title:
Toward connecting core-collapse supernova theory with observations: I.
  Shock revival in a 15 Msun blue supergiant progenitor with SN 1987A
  energetics

abstract:
  We study the evolution of the collapsing core of a 15 Msun blue supergiant
supernova progenitor from the core bounce until 1.5 seconds later. We present a
sample of hydrodynamic models parameterized to match the explosion energetics
of SN 1987A.
  We find the spatial model dimensionality to be an important contributing
factor in the explosion process. Compared to two-dimensional simulations, our
three-dimensional models require lower neutrino luminosities to produce equally
energetic explosions. We estimate that the convective engine in our models is
4% more efficient in three dimensions than in two dimensions. We propose that
the greater efficiency of the convective engine found in three-dimensional
simulations might be due to the larger surface-to-volume ratio of convective
plumes, which aids in distributing energy deposited by neutrinos.
  We do not find evidence of the standing accretion shock instability nor
turbulence being a key factor in powering the explosion in our models. Instead,
the analysis of the energy transport in the post-shock region reveals
characteristics of penetrative convection. The explosion energy decreases
dramatically once the resolution is inadequate to capture the morphology of
convection on large scales. This shows that the role of dimensionality is
secondary to correctly accounting for the basic physics of the explosion.
  We also analyze information provided by particle tracers embedded in the
flow, and find that the unbound material has relatively long residency times in
two-dimensional models, while in three dimensions a significant fraction of the
explosion energy is carried by particles with relatively short residency times.

categories: astro-ph.SR physics.comp-ph physics.data-an physics.flu-dyn


title: Lattice structure of torsion classes for path algebras

abstract:
  We consider module categories of path algebras of connected acyclic quivers.
It is shown in this paper that the set of functorially finite torsion classes
form a lattice if and only if the quiver is either Dynkin quiver of type A, D,
E, or the quiver has exactly two vertices.


title:
Partially-PT-symmetric optical potentials with all-real spectra and
  soliton families in multi-dimensions

abstract:
  Multi-dimensional complex optical potentials with partial parity-time (PT)
symmetry are proposed. The usual PT symmetry requires that the potential is
invariant under complex conjugation and simultaneous reflection in all spatial
directions. However, we show that if the potential is only partially
PT-symmetric, i.e., it is invariant under complex conjugation and reflection in
a single spatial direction, then it can also possess all-real spectra and
continuous families of solitons. These results are established analytically and
corroborated numerically.


title:
A Bond Option Pricing Formula in the Extended CIR Model, with an
  Application to Stochastic Volatility

abstract:
  We provide a complete representation of the interest rate in the extended CIR
model. Since it was proved in Maghsoodi (1996) that the representation of the
CIR process as a sum of squares of independent Ornstein-Uhlenbeck processes is
possible only when the dimension of the interest rate process is integer, we
use a slightly different representation, valid when the dimension is not
integer. Our representation consists in an infinite sum of squares of basic
processes. Each basic process can be described as an Ornstein-Uhlenbeck process
with jumps at fixed times. In this case, the price of a bond option resembles
the Black-Scholes formula, where the normal distribution is replaced by the
generalized chi-square distribution. The formula is in closed form, up to the
solution of a Riccati equation for the bond price of the option. We then
provide a generalization of our representation to an extended CIR model with
stochastic volatility. We present a closed form approximation of the price of a
bond option, valid when the expiration of the option is small and the speed of
mean-reversion of volatility is high. The approximation is in "full" closed
form, i.e., it does not require to solve an ordinary differential equation.


title: Partially Overlapping Tones for Uncoordinated Networks

abstract:
  In an uncoordinated network, the link performance between the devices might
degrade significantly due to the interference from other links in the network
sharing the same spectrum. As a solution, in this study, the concept of
partially overlapping tones (POT) is introduced. The interference energy
observed at the victim receiver is mitigated by partially overlapping the
individual subcarriers via an intentional carrier frequency offset between the
links. Also, it is shown that while orthogonal transformations at the receiver
cannot mitigate the other-user interference without losing spectral efficiency,
non-orthogonal transformations are able to mitigate the other-user interference
without any spectral efficiency loss at the expense of self-interference. Using
spatial Poisson point process, a tractable bit error rate analysis is provided
to demonstrate potential benefits emerging from POT.


title:
Microwave manipulation of electrically injected spin polarized electrons
  in silicon

abstract:
  We demonstrate microwave manipulation of the spin states of electrically
injected spin-polarized electrons in silicon. Although the silicon channel is
bounded by ferromagnetic metal films, we show that moderate microwave power can
be applied to the devices without altering the device operation significantly.
Resonant microwave irradiation is used to induce spin rotation of
spin-polarized electrons as they travel across a silicon channel, and the
resultant spin polarization is subsequently detected by a ferromagnetic
Schottky barrier spin detector. These results demonstrate the potential for
combining advanced electron spin resonance techniques to complement the study
of semiconductor spintronic devices beyond standard magnetotransport
measurements.


title: At what chain length do unbranched alkanes prefer folded conformations?

abstract:
  Short unbranched alkanes are known to prefer linear conformations, while long
unbranched alkanes are folded. It is not known with certainty at what chain
length the linear conformation is no longer the global minimum. To clarify this
point, we use {\it ab initio} and density functional methods to compute the
relative energies of the linear and hairpin alkane conformers for increasing
chain lengths. Extensive electronic structure calculations are performed to
obtain optimized geometries, harmonic frequencies and accurate single point
energies for the selected alkane conformers from octane through octadecane.
Benchmark CCSD(T)/cc-pVTZ single point calculations are performed for chains
through tetradecane, while approximate methods are required for the longer
chains up to octadecane. Using frozen natural orbitals to unambiguously
truncate the virtual orbital space, we are able to compute composite CCSD
FNO(T) single point energies for all the chain lengths. This approximate
composite method has significant computational savings compared to full CCSD(T)
while retaining $\sim0.15$ kcal/mol accuracy compared to the benchmark results.
More approximate dual-basis resolution-of-the-identity double-hybrid DFT
calculations are also performed and shown to have reasonable $0.2-0.4$ kcal/mol
errors compared with our benchmark values. After including contributions from
temperature dependent internal energy shifts, we find the preference for folded
conformations to lie between hexadecane and octadecane, in excellent agreement
with recent experiments [L\"{u}ttschwager, N. O.; Wassermann, T. N.; Mata, R.
A.; Suhm, M. A. {\it Angew. Chem. Int. Ed.} 2013, 52, 463].


title: Managing NymBoxes for Identity and Tracking Protection

abstract:
  Despite the attempts of well-designed anonymous communication tools to
protect users from tracking or identification, flaws in surrounding software
(such as web browsers) and mistakes in configuration may leak the user's
identity. We introduce Nymix, an anonymity-centric operating system
architecture designed "top-to-bottom" to strengthen identity- and
tracking-protection. Nymix's core contribution is OS support for nym-browsing:
independent, parallel, and ephemeral web sessions. Each web session, or
pseudonym, runs in a unique virtual machine (VM) instance evolving from a
common base state with support for long-lived sessions which can be anonymously
stored to the cloud, avoiding de-anonymization despite potential confiscation
or theft. Nymix allows a user to safely browse the Web using various different
transports simultaneously through a pluggable communication model that supports
Tor, Dissent, and a private browsing mode. In evaluations, Nymix consumes 600
MB per nymbox and loads within 15 to 25 seconds.


title:
Global Existence for the "One and one-half" dimensional relativistic
  Vlasov-Maxwell-Fokker-Planck system

abstract:
  In a recent paper Calogero and Alcantara derived a Lorentz-invariant
Fokker-Planck equation, which corresponds to the evolution of a particle
distribution associated with relativistic Brownian Motion. We study the "one
and one-half" dimensional version of this problem with nonlinear
electromagnetic interactions - the relativistic Vlasov-Maxwell-Fokker-Planck
system - and obtain the first results concerning well-posedness of solutions.
Specifically, we prove the global-in-time existence and uniqueness of classical
solutions to the Cauchy problem and a gain in regularity of the distribution
function in its momentum argument.


title:
The status of determinism in proofs of the impossibility of a
  noncontextual model of quantum theory

abstract:
  In order to claim that one has experimentally tested whether a noncontextual
ontological model could underlie certain measurement statistics in quantum
theory, it is necessary to have a notion of noncontextuality that applies to
unsharp measurements, i.e., those that can only be represented by positive
operator-valued measures rather than projection-valued measures. This is
because any realistic measurement necessarily has some nonvanishing amount of
noise and therefore never achieves the ideal of sharpness. Assuming a
generalized notion of noncontextuality that applies to arbitrary experimental
procedures, it is shown that the outcome of a measurement depends
deterministically on the ontic state of the system being measured if and only
if the measurement is sharp. Hence for every unsharp measurement, its outcome
necessarily has an indeterministic dependence on the ontic state. We defend
this proposal against alternatives. In particular, we demonstrate why
considerations parallel to Fine's theorem do not challenge this conclusion.


title:
Classical-Nova Contribution to the Milky Way's $^{26}$Al Abundance: Exit
  Channel of the Key $^{25}$Al($p,\gamma$)$^{26}$Si Resonance

abstract:
  Classical novae are expected to contribute to the 1809-keV Galactic
$\gamma$-ray emission by producing its precursor $^{26}$Al, but the yield
depends on the thermonuclear rate of the unmeasured
$^{25}$Al($p,\gamma$)$^{26}$Si reaction. Using the $\beta$ decay of $^{26}$P to
populate the key $J^{\pi}=3^+$ resonance in this reaction, we report the first
evidence for the observation of its exit channel via a $1741.6 \pm 0.6
(\textrm{stat}) \pm 0.3 (\textrm{syst})$ keV primary $\gamma$ ray, where the
uncertainties are statistical and systematic, respectively. By combining the
measured $\gamma$-ray energy and intensity with other experimental data on
$^{26}$Si, we find the center-of-mass energy and strength of the resonance to
be $E_r = 414.9 \pm 0.6(\textrm{stat}) \pm 0.3 (\textrm{syst}) \pm
0.6(\textrm{lit.})$ keV and $\omega\gamma = 23 \pm 6
(\textrm{stat})^{+11}_{-10}(\textrm{lit.})$ meV, respectively, where the last
uncertainties are from adopted literature data. We use hydrodynamic nova
simulations to model $^{26}$Al production showing that these measurements
effectively eliminate the dominant experimental nuclear-physics uncertainty and
we estimate that novae may contribute up to 30% of the Galactic $^{26}$Al.


title:
Changes of statistical structural fluctuations unveils an early
  compacted degraded stage of PNS myelin

abstract:
  Degradation of the myelin sheath is a common pathology underlying
demyelinating neurological diseases from Multiple Sclerosis to
Leukodistrophies. Although large malformations of myelin ultrastructure in the
advanced stages of Wallerian degradation is known, its subtle structural
variations at early stages of demyelination remains poorly characterized. This
is partly due to the lack of suitable and non-invasive experimental probes
possessing sufficient resolution to detect the degradation. Here we report the
feasibility of the application of an innovative non-invasive local structure
experimental approach for imaging the changes of statistical structural
fluctuations in the first stage of myelin degeneration. Scanning micro X-ray
diffraction, using advances in synchrotron x-ray beam focusing, fast data
collection, paired with spatial statistical analysis, has been used to unveil
temporal changes in the myelin structure of dissected nerves following
extraction of the Xenopus laevis sciatic nerve. The early myelin degeneration
is a specific ordered compacted phase preceding the swollen myelin phase of
Wallerian degradation. Our demonstration of the feasibility of the statistical
analysis of SmXRD measurements using biological tissue paves the way for
further structural investigations of degradation and death of neurons and other
cells and tissues in diverse pathological states where nanoscale structural
changes may be uncovered.


title: The Effects of Latent Infection on the Dynamics of HIV

abstract:
  One way in which the human immunodeficiency virus (HIV-1) replicates within a
host is by infecting activated CD4+ T-cells, which then produce additional
copies of the virus. Even with the introduction of antiretroviral drug therapy,
which has been very successful over the past decade, a large obstacle to the
complete eradication of the virus is the presence of viral reservoirs in the
form of latently infected CD4+ T-cells. We consider a model of HIV infection
that describes T-cell and viral interactions, as well as, the production and
activation of latently infected T-cells. Upon determining equilibrium states of
the latent cell model, the local and global asymptotic behavior of solutions is
examined, and the basic reproduction number of the system is computed to be
strictly less than that of the corresponding three-component model, which omits
the effects of latent infection. In particular, this implies that a wider
variety of parameter values will lead to viral eradication as $t \to \infty$
due to the appearance of latent CD4+ T-cells. With this realization we discuss
possible alternative notions for eradication and persistence of infection other
than traditional tools. These results are further illustrated by a number of
numerical simulations.


title: Analysis and Simulation of the Three-Component Model of HIV Dynamics

abstract:
  Mathematical modeling of biological systems is crucial to effectively and
efficiently developing treatments for medical conditions that plague humanity.
Often, systems of ordinary differential equations are a traditional tool used
to describe the spread of disease within the body. We consider the dynamics of
the Human Immunodeficiency Virus (HIV) in vivo during the initial stage of
infection. In particular, we examine the well-known three-component model and
prove the existence, uniqueness, and boundedness of solutions. Furthermore, we
prove that solutions remain biologically meaningful, i.e., are positivity
preserving, and perform a thorough, local stability analysis for the
equilibrium states of the system. Finally, we incorporate random coefficients
within the model and obtain numerical results to predict the probability of
infection given the transmission of the virus to a new individual.


title:
Models of magnetic-field evolution and effective viscosity in weakly
  collisional extragalactic plasmas

abstract:
  In weakly collisional extragalactic plasmas such as the intracluster medium,
viscous stress and the rate of change of the magnetic-field strength are
proportional to the local pressure anisotropy, so subject to constraints
imposed by the pressure-anisotropy-driven mirror and firehose instabilities and
controlled by the local instantaneous plasma beta. The dynamics of such plasmas
is dramatically different from a conventional MHD fluid. The plasma is expected
to stay locally in a marginal state with respect to the instabilities, but how
it does this is an open question. Two models of magnetic-field evolution are
investigated. In the first, marginality is achieved via suppression of the rate
of change of the field. In the second, the instabilities give rise to anomalous
collisionality, reducing pressure anisotropy to marginal - at the same time
decreasing viscosity and so increasing the turbulent rate of strain.
Implications of these models are studied in a simplified 0D setting. In the
first model, the field grows explosively but on a time scale that scales with
initial beta, while in the second, dynamical field strength can be reached in
one large-scale turbulence turn-over time regardless of the initial seed. Both
models produce very intermittent fields. Both also suffer from strong
constraints on their applicability: for typical cluster-core conditions, scale
separation between the fluid motions and the microscale fluctuations breaks
down at beta~10^5-10^4. At larger beta (weaker fields), a fully collisionless
plasma dynamo theory is needed in order to justify the growth of the field from
a tiny primordial seed. However, the models discussed here are appropriate for
studying the structure of the currently observed field as well as large-scale
dynamics and thermodynamics of the magnetized ICM or similarly dilute
astrophysical plasmas.

categories: astro-ph.CO astro-ph.HE nlin.CD physics.plasm-ph


title: Lag, lock, sync, slip: the many "phases" of coupled flagella

abstract:
  In a multitude of life's processes, cilia and flagella are found
indispensable. Recently, the biflagellated chlorophyte alga Chlamydomonas has
become a model organism for the study of ciliary coordination and
synchronization. Here, we use high-speed imaging of single pipette-held cells
to quantify the rich dynamics exhibited by their flagella. Underlying this
variability in behaviour, are biological dissimilarities between the two
flagella - termed cis and trans, with respect to a unique eyespot. With
emphasis on the wildtype, we use digital tracking with sub-beat-cycle
resolution to obtain limit cycles and phases for self-sustained flagellar
oscillations. Characterizing the phase-synchrony of a coupled pair, we find
that during the canonical swimming breaststroke the cis flagellum is
consistently phase-lagged relative to, whilst remaining robustly phase-locked
with, the trans flagellum. Transient loss of synchrony, or phase-slippage, may
be triggered stochastically, in which the trans flagellum transitions to a
second mode of beating with attenuated beat-envelope and increased frequency.
Further, exploiting this alga's ability for flagellar regeneration, we
mechanically induced removal of one or the other flagellum of the same cell to
reveal a striking disparity between the beating of the cis vs trans flagellum,
in isolation. This raises further questions regarding the synchronization
mechanism of Chlamydomonas.


title: Scalar Field Theory in Curved Momentum Space

abstract:
  We derive an action for scalar quantum field theory with cubic interaction in
the context of relative locality. Beginning with the generating functional for
standard $\varphi^3$--theory and the corresponding Feynman rules we modify them
to account for the non--trivial geometry of momentum space. These modified
rules are then used to reconstruct the generating functional and extract the
action for the theory. A method for performing a covariant Fourier transform is
then developed and applied to the action. We find that the transformed fields
depend implicitly on a fixed point in momentum space with fields based at
different points being related by a non-local transformation. The interaction
term in the action is also non--local, but the kinetic term can be made local
by choosing the base point to be the origin of momentum space.


title:
Suppression of Upsilon Production in d+Au and Au+Au Collisions at
  sqrt(s_NN) = 200 GeV

abstract:
  We report measurements of Upsilon meson production in p+p, d+Au, and Au+Au
collisions using the STAR detector at RHIC. We compare the Upsilon yield to the
measured cross section in p+p collisions in order to quantify any modifications
of the yield in cold nuclear matter using d+Au data and in hot nuclear matter
using Au+Au data separated into three centrality classes. Our p+p measurement
is based on three times the statistics of our previous result. We obtain a
nuclear modification factor for Upsilon(1S+2S+3S) in the rapidity range |y|<1
in d+Au collisions of R_dAu = 0.79 +/- 0.24 (stat.) +/- 0.03 (sys.) +/- 0.10
(pp sys.). A comparison with models including shadowing and initial state
parton energy loss indicates the presence of additional cold-nuclear matter
suppression. Similarly, in the top 10% most-central Au+Au collisions, we
measure a nuclear modification factor of R_AA=0.49 +/- 0.1 (stat.) +/- 0.02
(sys.) +/- 0.06 (pp sys.), which is a larger suppression factor than that seen
in cold nuclear matter. Our results are consistent with complete suppression of
excited-state Upsilon mesons in Au+Au collisions. The additional suppression in
Au+Au is consistent with the level expected in model calculations that include
the presence of a hot, deconfined Quark-Gluon Plasma. However, understanding
the suppression seen in d+Au is still needed before any definitive statements
about the nature of the suppression in Au+Au can be made.


title: DOOp, an automated wrapper for DAOSPEC

abstract:
  Large spectroscopic surveys such as the Gaia-ESO Survey produce huge
quantities of data. Automatic tools are necessary to efficiently handle this
material. The measurement of equivalent widths in stellar spectra is
traditionally done by hand or with semi-automatic procedures that are
time-consuming and not very robust with respect to the repeatability of the
results. The program DAOSPEC is a tool that provides consistent measurements of
equivalent widths in stellar spectra while requiring a minimum of user
intervention. However, it is not optimised to deal with large batches of
spectra, as some parameters still need to be modified and checked by the user.
Exploiting the versatility and portability of BASH, we have built a pipeline
called DAOSPEC Option Optimiser (DOOp) automating the procedure of equivalent
widths measurement with DAOSPEC. DOOp is organised in different modules that
run one after the other to perform specific tasks, taking care of the
optimisation of the parameters needed to provide the final equivalent widths,
and providing log files to ensure better control over the procedure. In this
paper, making use of synthetic and observed spectra, we compare the performance
of DOOp with other methods, including DAOSPEC used manually. The measurements
made by DOOp are identical to the ones produced by DAOSPEC when used manually,
while requiring less user intervention, which is convenient when dealing with a
large quantity of spectra. DOOp shows its best performance on high-resolution
spectra (R>20 000) and high signal-to-noise ratio (S/N>30), with uncertainties
ranging from 6 m{\AA} to 2 m{\AA}. The only subjective parameter that remains
is the normalisation, as the user still has to make a choice on the order of
the polynomial used for the continuum fitting. As a test, we use the equivalent
widths measured by DOOp to re-derive the stellar parameters of four
well-studied stars.


title: Foil Diffuser Investigation with GEANT4

abstract:
  An investigation into the appropriate materials for use as a diffuser foil in
electron radiography was undertaken in GEANT4. Simulations were run using
various refractory materials to determine a material of appropriate Z number
such that energy loss is minimal. The plotted results of angular spread and
energy spread are shown. It is concluded that higher Z number materials such as
tungsten, tantalum, platinum or uranium could be used as diffuser materials.
Also, an investigation into the handling of bremsstrahlung, multiple coulomb
scattering, and ionization in GEANT4 was performed.


title:
Precision spectroscopy with COMPASS and the observation of a new
  iso-vector resonance

abstract:
  We report on the results of a novel partial-wave analysis based on $50\cdot
10^6$ events from the reaction $\pi^- + p \to \pi^-\pi-^\pi^+ +
p_\text{recoil}$ at 190 $\text{GeV/c}$ incoming beam momentum using the COMPASS
spectrometer. A separated analysis in bins of $m_{3\pi}$ and four-momentum
transfer $t'$ reveals the interference of resonant and non-resonant particle
production and allows their spectral separation. Besides well known resonances
we observe a new iso-vector meson $a_1(1420)$ at a mass of 1420
$\text{MEV\c}^2$ in the $f_0(980)\pi$ final state only, the origin of which is
unclear. We have also examined the structure of the $0^{++}$ $\pi\pi$-isobar in
the $J^{PC}=0^{-+}, 1^{++}, 2^{-+}$ three pion waves. This clearly reveals the
various $0^{++}$ $\pi\pi$-isobar components and its correlation to the decay of
light mesons.


title:
Crossing numbers and combinatorial characterization of monotone drawings
  of $K_n$

abstract:
  In 1958, Hill conjectured that the minimum number of crossings in a drawing
of $K_n$ is exactly $Z(n) = \frac{1}{4} \lfloor\frac{n}{2}\rfloor
\left\lfloor\frac{n-1}{2}\right\rfloor
\left\lfloor\frac{n-2}{2}\right\rfloor\left\lfloor\frac{n-3}{2}\right\rfloor$.
Generalizing the result by \'{A}brego et al. for 2-page book drawings, we prove
this conjecture for plane drawings in which edges are represented by
$x$-monotone curves. In fact, our proof shows that the conjecture remains true
for $x$-monotone drawings of $K_n$ in which adjacent edges may cross an even
number of times, and instead of the crossing number we count the pairs of edges
which cross an odd number of times. We further discuss a generalization of this
result to shellable drawings, a notion introduced by \'{A}brego et al. We also
give a combinatorial characterization of several classes of $x$-monotone
drawings of complete graphs using a small set of forbidden configurations. For
a similar local characterization of shellable drawings, we generalize
Carath\'eodory's theorem to simple drawings of complete graphs.


title:
A Measurement of the Kinetic Sunyaev-Zel'dovich Signal Toward MACS
  J0717.5+3745

abstract:
  We report our analysis of MACS J0717.5+3745 using 140 and 268 GHz Bolocam
data collected at the Caltech Submillimeter Observatory. We detect extended
Sunyaev-Zel'dovich (SZ) effect signal at high significance in both Bolocam
bands, and we employ Herschel-SPIRE observations to subtract the signal from
dusty background galaxies in the 268 GHz data. We constrain the two-band SZ
surface brightness toward two of the sub-clusters of MACS J0717.5+3745: the
main sub-cluster (named C), and a sub-cluster identified in spectroscopic
optical data to have a line-of-sight velocity of +3200 km/s (named B). We
determine the surface brightness in two separate ways: via fits of parametric
models and via direct integration of the images. For both sub-clusters, we find
consistent surface brightnesses from both analysis methods. We constrain
spectral templates consisting of relativistically corrected thermal and kinetic
SZ signals, using a jointly-derived electron temperature from Chandra and
XMM-Newton under the assumption that each sub-cluster is isothermal. The data
show no evidence for a kinetic SZ signal toward sub-cluster C, but they do
indicate a significant kinetic SZ signal toward sub-cluster B. The
model-derived surface brightnesses for sub-cluster B yield a best-fit
line-of-sight velocity of v_z = +3450 +- 900 km/s, with (1 - Prob[v_z > 0]) =
1.3 x 10^-5 (4.2 sigma away from 0 for a Gaussian distribution). The directly
integrated sub-cluster B SZ surface brightnesses provide a best-fit v_z = +2550
+- 1050 km/s, with (1 - Prob[v_z > 0]) = 2.2 x 10^-3 (2.9 sigma).


title: Vulnerability of LTE to Hostile Interference

abstract:
  LTE is well on its way to becoming the primary cellular standard, due to its
performance and low cost. Over the next decade we will become dependent on LTE,
which is why we must ensure it is secure and available when we need it.
Unfortunately, like any wireless technology, disruption through radio jamming
is possible. This paper investigates the extent to which LTE is vulnerable to
intentional jamming, by analyzing the components of the LTE downlink and uplink
signals. The LTE physical layer consists of several physical channels and
signals, most of which are vital to the operation of the link. By taking into
account the density of these physical channels and signals with respect to the
entire frame, as well as the modulation and coding schemes involved, we come up
with a series of vulnerability metrics in the form of jammer to signal ratios.
The ``weakest links'' of the LTE signals are then identified, and used to
establish the overall vulnerability of LTE to hostile interference.


title: Cosmological black holes from self-gravitating fields

abstract:
  Both cosmological expansion and black holes are ubiquitous features of our
observable Universe, yet exact solutions connecting the two have remained
elusive. To this end, we study self-gravitating classical fields within
dynamical spherically symmetric solutions that can describe black holes in an
expanding universe. After attempting a perturbative approach of a known
black-hole solution with scalar hair, we show by exact methods that the unique
scalar field action with first-order derivatives that can source shear-free
expansion around a black hole requires noncanonical kinetic terms. The
resulting action is an incompressible limit of k-essence, otherwise known as
the cuscuton theory, and the spacetime it describes is the McVittie metric. We
further show that this solution is an exact solution to the vacuum
Ho\v{r}ava-Lifshitz gravity with anisotropic Weyl symmetry.


title: Non-linear growth and condensation in multiplex networks

abstract:
  Different types of interactions coexist and coevolve to shape the structure
and function of a multiplex network. We propose here a general class of growth
models in which the various layers of a multiplex network coevolve through a
set of non-linear preferential attachment rules. We show, both numerically and
analytically, that by tuning the level of non-linearity these models allow to
reproduce either homogeneous or heterogeneous degree distributions, together
with positive or negative degree correlations across layers. In particular, we
derive the condition for the appearance of a condensed state in which one node
in each layer attracts an extensive fraction of all the edges.

categories: physics.soc-ph cond-mat.dis-nn cond-mat.stat-mech cs.SI


title: Revisting the boiling of quark nuggets at nonzero chemical potential

abstract:
  The boiling of possible quark nuggets during the quark-hadron phase
transition of the Universe at nonzero chemical potential is revisited within
the microscopic Brueckner-Hartree-Fock approach employed for the hadron phase,
using two kinds of baryon interactions as fundamental inputs. To describe the
deconfined phase of quark matter, we use a recently developed quark mass
density-dependent model with a fully self-consistent thermodynamic treatment of
confinement. We study the baryon number limit $A_{\rm boil}$ (above which
boiling may be important) with three typical values for the confinement
parameter $D$. It is firstly found that the baryon interaction with a softer
equation of state for the hadron phase would only lead to a small increase of
$A_{\rm boil}$. However, results depend sensitively on the confinement
parameter in the quark model. Specifically, boiling might be important during
the Universe cooling for a limited parameter range around $D^{1/2} = 170$ MeV,
a value satisfying recent lattice QCD calculations of the vacuum chiral
condensate, while for other choices of this parameter, boiling might not happen
and cosmological quark nuggets of $10^2 < A < 10^{50}$ could survive.


title: Numerical computation of an Evans function for travelling waves

abstract:
  We demonstrate a geometrically inspired technique for computing Evans
functions for the linearised operators about travelling waves. Using the
examples of the F-KPP equation and a Keller-Segel model of bacterial
chemotaxis, we produce an Evans function which is computable through several
orders of magnitude in the spectral parameter and show how such a function can
naturally be extended into the continuous spectrum. In both examples, we use
this function to numerically verify the absence of eigenvalues in a large
region of the right half of the spectral plane. We also include a new proof of
spectral stability in the appropriate weighted space of travelling waves of
speed $c \geq 2 \sqrt{\delta}$ in the F-KPP equation.


title:
Deformations of constant scalar curvature Sasakian metrics and
  K-stability

abstract:
  Extending the work of G. Sz\'ekelyhidi and T. Br\"onnle to Sasakian manifolds
we prove that a small deformation of the complex structure of the cone of a
constant scalar curvature Sasakian manifold admits a constant scalar curvature
structure if it is K-polystable. This also implies that a small deformation of
the complex structure of the cone of a constant scalar curvature structure is
K-semistable. As applications we give examples of constant scalar curvature
Sasakian manifolds which are deformations of toric examples, and we also show
that if a 3-Sasakian manifold admits a non-trivial transversal complex
deformation then it admits a non-trivial Sasaki-Einstein deformation.


title:
Phase diagram of a three-dimensional antiferromagnet with random
  magnetic anisotropy

abstract:
  Three-dimensional (3D) antiferromagnets with random magnetic anisotropy (RMA)
experimentally studied to date do not have random single-ion anisotropies, but
rather have competing two-dimensional and three-dimensional exchange
interactions which can obscure the authentic effects of RMA. The magnetic phase
diagram Fe$_{x}$Ni$_{1-x}$F$_{2}$ epitaxial thin films with true random
single-ion anisotropy was deduced from magnetometry and neutron scattering
measurements and analyzed using mean field theory. Regions with uniaxial,
oblique and easy plane anisotropies were identified. A RMA-induced glass region
was discovered where a Griffiths-like breakdown of long-range spin order
occurs.


title:
Newton's law for a trajectory of concentration of solutions to nonlinear
  Schrodinger equation

abstract:
  One of important problems in mathematical physics concerns derivation of
point dynamics from field equations. The most common approach to this problem
is based on WKB method. Here we describe a different method based on the
concept of trajectory of concentration. When we applied this method to
nonlinear Klein-Gordon equation, we derived relativistic Newton's law and
Einstein's formula for inertial mass. Here we apply the same approach to
nonlinear Schrodinger equation and derive non-relativistic Newton's law for the
trajectory of concentration.


title: Plane correlations and hydrodynamic simulations of heavy ion collisions

abstract:
  We use a nonlinear response formalism to describe the event plane
correlations measured by the ATLAS collaboration. With one exception
($\left\langle \cos(2\Psi_2 - 6\Psi_3 + 4 \Psi_4) \right\rangle$), the event
plane correlations are qualitatively reproduced by considering the linear and
quadratic response to the lowest cumulants. For the lowest harmonics such as
$\left\langle \cos(2\Psi_2+3\Psi_3 - 5\Psi_5) \right\rangle$, the correlations
are quantitatively reproduced, even when the naive Glauber model prediction has
the wrong sign relative to experiment. The quantitative agreement for the
higher plane correlations (especially those involving $\Psi_6$) is not as good.
The centrality dependence of the correlations is naturally explained as an
average of the linear and quadratic response.


title: Giant $g$-factors of Natural Impurities in Synthetic Quartz

abstract:
  We report the observation of $g$-factors of natural paramagnetic impurities
in a pure synthetic quartz crystal at milli-Kelvin temperatures. Measurements
are made by performing spectroscopy using multiple high-$Q$ Whispering Gallery
Modes sustained in the crystal. Extreme sensitivity of the method at low
temperatures allows the determination of natural residual impurities introduced
during the crystal growth. We observe $g$-factors that significantly differ
from integer multiples of the electron $g$-factor in vacuum, and with values of
up to $7.6$, which reveals much stronger coupling between impurities and the
crystal lattice than in previous studies. Both substitutional and interstitial
ions are proposed as candidates for the observed interactions.


title:
Finding the Force -- Consistent Particle Seeding for Satellite
  Aerodynamics

abstract:
  When calculating satellite trajectories in low-earth orbit, engineers need to
adequately estimate aerodynamic forces. But to this day, obtaining the drag
acting on the complicated shapes of modern spacecraft suffers from many sources
of error. While part of the problem is the uncertain density in the upper
atmosphere, this works focuses on improving the modeling of interacting
rarified gases and satellite surfaces. The only numerical approach that
currently captures effects in this flow regime---like self-shadowing and
multiple molecular reflections---is known as test-particle Monte Carlo. This
method executes a ray-tracing algorithm to follow particles that pass through a
control volume containing the spacecraft and accumulates the momentum transfer
to the body surfaces. Statistical fluctuations inherent in the approach demand
particle numbers in the order of millions, often making this scheme too costly
to be practical. This work presents a parallel test-particle Monte Carlo method
that takes advantage of both GPUs and multi-core CPUs. The speed at which this
model can run with millions of particles allowed exploring a regime where a
flaw in the model's initial particle seeding was revealed. Our new model
introduces an analytical fix based on seeding the calculation with an initial
distribution of particles at the boundary of a spherical control volume and
computing the integral for the correct number flux. This work includes
verification of the proposed model using analytical solutions for several
simple geometries and demonstrates uses for studying aero-stabilization of the
Phobos-Grunt Martian probe and pose-estimation for the ICESat mission.


title:
Designing a brown planthoppers surveillance network based on wireless
  sensor network approach

abstract:
  This paper proposes a new approach for monitoring brown planthoppers (BPH)
swarms using a surveillance network at provincial scale. The topology of this
network is identified to a wireless sensor network (WSN), where each node is a
real light trap and each edge describes the influence between two nodes,
allowing gathering BPH information. Different communication ranges are
evaluated to choose a suitable network. The experiments are performed on the
light traps surveillance network of Hau Giang province, a typical rice province
in the Mekong Delta region of Vietnam.


title: Policy Network Approach to Coordinated Disaster Response

abstract:
  In this paper, we explore the formation of network relationships among
disaster relief agencies during the process of responding to an unexpected
event. The relationship is investigated through variables derived from the
policy network theory, and four cases from three developed countries such as
(i) Hurricane Katrina in the US; (ii) Typhoon Maemi in South Korea; (iii) Kobe;
and, (iv) Tohoku Earthquake in Japan that failed to cope with extreme events
forms the basis for case study presented here. We argue that structural
characteristics of multi-jurisdictional coordination may facilitate or impede
in responding to a complex nature of recent disaster. We further highlight the
promise of policy network approach in facilitating the development of
multi-jurisdictional coordination process which may provide new avenue to
improve the communication and coordination of hierarchical command control
driven organizations with the local community. Our proposed novel approach in
investigating the usefulness of network approach through media content analysis
for emergency may provide opportunity as a countermeasure to a traditional
hierarchical coordination, which may give further insights in establishing a
more effective network for emergency.


title:
Mesoscale computational study of the nano-crystallization of amorphous
  Ge via a self-consistent atomistic - phase field coupling

abstract:
  Germanium is the base element in many phase-change materials, i.e. systems
that can undergo reversible transformations between their crystalline and
amorphous phases. They are widely used in current digital electronics and hold
great promise for the next generation of non-volatile memory devices. However,
the ultra fast phase transformations required for these applications can be
exceedingly complex even for single component systems, and a full physical
understanding of these phenomena is still lacking. In this paper we study
nucleation and growth of crystalline Ge from amorphous thin films at high
temperature using phase field models informed by atomistic calculations of
fundamental material properties. The atomistic calculations capture the full
anisotropy of the Ge crystal lattice, which results in orientation dependences
for interfacial energies and mobilities. These orientation relations are then
exactly recovered by the phase field model at finite thickness via a novel
parametrization strategy based on invariance solutions of the Allen-Cahn
equations. By means of this multiscale approach, we study the interplay between
nucleation and growth and find that the relation between the mean radius of the
crystallized Ge grains and the nucleation rate follows simple Avrami-type
scaling laws. We argue that these can be used to cover a wide region of the
nucleation rate space, hence facilitating comparison with experiments.


title:
Secure Beamforming for MIMO Two-Way Communications with an Untrusted
  Relay

abstract:
  This paper studies the secure beamforming design in a multiple-antenna
three-node system where two source nodes exchange messages with the help of an
untrusted relay node. The relay acts as both an essential signal forwarder and
a potential eavesdropper. Both two-phase and three-phase two-way relay
strategies are considered. Our goal is to jointly optimize the source and relay
beamformers for maximizing the secrecy sum rate of the two-way communications.
We first derive the optimal relay beamformer structures. Then, iterative
algorithms are proposed to find source and relay beamformers jointly based on
alternating optimization. Furthermore, we conduct asymptotic analysis on the
maximum secrecy sum-rate. Our analysis shows that when all transmit powers
approach infinity, the two-phase two-way relay scheme achieves the maximum
secrecy sum rate if the source beamformers are designed such that the received
signals at the relay align in the same direction. This reveals an important
advantage of signal alignment technique in against eavesdropping. It is also
shown that if the source powers approach zero the three-phase scheme performs
the best while the two-phase scheme is even worse than direct transmission.
Simulation results have verified the efficiency of the secure beamforming
algorithms as well as the analytical findings.


title: Theory of Classical Higgs Fields. I. Matter Fields

abstract:
  Higgs fields are attributes of classical gauge theory on a principal bundle
$P\to X$ whose structure Lie group $G$ if is reducible to a closed subgroup
$H$. They are represented by sections of the quotient bundle $P/H\to X$. A
problem lies in description of matter fields with an exact symmetry group $H$.
They are represented by sections of a composite bundle which is associated to
an $H$-principal bundle $P\to P/H$. It is essential that they admit an action
of a gauge group $G$.


title:
First-Quantized Theory of Expanding Universe from Field Quantization in
  Mini-Superspace

abstract:
  We propose an improved variant of the third-quantization scheme, for the
spatially homogeneous and isotropic cosmological models in Einstein gravity
coupled with a neutral massless scalar field. Our strategy is to specify a
semi-Riemannian structure on the mini-superspace and to consider the quantum
Klein-Gordon field on the mini-superspace. Then, the Hilbert space of this
quantum system becomes inseparable, which causes the creation of infinite
number of universes. To overcome this issue, we introduce a vector bundle
structure on the Hilbert space and the connection of the vector bundle. Then,
we can define a consistent unitary time evolution of the quantum universe in
terms of the connection field on the vector bundle. By doing this, we are able
to treat the quantum dynamics of a single-universe state. We also find an
appropriate observable set constituting the CCR-algebra, and obtain the
Schr\"odinger equation for the wave function of the single-universe state. We
show that the present quantum theory correctly reproduces the classical
solution to the Einstein equation.


title: How typical is the Coma cluster?

abstract:
  Coma is frequently used as the archetype z~0 galaxy cluster to compare higher
redshift work against. It is not clear, however, how representative the Coma
cluster is for galaxy clusters of its mass or X-ray luminosity, and
significantly: recent works have suggested that the galaxy population of Coma
may be in some ways anomolous. In this work, we present a comparison of Coma to
an X-ray selected control sample of clusters. We show that although Coma is
typical against the control sample in terms of its internal kinematics
(substructure and velocity dispersion profile), it has a significantly high
(~3sigma) X-ray temperature set against clusters of comparable mass. By
de-redshifting our control sample cluster galaxies star-formation rates using a
fit to the galaxy main sequence evolution at z < 0.1, we determine that the
typical star-formation rate of Coma galaxies as a function of mass is higher
than for galaxies in our control sample at a confidence level of > 99 per cent.
One way to alleviate this discrepency and bring Coma in-line with the control
sample would be to have the distance to Coma to be slightly lower, perhaps
through a non-negligible peculiar velocity with respect to the Hubble
expansion, but we do not regard this as likely given precision measurements
using a variety of approaches. Therefore in summary, we urge caution in using
Coma as a z~0 baseline cluster in galaxy evolution studies.


title: Extremal Surface Barriers

abstract:
  We present a generic condition for Lorentzian manifolds to have a barrier
that limits the reach of boundary-anchored extremal surfaces of arbitrary
dimension. We show that any surface with nonpositive extrinsic curvature is a
barrier, in the sense that extremal surfaces cannot be continuously deformed
past it. Furthermore, the outermost barrier surface has nonnegative extrinsic
curvature. Under certain conditions, we show that the existence of trapped
surfaces implies a barrier, and conversely. In the context of AdS/CFT, these
barriers imply that it is impossible to reconstruct the entire bulk using
extremal surfaces. We comment on the implications for the firewall controversy.


title:
The solution of complex problems on calculation of the electrostatic
  fields on lessons on computer modeling

abstract:
  In article the following tasks on computer modeling of electric fields are
analyzed: 1) calculation of distribution of potential for the field created by
two parallel plates and charged bodies in the non-uniform environment; 2)
calculation of distribution of potential and force lines of electric field in
which are brought the cylinder, a pipe, a plate, a rectangular parallelepiped
from dielectric, and also the metal cylinder; 3) calculation of distribution of
potential in the one-dimensional nonuniform environment; 4) the solution of the
equation of Poisson in spherical coordinates; 5) calculation of distribution of
potential in cylindrical coordinates with the subsequent creation of
equipotential surfaces and force lines.


title:
Constraints on Dark Matter annihilation and Its Equation of State after
  Planck Data

abstract:
  In this paper, the annihilation of dark matter $f_d\epsilon_0$ with nonzero
equation of state $w_{dm}$ was studied by using the currently available cosmic
observations which include the geometric and dynamic measurements. The
constrained results show they are anti-correlated and are
$w_{dm}=0.000390_{-0.000753}^{+0.000754}$ and
$f_d\epsilon_0=1.172_{-1.172}^{+0.243}$ respectively in $1\sigma$ regions. With
the including of possible annihilation of dark matter, no significant deviation
from $\Lambda$CDM model was found in the $1\sigma$ region.


title: Outage Analysis of Uplink Two-tier Networks

abstract:
  Employing multi-tier networks is among the most promising approaches to
address the rapid growth of the data demand in cellular networks. In this
paper, we study a two-tier uplink cellular network consisting of femtocells and
a macrocell. Femto base stations, and femto and macro users are assumed to be
spatially deployed based on independent Poisson point processes. We consider an
open access assignment policy, where each macro user based on the ratio between
its distances from its nearest femto access point (FAP) and from the macro base
station (MBS) is assigned to either of them. By tuning the threshold, this
policy allows controlling the coverage areas of FAPs. For a fixed threshold,
femtocells coverage areas depend on their distances from the MBS; Those closest
to the fringes will have the largest coverage areas. Under this open-access
policy, ignoring the additive noise, we derive analytical upper and lower
bounds on the outage probabilities of femto users and macro users that are
subject to fading and path loss. We also study the effect of the distance from
the MBS on the outage probability experienced by the users of a femtocell. In
all cases, our simulation results comply with our analytical bounds.


title: Truncation scheme of time-dependent density-matrix approach

abstract:
  A truncation scheme of the Bogoliubov-Born-Green-Kirkwood-Yvon hierarchy for
reduced density matrices, where a three-body density matrix is approximated by
the antisymmetrized products of two-body density matrices, is proposed. This
truncation scheme is tested for three model hamiltonians. It is shown that the
obtained results are in good agreement with the exact solutions.


title: Inference of dispersion measure from incoherent time-steady sources

abstract:
  Several recent papers have proposed schemes by which a dispersion measure,
and hence electron column, could be obtained from a time-steady, incoherent
radio source at a cosmological distance (such as an active galactic nucleus).
If correct, this would open a new window on the distribution of intergalactic
baryons. These schemes are based on the statistical properties of the received
radiation, such as the 2- or 4-point correlation function of the received
electric field, and in one case on the quantum nature of the electromagnetic
field. We show, on the basis of general principles, that these schemes are not
sensitive to dispersion measure (or have an extremely small signal-to-noise
ratio), because (i) the classical 2-point correlation function is unaffected by
dispersion; (ii) for a source with a large number of incoherently emitting
electrons, the central limit theorem obliterates additional information in
higher-order functions; and (iii) such an emitter produces a radiation density
matrix that is equivalent to a statistical distribution of coherent states,
which contains no information that is not already in the statistics of the
classical waveforms. Why the proposed observables do not depend on dispersion
measure (or have extremely tiny dependences) is discussed in detail.


title: On Kauffman Bracket Skein Modules at Root of Unity

abstract:
  We reprove and expand results of Bonahon and Wong on central elements of the
Kauffman bracket skein modules at root of 1 and on the existence of the
Chebyshev homomorphism, using elementary skein methods.


title:
Radio-continuum study of Large Magellanic Cloud Supernova Remnant
  J0509-6731

abstract:
  We present a detailed study of Australia Telescope Compact Array (ATCA)
observations ($\lambda$ = 20, 13, 6 & 3~cm) of supernova remnant (SNR)
J0509--6731 in the Large Magellanic Cloud (LMC). The remnant has a ring
morphology with brightened regions towards the south-western limb. We also find
a second brightened inner ring which is only seen in the radio-continuum. The
SNR is almost circular, with a diameter ranging from 7 to 8~pc, and a steep
radio spectral index between 36 and 3~cm of $\alpha=-0.73\pm0.02$, which is
characteristic of younger SNRs. We also report detection of radially orientated
polarisation across the remnant at 6~cm, with a mean fractional polarisation
level of $P\cong$~(26~$\pm$~13)%. We find the magnetic field ($\sim$168~$\mu$G)
and $\Sigma - D$ ($\Sigma = $ $1.1\times 10^{-19}$~W
m$^{-2}$~Hz$^{-1}$~sr$^{-1}$ , $D=$ 7.35~pc) to be consistent with other young
remnants.


title:
Superconducting and magneto-transport properties of BiS2 based
  superconductor PrO1-xFxBiS2 (x = 0 to 0.9)

abstract:
  We report superconducting properties of PrO1-xFxBiS2 compounds, synthesized
by the vacuum encapsulation technique. The synthesized PrO1-xFxBiS2 (x=0.1,
0.3, 0.5, 0.7 and 0.9) samples are crystallized in a tetragonal P4/nmm space
group. Both transport and DC magnetic susceptibility measurements showed bulk
superconductivity below 4 K. The maximum Tc is obtained for x = 0.7 sample.
Under applied magnetic field both Tc onset and Tc (R =0) decrease to lower
temperatures. We estimated highest upper critical field [Hc2(0)] for
PrO0.3F0.7BiS2 sample to be above 4 T (Tesla). The thermally activated flux
flow (TAFF) activation energy (U0) is estimated 54.63 meV in 0.05 Tesla field
for PrO0.3F0.7BiS2 sample. Hall measurement results showed that electron charge
carriers are the dominating ones in these compounds. Thermoelectric effects
(Thermal conductivity and Seebeck coefficient) data suggest strong
electron-electron correlations in this material.


title: Fusion procedure for Degenerate cyclotomic Hecke algebras

abstract:
  The primitive idempotents of the generic degenerate cycloctomic Hecke
algebras are derived by consecutive evaluations of a certain rational function.
This rational function depends only on the Specht modules and the normalization
factors are the weights of the Brundan-Kleshchev trace.


title: Hochschild and cyclic (co)homology of superadditive categories

abstract:
  We define the Hochschild and cyclic (co)homology groups for superadditive
categories and show that these (co)homology groups are graded Morita
invariants. We also show that the Hochschild and cyclic homology are compatible
with the tensor product of superadditive categories.


title: An Example of an Automatic Graph of Intermediate Growth

abstract:
  We give an example of a 4-regular infinite automatic graph of intermediate
growth. It is constructed as a Schreier graph of a certain group generated by
3-state automaton. The question was motivated by an open problem on the
existence of Cayley automatic groups of intermediate growth.


title:
Computing the $L_1$ Geodesic Diameter and Center of a Simple Polygon in
  Linear Time

abstract:
  In this paper, we show that the $L_1$ geodesic diameter and center of a
simple polygon can be computed in linear time. For the purpose, we focus on
revealing basic geometric properties of the $L_1$ geodesic balls, that is, the
metric balls with respect to the $L_1$ geodesic distance. More specifically, in
this paper we show that any family of $L_1$ geodesic balls in any simple
polygon has Helly number two, and the $L_1$ geodesic center consists of
midpoints of shortest paths between diametral pairs. These properties are
crucial for our linear-time algorithms, and do not hold for the Euclidean case.


title: Characterizing 2-crossing-critical graphs

abstract:
  It is very well-known that there are precisely two minimal non-planar graphs:
$K_5$ and $K_{3,3}$ (degree 2 vertices being irrelevant in this context). In
the language of crossing numbers, these are the only 1-crossing-critical
graphs: they each have crossing number at least one, and every proper subgraph
has crossing number less than one. In 1987, Kochol exhibited an infinite family
of 3-connected, simple 2-crossing-critical graphs. In this work, we: (i)
determine all the 3-connected 2-crossing-critical graphs that contain a
subdivision of the M\"obius Ladder $V_{10}$; (ii) show how to obtain all the
not 3-connected 2-crossing-critical graphs from the 3-connected ones; (iii)
show that there are only finitely many 3-connected 2-crossing-critical graphs
not containing a subdivision of $V_{10}$; and (iv) determine all the
3-connected 2-crossing-critical graphs that do not contain a subdivision of
$V_{8}$.


title: Topological Superconductor Bi2Te3/NbSe2 heterostructures

abstract:
  Topological superconductors (TSCs) have a full gap in the bulk and gapless
surface states consisting of Majorana fermions, which have potential
applications in fault-tolerant topological quantum computation. Because TSCs
are very rare in nature, an alternative way to study the TSC is to artificially
introduce superconductivity into the surface states of a topological insulator
(TI) through proximity effect (PE)1-4. Here we report the first experimental
realization of the PE induced TSC in Bi2Te3/NbSe2 thin films as demonstrated by
the density of states probed using scanning tunneling microscope. We observe
Abrikosov vortices and lower energy bound states on the surface of topological
insulator and the dependence of superconducting coherence length on the film
thickness and magnetic field, which are attributed to the superconductivity in
the topological surface states. This work demonstrates the practical
feasibility of fabricating a TSC with individual Majorana fermions inside
superconducting vortex as predicted in theory and accomplishes the
pre-requisite step towards searching for Majorana fermions in the PE induced
TSCs.


title: Measurements of neutron-induced reactions in inverse kinematics

abstract:
  Neutron capture cross sections of unstable isotopes are important for neutron
induced nucleosynthesis as well as for technological applications. A
combination of a radioactive beam facility, an ion storage ring and a high flux
reactor would allow a direct measurement of neutron induced reactions over a
wide energy range on isotopes with half lives down to minutes.


title: Rotation curves in Bose-Einstein Condensate Dark Matter Halos

abstract:
  The study of the rotation curves of spiral galaxies reveals a nearly constant
cored density distribution of Cold Dark Matter. N-body simulations however lead
to a cuspy distribution on the galactic scale, with a central peak. A
Bose-Einstein condensate (BEC) of light particles naturally solves this problem
by predicting a repulsive force, obstructing the formation of the peak. After
succinctly presenting the BEC model, we test it against rotation curve data for
a set of 3 High Surface Brightness (HSB), 3 Low Surface Brightness (LSB) and 3
dwarf galaxies. The BEC model gives a similar fit to the Navarro-Frenk-White
(NFW) dark matter model for all HSB and LSB galaxies in the sample. For dark
matter dominated dwarf galaxies the addition of the BEC component improved more
upon the purely baryonic fit than the NFW component. Thus despite the sharp
cut-off of the halo density, the BEC dark matter candidate is consistent with
the rotation curve data of all types of galaxies.


title: A generalized magnetic refrigeration scheme

abstract:
  We have investigated the magnetocaloric effects in antiferromagnets and
compared them with those in ferromagnets using Monte Carlo simulations. In
antiferromagnets, the magnetic entropy reaches a maximum value at a finite
magnetic field when the temperature is fixed below the N\'eel temperature.
Using the fact, we proposed a protocol for applying magnetic fields to achieve
the maximum efficiency for magnetic refrigeration in antiferromagnets. In
particular, we found that at low temperatures, antiferromagnets are more useful
for magnetic refrigeration than ferromagnets.


title: Optimal algorithms for linear algebra by quantum inspiration

abstract:
  Recent results by Harrow et. al. and by Ta-Shma, suggest that quantum
computers may have an exponential advantage in solving a wealth of linear
algebraic problems, over classical algorithms. Building on the quantum
intuition of these results, we step back into the classical domain, and explore
its usefulness in designing classical algorithms. We achieve an algorithm for
solving the major linear-algebraic problems in time $O(n^{\omega+\nu})$ for any
$\nu>0$, where $\omega$ is the optimal matrix-product constant. Thus our
algorithm is optimal w.r.t. matrix multiplication, and comparable to the
state-of-the-art algorithm for these problems due to Demmel et. al. Being
derived from quantum intuition, our proposed algorithm is completely disjoint
from all previous classical algorithms, and builds on a combination of
low-discrepancy sequences and perturbation analysis. As such, we hope it
motivates further exploration of quantum techniques in this respect, hopefully
leading to improvements in our understanding of space complexity and numerical
stability of these problems.


title:
Spectral Characteristics of Large-Scale Radio Emission Areas in Coronal
  Holes

abstract:
  The spectra of the coronal hole radio emission in solar cycles 23 and 24 have
been studied based on RATAN-600 data in the 4-16.5 GHz range at frequencies of
5.7 and 17 GHz and 327 MHz. It has been found that bright features of coronal
hole microwave emission at 17 GHz and dark features at 5.7 GHz can exist in
coronal holes when the spectral index is 1.25-1.5 in the 6.5-16.5 GHz range;
the radio spectrum in this range is flat when coronal holes are indiscernible
against the background of a quiet Sun. The possible vertical scale of the solar
atmosphere over coronal holes is discussed.


title:
Room temperature formation of high-mobility two-dimensional electron
  gases at crystalline complex oxide interfaces

abstract:
  Well-controlled sub-unit-cell layer-by-layer epitaxial growth of spinel
alumina is achieved at room temperature on the TiO2-terminated SrTiO3 single
crystalline substrate. By tailoring the interface redox reaction,
two-dimensional electron gases with mobilities exceeding 3000 cm2V-1s-1 are
achieved at this novel oxide interface.


title: Inflation after Planck: and the winners are

abstract:
  We review the constraints that the recently released Cosmic Microwave
Background (CMB) Planck data put on inflation and we argue that single field
slow-roll inflationary scenarios (with minimal kinetic term) are favored. Then,
within this class of models, by means of Bayesian inference, we show how one
can rank the scenarios according to their performances, leading to the
identification of ``the best models of inflation''.


title: A local equivariant index theorem for sub-signature operators

abstract:
  In this paper, we prove a local equivariant index theorem for sub-signature
operators which generalizes the Zhang's index theorem for sub-signature
operators.


title:
Perfectly matched layer for second-order time-domain elastic wave
  equation: formulation and stability

abstract:
  A time domain system of equations is proposed to model elastic wave
propagation in an unbounded two-dimensional anisotropic solid using perfectly
matched layer (PML). Starting from a system of first-order frequency domain
stress-velocity equations and using complex coordinate stretching approach with
a two-parameter stretch function, a second-order formulation is obtained. The
final system, which consists of just two second order equations along with four
auxiliary equations, is smaller than existing formulations, thereby simplifying
the problem and reducing the computational cost. The discrete stability of the
solutions for a given mesh size is examined with the help of a plane-wave
analysis of the corresponding continuous problem. It is shown that increasing
the scaling parameter of the stretch function leads to significant stability
improvements for certain anisotropic media that have known issues. Numerical
computations for different isotropic and anisotropic media are used to
illustrate the results.


title: Partial Penalized Likelihood Ratio Test under Sparse Case

abstract:
  This work is concern with testing the low-dimensional parameters of interest
with divergent dimensional data and variable selection for the rest under the
sparse case. A consistent test via the partial penalized likelihood approach,
called the partial penalized likelihood ratio test statistic is derived, and
its asymptotic distributions under the null hypothesis and the local
alternatives of order $n^{-1/2}$ are obtained under some regularity conditions.
Meanwhile, the oracle property of the partial penalized likelihood estimator
also holds. The proposed partial penalized likelihood ratio test statistic
outperforms the full penalized likelihood ratio test statistic in term of size
and power, and performs as well as the classical likelihood ratio test
statistic. Moreover, the proposed method obtains the variable selection results
as well as the p-values of testing. Numerical simulations and an analysis of
Prostate Cancer data confirm our theoretical findings and demonstrate the
promising performance of the proposed partial penalized likelihood in
hypothesis testing and variable selection.


title:
ARIANNA: pAth Recognition for Indoor Assisted NavigatioN with Augmented
  perception

abstract:
  ARIANNA stands for pAth Recognition for Indoor Assisted Navigation with
Augmented perception. It is a flexible and low cost navigation system for vi-
sually impaired people. Arianna permits to navigate colored paths painted or
sticked on the floor revealing their directions through vibrational feedback on
commercial smartphones.


title:
Magnetic field-dependence of the basal-plane superconducting anisotropy
  in YBa2Cu4O8 from small-angle neutron scattering measurements of the vortex
  lattice

abstract:
  We report a study of the basal-plane anisotropy of the superfluid density in
underdoped YBa$_{2}$Cu$_{4}$O$_{8}$ (Y124), showing the effects of both the
CuO$_{2}$ planes and the fully occupied CuO chains. From small-angle neutron
scattering measurements of the vortex lattice, we can infer the superconducting
(SC) properties for a temperature ($T$) range $T=$ 1.5 K to $T_{\rm c}$ and
magnetic induction $B$ from 0.1 to 6 T. We find that the superfluid density
along \textbf{a} has a simple $d$-wave T-dependence. However, along \textbf{b}
(the chain direction) the superfluid density falls much more rapidly with $T$
and also with increasing field. This strongly suggests the suppression of
proximity-effect induced superconductivity in the CuO chains. In addition, our
results do not support a common framework for the low field in-plane SC
response in Y124 and related YBa$_{2}$Cu$_{3}$O$_{7}$, and also indicate that
any magnetic field-induced charge-density-wave order in Y124 exists only for
fields above 6 T.


title:
Evaluation of the neutron background in CsI target for WIMP direct
  detection when using a reactor neutrino detector as a neutron veto system

abstract:
  A direct WIMP (Weakly Interacting Massive Particle) detector with a neutron
veto system is designed to better reject neutrons. An experimental
configuration is studied in the present paper: a WIMP detectors with CsI(Na)
target is placed inside a reactor neutrino detector. The neutrino detector is
used as a neutron veto device. The neutron background for the experimental
design has been estimated using the Geant4 simulation. The results show that
the neutron background can decrease to O(0.01) events per year per tonne of
CsI(Na). We calculate the sensitivity to spin-independent WIMP-nucleon elastic
scattering. An exposure of one tonne $\times$ year could reach a cross-section
of about 3$\times$$10^{-11}$ pb.


title: Three-point functions in the SU(2) sector at strong coupling

abstract:
  Extending the methods developed in our previous works (arXiv:1110.3949,
arXiv:1205.6060), we compute the three-point functions at strong coupling of
the non-BPS states with large quantum numbers corresponding to the composite
operators belonging to the so-called SU(2) sector in the $\mathcal{N}=4$
super-Yang-Mills theory in four dimensions. This is achieved by the
semi-classical evaluation of the three-point functions in the dual string
theory in the $AdS_3 \times S^3$ spacetime, using the general one-cut finite
gap solutions as the external states. In spite of the complexity of the
contributions from various parts in the intermediate stages, the final answer
for the three-point function takes a remarkably simple form, exhibiting the
structure reminiscent of the one obtained at weak coupling. In particular, in
the Frolov-Tseytlin limit the result is expressed in terms of markedly similar
integrals, however with different contours of integration. We discuss a natural
mechanism for introducing additional singularities on the worldsheet without
affecting the infinite number of conserved charges, which can modify the
contours of integration.


title:
Theoretical transition frequencies beyond 0.1 ppb accuracy in H$_2^+$,
  HD$^+$, and antiprotonic helium

abstract:
  We present improved theoretical calculations of transition frequencies for
the fundamental transitions $(L\!=\!0,v\!=\!1)\to(L'\!=\!0,v'\!=\!0)$ in the
hydrogen molecular ions H$_2^+$ and HD$^+$ with a relative uncertainty
$4\cdot10^{-11}$ and for the two-photon transitions in the antiprotonic helium
atom with a relative uncertainty $10^{-10}$. To do that, the one-loop
self-energy correction of order $\alpha(Z\alpha)^6$ is derived in the two
Coulomb center approximation, and numerically evaluated in the case of the
aforementioned transitions. The final results also include a complete set of
other spin-independent corrections of order $m\alpha^7$. The leading order
corrections of $\alpha^2\ln^3(Z\alpha)^{-2}(Z\alpha)^6$ are also considered
that allows to estimate a magnitude of yet uncalculated contributions.


title:
Lattice Vibrational Modes and Phonon Thermal Conductivity of Monolayer
  MoS2

abstract:
  The anharmonic behavior of phonons and intrinsic thermal conductivity
associated with the Umklapp scattering in monolayer MoS2 sheet are investigated
via first-principles calculations within the framework of density functional
perturbation theory. In contrast to the negative Gruneissen parameter occurring
in low frequency modes in graphene, positive Gruneissen parameter in the whole
Brillouin zone is demonstrated in monolayer MoS2 with much larger Gruneissen
parameter for acoustic modes than that for the optical modes, suggesting that
monolayer MoS2 sheet possesses a positive coefficient of thermal-expansion. The
calculated phonon lifetimes of the infrared active modes are 5.50 and 5.72 ps
for E'and A2'' respectively, in good agreement with experimental result
obtained by fitting the dielectric oscillators with the infrared reflectivity
spectrum. The lifetime of Raman A1' mode (38.36 ps) is about 7 times longer
than those of the infrared modes. The dominated phonon mean free path of
monolayer MoS2 is less than 20 nm, about 30-fold smaller than that of graphene.
Combined with the non-equilibrium Green's function calculations, the room
temperature thermal conductivity of monolayer MoS2 is found to be around 23.2
Wm-1K-1, two orders of magnitude lower than that of graphene.


title:
Entanglement of Bipartite Quantum Systems driven by Repeated
  Interactions

abstract:
  We consider a non-interacting bipartite quantum system $\mathcal
H_S^A\otimes\mathcal H_S^B$ undergoing repeated quantum interactions with an
environment modeled by a chain of independant quantum systems interacting one
after the other with the bipartite system. The interactions are made so that
the pieces of environment interact first with $\mathcal H_S^A$ and then with
$\mathcal H_S^B$. Even though the bipartite systems are not interacting, the
interactions with the environment create an entanglement. We show that, in the
limit of short interaction times, the environment creates an effective
interaction Hamiltonian between the two systems. This interaction Hamiltonian
is explicitly computed and we show that it keeps track of the order of the
successive interactions with $\mathcal H_S^A$ and $\mathcal H_S^B$. Particular
physical models are studied, where the evolution of the entanglement can be
explicitly computed. We also show the property of return of equilibrium and
thermalization for a family of examples.


title: Complex Obtuse Random Walks and their Continuous-Time Limits

abstract:
  We study a particular class of complex-valued random variables and their
associated random walks: the complex obtuse random variables. They are the
generalization to the complex case of the real-valued obtuse random variables
which were introduced in \cite{A-E} in order to understand the structure of
normal martingales in $\RR^n$.The extension to the complex case is mainly
motivated by considerations from Quantum Statistical Mechanics, in particular
for the seek of a characterization of those quantum baths acting as classical
noises. The extension of obtuse random variables to the complex case is far
from obvious and hides very interesting algebraical structures. We show that
complex obtuse random variables are characterized by a 3-tensor which admits
certain symmetries which we show to be the exact 3-tensor analogue of the
normal character for 2-tensors (i.e. matrices), that is, a necessary and
sufficient condition for being diagonalizable in some orthonormal basis. We
discuss the passage to the continuous-time limit for these random walks and
show that they converge in distribution to normal martingales in $\CC^N$. We
show that the 3-tensor associated to these normal martingales encodes their
behavior, in particular the diagonalization directions of the 3-tensor indicate
the directions of the space where the martingale behaves like a diffusion and
those where it behaves like a Poisson process. We finally prove the
convergence, in the continuous-time limit, of the corresponding multiplication
operators on the canonical Fock space, with an explicit expression in terms of
the associated 3-tensor again.


title: Positivity of rational functions and their diagonals

abstract:
  The problem to decide whether a given rational function in several variables
is positive, in the sense that all its Taylor coefficients are positive, goes
back to Szeg\H{o} as well as Askey and Gasper, who inspired more recent work.
It is well known that the diagonal coefficients of rational functions are
$D$-finite. This note is motivated by the observation that, for several of the
rational functions whose positivity has received special attention, the
diagonal terms in fact have arithmetic significance and arise from differential
equations that have modular parametrization. In each of these cases, this
allows us to conclude that the diagonal is positive.
  Further inspired by a result of Gillis, Reznick and Zeilberger, we
investigate the relation between positivity of a rational function and the
positivity of its diagonal.


title: Propagation of an ultrashort electromagnetic pulse in solid-state plasma

abstract:
  The change of the shape of an ultrashort electromagnetic pulse in its
propagation in solid-state plasma was calculated in the linear approximation. A
case of solid-state silver plasma and of a "Mexican hat" wavelet pulse was
considered. The dielectric permittivity of the medium was calculated in the
Drude model. Strong dispersion spreading of a pulse at distances of the order
of several microns was shown, and the comparison of evolution of the pulse
shape for different center frequencies was carried out.


title: Differentiable but exact formulation of density-functional theory

abstract:
  The universal density functional $F$ of density-functional theory is a
complicated and ill-behaved function of the density-in particular, $F$ is not
differentiable, making many formal manipulations more complicated. Whilst $F$
has been well characterized in terms of convex analysis as forming a conjugate
pair $(E,F)$ with the ground-state energy $E$ via the Hohenberg-Kohn and Lieb
variation principles, $F$ is nondifferentiable and subdifferentiable only on a
small (but dense) set of its domain. In this article, we apply a tool from
convex analysis, Moreau-Yosida regularization, to construct, for any
$\epsilon>0$, pairs of conjugate functionals $({}^\epsilon\!E,{}^\epsilon\!F)$
that converge to $(E,F)$ pointwise everywhere as $\epsilon\rightarrow 0^+$, and
such that ${}^\epsilon\!F$ is (Fr\'echet) differentiable. For technical
reasons, we limit our attention to molecular electronic systems in a finite but
large box. It is noteworthy that no information is lost in the Moreau-Yosida
regularization: the physical ground-state energy $E(v)$ is exactly recoverable
from the regularized ground-state energy ${}^\epsilon\!E(v)$ in a simple way.
All concepts and results pertaining to the original $(E,F)$ pair have direct
counterparts in results for $({}^\epsilon\! E, {}^\epsilon\!F)$. The
Moreau-Yosida regularization therefore allows for an exact, differentiable
formulation of density-functional theory. In particular, taking advantage of
the differentiability of ${}^\epsilon\!F$, a rigorous formulation of Kohn-Sham
theory is presented that does not suffer from the noninteracting
representability problem in standard Kohn-Sham theory.

categories: physics.chem-ph cond-mat.quant-gas math-ph math.MP physics.comp-ph quant-ph


title: Codes for Tasks and R\'enyi Entropy Rate

abstract:
  A task is randomly drawn from a finite set of tasks and is described using a
fixed number of bits. All the tasks that share its description must be
performed. Upper and lower bounds on the minimum $\rho$-th moment of the number
of performed tasks are derived. The key is an analog of the Kraft Inequality
for partitions of finite sets. When a sequence of tasks is produced by a source
of a given R\'enyi entropy rate of order $1/(1+\rho)$ and $n$ tasks are jointly
described using $nR$ bits, it is shown that for $R$ larger than the R\'enyi
entropy rate, the $\rho$-th moment of the ratio of performed tasks to $n$ can
be driven to one as $n$ tends to infinity, and that for $R$ less than the
R\'enyi entropy rate it tends to infinity. This generalizes a recent result for
IID sources by the same authors. A mismatched version of the direct part is
also considered, where the code is designed according to the wrong law. The
penalty incurred by the mismatch can be expressed in terms of a divergence
measure that was shown by Sundaresan to play a similar role in the
Massey-Arikan guessing problem.


title:
Casimir energy and force induced by an impenetrable flux tube of finite
  radius

abstract:
  A perfectly reflecting (Dirichlet) boundary condition at the edge of an
impenetrable magnetic-flux-carrying tube of nonzero transverse size is imposed
on the charged massive scalar matter field which is quantized outside the tube.
We show that the vacuum polarization effects outside the tube give rise to a
macroscopic force acting at the increase of the tube radius (if the magnetic
flux is held steady). The Casimir energy and force are periodic in the value of
the magnetic flux, being independent of the coupling to the space-time
curvature scalar. We conclude that a topological defect of the vortex type can
polarize the vacuum of only those quantum fields that have masses which are
much less than a scale of the spontaneous symmetry breaking.


title: High performance bilayer-graphene Terahertz detectors

abstract:
  We report bilayer-graphene field effect transistors operating as THz
broadband photodetectors based on plasma-waves excitation. By employing
wide-gate geometries or buried gate configurations, we achieve a responsivity
$\sim 1.2V/W (1.3 mA/W)$ and a noise equivalent power $\sim 2\times 10^{-9}
W/Hz^{-1/2}$ in the 0.29-0.38 THz range, in photovoltage and photocurrent mode.
The potential of this technology for scalability to higher frequencies and the
development of flexible devices makes our approach competitive for a future
generation of THz detection systems.


title: Path Based Mapping Technique for Robots

abstract:
  The purpose of this paper is to explore a new way of autonomous mapping.
Current systems using perception techniques like LAZER or SONAR use
probabilistic methods and have a drawback of allowing considerable uncertainty
in the mapping process. Our approach is to break down the environment,
specifically indoor, into reachable areas and objects, separated by boundaries,
and identifying their shape, to render various navigable paths around them.
This is a novel method to do away with uncertainties, as far as possible, at
the cost of temporal efficiency. Also this system demands only minimum and
cheap hardware, as it relies on only Infra-Red sensors to do the job.


title: Semantics of (Resilient) X10

abstract:
  We present a formal small-step structural operational semantics for a large
fragment of X10, unifying past work. The fragment covers multiple places,
mutable objects on the heap, sequencing, \code{try/catch}, \code{async},
\code{finish}, and \code{at} constructs. This model accurately captures the
behavior of a large class of concurrent, multi-place X10 programs. Further, we
introduce a formal model of resilience in X10. During execution of an X10
program, a place may fail for many reasons. Resilient X10 permits the program
to continue executing, losing the data at the failed place, and most of the
control state, and repairing the global control state in such a way that key
semantic principles hold, the Invariant Happens Before Principle, and the
Failure Masking Principle. These principles permit an X10 programmer to write
clean code that continues to work in the presence of place failure. The given
semantics have additionally been mechanized in Coq.


title: Analytical Observations on Knapsack Cipher 0/255

abstract:
  We observed few important facts that concerns with the new proposal of
knapsack cipher 0/255, recently published by Pham [1]. The author claimed that
the time complexity for solving new improved trapdoor knapsack is O(256^N). In
this paper, we show that the knapsack cipher 0/255 can be solved in the same
time that is required for solving the basic knapsack-cipher proposed by Merkle
and Hellman [2]. In other words we claim that the improved version proposed by
Pham [1] is technically same as the basic Merkle and Hellman Knapsack-based
cryptosystem.


title:
Sensitivity limits of a Raman atom interferometer as a gravity
  gradiometer

abstract:
  We evaluate the sensitivity of a dual cloud atom interferometer to the
measurement of vertical gravity gradient. We study the influence of most
relevant experimental parameters on noise and long-term drifts. Results are
also applied to the case of doubly differential measurements of the
gravitational signal from local source masses. We achieve a short term
sensitivity of 3*10^(-9) g/Hz^(-1/2) to differential gravity acceleration,
limited by the quantum projection noise of the instrument. Active control of
the most critical parameters allows to reach a resolution of 5*10^(-11) g after
8000 s on the measurement of differential gravity acceleration. The long term
stability is compatible with a measurement of the gravitational constant G at
the level of 10^(-4) after an integration time of about 100 hours.


title:
Alternative way to understand the unexpected results of the JLab
  polarization experiments to measure the Sachs form factors ratio

abstract:
  In the one-photon exchange approximation we discuss questions related to the
interpretation of unexpected results of the JLab polarization experiments to
measure the Sachs form factors ratio $G_E/G_M$ in the region $1. 0 \leq Q^2
\leq 8.5$ GeV$^2$. For this purpose, we developed an approach which essentially
is a generalization of the constituent-counting rules of the perturbative QCD
(pQCD) for the case of massive quarks. We assume that at the lower boundary of
the considered region the hard-scattering mechanism of pQCD is realized. Within
the framework of the developed approach we calculated the hard kernel of the
proton current matrix elements $J^{\pm \delta, \delta }_{p}$ for the full set
of spin combinations corresponding to the number of the spin-flipped quarks,
which contribute to the proton transition without spin-flip ($J^{\delta, \delta
}_{p}$) and with the spin-flip ($J^{-\delta, \delta }_{p}$). This allows us to
state that (i) around the lower boundary of the considered region, the leading
scaling behavior of the Sachs form factors has the form $G_E, G_M \sim 1/Q^6$,
(ii) the dipole dependence ($G_E, G_M \sim 1/Q^4$) is realized in the
asymptotic regime of pQCD when $\tau \gg 1$ ($\tau=Q^2/4M^2$) in the case when
the quark transitions with spin-flip dominate, (iii) the asymptotic regime of
pQCD in the JLab experiments has not yet been achieved, and (iv) the linear
decrease of the ratio $G_{E}/G_{M}$ at $\tau < 1$ is due to additional
contributions to $J^{\delta, \delta }_{p}$ by spin-flip transitions of two
quarks and an additional contribution to $J^{-\delta, \delta }_{p}$ by
spin-flip transitions of three quarks.


title:
Spin Squeezing of One-Axis Twisting Model in The Presence of Phase
  Dephasing

abstract:
  We present a detailed analysis of spin squeezing of the one-axis twisting
model with a many-body phase dephasing, which is induced by external field
fluctuation in a two-mode Bose-Einstein condensates. Even in the presence of
the dephasing, our analytical results show that the optimal initial state
corresponds to a coherent spin state $|\theta_{0}, \phi_0\rangle$ with the
polar angle $\theta_0=\pi/2$. If the dephasing rate $\gamma\ll S^{-1/3}$, where
$S$ is total atomic spin, we find that the smallest value of squeezing
parameter (i.e., the strongest squeezing) obeys the same scaling with the ideal
one-axis twisting case, namely $\xi^2\propto S^{-2/3}$. While for a moderate
dephasing, the achievable squeezing obeys the power rule $S^{-2/5}$, which is
slightly worse than the ideal case. When the dephasing rate $\gamma>S^{1/2}$,
we show that the squeezing is weak and neglectable.


title: Dunkl-spherical maximal function

abstract:
  In this paper, we study the Lp-bondedness of the spherical maximal function
associated to the Dunkl operators.


title:
Identifying new opportunities for exoplanet characterisation at high
  spectral resolution

abstract:
  [Abridged] Recently, there have been a series of detections of molecules in
the atmospheres of extrasolar planets using high spectral resolution
(R~100,000) observations, mostly using the CRyogenic high-resolution InfraRed
Echelle Spectrograph (CRIRES) on the Very Large Telescope. These measurements
are able to resolve molecular bands into individual absorption lines. Observing
many lines simultaneously as their Doppler shift changes with time allows the
detection of specific molecules in the atmosphere of the exoplanet. We
performed simulations of high-resolution CRIRES observations of a planet's
thermal emission and transit between 1-5 micron and performed a
cross-correlation analysis on these results to assess how well the planet
signal can be extracted. We also simulated day-side and night-side spectra at
high spectral resolution for planets with and without a day-side temperature
inversion, based on the cases of HD 189733b and HD 209458b. Several small
wavelength regions in the L-band promise to yield cross-correlation signals
from the thermal emission of hot Jupiters that can exceed those of the current
detections by up to a factor of 2-3 for the same integration time. For transit
observations, the H-band is also attractive, with the H, K, and L-band giving
cross-correlation signals of similar strength. High-resolution night-side
spectra of hot Jupiters can give cross-correlation signals as high as the
day-side, or even higher. We show that there are many new possibilities for
high-resolution observations of exoplanet atmospheres that have expected planet
signals at least as high as those already detected. Hence, high-resolution
observations at well-chosen wavelengths and at different phases can improve our
knowledge about hot Jupiter atmospheres significantly, already with currently
available instrumentation.


title:
Pre-yield non-affine fluctuations and a hidden critical point in
  strained crystals

abstract:
  A crystalline solid exhibits thermally induced localised {\em non-affine}
droplets in the absence of external stress. Here we show that upon an imposed
shear, the size of these droplets grow until they percolate at a critical
strain, well {\em below} the value at which the solid begins to yield. This
critical point does not manifest in bulk thermodynamic or mechanical
properties, but is {\em hidden} and reveals itself in the onset of
inhomogeneities in elastic moduli, marked changes in the appearance and local
properties of non-affine droplets and a sudden enhancement in defect pair
concentration. Slow relaxation of stress and an-elasticity appear as observable
dynamical consequences of this hidden criticality. Our results may be directly
verified in colloidal crystals with video microscopy techniques but are
expected to have more general validity.


title:
Convergence rates of the spectral distributions of large random
  quaternion self-dual Hermitian matrices

abstract:
  In this paper, convergence rates of the spectral distributions of quaternion
self-dual Hermitian matrices are investigated. We show that under conditions of
finite 6th moments, the expected spectral distribution of a large quaternion
self-dual Hermitian matrix converges to the semicircular law in a rate of
$O(n^{-1/2})$ and the spectral distribution itself converges to the
semicircular law in rates $O_p(n^{-2/5})$ and $O_{a.s.}(n^{-2/5+\eta})$. Those
results include GSE as a special case.


title: On Eavesdropper-Tolerance Capability of Two-Hop Wireless Networks

abstract:
  Two-hop wireless network serves as the basic net-work model for the study of
general wireless networks, while cooperative jamming is a promising scheme to
achieve the physi-cal layer security. This paper establishes a theoretical
framework for the study of eavesdropper-tolerance capability (i.e., the exact
maximum number of eavesdroppers that can be tolerated) in a two-hop wireless
network, where the cooperative jamming is adopted to ensure security defined by
secrecy outage probability (SOP) and opportunistic relaying is adopted to
guarantee relia-bility defined by transmission outage probability (TOP). For
the concerned network, closed form modeling for both SOP and TOP is first
conducted based on the Central Limit Theorem. With the help of SOP and TOP
models and also the Stochastic Ordering Theory, the model for
eavesdropper-tolerance capability analysis is then developed. Finally,
extensive simulation and numerical results are provided to illustrate the
efficiency of our theoretical framework as well as the eavesdropper-tolerance
capability of the concerned network from adopting cooperative jamming and
opportunistic relaying.


title: Fibonacci Binning

abstract:
  This note argues that when dot-plotting distributions typically found in
papers about web and social networks (degree distributions, component-size
distributions, etc.), and more generally distributions that have high
variability in their tail, an exponentially binned version should always be
plotted, too, and suggests Fibonacci binning as a visually appealing,
easy-to-use and practical choice.


title:
Bimodal Distribution of Sulfuric Acid Aerosols in the Upper Haze of
  Venus

abstract:
  The upper haze (UH) of Venus is variable on the order of days and it is
populated by two particle modes. We use a 1D microphysics and vertical
transport model based on the Community Aerosol and Radiation Model for
Atmospheres to evaluate whether interaction of upwelled cloud particles and
sulfuric acid particles nucleated in situ on meteoric dust are able to generate
the two size modes and whether their observed variability are due to cloud top
vertical transient winds. Nucleation of photochemically produced sulfuric acid
onto polysulfur condensation nuclei generates mode 1 cloud droplets that then
diffuse upwards into the UH. Droplets generated in the UH from nucleation of
sulfuric acid onto meteoric dust coagulate with the upwelled cloud particles
and cannot reproduce the observed bimodal size distribution. The mass transport
enabled by cloud top transient winds are able to generate a bimodal size
distribution in a time scale consistent with observations. Sedimentation and
convection in the middle and lower clouds causes the formation of large mode 2
and mode 3 particles. Evaporation of these particles below the clouds creates a
local sulfuric acid vapor maximum that causes upwelling of sulfuric acid back
into the clouds. If the polysulfur condensation nuclei are small and their
production rate is high, coagulation of small droplets onto larger droplets in
the middle cloud may result in sulfuric acid "rain" below the clouds once every
few Earth months. Reduction of the polysulfur condensation nuclei production
rate destroys this oscillation and reduces the mode 1 particle abundance in the
middle cloud by two orders of magnitude, though it better reproduces the
sulfur-to-sulfuric-acid mass ratio in the cloud and haze droplets. In general
we find satisfactory agreement between our results and observations, though
improvements could be made by incorporating sulfur microphysics.


title:
The Coevolution of Supermassive Black Holes and Massive Galaxies at High
  Redshift

abstract:
  We exploit the recent, wide samples of far-infrared (FIR) selected galaxies
followed-up in X rays and of X-ray/optically selected active galactic nuclei
(AGNs) followed-up in the FIR band, along with the classic data on AGN and
stellar luminosity functions at high redshift z>1.5, to probe different stages
in the coevolution of supermassive black holes (BHs) and host galaxies. The
results of our analysis indicate the following scenario: (i) the star formation
in the host galaxy proceeds within a heavily dust-enshrouded medium at an
almost constant rate over a timescale ~0.5-1 Gyr, and then abruptly declines
due to quasar feedback; over the same timescale, (ii) part of the interstellar
medium loses angular momentum, reaches the circum-nuclear regions at a rate
proportional to the star formation and is temporarily stored into a massive
reservoir/proto-torus wherefrom it can be promptly accreted; (iii) the BH grows
by accretion in a self-regulated regime with radiative power that can slightly
exceed the Eddington limit L/L_Edd< 4, particularly at the highest redshifts;
(iv) for massive BHs the ensuing energy feedback at its maximum exceeds the
stellar one and removes the interstellar gas, thus stopping the star formation
and the fueling of the reservoir; (v) afterwards, if the latter has retained
enough gas, a phase of supply-limited accretion follows exponentially declining
with a timescale of about 2 e-folding times. We show that the ratio of the FIR
luminosity of the host galaxy to the bolometric luminosity of the AGN maps the
various stages of the above sequence. Finally, we discuss how the detailed
properties and the specific evolution of the reservoir can be investigated via
coordinated, high-resolution observations of starforming, strongly-lensed
galaxies in the (sub-)mm band with ALMA and in the X-ray band with Chandra and
the next generation X-ray instruments.


title:
Deep GMRT radio observations and a multi-wavelength study of the region
  around HESS J1858+020

abstract:
  There are a number of very high energy sources in the Galaxy that remain
unidentified. Multi-wavelength and variability studies, and catalogue searches,
are powerful tools to identify the physical counterpart, given the uncertainty
in the source location and extension. This work carries out a thorough
multi-wavelength study of the unidentified, very high energy source HESS
J1858+020 and its environs. Giant Metrewave Radio Telescope observations at 610
MHz and 1.4 GHz have been done to obtain a deep, low-frequency radio image of
the region surrounding HESS J1858+020. Archival radio, infrared, and X-ray data
have been analysed as well. This observational information, combined with
molecular data, catalogue sources, and a nearby Fermi gamma-ray detection of
unidentified origin, are combined to explore possible counterparts to the very
high energy source. We provide with a deep radio image of a supernova remnant
that might be related to the GeV and TeV emission in the region. We confirm the
presence of an H II region next to the supernova remnant and coincident with
molecular emission. A potential region of star formation is also identified. We
identify several radio and X-ray sources in the surroundings. Some of these
sources are known planetary nebulae, whereas others may be non-thermal extended
emitters and embedded young stellar objects. Three old, background Galactic
pulsars also neighbour HESS J1858+020 along the line of sight. The region
surrounding HESS J1858+020 is rich in molecular structures and non-thermal
objects that may potentially be linked to this unidentified very high energy
source. In particular, a supernova remnant interacting with nearby molecular
clouds may be a good candidate, but a star forming region, or a non-thermal
radio source of yet unclear nature, may also be behind the gamma-ray source.
Further observational studies are needed.