title: On phi-Recurrent Contact Metric Manifolds

abstract:
  In this paper, we prove that evry 3-dimensional manifold M is a ?- recurrent
N(k)-contact metric manifold if and only if it is flat. Then we classify the
?-recurrent contact metric manifolds of constant curvature. This implies that
there exists no ?-recurrent N(k)-contact metric manifold, which is neither
symmetric nor locally ?-symmetric.


title: On phi-Recurrent (k, m)-Contact Metric Manifolds

abstract:
  In this paper, we show that there is no phi-recurrent Sasakian manifold. Then
we prove that the only flat 3-dimensional manifolds are phi-recurrent (k,
m)-contact metric manifolds.


title:
Role of Energy-Level Mismatches in a Multi-Pathway Complex of
  Photosynthesis

abstract:
  Considering a multi-pathway structure in a light-harvesting complex of
photosynthesis, we investigate the role of energy-level mismatches between
antenna molecules in transferring the absorbed energy to a reaction center. We
find a condition in which the antenna molecules faithfully play their roles:
Their effective absorption ratios are larger than those of the receiver
molecule directly coupled to the reaction center. In the absence of
energy-level mismatches and dephasing noise, there arises quantum destructive
interference between multiple paths that restricts the energy transfer. On the
other hand, the destructive interference diminishes as asymmetrically biasing
the energy-level mismatches and/or introducing quantum noise of dephasing for
the antenna molecules, so that the transfer efficiency is greatly enhanced to
near unity. Remarkably, the near-unity efficiency can be achieved at a wide
range of asymmetric energy-level mismatches. Temporal characteristics are also
optimized at the energy-level mismatches where the transfer efficiency is near
unity. We discuss these effects, in particular, for the Fenna-Matthews-Olson
complex.


title: $L^1$ Hardy inequalities with weights

abstract:
  We prove sharp homogeneous improvements to $L^1$ weighted Hardy inequalities
involving distance from the boundary. In the case of a smooth domain, we obtain
lower and upper estimates for the best constant of the remainder term. These
estimates are sharp in the sense that they coincide when the domain is a ball
or an infinite strip. In the case of a ball, we also obtain further
improvements.


title: An optimal Hardy-Morrey inequality

abstract:
  In this work we improve the sharp Hardy inequality in the case $p>n$ by
adding an optimal weighted Hoelder semi-norm. To achieve this we first obtain a
local improvement. We also obtain a refinement of both the Sobolev inequality
for $p>n$ and the Hardy inequality, the latter having the best constant.


title:
Adaptive Minimum BER Reduced-Rank Linear Detection for Massive MIMO
  Systems

abstract:
  In this paper, we propose a novel adaptive reduced-rank strategy for very
large multiuser multi-input multi-output (MIMO) systems. The proposed
reduced-rank scheme is based on the concept of joint iterative optimization
(JIO) of filters according to the minimization of the bit error rate (BER) cost
function. The proposed optimization technique adjusts the weights of a
projection matrix and a reduced-rank filter jointly. We develop stochastic
gradient (SG) algorithms for their adaptive implementation and introduce a
novel automatic rank selection method based on the BER criterion. Simulation
results for multiuser MIMO systems show that the proposed adaptive algorithms
significantly outperform existing schemes.


title: Topological monomorphisms between free paratopological groups

abstract:
  Suppose that $X$ is a subspace of a Tychonoff space $Y$. Then the embedding
mapping $e_{X, Y}: X\rightarrow Y$ can be extended to a continuous monomorphism
$\hat{e}_{X, Y}: AP(X)\rightarrow AP(Y)$, where $AP(X)$ and $AP(Y)$ are the
free Abelian paratopological groups over $X$ and $Y$, respectively. In this
paper, we mainly discuss when $\hat{e}_{X, Y}$ is a topological monomorphism,
that is, when $\hat{e}_{X, Y}$ is a topological embedding of $AP(X)$ to
$AP(Y)$.


title: Two Families of Finsler Metrics Projectively Related to a Kropina Metric

abstract:
  In this paper, we find the necessary and sufficient conditions under which
two classes of (q, a, b)-metrics are projectively related to a Kropina metric.


title:
Herschel-ATLAS: a binary HyLIRG pinpointing a cluster of starbursting
  proto-ellipticals

abstract:
  Panchromatic observations of the best candidate HyLIRG from the widest
Herschel extragalactic imaging survey have led to the discovery of at least
four intrinsically luminous z=2.41 galaxies across a ~100-kpc region - a
cluster of starbursting proto-ellipticals. Via sub-arcsecond interferometric
imaging we have measured accurate gas and star-formation surface densities. The
two brightest galaxies span ~3 kpc FWHM in submm/radio continuum and CO J=4-3,
and double that in CO J=1-0. The broad CO line is due partly to the multitude
of constituent galaxies and partly to large rotational velocities in two
counter-rotating gas disks -- a scenario predicted to lead to the most intense
starbursts, which will therefore come in pairs. The disks have M(dyn) of
several x 10^11 Msun, and gas fractions of ~40%. Velocity dispersions are
modest so the disks are unstable, potentially on scales commensurate with their
radii: these galaxies are undergoing extreme bursts of star formation, not
confined to their nuclei, at close to the Eddington limit. Their specific
star-formation rates place them ~>5x above the main sequence, which supposedly
comprises large gas disks like these. Their high star-formation efficiencies
are difficult to reconcile with a simple volumetric star-formation law. N-body
and dark matter simulations suggest this system is the progenitor of a
B(inary)-type ~10^14.6-Msun cluster.


title:
Enhanced off-center stellar tidal disruptions by supermassive black
  holes in merging galaxies

abstract:
  Off-center stellar tidal disruption flares have been suggested to be a
powerful probe of recoiling supermassive black holes (SMBHs) out of galactic
centers due to anisotropic gravitational wave radiations. However, off-center
tidal flares can also be produced by SMBHs in merging galaxies. In this paper,
we computed the tidal flare rates by dual SMBHs in two merging galaxies before
the SMBHs become self-gravitationally bounded. We employ an analytical model to
calculate the tidal loss-cone feeding rates for both SMBHs, taking into account
two-body relaxation of stars, tidal perturbations by the companion galaxy, and
chaotic stellar orbits in triaxial gravitational potential. We show that for
typical SMBHs with mass 10^7 M_\sun, the loss-cone feeding rates are enhanced
by mergers up to \Gamma ~ 10^{-2} yr^{-1}, about two order of magnitude higher
than those by single SMBHs in isolated galaxies and about four orders of
magnitude higher than those by recoiling SMBHs. The enhancements are mainly due
to tidal perturbations by the companion galaxy. We suggest that off-center
tidal flares are overwhelmed by those from merging galaxies, making the
identification of recoiling SMBHs challenging. Based on the calculated rates,
we estimate the relative contributions of tidal flare events by single, binary,
and dual SMBH systems during cosmic time. Our calculations show that the
off-center tidal disruption flares by un-bound SMBHs in merging galaxies
contribute a fraction comparable to that by single SMBHs in isolated galaxies.
We conclude that off-center tidal disruptions are powerful tracers of the
merging history of galaxies and SMBHs.


title: Gauge Coupling Unification and Non-Equilibrium Thermal Dark Matter

abstract:
  We study a new mechanism for the production of dark matter in the universe
which does not rely on thermal equilibrium. Dark matter is populated from the
thermal bath subsequent to inflationary reheating via a massive mediator whose
mass is above the reheating scale, T_R. To this end, we consider models with an
extra U(1) gauge symmetry broken at some intermediate scale M, of the order of
10^10 -- 10^12 GeV. We show that not only does the model allow for gauge
coupling unification (at a higher scale associated with grand unification) but
can naturally provide a dark matter candidate which is a Standard Model singlet
but charged under the extra U(1). The intermediate scale gauge boson(s) which
are predicted in several E6/SO(10) constructions can be a natural mediator
between dark matter and the thermal bath. We show that the dark matter
abundance, while never having achieved thermal equilibrium, is fixed shortly
after the reheating epoch by the relation T_R^3/M^4. As a consequence, we show
that the unification of gauge couplings which determines M also fixes the
reheating temperature T_R, which can be as high as 10^11 GeV.


title: Extraction of $\alpha_s$ from deep inelastic scattering at large $x$

abstract:
  We present an analysis of the role of the running coupling constant at the
intersection of perturbative and nonperturbative QCD. Although the approaches
that have been considered so far in these two regimes appear to be
complementary to each other, a unified description might derive through the
definition of the effective coupling, as they both provide ways of analyzing
its freezing at low values of the scale. We extract the effective coupling from
all available experimental data on the unpolarized structure function of the
proton, $F_2^p$, at large values of Bjorken $x$, including the resonance
region. We suggest that parton-hadron duality observed in this region can be
explained if nonperturbative effects are included in the coupling constant. The
outcome of our analysis is a smooth transition from perturbative to
nonperturbative QCD physics, embodied in the running of the coupling constant
at intermediate scales.


title: Numerical Simulations of Radiatively-Driven Dusty Winds

abstract:
  [abridged] Radiation pressure on dust grains may be an important mechanism in
driving winds in a wide variety of astrophysical systems. However, the
efficiency of the coupling between the radiation field and the dusty gas is
poorly understood in environments characterized by high optical depths. We
present a series of idealized numerical experiments, performed with the
radiation-hydrodynamic code ORION, in which we study the dynamics of such winds
and quantify their properties. We find that, after wind acceleration begins,
radiation Rayleigh-Taylor instability forces the gas into a configuration that
reduces the rate of momentum transfer from the radiation field to the gas by a
factor ~ 10 - 100 compared to an estimate based on the optical depth at the
base of the atmosphere; instead, the rate of momentum transfer from a driving
radiation field of luminosity L to the gas is roughly L/c multiplied by one
plus half the optical depth evaluated using the photospheric temperature, which
is far smaller than the optical depth one would obtain using the interior
temperature. When we apply our results to conditions appropriate to ULIRGs and
star clusters, we find that the asymptotic wind momentum flux from such objects
should not significantly exceed that carried by the direct radiation field,
L/c. This result constrains the expected mass loss rates from systems that
exceed the Eddington limit to be of order the so-called "single-scattering"
limit, and not significantly higher. We present an approximate fitting formula
for the rate of momentum transfer from radiation to dusty gas through which it
passes, which is suitable for implementation in sub-grid models of galaxy
formation. Finally, we provide a first map of the column density distribution
of gas in a radiatively-driven wind as a function of velocity, and velocity
dispersion.


title:
Wind Roche-lobe overflow: Application to carbon-enhanced metal-poor
  stars

abstract:
  Carbon-enhanced metal-poor stars (CEMP) are observed as a substantial
fraction of the very metal-poor stars in the Galactic halo. Most CEMP stars are
also enriched in s-process elements and these are often found in binary
systems. This suggests that the carbon enrichment is due to mass transfer in
the past from an asymptotic giant branch (AGB) star on to a low-mass companion.
Models of binary population synthesis are not able to reproduce the observed
fraction of CEMP stars without invoking non-standard nucleosynthesis or a
substantial change in the initial mass function. This is interpreted as
evidence of missing physical ingredients in the models. Recent hydrodynamical
simulations show that efficient wind mass transfer is possible in the case of
the slow and dense winds typical of AGB stars through a mechanism called wind
Roche-lobe overflow (WRLOF), which lies in between the canonical
Bondi-Hoyle-Lyttleton (BHL) accretion and Roche-lobe overflow. WRLOF has an
effect on the accretion efficiency of mass transfer and on the angular momentum
lost by the binary system. The aim of this work is to understand the overall
effect of WRLOF on the population of CEMP stars. To simulate populations of
low-metallicity binaries we combined a synthetic nucleosynthesis model with a
binary population synthesis code. In this code we implemented the WRLOF
mechanism. We used the results of hydrodynamical simulations to model the
effect of WRLOF on the accretion efficiency and we took the effect on the
angular momentum loss into account by assuming a simple prescription. As a
result the number of CEMP stars predicted by our model increases by a factor
1.2-1.8 compared to earlier results that consider the BHL prescription.
Moreover, higher enrichments of carbon are produced and the final orbital
period distribution is shifted towards shorter periods.


title:
Resonant-plane locking and spin alignment in stellar-mass black-hole
  binaries: a diagnostic of compact-binary formation

abstract:
  We study the influence of astrophysical formation scenarios on the
precessional dynamics of spinning black-hole binaries by the time they enter
the observational window of second- and third-generation gravitational-wave
detectors, such as Advanced LIGO/Virgo, LIGO-India, KAGRA and the Einstein
Telescope. Under the plausible assumption that tidal interactions are efficient
at aligning the spins of few-solar mass black-hole progenitors with the orbital
angular momentum, we find that black-hole spins should be expected to
preferentially lie in a plane when they become detectable by gravitational-wave
interferometers. This "resonant plane" is identified by the conditions
\Delta\Phi=0{\deg} or \Delta\Phi=+/-180{\deg}, where \Delta\Phi is the angle
between the components of the black-hole spins in the plane orthogonal to the
orbital angular momentum. If the angles \Delta \Phi can be accurately measured
for a large sample of gravitational-wave detections, their distribution will
constrain models of compact binary formation. In particular, it will tell us
whether tidal interactions are efficient and whether a mechanism such as mass
transfer, stellar winds, or supernovae can induce a mass-ratio reversal (so
that the heavier black hole is produced by the initially lighter stellar
progenitor). Therefore our model offers a concrete observational link between
gravitational-wave measurements and astrophysics. We also hope that it will
stimulate further studies of precessional dynamics, gravitational-wave template
placement and parameter estimation for binaries locked in the resonant plane.


title: Low stellar obliquities in compact multiplanet systems

abstract:
  We measure the sky-projected stellar obliquities (\lambda) in the
multiple-transiting planetary systems KOI-94 and Kepler-25, using the
Rossiter-McLaughlin effect. In both cases the host stars are well-aligned with
the orbital planes of the planets. For KOI-94 we find \lambda=-11+-11 deg,
confirming a recent result by Hirano and coworkers. Kepler-25 was a more
challenging case because the transit depth is unusually small (0.13 %). To
obtain the obliquity it was necessary to use prior knowledge of the star's
projected rotation rate, and apply two different analysis methods to
independent wavelength regions of the spectra. The two methods gave consistent
results, \lambda=7+-8 deg and -0.5+-5.7 deg.
  There are now a total of five obliquity measurements for host stars of
systems of multiple transiting planets, all of which are consistent with
spin-orbit alignment. This alignment is unlikely to be the result of tidal
interactions, because of the relatively large orbital distances and low
planetary masses in the systems. In this respect the multiplanet host stars
differ from hot-Jupiter host stars, which commonly have large spin-orbit
misalignments whenever tidal interactions are weak. In particular the weak-tide
subset of hot-Jupiter hosts have obliquities consistent with an isotropic
distribution (p=0.6), but the multiplanet hosts are incompatible with such a
distribution (p~10^-6). This suggests that high obliquities are confined to
hot-Jupiter systems, and provides further evidence that hot Jupiter formation
involves processes that tilt the planetary orbit.


title: The red blazar PMN J2345-1555 becomes blue

abstract:
  The Flat Spectrum Radio Quasar PMN J2345-1555 is a bright gamma-ray source,
that recently underwent a flaring episode in the IR, UV and gamma-ray bands.
The flux changed quasi simultaneously at different frequencies, suggesting that
it was produced by a single population of emitting particles, hence by a single
and well localized region of the jet. While the overall Spectral Energy
Distribution (SED) before the flare was typical of powerful blazars (namely two
broad humps peaking in the far IR and below 100 MeV bands, respectively),
during the flare the peaks moved to the optical-UV and to energies larger than
1 GeV, to resemble low power BL Lac objects, even if the observed bolometric
luminosity increased by more than one order of magnitude. We interpret this
behavior as due to a change of the location of the emission region in the jet,
from within the broad line region, to just outside. The corresponding decrease
of the radiation energy density as seen in the comoving frame of the jet
allowed the relativistic electrons to be accelerated to higher energies, and
thus produce a "bluer" SED.


title:
Kepler observations of rapid optical variability in the BL Lac object
  W2R1926+42

abstract:
  We present the first Kepler monitoring of a strongly variable BL Lac,
W2R1926+42. The light curve covers 181 days with ~0.2% errors, 30 minute
sampling and >90% duty cycle, showing numerous delta I/I > 25% flares over
timescales as short as a day. The flux distribution is highly skewed and
non-Gaussian. The variability shows a strong rms-flux correlation with the
clearest evidence to date for non-linearity in this relation. We introduce a
method to measure periodograms from the discrete autocorrelation function, an
approach that may be well-suited to a wide range of Kepler data. The
periodogram is not consistent with a simple power-law, but shows a flattening
at frequencies below 7x10-5 Hz. Simple models of the power spectrum, such as a
broken power law, do not produce acceptable fits, indicating that the Kepler
blazar light curve requires more sophisticated mathematical and physical
descriptions than currently in use.


title: A short note on the concept of free choice

abstract:
  We argue that the concepts of "freedom of choice" and of "causal order" are
intrinsically linked: a choice is considered "free" if it is correlated only to
variables in its causal future. We discuss the implications of this to
Bell-type scenarios, where two separate measurements are carried out, neither
of which lies in the causal future of the other, and where one typically
assumes that the measurement settings are chosen freely. Furthermore, we refute
a recent criticism made by Ghirardi and Romano in [arXiv:1301.5040] and
[arXiv:1302.1635] that we used an unphysical freedom of choice assumption in
our previous works, [Nat. Commun. 2, 411 (2011)] and [Phys. Rev. Lett. 108,
150402 (2012)].


title: Weak Massive Gravity

abstract:
  We find a new class of theories of massive gravity with five propagating
degrees of freedom where only rotations are preserved. Our results are based on
a non-perturbative and background-independent Hamiltonian analysis. In these
theories the weak field approximation is well behaved and the static
gravitational potential is typically screened \`a la Yukawa at large distances,
while at short distances no vDVZ discontinuity is found and there is no need to
rely on nonlinear effects to pass the solar system tests. The effective field
theory analysis shows that the ultraviolet cutoff is (m M_PL)^1/2 ~ 1/\mu m,
the highest possible. Thus, these theories can be studied in weak-field regime
at all the phenomenologically interesting scales, and are candidates for a
calculable large-distance modified gravity.


title:
Timing Noise in Pulsars and Magnetars and the Magnetospheric Moment of
  Inertia

abstract:
  We examine timing noise in both magnetars and regular pulsars, and find that
there exists a component of the timing noise with strong magnetic field
dependence above B ~ 10^{12.5} G. The dependence of the timing noise floor on
the magnetic field is also reflected in the smallest observable glitch size. We
find that magnetospheric torque variation cannot explain this component of
timing noise. We calculate the moment of inertia of the magnetic field outside
of a neutron star and show that this timing noise component may be due to
variation of this moment of inertia, and could be evidence of rapid global
magnetospheric variability.


title:
Surface composition and taxonomic classification of a group of
  near-Earth and Mars-crossing asteroids

abstract:
  In the past, constraining the surface composition of near-Earth asteroids
(NEAs) has been difficult due to the lack of high quality near-IR spectral data
(0.7-2.5 microns) that contain mineralogically diagnostic absorption bands.
Here we present visible (0.43-0.95 microns) and near-infrared (0.7-2.5 microns)
spectra of nine NEAs and five Mars-crossing asteroids (MCs). The studied NEAs
are: 4055 Magellan, 19764 (2000 NF5), 89830 (2002 CE), 138404 (2000 HA24),
143381 (2003 BC21), 159609 (2002 AQ3), 164121 (2003 YT1), 241662 (2000 KO44)
and 2007 ML13. The studied MCs are: 1656 Suomi, 2577 Litva, 5407 (1992 AX),
22449 Ottijeff and 47035 (1998 WS). The observations were conducted with the
NTT at La Silla, Chile, the 2.2 m telescope at Calar Alto, Spain, and the IRTF
on Mauna Kea, Hawai'i. The taxonomic classification (Bus system) of asteroids
showed that all observed MC asteroids belong to the S-complex, including the S,
Sr and Sl classes. Seven of the NEAs belong to the S-complex, including the S,
Sa, Sk and Sl classes, and two NEAs were classified as V-types. The
classification of the NEA 164121 (2003 YT1) as a V-type was made on the basis
of its near-infrared spectrum since no visible spectrum is available for this
asteroid. A mineralogical analysis was performed on six of the asteroids (those
for which near-IR spectra were obtained or previously available). We found that
three asteroids (241662 (2000 KO44), 19764 (2000 NF5), 138404 (2000 HA24)) have
mafic silicate compositions consistent with ordinary chondrites, while three
others (4055 Magellan, 164121 (2003 YT1), 5407 (1992 AX)) are
pyroxene-dominated basaltic achondrite assemblages. In the case of 5407 (1992
AX) we found that its basaltic surface composition contrasts its taxonomic
classification as a S-type.


title: A phenomenological approach to the evolution of galaxies

abstract:
  Increasingly good statistical data on the galaxy population at high and low
redshift enable the development of new phenomenological approaches to galaxy
evolution based on application of the simplest continuity equations. This has
given new insights into the different ways in which star-formation in galaxies
is quenched, the role of merging in the population, and into the control of
star-formation in star-forming galaxies and the links between this and chemical
evolution, in particular the existence of SFR as a second parameter in the
mass-metallicity relation. The continuity approach provides a self-consistent
view of the evolving population and exposes linkages between different aspects
of galaxy evolution.


title: Two-dimensional SCFTs from wrapped branes and c-extremization

abstract:
  We apply c-extremization, whose proof we review in full detail, to study
two-dimensional N=(0,2) superconformal field theories arising from the
low-energy dynamics of D3-branes wrapped on Riemann surfaces and M5-branes
wrapped on four-manifolds. We compute the exact central charges of these
theories using anomalies and c-extremization. In all cases we also construct
AdS_3 supergravity solutions of type IIB and eleven-dimensional supergravity,
which are holographic duals to the field theories at large N, and exactly
reproduce the central charges computed via c-extremization.


title: Herschel views on ultra-luminous X-ray sources

abstract:
  The nature of ultra-luminous X-ray sources (ULXs), which are off-nuclear
extragalactic X-ray sources that exceed the Eddington luminosity for a
stellar-mass black hole, is still largely unknown. They might be black hole
X-ray binaries in a super-Eddington accretion state, possibly with significant
beaming of their emission, or they might harbor a black hole of intermediate
mass (10^2 to 10^5 solar masses). Due to the enormous amount of energy
radiated, ULXs can have strong interactions with their environment,
particularly if the emission is not beamed and if they host a massive black
hole. We present early results of a project that uses archival Herschel
infrared observations of galaxies hosting bright ULXs in order to constrain the
nature of the environment surrounding the ULXs and possible interactions. We
already observe a spatial correlation between ULXs and dense clouds of cold
material, that will be quantified in subsequent work. Those observations will
allow us to test the similarities with the environment of Galactic high mass
X-ray binaries. This project will also shed light on the nature of the host
galaxies, and the possible factors that could favor the presence of a ULX in a
galaxy.


title: Soft quantum vibrations of PT-symmetric nonlinear ion chain

abstract:
  We theoretically study the quantum dynamics of transverse vibrations of a
one-dimensional chain of trapped ions in harmonic potentials interacting via a
Reggeon-type cubic nonlinearity that is nonunitary but preserves PT symmetry.
We propose the notion of quantum fragility for the dissipative structural phase
transition that spontaneously breaks the PT symmetry. In the quantum fragile
regime, the nonlinearity dominates the response to mechanical perturbations and
the chain supports neither the ordinary quantum phonons of a Luttinger liquid,
nor the supersonic solitons that arise in classical fragile critical points in
the absence of fluctuations. Quantum fluctuations, approximately captured
within a one-loop renormalization group, give rise to mechanical excitations
with a strongly momentum-dependent phonon velocity and dissipative spectral
behavior. Observable signatures of the quantum fragile chain in trapped ion
systems are discussed.

categories: cond-mat.quant-gas cond-mat.stat-mech hep-th quant-ph


title:
On the importance of loop-induced spin-independent interactions for dark
  matter direct detection

abstract:
  The latest results from LHC searches for jets in association with missing
transverse energy place strong bounds on the scattering cross section of dark
matter. For the case of spin-dependent or momentum suppressed interactions
these limits seem to be superior to the bounds from direct detection
experiments. In this article, we show that loop contributions can significantly
alter this conclusion and boost direct detection bounds, whenever they induce
spin-independent interactions. This effect is most striking for tensor and
pseudotensor interactions, which induce magnetic and electric dipole moments at
loop level. For axialvector and anapole interactions a relevant contribution to
direct detection signals arises from loop-induced Yukawa-like couplings between
dark matter and quarks. We furthermore compare the resulting bounds to
additional constraints on these effective operators arising from indirect
searches and relic density requirements.


title:
Radio studies of novae: a current status report and highlights of new
  results

abstract:
  Novae, which are the sudden visual brightening triggered by runaway
thermonuclear burning on the surface of an accreting white dwarf, are fairly
common and bright events. Despite their astronomical significance as nearby
laboratories for the study of nuclear burning and accretion phenomena, many
aspects of these common stellar explosions are observationally not
well-constrained and remain poorly understood. Radio observations, modeling and
interpretation can potentially play a crucial role in addressing some of these
puzzling issues. In this review on radio studies of novae, we focus on the
possibility of testing and improving the nova models with radio observations,
and present a current status report on the progress in both the observational
front and theoretical developments. We specifically address the issues of
accurate estimation of ejecta mass, multi-phase and complex ejection phenomena,
and the effect of a dense environment around novae. With highlights of new
observational results, we illustrate how radio observations can shed light on
some of these long-standing puzzles.


title: Monte Carlo simulations of the photospheric emission in GRBs

abstract:
  We studied the decoupling of photons from ultra-relativistic spherically
symmetric outflows expanding with constant velocity by means of Monte-Carlo
(MC) simulation. For outflows with finite width we confirm the existence of two
regimes: photon thick and photon thin introduced recently by Ruffini, Siutsou,
Vereshchagin (2011), hereafter RSV. The probability density function of photon
last scattering is shown to be very different in these two cases. We also
obtained spectra as well as light curves. In photon thick case, the time
integrated spectrum is much broader than the Planck function and its shape is
well described by the fuzzy photosphere approximation introduced by RSV. In the
photon thin case we confirm the crucial role of photon diffusion, hence the
probability density of decoupling has a maximum near the diffusion radius, well
below the photosphere. Its spectrum has Band shape. It is produced when the
outflow is optically thick and its peak is formed at diffusion radius.


title:
Steady Outflows in Giant Clumps of High-z Disk Galaxies During Migration
  and Growth by Accretion

abstract:
  We predict the evolution of giant clumps undergoing star-driven outflows in
high-z gravitationally unstable disk galaxies. We find that the mass loss is
expected to occur through a steady wind over many tens of free-fall times (t_ff
~ 10 Myr) rather than by an explosive disruption in one or a few t_ff. Our
analysis is based on the finding from simulations that radiation trapping is
negligible because it destabilizes the wind (Krumholz & Thompson 2012, 2013).
Each photon can therefore contribute to the wind momentum only once, so the
radiative force is limited to L/c. When combining radiation, protostellar and
main-sequence winds, and supernovae, we estimate the total direct injection
rate of momentum into the outflow to be 2.5 L/c. The adiabatic phase of
supernovae and main-sequence winds can double this rate. The resulting outflow
mass-loading factor is of order unity, and if the clumps were to deplete their
gas the timescale would have been a few disk orbital times, to end with half
the original clump mass in stars. However, the clump migration time to the disk
center is on the order of an orbital time, about 250 Myr, so the clumps are
expected to complete their migration prior to depletion. Furthermore, the
clumps are expected to double their mass in a disk orbital time by accretion
from the disk and clump-clump mergers, so their mass actually grows in time and
with decreasing radius. From the 6-7 giant clumps with observed outflows, 5 are
consistent with these predictions, and one has a much higher mass-loading
factor and momentum injection rate. The latter either indicates that the
estimated outflow is an overestimate (within the 1-sigma error), that the SFR
has dropped since the time when the outflow was launched, or that the driving
mechanism is different, e.g. supernova feedback in a cavity generated by the
other feedbacks.


title: A Captured Runaway Black Hole in NGC 1277?

abstract:
  Recent results indicate that the compact lenticular galaxy NGC 1277 in the
Perseus Cluster contains a black hole of approximately 10 billion solar masses.
This far exceeds the expected mass of the central black hole in a galaxy of the
modest dimensions of NGC 1277. We suggest that this giant black hole was
ejected from the nearby giant galaxy NGC 1275 and subsequently captured by NGC
1277. The ejection was the result of gravitational radiation recoil when two
large black holes merged following the merger of two giant ellipticals that
helped to form NGC 1275. The black hole wandered in the cluster core until it
was captured in a close encounter with NGC 1277. The migration of black holes
in clusters may be a common occurrence.


title: A link between Quantum Entanglement, Secant varieties and Sphericity

abstract:
  In this paper, we shed light on relations between three concepts studied in
representations theory, algebraic geometry and quantum information theory.
First - spherical actions of reductive groups on projective spaces. Second -
secant varieties of homogeneous projective varieties, and the related notions
of rank and border rank. Third - quantum entanglement. Our main result concerns
the relation between the problem of the state reconstruction from its reduced
one-particle density matrices and the minimal number of separable summands in
its decomposition. More precisely, we show that sphericity implies that states
of a given rank cannot be approximated by states of a lower rank. We call
states for which such approximation is possible exceptional states. For three,
important from quantum entanglement perspective cases of distinguishable,
fermionic and bosonic particles, we also show that non-sphericity implies the
existence of exceptional states. Remarkably, the exceptional states belong to
non-bipartite entanglement classes. In particular, we show that the $W$-type
states and their appropriate modifications are exceptional states stemming from
the second secant variety for three cases above. We point out that the
existence of the exceptional states is a physical obstruction for deciding the
local unitary equivalence of states by means of the one-particle reduced
density matrices. Finally, for a number of systems of distinguishable particles
with known orbit structure we list all exceptional states and discuss their
possible importance in entanglement theory.

categories: quant-ph math-ph math.AG math.MP math.RT


title:
Magnetization and phase transition induced by circularly polarized laser
  in quantum magnets

abstract:
  We theoretically predict a nonequilibrium phase transition in quantum spin
systems induced by a laser, which provides a purely quantum-mechanical way of
coherently controlling magnetization. Namely, when a circularly polarized laser
is applied to a spin system, the magnetic component of a laser is shown to
induce a magnetization normal to the plane of polarization, leading to an
ultrafast phase transition. We first demonstrate this phenomenon numerically
for an $S=1$ antiferromagnetic Heisenberg spin chain, where a new state emerges
with magnetization perpendicular to the polarization plane of the laser in
place of the topologically ordered Haldane state. We then elucidate its
physical mechanism by mapping the system to an effective static model. The
theory also indicates that the phenomenon should occur in general quantum spin
systems with a magnetic anisotropy. The required laser frequency is in the
terahertz range, with the required intensity being within a prospective
experimental feasibility.


title: Universal Groebner bases for maximal minors

abstract:
  A set of polynomials G in a polynomial ring S over a field is said to be a
universal Groebner basis, if G is a Groebner basis with respect to every term
order on S. Twenty years ago Bernstein, Sturmfels, and Zelevinsky proved that
the set of the maximal minors of a matrix X of variables is a universal
Groebner basis. Boocher recently proved that any initial ideal of the ideal of
maximal minors of X has a linear resolution.
  In this paper we give a quick proof of the results mentioned above. Our proof
is based on a specialization argument. Then we show that similar statements
hold in a more general setting, for matrices of linear forms satisfying certain
homogeneity conditions. More precisely, we show that the set of maximal minors
of a matrix L of linear forms is a universal Groebner basis for the ideal I
that it generates, provided that L is column-graded. Under the same assumption
we show that every initial ideal of I has a linear resolution. Furthermore, the
projective dimension of I and of its initial ideals is n-m, unless I=0 or a
column of L is identically 0. Here L is a matrix of size m times n, and m is
smaller than or equal to n. If instead L is row-graded, then we prove that I
has a universal Groebner basis of elements of degree m and that every initial
ideal of I has a linear resolution, provided that I has the expected
codimension.
  The proofs are based on a rigidity property of radical Borel fixed ideals in
a multigraded setting: We prove that if two Borel fixed ideals I and J have the
same multigraded Hilbert series and I is radical, then I = J. We also discuss
some of the consequences of this rigidity property.


title: LEDDB: LOFAR Epoch of Reionization Diagnostic Database

abstract:
  One of the key science projects of the Low-Frequency Array (LOFAR) is the
detection of the cosmological signal coming from the Epoch of Reionization
(EoR). Here we present the LOFAR EoR Diagnostic Database (LEDDB) that is used
in the storage, management, processing and analysis of the LOFAR EoR
observations. It stores referencing information of the observations and
diagnostic parameters extracted from their calibration. This stored data is
used to ease the pipeline processing, monitor the performance of the telescope
and visualize the diagnostic parameters which facilitates the analysis of the
several contamination effects on the signals. It is implemented with PostgreSQL
and accessed through the psycopg2 python module. We have developed a very
flexible query engine, which is used by a web user interface to access the
database, and a very extensive set of tools for the visualization of the
diagnostic parameters through all their multiple dimensions.


title:
A Low-Power Content-Addressable-Memory Based on
  Clustered-Sparse-Networks

abstract:
  A low-power Content-Addressable-Memory (CAM) is introduced employing a new
mechanism for associativity between the input tags and the corresponding
address of the output data. The proposed architecture is based on a recently
developed clustered-sparse-network using binary-weighted connections that
on-average will eliminate most of the parallel comparisons performed during a
search. Therefore, the dynamic energy consumption of the proposed design is
significantly lower compared to that of a conventional low-power CAM design.
Given an input tag, the proposed architecture computes a few possibilities for
the location of the matched tag and performs the comparisons on them to locate
a single valid match. A 0.13 um CMOS technology was used for simulation
purposes. The energy consumption and the search delay of the proposed design
are 9.5%, and 30.4% of that of the conventional NAND architecture respectively
with a 3.4% higher number of transistors.


title: Dynamic Power Reduction in a Novel CMOS 5T-SRAM for Low-Power SoC

abstract:
  This paper addresses a novel five-transistor (5T) CMOS SRAM design with high
performance and reliability in 65nm CMOS, and illustrates how it reduces the
dynamic power consumption in comparison with the conventional and low-power 6T
SRAM counterparts. This design can be used as cache memory in processors and
low-power portable devices. The proposed SRAM cell features ~13% area reduction
compared to a conventional 6T cell, and features a unique bit-line and negative
supply voltage biasing methodology and ground control architecture to enhance
performance, and suppress standby leakage power.


title:
Unveiling the relationship between complex networks metrics and word
  senses

abstract:
  The automatic disambiguation of word senses (i.e., the identification of
which of the meanings is used in a given context for a word that has multiple
meanings) is essential for such applications as machine translation and
information retrieval, and represents a key step for developing the so-called
Semantic Web. Humans disambiguate words in a straightforward fashion, but this
does not apply to computers. In this paper we address the problem of Word Sense
Disambiguation (WSD) by treating texts as complex networks, and show that word
senses can be distinguished upon characterizing the local structure around
ambiguous words. Our goal was not to obtain the best possible disambiguation
system, but we nevertheless found that in half of the cases our approach
outperforms traditional shallow methods. We show that the hierarchical
connectivity and clustering of words are usually the most relevant features for
WSD. The results reported here shine light on the relationship between semantic
and structural parameters of complex networks. They also indicate that when
combined with traditional techniques the complex network approach may be useful
to enhance the discrimination of senses in large texts

categories: physics.soc-ph cs.CL cs.SI physics.data-an


title: On the support of measures in multiplicative free convolution semigroups

abstract:
  In this paper, we study the supports of measures in multiplicative free
semigroups on the positive real line and on the unit circle. We provide
formulas for the density of the absolutely continuous parts of measures in
these semigroups. The descriptions rely on the characterizations of the images
of the upper half-plane and the unit disc under certain subordination
functions. These subordination functions are $\eta$-transforms of infinitely
divisible measures with respect to multiplicative free convolution. The
characterizations also help us study the regularity properties of these
measures. One of the main results is that the number of components in the
support of measures in the semigroups is a decreasing function of the semigroup
parameter.


title:
Green's functions and equations of motion in correlated many body
  systems

abstract:
  In this paper some new physical notations are given for the Green's functions
and equations of motion (EOM) in many body physics with the concept of
quasiparticles. It shows how the many body correlations existing in many body
systems can be taken into account through the derivation of EOMs
self-consistently. The scheme is compared with the expansion of Feynman
diagrams. Finally some further discussions are given for the unique properties
of EOM techniques in helping to model a system and the interactions
self-consistently.


title: A Dixmier-Douady theory for strongly self-absorbing C*-algebras

abstract:
  We show that the Dixmier-Douady theory of continuous field $C^*$-algebras
with compact operators $\mathbb{K}$ as fibers extends significantly to a more
general theory of fields with fibers $A\otimes \mathbb{K}$ where $A$ is a
strongly self-absorbing C*-algebra. The classification of the corresponding
locally trivial fields involves a generalized cohomology theory which is
computable via the Atiyah-Hirzebruch spectral sequence. An important feature of
the general theory is the appearance of characteristic classes in higher
dimensions. We also give a necessary and sufficient $K$-theoretical condition
for local triviality of these continuous fields over spaces of finite covering
dimension.


title:
SuperLFV: An SLHA tool for lepton flavor violating observables in
  supersymmetric models

abstract:
  We introduce SuperLFV, a numerical tool for calculating low-energy
observables that exhibit charged lepton flavor violation (LFV) in the context
of the minimal supersymmetric standard model (MSSM). As the Large Hadron
Collider and MEG, a dedicated mu -> e gamma experiment, are presently acquiring
data, there is need for tools that provide rapid discrimination of models that
exhibit LFV. SuperLFV accepts a spectrum file compliant with the SUSY Les
Houches Accord (SLHA), containing the MSSM couplings and masses with complex
phases at the supersymmetry breaking scale. In this manner, SuperLFV is
compatible with but divorced from existing SLHA spectrum calculators that
provides the low energy spectrum. Hence, input spectra are not confined to the
LFV sources provided by established SLHA spectrum calculators. Input spectra
may be generated by personal code or by hand, allowing for arbitrary models not
supported by existing spectrum calculators.


title: Cores of Vertex Transitive Graphs

abstract:
  A core of a graph X is a vertex minimal subgraph to which X admits a
homomorphism. Hahn and Tardif have shown that for vertex transitive graphs, the
size of the core must divide the size of the graph. This motivates the
following question: when can the vertex set of a vertex transitive graph be
partitioned into sets each of which induce a copy of its core? We show that
normal Cayley graphs and vertex transitive graphs with cores half their size
always admit such partitions. We also show that the vertex sets of vertex
transitive graphs with cores less than half their size do not, in general, have
such partitions.


title: Word sense disambiguation via high order of learning in complex networks

abstract:
  Complex networks have been employed to model many real systems and as a
modeling tool in a myriad of applications. In this paper, we use the framework
of complex networks to the problem of supervised classification in the word
disambiguation task, which consists in deriving a function from the supervised
(or labeled) training data of ambiguous words. Traditional supervised data
classification takes into account only topological or physical features of the
input data. On the other hand, the human (animal) brain performs both low- and
high-level orders of learning and it has facility to identify patterns
according to the semantic meaning of the input data. In this paper, we apply a
hybrid technique which encompasses both types of learning in the field of word
sense disambiguation and show that the high-level order of learning can really
improve the accuracy rate of the model. This evidence serves to demonstrate
that the internal structures formed by the words do present patterns that,
generally, cannot be correctly unveiled by only traditional techniques.
Finally, we exhibit the behavior of the model for different weights of the low-
and high-level classifiers by plotting decision boundaries. This study helps
one to better understand the effectiveness of the model.


title: Measurement of the top quark mass with the ATLAS detector

abstract:
  An overview is presented of the measurements of the top quark mass performed
by the ATLAS experiment at the LHC with an integrated luminosity varying
between 35 pb$^{-1}$ and 4.7 fb$^{-1}$. Different techniques are used to
measure the top quark mass looking at events in all three signatures:
fully-hadronic, lepton+jets and di-leptonic ones. The most precise measurement,
using a template method on lepton+jets events, yields a top quark mass of 174.5
$\pm$ 0.6 (stat) $\pm$ 2.3 (syst) GeV. The dominant systematic uncertainties
are related to the determination of the $b-$jet energy scale and the modelling
of additional radiation accompanying the $t\bar{t}$ pair production.


title:
Atomistic deconstruction of current flow in graphene based
  hetero-junctions

abstract:
  We describe the numerical modeling of current flow in graphene
heterojunctions, within the Keldysh Landauer Non-equilibrium Green's function
(NEGF) formalism. By implementing a $k$-space approach along the transverse
modes, coupled with partial matrix inversion using the Recursive Green's
function Algorithm (RGFA), we can simulate on an atomistic scale current flow
across devices approaching experimental dimensions. We use the numerical
platform to deconstruct current flow in graphene, compare with experimental
results on conductance, conductivity and quantum Hall, and deconstruct the
physics of electron `optics' and pseudospintronics in graphene $p-n$ junctions.
We also demonstrate how to impose exact open boundary conditions along the
edges to minimize spurious edge reflections.


title:
On the multiple unicast capacity of 3-source, 3-terminal directed
  acyclic networks

abstract:
  We consider the multiple unicast problem with three source-terminal pairs
over directed acyclic networks with unit-capacity edges. The three $s_i-t_i$
pairs wish to communicate at unit-rate via network coding. The connectivity
between the $s_i - t_i$ pairs is quantified by means of a connectivity level
vector, $[k_1 k_2 k_3]$ such that there exist $k_i$ edge-disjoint paths between
$s_i$ and $t_i$. In this work we attempt to classify networks based on the
connectivity level. It can be observed that unit-rate transmission can be
supported by routing if $k_i \geq 3$, for all $i = 1, \dots, 3$. In this work,
we consider, connectivity level vectors such that $\min_{i = 1, \dots, 3} k_i <
3$. We present either a constructive linear network coding scheme or an
instance of a network that cannot support the desired unit-rate requirement,
for all such connectivity level vectors except the vector $[1~2~4]$ (and its
permutations). The benefits of our schemes extend to networks with higher and
potentially different edge capacities. Specifically, our experimental results
indicate that for networks where the different source-terminal paths have a
significant overlap, our constructive unit-rate schemes can be packed along
with routing to provide higher throughput as compared to a pure routing
approach.


title: In Love With a Robot: the Dawn of Machine-To-Machine Marketing

abstract:
  The article looks at mass market artificial intelligence tools in the context
of their ever-growing sophistication, availability and market penetration. The
subject is especially relevant today for these exact reasons - if a few years
ago AI was the subject of high tech research and science fiction novels, today,
we increasingly rely on cloud robotics to cater to our daily needs - to trade
stock, predict weather, manage diaries, find friends and buy presents online.


title: Air flow in a collapsing cavity

abstract:
  We experimentally study the airflow in a collapsing cavity created by the
impact of a circular disk on a water surface. We measure the air velocity in
the collapsing neck in two ways: Directly, by means of employing particle image
velocimetry of smoke injected into the cavity and indirectly, by determining
the time rate of change of the volume of the cavity at pinch-off and deducing
the air flow in the neck under the assumption that the air is incompressible.
We compare our experiments to boundary integral simulations and show that close
to the moment of pinch-off, compressibility of the air starts to play a crucial
role in the behavior of the cavity. Finally, we measure how the air flow rate
at pinch-off depends on the Froude number and explain the observed dependence
using a theoretical model of the cavity collapse.


title:
Mid-Infrared Properties of Nearby Luminous Infrared Galaxies I: Spitzer
  IRS Spectra for the GOALS Sample

abstract:
  The Great Observatories All-Sky LIRG Survey (GOALS) is a multiwavelength
study of luminous infrared galaxies (LIRGs) in the local universe. Here we
present low resolution Spitzer spectra covering 5-38um and provide a basic
analysis of the mid-IR spectral properties for nearby LIRGs. In a companion
paper, we discuss detailed fits to the spectra. The GOALS sample of 244 nuclei
in 180 luminous and 22 ultraluminous IR galaxies represents a complete subset
of the IRAS RBGS and covers a range of merger stages, morphologies and spectral
types. The majority (>60%) of GOALS LIRGs have high 6.2um PAH equivalent widths
(EQW > 0.4um) and low levels of silicate absorption (s_9.7um >-1.0). There is a
general trend among the U/LIRGs for silicate depth and MIR slope to increase
with LIR. U/LIRGs in the late stages of a merger also have on average steeper
MIR slopes and higher levels of dust obscuration. Together these trends suggest
that as gas & dust is funneled towards the center of a coalescing merger, the
nuclei become more compact and obscured. The sources that depart from these
correlations have very low PAH EQW (EQW < 0.1um) consistent with their MIR
emission being dominated by an AGN. The most heavily dust obscured sources are
the most compact in their MIR emission, suggesting that the obscuring (cool)
dust is associated with the outer regions of the starburst. As the merger
progresses a marked decline is seen for the fraction of high EQW (star
formation dominated) sources while the fraction of composite sources increases
but the fraction of AGN-dominated sources remains low. When compared to the MIR
spectra of submillimeter galaxies (SMGs) at z~2, the average GOALS LIRG is more
absorbed at 9.7um and has more PAH emission. However, when the AGN
contributions to both the local LIRGs and the high-z SMGs are removed, the
average local starbursting LIRG closely resembles the starbursting SMGs.


title: Low-energy limit of the radiative dipole strength in nuclei

abstract:
  We explain the low-energy anomaly reported in several experimental studies of
the radiative dipole strength functions in medium-mass nuclei. These strength
functions at very low gamma-energies correspond to the gamma-transitions
between very close nuclear excited states in the quasicontinuum. In terms of
the thermal mean-field, the low-energy enhancement of the strength functions in
highly-excited compound nuclei is explained by nucleonic transitions from the
thermally unblocked single-quasiparticle states to the single-(quasi)particle
continuum. This result is obtained within the finite-temperature quasiparticle
random phase approximation in the coordinate space with exact treatment of the
single-particle continuum and exactly eliminated spurious translational mode.
The case of radiative dipole strength functions at the nuclear excitation
energies typical for the thermal neutron capture is illustrated for 94-Mo and
144-Nd in comparison to available data.


title:
Metallicity Differences in Type Ia Supernova Progenitors Inferred from
  Ultraviolet Spectra

abstract:
  Two "twin" Type Ia supernovae (SNe Ia), SNe 2011by and 2011fe, have extremely
similar optical light-curve shapes, colors, and spectra, yet have different
ultraviolet (UV) continua as measured in Hubble Space Telescope spectra and
measurably different peak luminosities. We attribute the difference in the UV
continua to significantly different progenitor metallicities. This is the first
robust detection of different metallicities for SN Ia progenitors. Theoretical
reasoning suggests that differences in metallicity also lead to differences in
luminosity. SNe Ia with higher progenitor metallicities have lower 56Ni yields,
and lower luminosities, for the same light-curve shape. SNe 2011by and 2011fe
have different peak luminosities (Delta M_V = 0.6 mag), which correspond to
different 56Ni yields: M_11fe(56Ni)/M_11by(56Ni) = 1.7^+0.7_-0.5. From
theoretical models that account for different neutron to proton ratios in
progenitors, the differences in 56Ni yields for SNe 2011by and 2011fe imply
that their progenitor stars were above and below solar metallicity,
respectively. Although we can distinguish progenitor metallicities in a
qualitative way from UV data, the quantitative interpretation in terms of
abundances is limited by the present state of theoretical models.


title: Time Domain Mapping of Spin Torque Oscillator Effective Energy

abstract:
  Stochastic dynamics of spin torque oscillators (STOs) can be described in
terms of magnetization drift and diffusion over a current-dependent effective
energy surface given by the Fokker-Planck equation. Here we present a method
that directly probes this effective energy surface via time-resolved
measurements of the microwave voltage generated by a STO. We show that the
effective energy approach provides a simple recipe for predicting spectral line
widths and line shapes near the generation threshold. Our time domain technique
also accurately measures the field-like component of spin torque in a wide
range of the voltage bias values.


title: On the Holonomic Rank Problem

abstract:
  A tautological system, introduced in \cite{LSY}\cite{LY}, arises as a regular
holonomic system of partial differential equations that govern the period
integrals of a family of complete intersections in a complex manifold $X$,
equipped with a suitable Lie group action. In this article, we introduce two
formulas -- one purely algebraic, the other geometric -- to compute the rank of
the solution sheaf of such a system for CY hypersurfaces in a generalized flag
variety. The algebraic version gives the local solution space as a Lie algebra
homology group, while the geometric one as the middle de Rham cohomology of the
complement of a hyperplane section in $X$. We use both formulas to find certain
degenerate points for which the rank of the solution sheaf becomes 1. These
rank 1 points appear to be good candidates for the so-called large complex
structure limits in mirror symmetry. The formulas are also used to prove a
conjecture of Hosono, Lian and Yau on the completeness of the extended GKZ
system when $X$ is $\P^n$.


title:
Ultrahigh Energy Cosmic Ray Nuclei from Extragalactic Pulsars and the
  effect of their Galactic counterparts

abstract:
  The acceleration of ultrahigh energy nuclei in fast spinning newborn pulsars
can explain the observed spectrum of ultrahigh energy cosmic rays and the trend
towards heavier nuclei for energies above $10^{19}\,$eV as reported by the
Auger Observatory. Pulsar acceleration implies a hard injection spectrum ($\sim
E^{-1}$) due to pulsar spin down and a maximum energy $E_{\rm max} \sim Z \,
10^{19}$ eV due to the limit on the spin rate of neutron stars. We have
previously shown that the escape through the young supernova remnant softens
the spectrum, decreases slightly the maximum energy, and generates secondary
nuclei. Here we show that the distribution of pulsar birth periods and the
effect of propagation in the interstellar and intergalactic media modifies the
combined spectrum of all pulsars. By assuming a normal distribution of pulsar
birth periods centered at 300 ms, we show that the contribution of
extragalactic pulsar births to the ultrahigh energy cosmic ray spectrum
naturally gives rise to a contribution to very high energy cosmic rays (VHECRs,
between $10^{16}$ and $10^{18}$ eV) by Galactic pulsar births. The required
injected composition to fit the observed spectrum depends on the absolute
energy scale, which is uncertain, differing between Auger Observatory and
Telescope Array. The contribution of Galactic pulsar births can also bridge the
gap between predictions for cosmic ray acceleration in supernova remnants and
the observed spectrum just below the ankle, depending on the composition of the
cosmic rays that escape the supernova remnant and the diffusion behavior of
VHECRs in the Galaxy.


title: Decay of correlations for normally hyperbolic trapping

abstract:
  We prove that for evolution problems with normally hyperbolic trapping in
phase space, correlations decay exponentially in time. Normal hyperbolic
trapping means that the trapped set is smooth and symplectic and that the flow
is hyperbolic in directions transversal to it. Flows with this structure
include contact Anosov flows, classical flows in molecular dynamics, and null
geodesic flows for black holes metrics.
  The decay of correlations is a consequence of the existence of resonance free
strips for Green's functions (cut-off resolvents) and polynomial bounds on the
growth sof those functions in the semiclassical parameter.


title: Electro-optical switching by liquid-crystal controlled metasurfaces

abstract:
  We study the optical response of a metamaterial surface created by a lattice
of split-ring resonators covered with a nematic liquid crystal and demonstrate
millisecond timescale switching between electric and magnetic resonances of the
metasurface. This is achieved due to a high sensitivity of liquid-crystal
molecular reorientation to the symmetry of the metasurface as well as to the
presence of a bias electric field. Our experiments are complemented by
numerical simulations of the liquid-crystal reorientation.


title: The 2013 Release of Cloudy

abstract:
  This is a summary of the 2013 release of the plasma simulation code Cloudy.
Cloudy models the ionization, chemical, and thermal state of material that may
be exposed to an external radiation field or other source of heating, and
predicts observables such as emission and absorption spectra. It works in terms
of elementary processes, so is not limited to any particular temperature or
density regime. This paper summarizes advances made since the last major review
in 1998. Much of the recent development has emphasized dusty molecular
environments, improvements to the ionization / chemistry solvers, and how
atomic and molecular data are used. We present two types of simulations to
demonstrate the capability of the code. We consider a molecular cloud
irradiated by an X-ray source such as an Active Nucleus and show how treating
EUV recombination lines and the full SED affects the observed spectrum. A
second example illustrates the very wide range of particle and radiation
density that can be considered.


title:
Gravitational self-force in the ultra-relativistic limit: The 'large-N'
  expansion

abstract:
  We study the gravitational self-force using the effective field theory
formalism. We show that in the ultra-relativistic limit \gamma \to \infty, with
\gamma the boost factor, many simplifications arise. Drawing parallels with the
large N limit in quantum field theory, we introduce the parameter 1/N =
1/\gamma^2 and show that the effective action admits a well defined expansion
in powers of \lambda = N\epsilon, at each order in 1/N, where \epsilon = E_m/M
and E_m=\gamma m is the (kinetic) energy of the small mass. Moreover, we show
that diagrams with nonlinear bulk interactions first enter at O(\lambda^2/N^2)
and only diagrams with nonlinearities in the worldline couplings, which are
significantly easier to compute, survive in the large N/ultra-relativistic
limit. Finally, we derive the self-force to O(\lambda^4/N) and provide
expressions for some conservative quantities for circular orbits.

categories: gr-qc astro-ph.CO astro-ph.HE hep-ph hep-th


title: A connection between filter stabilization and eddy viscosity models

abstract:
  Recently, a new approach for the stabilization of the incompressible
Navier-Stokes equations for higher Reynolds numbers was introduced based on the
nonlinear differential filtering of solutions on every time step of a discrete
scheme. In this paper, the stabilization is shown to be equivalent to a certain
eddy-viscosity model in LES. This allows a refined analysis and further
understanding of desired filter properties. We also consider the application of
the filtering in a projection (pressure correction) method, the standard
splitting algorithm for time integration of the incompressible fluid equations.
The paper proves an estimate on the convergence of the filtered numerical
solution to the corresponding DNS solution.


title: Triangulations, orientals, and skew monoidal categories

abstract:
  A concrete model of the free skew-monoidal category Fsk on a single
generating object is obtained. The situation is clubbable in the sense of G.M.
Kelly, so this allows a description of the free skew-monoidal category on any
category. As the objects of Fsk are meaningfully bracketed words in the skew
unit I and the generating object X, it is necessary to examine bracketings and
to find the appropriate kinds of morphisms between them. This leads us to
relationships between triangulations of polygons, the Tamari lattice, left and
right bracketing functions, and the orientals. A consequence of our description
of Fsk is a coherence theorem asserting the existence of a strictly
structure-preserving faithful functor from Fsk to the skew-monoidal category of
finite non-empty ordinals and first-element-and-order-preserving functions.
This in turn provides a complete solution to the word problem for skew monoidal
categories.


title:
Termhood-based Comparability Metrics of Comparable Corpus in Special
  Domain

abstract:
  Cross-Language Information Retrieval (CLIR) and machine translation (MT)
resources, such as dictionaries and parallel corpora, are scarce and hard to
come by for special domains. Besides, these resources are just limited to a few
languages, such as English, French, and Spanish and so on. So, obtaining
comparable corpora automatically for such domains could be an answer to this
problem effectively. Comparable corpora, that the subcorpora are not
translations of each other, can be easily obtained from web. Therefore,
building and using comparable corpora is often a more feasible option in
multilingual information processing. Comparability metrics is one of key issues
in the field of building and using comparable corpus. Currently, there is no
widely accepted definition or metrics method of corpus comparability. In fact,
Different definitions or metrics methods of comparability might be given to
suit various tasks about natural language processing. A new comparability,
namely, termhood-based metrics, oriented to the task of bilingual terminology
extraction, is proposed in this paper. In this method, words are ranked by
termhood not frequency, and then the cosine similarities, calculated based on
the ranking lists of word termhood, is used as comparability. Experiments
results show that termhood-based metrics performs better than traditional
frequency-based metrics.


title: Complex networks analysis of language complexity

abstract:
  Methods from statistical physics, such as those involving complex networks,
have been increasingly used in quantitative analysis of linguistic phenomena.
In this paper, we represented pieces of text with different levels of
simplification in co-occurrence networks and found that topological regularity
correlated negatively with textual complexity. Furthermore, in less complex
texts the distance between concepts, represented as nodes, tended to decrease.
The complex networks metrics were treated with multivariate pattern recognition
techniques, which allowed us to distinguish between original texts and their
simplified versions. For each original text, two simplified versions were
generated manually with increasing number of simplification operations. As
expected, distinction was easier for the strongly simplified versions, where
the most relevant metrics were node strength, shortest paths and diversity.
Also, the discrimination of complex texts was improved with higher hierarchical
network metrics, thus pointing to the usefulness of considering wider contexts
around the concepts. Though the accuracy rate in the distinction was not as
high as in methods using deep linguistic knowledge, the complex network
approach is still useful for a rapid screening of texts whenever assessing
complexity is essential to guarantee accessibility to readers with limited
reading ability


title: Search for Supersymmetry with Like-Sign Lepton-Tau Events at CDF

abstract:
  We present a search for chargino-neutralino associated production using like
electric charge dilepton events collected by the CDF II detector at the
Fermilab Tevatron in proton-antiproton collisions at $\sqrt{s} = 1.96$ TeV. One
lepton is identified as the hadronic decay of a tau lepton, while the other is
an electron or muon. In data corresponding to 6.0 fb$^{-1}$ of integrated
luminosity, we obtain good agreement with standard model predictions, and set
limits on the chargino-neutralino production cross section for simplified
gravity- and gauge-mediated models. As an example, assuming that the chargino
and neutralino decays to taus dominate, in the simplified gauge-mediated model
we exclude cross sections greater than 300 fb at 95% credibility level for
chargino and neutralino masses of 225 \gevcc. This analysis is the first to
extend the LHC searches for electroweak supersymmetric production of gauginos
to high $\tan\beta$ and slepton next-to-lightest supersymmetric particle
scenarios.


title: Bilingual Terminology Extraction Using Multi-level Termhood

abstract:
  Purpose: Terminology is the set of technical words or expressions used in
specific contexts, which denotes the core concept in a formal discipline and is
usually applied in the fields of machine translation, information retrieval,
information extraction and text categorization, etc. Bilingual terminology
extraction plays an important role in the application of bilingual dictionary
compilation, bilingual Ontology construction, machine translation and
cross-language information retrieval etc. This paper addresses the issues of
monolingual terminology extraction and bilingual term alignment based on
multi-level termhood.
  Design/methodology/approach: A method based on multi-level termhood is
proposed. The new method computes the termhood of the terminology candidate as
well as the sentence that includes the terminology by the comparison of the
corpus. Since terminologies and general words usually have differently
distribution in the corpus, termhood can also be used to constrain and enhance
the performance of term alignment when aligning bilingual terms on the parallel
corpus. In this paper, bilingual term alignment based on termhood constraints
is presented.
  Findings: Experiment results show multi-level termhood can get better
performance than existing method for terminology extraction. If termhood is
used as constrain factor, the performance of bilingual term alignment can be
improved.


title: Modified Hamilton formalism for fields

abstract:
  In Hamiltonian mechanics the equations of motion may be considered as a
condition on the tangent vectors to the solution; they should be null-vectors
of the symplictic structure. Usually the formalism for the field case is done
by replacing the finite dimensional configuration space by an infinite
dimensional one. In the present paper we work in worldsheet-targetspace
formalism. The null-vectors of symplectic 2-form are replaced by
null-polyvectors of a higher rank form on a finite dimensional manifold. The
action in this case is an integral of a differential form over a surface in
phase space. The method to obtain such a description from the Lagrange
formalism generalizes the Legendre transformation. The requirement for this
transformation to preserve the value of the action and its extremality leads to
a natural definition of this procedure.


title: Standard multipartitions and a combinatorial affine Schur-Weyl duality

abstract:
  We introduce the notion of standard multipartitions and establish a
one-to-one correspondence between standard multipartitions and irreducible
representations with integral weights for the affine Hecke algebra of type A
with a parameter q which is not a root of unity. We then extend the
correspondence to all Kleshchev multipartitions for Ariki-Koike algebras of
integral type. By the affine Schur--Weyl duality, we further extend this to a
correspondence between standard multipartitions and Drinfeld multipolynomials
of integral type whose associated irreducible polynomial representations
completely determine all irreducible polynomial representations for the quantum
loop algebra. We will see, in particular, the notion of standard
multipartitions gives rise to a combinatorial description of the affine
Schur--Weyl duality in terms of a column-reading vs. row reading of residues of
a multipartition.


title: Time delay in valence shell photoionization of noble gas atoms

abstract:
  We use the non-relativistic random phase approximation with exchange to
perform calculations of valence shell photoionization of Ne, Ar, Kr and Xe from
their respective thresholds to photon energy of 200 eV. The energy derivative
of the complex phase of the photoionization matrix elements is converted to the
photoelectron group delay that can be measured in attosecond streaking or
two-photon transitions interference experiments. Comparison with reported time
delay measurements in Ne and Ar at a few selected photon energies is made.
Systematic mapping of time delay across a wide range of photon energies in
several atomic targets allows to highlight important aspects of fundamental
atomic physics that can be probed by attosecond time delay measurements.


title: Is $J^{PC}=3^{-+}$ molecule possible?

abstract:
  The confirmation of charged charmonium-like states indiates that heavy quark
molecules should exist. We here discuss the possibility of a molecule state
with $J^{PC}=3^{-+}$. In a one-boson-exchange model investigation for the S
wave $C=+$ $D^*\bar{D}_2^*$ states, one finds that the strongest attraction is
in the case $J=3$ and $I=0$ for both $\pi$ and $\sigma$ exchanges. Numerical
analysis indicates that this hadronic bound state might exist if a
phenomenological cutoff parameter around 2.3 GeV (1.5 GeV) is reasonable with a
dipole (monopole) type form factor in the one-pion-exchange model. The cutoff
for binding solutions may be reduced to a smaller value once the $\sigma$
exchange contribution is included. If a state around the $D^*\bar{D}_2^*$
threshold ($\approx$4472 MeV) in the channel $J/\psi\omega$ (P wave) is
observed, the heavy quark spin symmetry implies that it is not a $c\bar{c}$
meson and the $J^{PC}$ are likely to be $3^{-+}$.


title: Calculation of the determinant in the Wheeler-De Witt equation

abstract:
  The Riemann-zeta function regularization procedure has been studied
intensively as a good method in the computation of the determinant for
pseudo-diferential operator. In this paper we propose a different approach for
the computation of the determinant base on the Wheeler-De Witt equation.


title:
A family of Alltop functions that are EA-inequivalent to the cubic
  function

abstract:
  Sequences with optimal correlation properties are much sought after for
applications in communication systems. In 1980, Alltop (IEEE Trans. Inf. Theory
26(3):350-354, 1980) described a set of sequences based on a cubic function and
showed that these functions were optimal with respect to known bounds on auto
and crosscorrelation. Subsequently these sequences were used to construct
mutually unbiased bases, a structure of importance in quantum information
theory. The key feature of this cubic function is that its difference function
is a planar function. Functions with planar difference functions have been
called \emph{Alltop functions}. This paper provides a new family of Alltop
functions and establishes the use of Alltop functions for construction of
sequence sets and MUBs.


title: I-Love-Q

abstract:
  Neutron stars and quark stars are not only characterized by their mass and
radius, but also by how fast they spin, through their moment of inertia, and
how much they can be deformed, through their Love number and quadrupole moment.
These depend sensitively on the star's internal structure, and thus on unknown
nuclear physics. We find universal relations between the moment of inertia, the
Love number and the quadrupole moment that are independent of the neutron
star's and quark star's internal structure. These can be used to learn about
the deformability of these compact objects through observations of the moment
of inertia, break degeneracies in gravitational wave detection to measure spin
in binary inspirals and test General Relativity in a nuclear-structure
independent fashion.


title: The Alexandrov-Toponogov comparison theorem for radial curvature

abstract:
  We discuss the Alexandrov-Toponogov comparison theorem under the conditions
of radial curvature of a pointed manifold (M,o) with reference surface of
revolution. There are two obstructions to make the comparison theorem for a
triangle one of whose vertices is a base point o. One is the cut points of
another vertex of a comparison triangle in the reference surface of revolution.
The other is the cut points of the base point o in M. We find a condition under
which the omparison theorem is valid for any geodesic triangle with a vertex at
o in M.


title:
Giant conductance and phase time anomalous events of hole quantum
  transport

abstract:
  Events of giant conductance and anomalies of the phase transmission time for
holes, are theoretically investigated within the multicomponent scattering
approach. Based on this model, new analytical expressions for unitarity
relations in the uncoupled hole transport are obtained and directly applied to
study the behavior of the conductance and the phase transmission time in a
double barrier resonant tunneling (DBRT) and a superlattice $GaAs$-cladding
layer$/(AlAs/GaAs)^{n}/GaAs$-cladding layer. Clear-signature evidences of giant
conductance phenomena for hole transmission without valence-band mixing through
a DBRT and a superlattice were found. The giant conductance effect losses
robustness by manipulating the number of superlattice layers and by including
the valence-band particles coupling as well. Phase time through the
heterostructure exhibits extremal dependencies in the gaps and in the barriers,
as those reported before for electrons. We have detected an earlier arrival
phase time for the propagation of both flavors of holes within the barrier, in
the order of few tenths of picoseconds. An appealing filter-like effect is
presented, whenever a selective confinement strength arises independently for
both flavors of holes in the uncoupled regime. Our results also prescribe
noticeable evidences for both uncoupled and coupled hole fluxes, similar to
those foretold by Hartman, upon transmission of electrons through opaque
barriers.


title: An Algorithm for constructing Hjelmslev planes

abstract:
  Projective Hjelmslev planes and Affine Hjelmselv planes are generalisations
of projective planes and affine planes. We present an algorithm for
constructing a projective Hjelmslev planes and affine Hjelsmelv planes using
projective planes, affine planes and orthogonal arrays. We show that all
2-uniform projective Hjelmslev planes, and all 2-uniform affine Hjelsmelv
planes can be constructed in this way. As a corollary it is shown that all
2-uniform Affine Hjelmselv planes are sub-geometries of 2-uniform projective
Hjelmselv planes.


title:
Observations of the D/H ratio in Methane in the atmosphere of Saturn's
  moon, Titan - where did the Saturnian system form?

abstract:
  The details of the Solar system's formation are still heavily debated.
Questions remain about the formation locations of the giant planets, and the
degree to which volatile material was mixed throughout the proto-planetary
system. One diagnostic which offers great promise in helping to unravel the
history of planet formation is the study of the level of deuteration in various
Solar system bodies. For example, the D/H ratio of methane in the atmosphere of
Titan can be used as a diagnostic of the initial conditions of the solar nebula
within the region of giant planet formation, and can help us to determine where
Titan (and, by extension, the Saturnian system) accreted its volatile material.
The level of Titanian deuteration also has implications for both the sources
and long term evolution of Titan's atmospheric composition. We present the
results of observations taken in the 1.58 microns window using the NIFS
spectrometer on the Gemini telescope, and model our data using the VSTAR
line--by--line transfer model, which yields a D/H ratio for Titan's atmosphere
of 143+/-16) x 10^{-6} [1]. We are currently in the process of modeling the
Gemini high resolution GNIRS spectra using new sets of line parameters derived
for methane in the region between 1.2-1.7 microns [2].


title:
On the use of topological features and hierarchical characterization for
  disambiguating names in collaborative networks

abstract:
  Many features of complex systems can now be unveiled by applying statistical
physics methods to treat them as social networks. The power of the analysis may
be limited, however, by the presence of ambiguity in names, e.g., caused by
homonymy in collaborative networks. In this paper we show that the ability to
distinguish between homonymous authors is enhanced when longer-distance
connections are considered, rather than looking at only the immediate neighbors
of a node in the collaborative network. Optimized results were obtained upon
using the 3rd hierarchy in connections. Furthermore, reasonable distinction
among authors could also be achieved upon using pattern recognition strategies
for the data generated from the topology of the collaborative network. These
results were obtained with a network from papers in the arXiv repository, into
which homonymy was deliberately introduced to test the methods with a
controlled, reliable dataset. In all cases, several methods of supervised and
unsupervised machine learning were used, leading to the same overall results.
The suitability of using deeper hierarchies and network topology was confirmed
with a real database of movie actors, with the additional finding that the
distinguishing ability can be further enhanced by combining topology features
and long-range connections in the collaborative network.


title: Coupling of two Dirac particles

abstract:
  A study of the formation of excitons as a problem of two Dirac particles in a
gapped graphene layer and in two gapped graphene layers separated by a
dielectric is presented. In the low energy limit the separation of the
center-of-mass and relative motions is obtained. Analytical solutions for the
wave function and energy dispersion for both cases when electron and hole
interact via a Coulomb potential are found. It is shown that the energy
spectrum and the effective exciton mass are functions of the energy gaps as
well as interlayer separation in case of two layer gapped graphene.


title: More symmetric polynomials related to p-norms

abstract:
  It is known that the elementary symmetric polynomials $e_k(x)$ have the
property that if $ x, y \in [0,\infty)^n$ and $e_k(x) \leq e_k(y)$ for all $k$,
then $||x||_p \leq ||y||_p$ for all real $0\leq p \leq 1$, and moreover
$||x||_p \geq ||y||_p$ for $1\leq p \leq 2$ provided $||x||_1 =||y||_1$.
Previously the author proved this kind of property for $p>2$, for certain
polynomials $F_{k,r}(x)$ which generalize the $e_k(x)$. In this paper we give
two additional generalizations of this type, involving two other families of
polynomials. When $x$ consists of the eigenvalues of a matrix $A$, we give a
formula for the polynomials in terms of the entries of $A$, generalizing sums
of principal $k \times k$ subdeterminants.


title: Classical Model for Jellium

abstract:
  A simple, practical model for computing the equilibrium thermodynamics and
structure of jellium by classical strong coupling methods is proposed. An
effective pair potential and coupling constant are introduced, incorporating
the ideal gas, low density, and weak coupling quantum limits. The resulting
parameter free, analytic model is illustrated by the calculation of the pair
correlation function over a wide range of temperatures and densities via strong
coupling classical liquid state theory. The results compare favorably with the
first finite temperature restricted path integral Monte Carlo simulations
reported recently.


title:
Photoemission Imaging of 3D Fermi Surface Pairing at the Hidden Order
  Transition in URu2Si2

abstract:
  We report angle-resolved photoemission spectroscopy (ARPES) experiments
probing deep into the hidden order (HO) state of URu2Si2, utilizing tunable
photon energies with sufficient energy and momentum resolution to detect the
near Fermi surface (FS) behavior. Our results reveal: (i) the full itinerancy
of the 5f electrons; (ii) the crucial three-dimensional (3D) k-space nature of
the FS and its critical nesting vectors, in good comparison with
density-functional theory calculations, and (iii) the existence of hot-spot
lines and pairing of states at the FS, leading to FS gapping in the HO phase.


title:
Quantitative connection between the nanoscale electronic inhomogeneity
  and the pseudogap of Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ superconductors

abstract:
  We have found a quantitative connection between the evolution of the
inhomogeneous nanoscale electronic gaps (INSEG) state detected in
Bi$_2$Sr$_2$CaCu$_2$O$_{8+\delta}$ by scanning tunneling
microscopy/spectroscopy (STM/S) and the two universal, the upper and the lower,
pseudogaps in high-temperature cuprate superconductors (HTCS). When the doping
and temperature dependent INSEG map were analyzed by using our proposed
hole-scale, we find that the two pseudogaps are connected to two specific
coverages of the CuO$_2$ plane by INSEG: the 50\% and 100\% coverages of the
CuO$_2$ planes by INSEG correspond to the upper and lower pseudogaps,
respectively. This quantitative connection to the two pseudogaps indicates that
the origin of the measured pseudogap energies and temperatures are intimately
related to the geometrical coverage of the CuO$_2$ planes by the INSEG state.
We find that INSEG and superconductivity coexist in the underdoped to the
overdoped regimes. We suggest that pseudogap states are microscopically
inhomogeneous and 100\% coverage of the CuO$_2$ planes by the INSEG is a
necessary condition for the high-$T_c$ superconductivity.


title:
An Approach Of Substitution Method Based On ASCII Codes In Encryption
  Technique

abstract:
  In poly alphabetic substitution the plain texts letters are enciphered
differently according to their position. The name poly alphabetic suggests that
there are more than one key so we have used two keys combination instead of
just one, in order to produce the cipher text. We can also use three or more
keys to make the enciphering process more complicated. In this paper have
produced ASCII Codes of the plain text and then we have reversed it said
reverse ASCII Codes and then we have generated two keys K1 is generated by
addition of reverse ASCII Codes and K2 is generated by addition of ASCII Codes.
Then these K1 and K2 Keys are alternatively applied on Reverse ASCII codes in
order to produce cipher text. On the Destination hand Deciphering is used to
produce the plain text again. Our technique generates random cipher text for
the same plain text and this is the major advantage of our technique.


title:
Study on the Energy Dependence of the Radii of Jets by the HBT
  Correlation Method in e+e- collisions

abstract:
  The energy dependence of the radii size of jets are studied in detail by the
HBT correlation method using Monte Carlo Simulation generator Jetset7.4 to
produce 40,000,000 events of e$^+$e$^-$ collisions at $\sqrt s =30$, 50, 70,
91.2, 110, 130, 150 and 170 GeV. The radii of jets are measured using the HBT
correlation method with the indistinguishability of identical final state
pions. It is found that the average radii of quark-jets and gluon-jets are
independent of the c.m. energy of e$^+$e$^-$ collisions. The average radius of
quark-jets are obviously larger than that of gluon-jets. The invariable average
radii of quark-jets and gluon-jets in e$^+$e$^-$ collisions are obtained at the
end of parton evolvement.


title:
Possible uniform-flux chiral spin liquid states in the SU(3)
  ring-exchange model on the triangular lattice

abstract:
  We consider a SU(3) model with antiferromagnetic three-site ring exchanges,
in addition to two-site exchanges, on the triangular lattice. We first present
numerical site-factorized state studies on the magnetic ordered states, which
shows two different three-sublattice-ordered states, the antiferro-quadrupolar
phase and the standard 120^o anti-ferromagnetic phase, along the axis of the
strength of the three-site ring exchanges. We further study the model using
slave-fermion mean field approaches in which we rewrite the exchange operators
in terms of three flavors of fermions. At the mean-field level, we find the
main competing trial states are the trimer state (triangular plaquette state),
gapped uniform \pi/3-flux chiral spin liquid, and gapped uniform 2\pi/3-flux
chiral spin liquid. The filled band of the \pi/3-flux chiral spin liquid has
Chern number +1, and that of the 2\pi/3-flux chiral spin liquid has Chern
number +2. We also give the effective Chern-Simons theory for each chiral spin
liquid at the mean-field level.


title: Discrete gradient methods have an energy conservation law

abstract:
  We show for a variety of classes of conservative PDEs that discrete gradient
methods designed to have a conserved quantity (here called energy) also have a
time-discrete conservation law. The discrete conservation law has the same
conserved density as the continuous conservation law, while its flux is found
by replacing all derivatives of the conserved density appearing in the
continuous flux by discrete gradients.


title:
Engineering three-dimensional topological insulators in Rashba-type
  spin-orbit coupled heterostructures

abstract:
  Topological insulators represent a new class of quantum phase defined by
invariant symmetries and spin-orbit coupling that guarantees metallic Dirac
excitations at its surface. The discoveries of these states have sparked the
hope of realizing nontrivial excitations and novel effects such as a
magnetoelectric effect and topological Majorana excitations. Here we develop a
theoretical formalism to show that a three dimensional topological insulator
can be designed artificially via stacking bilayers of two-dimensional Fermi
gases with opposite Rashba-type spin-orbit coupling on adjacent layers, and
with inter-layer quantum tunneling. We demonstrate that in the stack of
bilayers grown along a (001)-direction, a nontrivial topological phase
transition occurs above a critical number of Rashba-bilayers. In the
topological phase we find the formation of a single spin-polarized Dirac cone
at the $\Gamma$-point. This approach offers an accessible way to design
artificial topological insulators in a set up that takes full advantage of the
atomic layer deposition approach. This design principle is tunable and also
allows us to bypass limitations imposed by bulk crystal geometry.


title:
Magnetoelectric susceptibility tensor of multiferroic TbMnO3 with
  cycloidal antiferromagnetic structure in external field

abstract:
  Magnetoelectric, dielectric and magnetic susceptibility tensors of
multiferroic TbMnO3 with cycloidal antiferromagnetic structure in external
electric and magnetic fields have been investigated with taking into account
dynamics of spin, electro-dipole and acoustic subsystems. All components of
tensors depend on values of external electric and magnetic fields. The
possibility of control of electrodynamic properties of multiferroic TbMnO3 with
cycloidal antiferromagnetic structure by external electric and magnetic fields
has been shown. The resonant interaction of spin, electro-dipole,
electromagnetic and acoustic waves in such material is observed.


title: Bilayer Protograph Codes for Half-Duplex Relay Channels

abstract:
  Despite encouraging advances in the design of relay codes, several important
challenges remain. Many of the existing LDPC relay codes are tightly optimized
for fixed channel conditions and not easily adapted without extensive
re-optimization of the code. Some have high encoding complexity and some need
long block lengths to approach capacity. This paper presents a high-performance
protograph-based LDPC coding scheme for the half-duplex relay channel that
addresses simultaneously several important issues: structured coding that
permits easy design, low encoding complexity, embedded structure for convenient
adaptation to various channel conditions, and performance close to capacity
with a reasonable block length. The application of the coding structure to
multi-relay networks is demonstrated. Finally, a simple new methodology for
evaluating the end-to-end error performance of relay coding systems is
developed and used to highlight the performance of the proposed codes.


title:
Positive energy theorem for (4+1)-dimensional asymptotically anti-de
  Sitter spacetimes

abstract:
  We define the total energy-momenta for (4+1)-dimensional asymptotically
anti-de Sitter spacetimes, and prove the positive energy theorem for such
spacetimes.


title:
Worst-case amplification of disturbances in inertialess Couette flow of
  viscoelastic fluids

abstract:
  Amplification of deterministic disturbances in inertialess shear-driven
channel flows of viscoelastic fluids is examined by analyzing the frequency
responses from spatio-temporal body forces to the velocity and polymer stress
fluctuations. In strongly elastic flows, we show that disturbances with large
streamwise length scales may be significantly amplified even in the absence of
inertia. For fluctuations without streamwise variations, we derive explicit
analytical expressions for the dependence of the worst-case amplification (from
different forcing to different velocity and polymer stress components) on the
Weissenberg number ($We$), the maximum extensibility of the polymer chains
($L$), the viscosity ratio, and the spanwise wavenumber. For the Oldroyd-B
model, the amplification of the most energetic components of velocity and
polymer stress fields scales as $We^2$ and $We^4$. On the other hand, finite
extensibility of polymer molecules limits the largest achievable amplification
even in flows with infinitely large Weissenberg numbers: in the presence of
wall-normal and spanwise forces the amplification of the streamwise velocity
and polymer stress fluctuations is bounded by quadratic and quartic functions
of $L$. This high amplification signals low robustness to modeling
imperfections of inertialess channel flows of viscoelastic fluids. The
underlying physical mechanism involves interactions of polymer stress
fluctuations with a base shear, and it represents a close analog of the lift-up
mechanism that initiates a bypass transition in inertial flows of Newtonian
fluids.


title:
A Genetic Algorithm for Power-Aware Virtual Machine Allocation in
  Private Cloud

abstract:
  Energy efficiency has become an important measurement of scheduling algorithm
for private cloud. The challenge is trade-off between minimizing of energy
consumption and satisfying Quality of Service (QoS) (e.g. performance or
resource availability on time for reservation request). We consider resource
needs in context of a private cloud system to provide resources for
applications in teaching and researching. In which users request computing
resources for laboratory classes at start times and non-interrupted duration in
some hours in prior. Many previous works are based on migrating techniques to
move online virtual machines (VMs) from low utilization hosts and turn these
hosts off to reduce energy consumption. However, the techniques for migration
of VMs could not use in our case. In this paper, a genetic algorithm for
power-aware in scheduling of resource allocation (GAPA) has been proposed to
solve the static virtual machine allocation problem (SVMAP). Due to limited
resources (i.e. memory) for executing simulation, we created a workload that
contains a sample of one-day timetable of lab hours in our university. We
evaluate the GAPA and a baseline scheduling algorithm (BFD), which sorts list
of virtual machines in start time (i.e. earliest start time first) and using
best-fit decreasing (i.e. least increased power consumption) algorithm, for
solving the same SVMAP. As a result, the GAPA algorithm obtains total energy
consumption is lower than the baseline algorithm on simulated experimentation.


title:
Uncertainty Relations and Quantum Effects of Constraints in Chern-Simons
  Theory

abstract:
  It is well known that Chern-Simons Theories are in the constrained systems
and their total Hamiltonians become identically zero, because of their gauge
invariance. While treating the constraints quantum mechanially, it will be
expected taht there remain the quantum fluctuations due to the uncertainty
principle. Using the projection operator method (POM) and the theory of
dynamical constraints, such fluctuation terms are systematically derived in the
case of Abelian Chern-Simons theory. It is shown that these terms produce the
effective mass in the complex scalar fields coupled to the CS fields.


title:
Higher comparison maps for the spectrum of a tensor triangulated
  category

abstract:
  For each object in a tensor triangulated category, we construct a natural
continuous map from the object's support---a closed subset of the category's
triangular spectrum---to the Zariski spectrum of a certain commutative ring of
endomorphisms. When applied to the unit object this recovers a construction of
P. Balmer. These maps provide an iterative approach for understanding the
spectrum of a tensor triangulated category by starting with the comparison map
for the unit object and iteratively analyzing the fibers of this map via
"higher" comparison maps. We illustrate this approach for the stable homotopy
category of finite spectra. In fact, the same underlying construction produces
a whole collection of new comparison maps, including maps associated to (and
defined on) each closed subset of the triangular spectrum. These latter maps
provide an alternative strategy for analyzing the spectrum by iteratively
building a filtration of closed subsets by pulling back filtrations of affine
schemes.


title:
Real-time manifestation of strongly coupled spin and charge order
  parameters in stripe-ordered nickelates via time-resolved resonant x-ray
  diffraction

abstract:
  We investigate the order parameter dynamics of the stripe-ordered nickelate,
La$_{1.75}$Sr$_{0.25}$NiO$_4$, using time-resolved resonant X-ray diffraction.
In spite of distinct spin and charge energy scales, the two order parameters'
amplitude dynamics are found to be linked together due to strong coupling.
Additionally, the vector nature of the spin sector introduces a longer
re-orientation time scale which is absent in the charge sector. These findings
demonstrate that the correlation linking the symmetry-broken states does not
unbind during the non-equilibrium process, and the time scales are not
necessarily associated with the characteristic energy scales of individual
degrees of freedom.