding and fusion matrix by braiding the thimble from the generalized
Yang-Yang function. One can construct a knots invariant $H(K)$ from the
braiding and fusion matrix. It is an isotropy invariant and obeys a skein
relation. From them, we show that the corresponding knots invariant is HOMFLY
polynomial.


title:
An Emergent Universe with Dark Sector Fields in a Chiral Cosmological
  Model

abstract:
  We consider the emergent universe scenario supported by a chiral cosmological
model with two interacting dark sector fields: phantom and canonical. We
investigate the general properties of the evolution of the kinetic and
potential energies as well as the development of the equation of state with
time. We present three models based on asymptotic solutions and investigate the
phantom part of the potential and chiral metric components. The exact solution
corresponding to a global emergent universe scenario, starting from the
infinite past and evolving to the infinite future, has been obtained for the
first time for a chiral cosmological model. The behavior of the chiral metric
components responsible for the kinetic interaction between the phantom and
canonical scalar fields has been analyzed as well.


title:
Degeneration of Orlik-Solomon algebras and Milnor fibers of complex line
  arrangements

abstract:
  We give a vanishing theorem for the monodromy eigenspaces of the Milnor
fibers of complex line arrangements. By applying the modular bound of the local
system cohomology groups given by Papadima-Suciu, the result is deduced from
the vanishing of the cohomology of certain Aomoto complex over finite fields.
In order to prove this, we introduce degeneration homomorphisms of
Orlik-Solomon algebras.


title: On Quantum Tunneling in Real Time

abstract:
  A detailed real time description of quantum tunneling in the semiclassical
limit is given, using complex classical trajectories. This picture connects
naturally with the ideas of post-selection and weak measurement introduced by
Aharonov and collaborators. I show that one can precisely identify the {\it
complex} classical trajectory which a post-selected tunneling particle has
followed, and which dominates the path integral in the limit as Planck's
constant $\hbar$ tends to zero. Detailed analytical calculations are presented
for tunneling in cubic and quartic potentials. For a long post-selected
tunneling time, the imaginary part of the tunneling coordinate is found to
achieve very large values just before the particle tunnels. I discuss how the
real and imaginary parts of the particle's coordinate may, in principle, be
independently measured using weak measurements. It would be very interesting to
observe this effect, which would demonstrate the essential role of complex
numbers in our closest possible classical description of reality. Extensions to
quantum field theory and general relativity are briefly discussed.


title:
Metabolizable Bi2Se3 Nanoplates: Biodistribution, Toxicity, and Uses for
  Cancer Radiation Therapy and Imaging

abstract:
  Bi, a high atom number element, has a high photoelectric absorption
coefficient, and Se element has anticancer activity. Hence, their compound
chalcogenide (Bi2Se3) deserves a thorough investigation for biomedical
applications. This study reveals that Bi2Se3 nanoplates (54 nm wide) protected
with poly(vinylpyrollidone) (PVP) are biocompatible and have low toxicity even
at a high dose of 20 mg/kg in mice. This conclusion was made through the
studies on the biodistribution and 90-day long term in vivo clearance of the
nanoplates. Liver and spleen were dominant organs for the nanoplates
accumulation which was mainly due to RES absorption, but 93 % the nanoplates
were cleared after 90 days treatment. Concentrations of Bi and Se in tumor
tissue continuously increased until 72 h after intraperitoneal injection into
mice. Such selective accumulation of Bi was utilized to enhance the contrast of
X-ray CT images. The Bi elements concentrated in a tumor led to damage on the
tumor cells when exposed to gamma radiation. Growth of the tumor significantly
delayed and stopped after 16 days after the tumor was treated with the Bi2Se3
nanoplates and radiation. This work clearly shows that the Bi2Se3 nanoplates
may be used for cancer radiation therapy and CT imaging. They deserve further
studies for biological and medical applications.


title: The surface and inner temperatures of magnetars

abstract:
  Assuming that the timescale of the magnetic field decay is approximately
equal to that of the stellar cooling via neutrino emission, we obtain a
one-to-one relationship between the effective surface thermal temperature and
the inner temperature. The ratio of the effective neutrino luminosity to the
effective X-ray luminosity decreases with decaying magnetic field.


title: First Principles Study of the Magnetic Properties of LaOMnAs

abstract:
  Recent experiments reported giant magnetoresistance at room temperature in
LaOMnAs. Here a density functional theory calculation is performed to
investigate magnetic properties of LaOMnAs. The ground state is found to be the
G-type antiferromagnetic order within the $ab$ plane but coupled
ferromagnetically between planes, in agreement with recent neutron
investigations. The electronic band structures suggest an insulating state
which is driven by the particular G-type magnetic order, while a metallic state
accompanies the ferromagnetic order. This relation between magnetism and
conductance may be helpful to qualitatively understand the giant
magnetoresistance effects.


title:
Hermite subdivision schemes, exponential polynomial generation, and
  annihilators

abstract:
  We consider the question when the so--called spectral condition} for Hermite
subdivision schemes extends to spaces generated by polynomials and exponential
functions. The main tool are convolution operators that annihilate the space in
question which apparently is a general concept in the study of various types of
subdivision operators. Based on these annihilators, we characterize the
spectral condition in terms of factorization of the subdivision operator.


title:
Cutoff in the hard X-ray spectra of the ultraluminous X-ray sources HoIX
  X-1 and M82 X-1

abstract:
  Using data from the XMM-Newton and INTEGRAL observatories, we have detected a
cutoff at energies above 10 keV in the X-ray spectra of the ultraluminous X-ray
sources HoIX X-1 and M82 X-1. The spectra obtained can be described by a model
of Comptonization of radiation in a gas cloud of moderate temperature (kT~2-3
keV) and high optical depth (tau~15-25). Such conditions can be fulfilled
during supercritical accretion of matter onto a stellar-mass black hole
accompanied by a strong gas outflow. The results of this work confirm the
existence of a spectral state specific to ultraluminous X-ray sources, which is
unlike any of the known spectral states in normal X-ray binaries.


title: Radius-Voltage Relation of Graphene Bubbles Controlled by Gate Voltage

abstract:
  Graphene on the substrate can form bubbles rising above the sheet. In some
cases, the bubble is a perfect spherical surface crown, and its radius can be
adjusted by external electric field. In this manuscript, we theoretically
investigate the voltage dependence of the spherical bubble's radius. The
calculated results are in good agreement with recent experiments on the
graphene bubble controlled by applied gate voltage [Appl. Phys. Lett. 99,
093103 (2011)].


title: Artificial Neural Network for search for metal poor galaxies

abstract:
  In order to find a fast and reliable method for selecting metal poor galaxies
(MPGs), especially in large surveys and huge database, an Artificial Neural
Network (ANN) method is applied to a sample of star-forming galaxies from the
Sloan Digital Sky Survey (SDSS) data release 9 (DR9) provided by the Max Planck
Institute and the Johns Hopkins University (MPA/JHU). A two-step approach is
adopted:(i) The ANN network must be trained with a subset of objects that are
known to be either MPGs or MRGs(Metal Rich galaxies), treating the strong
emission line flux measurements as input feature vectors in an n-dimensional
space, where n is the number of strong emission line flux ratios. (ii) After
the network is trained on a sample of star-forming galaxies, remaining galaxies
are classified in the automatic test analysis as either MPGs or MRGs. We
consider several random divisions of the data into training and testing sets:
for instance, for our sample, a total of 70 percent of the data are involved in
training the algorithm, 15 percent are involved in validating the algorithm and
the remaining 15 percent are used for blind testing of the resulting
classifier.
  For target selection, we have achieved an acquisition rate for MPGs of 96
percent and 92 percent for an MPGs threshold of 12+log(O/H)=8.00 and
12+log(O/H)=8.39, respectively.
  Running the code takes minutes in most cases under the Matlab 2013a software
environment.
  The ANN method can easily be extended to any MPGs target selection task when
the physical property of the target can be expressed as a quantitative
variable.


title:
Special Algorithm for Stability Analysis of Multistable Biological
  Regulatory Systems

abstract:
  We consider the problem of counting (stable) equilibriums of an important
family of algebraic differential equations modeling multistable biological
regulatory systems. The problem can be solved, in principle, using real
quantifier elimination algorithms, in particular real root classification
algorithms. However, it is well known that they can handle only very small
cases due to the enormous computing time requirements. In this paper, we
present a special algorithm which is much more efficient than the general
methods. Its efficiency comes from the exploitation of certain interesting
structures of the family of differential equations.


title: Star Formation Rate Indicators in WISE/SDSS

abstract:
  With the goal of investigating the degree to which the total infrared
luminosity ($L_{\rm TIR}$) traces the star formation rate (SFR), we analyze the
$L_{\rm TIR}$ from the dust in a sample of $\sim$ 6000 star-forming galaxies,
based on the 3.4, 4.6, 12 and 22 $\mu$m data from the Wide-field Infrared
Survey Explorer (WISE) and u, g, r, i, z band data from SDSS DR9. These
star-forming galaxies are selected by matching the WISE All Sky Catalog with
the star-forming galaxy catalog in SDSS DR9 provided by
JHU/MPA\thanks{$http://www.sdss3.org/dr9/spectro/spectroaccess.php$}. The
values of $L_{\rm TIR}$ and SFR are derived from the project Code Investigating
Galaxy Emission (CIGALE). We study the relationship between the $L_{\rm TIR}$
and SFR. From this study, we derive reference SFR indicators for use in our
analysis. Linear correlations between SFR and the $L_{\rm TIR}$ are found, and
calibrations of SFRs based on it are proposed. The calibration holds for
galaxies with verified observations and agrees well with previous works. The
dispersion in the relation between $L_{\rm TIR}$ and SFR could partly be
explained by the galaxy's properties, such as the 4000 {\AA} break.


title:
Shape transition of unstrained flattest single-walled carbon nanotubes
  under pressure

abstract:
  Single walled carbon nanotube's cross section can be flattened under
hydrostatic pressure. One example is the cross section of a single walled
carbon nanotube successively deforms from the original round shape to oval
shape, then to peanut-like shape. At the transition point of reversible
deformation between convex shape and concave shape, the side wall of nanotube
is flattest. This flattest tube has many attractive properties. In the present
work, an approximate approach is developed to determine the equilibrium shape
of this unstrained flattest tube and the curvature distribution of this tube.
Our results are in good agreement with recent numerical results, and can be
applied to the study of pressure controlled electric properties of single
walled carbon nanotubes. The present method can also be used to study other
deformed inorganic and organic tube-like structures.


title: Quantum Jumps Are More Quantum Than Quantum Diffusion

abstract:
  It was recently argued [Phys. Rev. Lett 108, 220402 (2012)] that the
stochastic dynamics of an open quantum system are not inherent to the system,
but rather depend on the existence and nature of a distant detector. The
proposed experimental tests involved homodyne detection, giving rise to quantum
diffusion, and required total efficiencies of well over 50%. Here we prove that
for no system is it possible to demonstrate detector-dependence using
diffusive-type detection of efficiency less than 50%. However, this no-go
theorem does not apply to quantum jumps, and we propose a test involving a
qubit, using different jump-type detectors, with a threshold efficiency of only
37%.