title:
Legendrian contact homology in the boundary of a subcritical Weinstein
  4-manifold

abstract:
  We give a combinatorial description of the Legendrian contact homology
algebra associated to a Legendrian link in $S^1\times S^2$ or any connected sum
$\#^k(S^1\times S^2)$, viewed as the contact boundary of the Weinstein manifold
obtained by attaching 1-handles to the 4-ball. In view of the surgery formula
for symplectic homology, this gives a combinatorial description of the
symplectic homology of any 4-dimensional Weinstein manifold (and of the
linearized contact homology of its boundary). We also study examples and
discuss the invariance of the Legendrian homology algebra under deformations,
from both the combinatorial and the analytical perspectives.


title:
NLO QCD corrections to Higgs boson production in association with a top
  quark pair and a jet

abstract:
  We present the calculation of the cross section for Higgs boson production in
association with a top quark pair plus one jet, at next-to-leading-order (NLO)
accuracy in QCD. All mass dependence is retained without recurring to any
approximation. After including the complete NLO QCD corrections, we observe a
strong reduction in the scale dependence of the result. We also show
distributions for the invariant mass of the top quark pair, with and without
the additional jet, and for the transverse momentum and the pseudorapidity of
the Higgs boson. Results for the virtual contributions are obtained with a
novel reduction approach based on integrand decomposition via Laurent
expansion, as implemented in the library Ninja. Cross sections and differential
distributions are obtained with an automated setup which combines the GoSam and
Sherpa frameworks.


title: Effective Gravity and Homogeneous Solutions

abstract:
  Near the singularity, gravity should be modified to an effective theory, in
the same sense as with the Euler-Heisenberg electrodynamics. This effective
gravity surmounts to higher derivative theory, and as is well known, a much
more reacher theory concerning the solution space. On the other hand, as a
highly non linear theory, the understanding of this solution space must go
beyond the linearized approach. In this talk we will present some results
previously published by collaborators and myself, concerning solutions for
vacuum spatially homogenous cases of Bianchi types $I$ and $VII_A$. These are
the anisotropic generalizations of the cosmological spatially "flat", and
"open" models respectively. The solutions present isotropisation in a weak
sense depending on the initial condition. Also, depending on the initial
condition, singular solutions are obtained.


title:
Cases of equality in certain multilinear inequalities of
  Hardy-Riesz-Brascamp-Lieb-Luttinger type

abstract:
  Certain rearrangement inequalities of a type considered by Hardy, Riesz, and
Brascamp-Lieb-Luttinger are studied. Subsets of the real line that extremize
these inequalities are characterized. Our results apply only to special cases,
and complement earlier results by Burchard treating other cases.
  This draft incorporates minor corrections and clarifications.


title: The Inner Kiloparsec of Mrk 273 with Keck Adaptive Optics

abstract:
  There is X-ray, optical, and mid-infrared imaging and spectroscopic evidence
that the late-stage ultraluminous infrared galaxy merger Mrk 273 hosts a
powerful active galactic nucleus (AGN). However, the exact location of the AGN
and the nature of the nuclei have been difficult to determine due to dust
obscuration and the limited wavelength coverage of available high-resolution
data. Here we present near-infrared integral-field spectra and images of the
nuclear region of Mrk 273 taken with OSIRIS and NIRC2 on the Keck II Telescope
with laser guide star adaptive optics. We observe three spatially resolved
components, and analyze the local molecular and ionized gas emission lines and
their kinematics. We confirm the presence of the hard X-ray AGN in the
southwest nucleus. In the north nucleus, we find a strongly rotating gas disk
whose kinematics indicate a central black hole of mass 1.04 +/- 0.1 x 10^9
Msun. The H2 emission line shows an increase in velocity dispersion along the
minor axis in both directions, and an increased flux with negative velocities
in the southeast direction; this provides direct evidence for a collimated
molecular outflow along the axis of rotation of the disk. The third spatially
distinct component appears to the southeast, 640 and 750 pc from the north and
southwest nuclei, respectively. This component is faint in continuum emission
but shows several strong emission line features, including [Si vi] 1.964 {\mu}m
which traces an extended coronal-line region. The geometry of the [Si vi]
emission combined with shock models and energy arguments suggest that [Si vi]
in the southeast component must be at least partly ionized by the SW AGN or a
putative AGN in the northern disk, either through photoionization or through
shock-heating from strong AGN- and circumnuclear starburst-driven outflows.
This lends support to a scenario in which Mrk 273 may be a dual AGN system.


title:
A Vertical Resonance Heating Model for X- or Peanut-Shaped Galactic
  Bulges

abstract:
  We explore a second order Hamiltonian vertical resonance model for X-shaped
or peanut-shaped galactic bulges. The X-shape is caused by the 2:1 vertical
Lindblad resonance with the bar, with two vertical oscillation periods per
orbital period in the bar frame. We examine N-body simulations and find that
due to the bar slowing down and disk thickening during bar buckling, the
resonance and associated peanut-shape moves outward. The peanut-shape is
consistent with the location of the vertical resonance, independent of whether
the bar buckled or not. We estimate the resonance width from the potential m=4
Fourier component and find that the resonance is narrow, affecting orbits over
a narrow range in the angular momentum distribution, dL/L ~ 0.05. As the
resonance moves outward, stars originally in the mid plane are forced out of
the mid plane into orbits just within the resonance separatrix. The height of
the separatrix orbits, estimated from the Hamiltonian model, is approximately
consistent with the peanut-shape height. The X-shape is comprised of stars in
the vicinity of the resonance separatrix. The velocity distributions from the
simulations illustrate that low inclination orbits are depleted within
resonance. Within resonance, the vertical velocity distribution is broad,
consistent with resonant heating caused by the passage of the resonance through
the disk. In the Milky Way bulge we relate the azimuthally averaged mid-plane
mass density near the vertical resonance to the rotation curve and bar pattern
speed. At an estimated vertical resonance galactocentric radius of ~1.3 kpc, we
confirm a mid-plane density of ~5x10^8 Msol/kpc^3, consistent with recently
estimated mass distributions. We find that the rotation curve, bar pattern
speed, 2:1 vertical resonance location, X-shape tips, and mid-plane mass
density, are all self-consistent in the Milky Way galaxy bulge.


title:
The optimal constants in Holder-Brascamp-Lieb inequalities for discrete
  Abelian groups

abstract:
  The optimal constants are found for Lebesgue norm multilinear inequalities of
Holder-Brascamp-Lieb type for arbitrary discrete Abelian groups. Previously a
criterion for finiteness of the constants had been established for finitely
generated Abelian groups, and the optimal constant had been found in the
torsion-free case. The main step here is the analysis of finite groups.


title: SOFIA/FORCAST Imaging of the Circumnuclear Ring at the Galactic Center

abstract:
  We present 19.7, 31.5, and 37.1 {\mu}m images of the inner 6 pc of the
Galactic Center of the Milky Way with a spatial resolution of 3.2 - 4.6'' taken
by the Faint Object Infrared Camera on the Stratospheric Observatory for
Infrared Astronomy (SOFIA). The images reveal in detail the "clumpy" structure
of the Circumnuclear Ring (CNR)--the torus of hot gas and dust orbiting the
supermassive black hole at the Galactic Center with an inner radius of 1.4 pc.
The CNR exhibits features of a classic HII region: the dust emission at 19.7
{\mu}m closely traces the ionized gas emission observed in the radio while the
31.5 and 37.1 {\mu}m emission traces the photo-dissociation region beyond the
ionized gas. The 19.7/37.1 color temperature map reveals a radial temperature
gradient across the CNR with temperatures ranging from 65-85 K, consistent with
the prevailing paradigm in which the dust is centrally heated by the inner
cluster of hot, young stars. We produce a 37.1 {\mu}m intensity model of the
CNR with the derived geometric properties and find that it is consistent with
the observed 37.1 {\mu}m map of the CNR. Dense ($5 to 9 \times 10^{4} \,
\mathrm{cm}^{-3}$) clumps with a FWHM of ~0.15 pc exist along the inner edge of
the CNR and shadow the material deeper into the ring. The clumps are unlikely
to be long-lived structures since they are not dense enough to be stable
against tidal shear from the supermassive black hole.


title: pMSSM Studies at the 7, 8 and 14 TeV LHC

abstract:
  The 19/20-parameter p(henomenological)MSSM with either a neutralino or
gravitino LSP offers a flexible framework for the study of a wide variety of
R-parity conserving MSSM SUSY phenomena at the 7, 8 and 14 TeV LHC. Here we
present the results of a study of SUSY signatures at these facilities obtained
via a fast Monte Carlo 'replication' of the ATLAS SUSY analysis suite. In
particular, we show the ranges of the sparticle masses that are either
disfavored or remain viable after all of the various searches at the 7 and 8
TeV runs are combined. We then extrapolate to 14 TeV with both 300 fb^-1 and 3
ab^-1 of integrated luminosity and determine the sensitivity of a jets + MET
search to the pMSSM parameter space. We find that the high-luminosity LHC
performs extremely well in probing natural SUSY models.


title:
Photometric determination of the mass accretion rate of pre-main
  sequence stars. IV. Recent star formation in NGC 602

abstract:
  We have studied the young stellar populations in NGC 602, in the Small
Magellanic Cloud, using a novel method that we have developed to combine Hubble
Space Telescope photometry in the V, I, and Halpha bands. We have identified
about 300 pre-main sequence (PMS) stars, all of which are still undergoing
active mass accretion, and have determined their physical parameters (effective
temperature, luminosity, age, mass and mass accretion rate). Our analysis shows
that star formation has been present in this field over the last 60 Myr. In
addition, we can recognise at least two clear, distinct, and prominent episodes
in the recent past: one about 2 Myr ago, but still ongoing in regions of higher
nebulosity, and one (or more) older than 30 Myr, encompassing both stars
dispersed in the field and two smaller clusters located about 100 arcsec north
of the centre of NGC 602. The relative locations of younger and older PMS stars
do not imply a causal effect or triggering of one generation on the other. The
strength of the two episodes appears to be comparable, but the episode
occurring more than 30 Myr ago might have been even stronger than the current
one. We have investigated the evolution of the mass accretion rate M_acc as a
function of the stellar parameters finding that log M_acc ~ -0.6 log t + log m
+ c, where t is the age of the star, m its mass and c is a decreasing function
of the metallicity.


title: Pre-main sequence stars older than 8 Myr in the Eagle Nebula

abstract:
  Attention is given to a population of 110 stars in the NGC 6611 cluster of
the Eagle Nebula that have prominent near-infrared (NIR) excess and optical
colours typical of pre-main sequence (PMS) stars older than 8 Myr. At least
half of those for which spectroscopy exists have a Halpha emission line profile
revealing active accretion. In principle, the V-I colours of all these stars
would be consistent with those of young PMS objects (< 1 Myr) whose radiation
is heavily obscured by a circumstellar disc seen at high inclination and in
small part scattered towards the observer by the back side of the disc.
However, using theoretical models it is shown here that objects of this type
can only account for a few percent of this population. In fact, the spatial
distribution of these objects, their X-ray luminosities, their optical
brightness, their positions in the colour-magnitude diagram and the weak Li
absorption lines of the stars studied spectroscopically suggest that most of
them are at least 8 times older than the ~1 Myr-old PMS stars already known in
this cluster and could be as old as ~30 Myr. This is the largest homogeneous
sample to date of Galactic PMS stars considerably older than 8 Myr that are
still actively accreting from a circumstellar disc and it allows us to set a
lower limit of 7% to the disc frequency at ~16 Myr in NGC 6611. These values
imply a characteristic exponential lifetime of ~6 Myr for disc dissipation.


title: Solvable Leibniz Algebras with Heisenberg Nilradical

abstract:
  All solvable Lie algebras with Heisenberg nilradical have already been
classified. We extend this result to a classification of solvable Leibniz
algebras with Heisenberg nilradical. As an example, we show the complete
classification of all real or complex Leibniz algebras whose nilradical is the
3-dimensional Heisenberg algebra.


title: Rayleigh-Ritz variational method with suitable asymptotic behaviour

abstract:
  We discuss Rayleigh-Ritz variational calculations with nonorthogonal basis
sets that exhibit the correct asymptotic behaviour. We construct the suitable
basis sets for general one-dimensional models and illustrate the application of
the approach on two double-well oscillators proposed recently by other authors.
The rate of convergence of the variational method proves to be considerably
greater than the one exhibited by the recently developed orthogonal polynomial
projection quantization.


title:
Packetized Predictive Control for Rate-Limited Networks via Sparse
  Representation

abstract:
  We study a networked control architecture for linear time-invariant plants in
which an unreliable data-rate limited network is placed between the controller
and the plant input. The distinguishing aspect of the situation at hand is that
an unreliable data-rate limited network is placed between controller and the
plant input. To achieve robustness with respect to dropouts, the controller
transmits data packets containing plant input predictions, which minimize a
finite horizon cost function. In our formulation, we design sparse packets for
rate-limited networks, by adopting an an ell-0 optimization, which can be
effectively solved by an orthogonal matching pursuit method. Our formulation
ensures asymptotic stability of the control loop in the presence of bounded
packet dropouts. Simulation results indicate that the proposed controller
provides sparse control packets, thereby giving bit-rate reductions for the
case of memoryless scalar coding schemes when compared to the use of, more
common, quadratic cost functions, as in linear quadratic (LQ) control.


title: Hole Conductivity in Heterogeneous DNA Fragments

abstract:
  The characteristics of cation radical (hole) migration in heterogeneous DNA
were investigated on the basis of Kubo formula, in which correlation functions
were obtained from solutions of systems of Bogoliubov hierarchy. The cutting of
Bogoliubov hierarchy was carried out by excepting correlations of the third and
higher order. The obtained system of non-linear differential equations was
investigated both analytically and numerically. The environment polarization,
caused by interaction of holes with base pairs vibrations, was shown to play
the key role in transport processes. The energy of the interaction can ten-fold
exceed vibration energy. The transfer rate between adjacent DNA bases in
one-dimensional case was shown to be almost independent of the nature and
behavior of more distant pairs. The charge probability amplitude oscillates in
the picosecond timescale. Nonetheless, the rates of hole transfer, obtained by
averaging over these oscillations, turned out to be very close to the
experimental data. The calculated dependence of the hole transfer rate between
two guanine bases on the number of intervening adenine bases was also in good
agreement with the experimental data. Besides, the temperature dependence of
the transfer rate was investigated. Hopping mechanism was shown to make the
main contribution to the hole transport process at 300 K.


title: The Casimir Atomic Pendulum

abstract:
  We want to introduce an atomic pendulum whose driving force (torque) is due
to the quantum vacuum fluctuations. Applying the well-known Casimir-Polder
effect to a special configuration (a combined structure of an atomic nanostring
and a conducting plate), an atomic pendulum (Casimir atomic pendulum) is
designed. Using practically acceptable data corresponding to the already known
world of nanotechnology and based on reasonable/reliable numerical estimates,
the period of oscillation for the pendulum is computed. This pendulum can be
considered as both a new Micro (Nano)-Eelectromechanical system and a new
simple vacuum machine. Its design may be considered as a first step towards
realizing the visualized vacuum (Casimir) clock!


title:
Dirac bound state solutions of spherically ring-shaped q-deformed
  Woods-Saxon potential for any L-state

abstract:
  Approximate bound state solutions of the Dirac equation with -deformed
Woods-Saxon plus a new generalized ring-shaped potential are obtained for any
arbitrary L-state. The energy eigenvalue equation and corresponding
two-component wave function are calculated by solving the radial and angular
wave equations within a shortcut of the Nikiforov-Uvarov method. The solutions
of the radial and polar angular parts of the wave function are expressed in
terms of the Jacobi polynomials. A new approximation being expressed in terms
of the potential parameters is carried out to deal with the strong singular
centrifugal potential term L(L+1)/r^2. Under some limitations, we can obtain
solution for the ring-shaped Hulth\'en potential and the standard usual
spherical Woods-Saxon potential (q=1).


title:
Casimir Torque for a Perfectly Conducting Wedge: A Canonical Quantum
  Field Theoretical Approach

abstract:
  The torque density per unit height exerted on a perfectly conducting wedge
due to the quantum vacuum fluctuations (the Casimir torque) is obtained. A
canonical quantum field theoretical approach with the method of calculating
vacuum-to-vacuum propagator (Green function) [1] is used.


title:
The Covariant Electromagnetic Casimir Effect for Real Conducting
  Cylindrical Shells

abstract:
  Using covariant quantization of the electromagnetic field, the Casimir force
per unit area experienced by a long conducting cylindrical shell, under both
Dirichlet and Neumann boundary conditions, is calculated. The renormalization
procedure is based on the plasma cut-off frequency for real conductors. The
real case of a gold (silver) cylindrical shell is considered and the
corresponding electromagnetic Casimir pressure is computed. It is discussed
that the Dirichlet and Neumann problems should be considered separately without
adding their corresponding results.


title:
Relativistic symmetries in trigonometric Poschl-Teller potential plus
  tensor interaction

abstract:
  The Dirac equation is solved to obtain its approximate bound states for a
spin-1/2 particle in the presence of trigonometric Poschl-Teller (tPT)
potential including a Coulomb-like tensor interaction with arbitrary spin-orbit
quantum number $\kappa$ using an approximation scheme to substitute the
centrifugal terms k(k+1)/r^2. In view of spin and pseudo-spin (p-spin)
symmetries, the relativistic energy eigenvalues and the corresponding
two-component wave functions of a particle moving in the field of attractive
and repulsive tPT potentials are obtained using the asymptotic iteration method
(AIM). We present numerical results in the absence and presence of tensor
coupling $A$ and for various values of spin and p-spin constants and quantum
numbers n and k. The non-relativistic limit is also obtained.


title:
Efficient, uninformative sampling of limb darkening coefficients for
  two-parameter laws

abstract:
  Stellar limb darkening affects a wide range of astronomical measurements and
is frequently modelled with a parametric model using polynomials in the cosine
of the angle between the line of sight and the emergent intensity.
Two-parameter laws are particularly popular for cases where one wishes to fit
freely for the limb darkening coefficients (i.e. an uninformative prior) due to
the compact prior volume and the fact that more complex models rarely obtain
unique solutions with present data. In such cases, we show that the two limb
darkening coefficients are constrained by three physical boundary conditions,
describing a triangular region in the two-dimensional parameter space. We show
that uniformly distributed samples may be drawn from this region with optimal
efficiency by a technique developed by computer graphical programming:
triangular sampling. Alternatively, one can make draws using a uniform,
bivariate Dirichlet distribution. We provide simple expressions for these
parametrizations for both techniques applied to the case of quadratic,
square-root and logarithmic limb darkening laws. For example, in the case of
the popular quadratic law, we advocate fitting for q_1 = (u_1+u_2)^2 and q_2 =
0.5u_1(u_1+u_2)^{-1} with uniform priors in the interval [0,1] to implement
triangular sampling easily. Employing these parametrizations allows one to
derive model parameters which fully account for our ignorance about the
intensity profile, yet never explore unphysical solutions, yielding robust and
realistic uncertainty estimates. Furthermore, in the case of triangular
sampling with the quadratic law, our parametrization leads to significantly
reduced mutual correlations and provides an alternative geometric explanation
as to why naively fitting the quadratic limb darkening coefficients
precipitates strong correlations in the first place.


title: Interpretation of the Weyl tensor

abstract:
  According to folklore in general relativity, the Weyl tensor can be
decomposed into parts corresponding to Newton-like, incoming and outgoing
wavelike field components. It is shown here that this one-to-one correspondence
does not hold for space-time geometries with cylindrical isometries. This is
done by investigating some well-known exact solutions of Einstein's field
equations with whole-cylindrical symmetry, for which the physical
interpretation is very clear, but for which the standard Weyl interpretation
would give contradictory results. For planar or spherical geometries, however,
the standard interpretation works for both, static and dynamical space-times.
It is argued that one reason for the failure in the cylindrical case is that
for waves spreading in two spatial dimensions there is no local criterion to
distinguish incoming and outgoing waves already at the linear level. It turns
out that Thorne's local energy notion, subject to certain qualifications,
provides an efficient diagnostic tool to extract the proper physical
interpretation of the space-time geometry in the case of cylindrical
configurations.


title:
Contamination of Dark Matter Experiments from Atmospheric Magnetic
  Dipoles

abstract:
  Dark matter collisions with heavy nuclei (Xe, Ge, Si, Na) may produce recoils
observable at direct-search experiments. Given that some of these experiments
are yielding conflicting information, however, it is worth asking if physics
other than dark matter may produce similar nuclear recoils. We examine under
what conditions an atmospherically-produced neutral particle with a relatively
large magnetic dipole moment could fake a dark matter signal. We argue that a
very definite flux could explain the signals seen at DAMA/LIBRA, CDMS/Si and
CoGeNT consistently with the bounds from XENON100 and CDMS/Ge. To explore the
plausibility of this scenario, we discuss a concrete model with 10-50 MeV
sterile neutrinos that was recently proposed to explain the LSND and MiniBooNE
anomalies.


title: Star formation and black hole growth at z=4.8

abstract:
  We report Herschel Spitzer and Wise observations of 44 z=4.8 optically
selected active galactic nuclei (AGNs). This sample contains the highest mass
black holes (BHs) at this redshift. Ten of the objects were detected by
Herschel and five show emission that is not associated with the AGNs. The star
formation (SF) luminosity (LSF) obtained by fitting the spectral energy
distribution (SED) with standard SF templates is in the range 10^(46.62-47.21)
erg/s corresponding to SF rates of 1090-4240 Msun/yr. Fitting with luminous
submillimeter galaxy SEDs gives SF rates that are smaller by 0.05 dex when
using all bands and 0.1 dex when ignoring the 250-mic band. A 40K gray-body
fits to only the 500-mic fluxes reduce LSF by about a factor two. Stacking
analysis of 29 undetected sources give significant signals in all three bands.
A SF template fit indicates LSF=10^(46.19-46.23) erg/s depending on the assume
AGN contribution. A 40K fit to the stacked 500-mic flux gives LSF=10^(45.95)
erg/s. The mean BH mass (mbh) and AGN luminosity (LAGN) of the detected sources
are significantly higher than those of the undetected ones. The spectral
differences are seen all the way from UV to far infrared wavelengths. The mean
optical-UV spectra are similar to the ones predicted for thin accretion disks
around BHs with the measured masses and accretion rates. We suggest two
alternative explanations to the correlation of LSF, LAGN and mbh, one involving
no AGN feedback and the second a moderate feedback that affects, but not
totally quench SF in 3/4 of the sources. We compare our LSF and LAGN to lower
redshift samples and show a new correlation between LSF and mbh. We also
examine several rather speculative ideas about the host galaxy properties
including the possibility that the detected sources are above the SF mass
sequence (MS) at z=4.8, perhaps in mergers, and most of the undetected sources
are on the MS.


title: Failed Supernovae Explain the Compact Remnant Mass Function

abstract:
  One explanation for the absence of higher mass red supergiants (16.5 Msun < M
< 25Msun) as the progenitors of Type IIP supernovae (SNe) is that they die in
failed SNe creating black holes. Simulations show that such failed SNe still
eject their hydrogen envelopes in a weak transient, leaving a black hole with
the mass of the star's helium core (5-8Msun). Here we show that this naturally
explains the typical masses of observed black holes and the gap between neutron
star and black hole masses without any fine-tuning of the SN mechanism beyond
having it fail in a mass range where many progenitor models have density
structures that make the explosions more likely to fail. There is no difficulty
including this ~20% population of failed SNe in any accounting of SN types over
the progenitor mass function. And, other than patience, there is no
observational barrier to either detecting these black hole formation events or
limiting their rates to be well below this prediction.


title: On a Possible Size/Color Relationship in the Kuiper Belt

abstract:
  Color measurements and albedo distributions introduce non-intuitive
observational biases in size-color relationships among Kuiper Belt Objects
(KBOs) that cannot be disentangled without a well characterized sample
population with systematic photometry. Peixinho et al. report that the form of
the KBO color distribution varies with absolute magnitude, H. However, Tegler
et al. find that KBO color distributions are a property of object
classification. We construct synthetic models of observed KBO colors based on
two B-R color distribution scenarios: color distribution dependent on H
magnitude (H-Model) and color distribution based on object classification
(Class-Model). These synthetic B-R color distributions were modified to account
for observational flux biases. We compare our synthetic B-R distributions to
the observed 'Hot' and 'Cold' detected objects from the Canada-France Ecliptic
Plane Survey and the Meudon Multicolor Survey. For both surveys, the Hot
population color distribution rejects the H-Model, but is well described by the
Class-Model. The Cold objects reject the H-Model, but the Class-Model (while
not statistically rejected) also does not provide a compelling match for data.
Although we formally reject models where the structure of the color
distribution is a strong function of H magnitude, we also do not find that a
simple dependence of color distribution on orbit classification is sufficient
to describe the color distribution of classical KBOs.


title:
Lower Limits on the Anisotropy of the Extragalactic Gamma-Ray Background
  implied by the 2FGL and 1FHL Catalogs

abstract:
  In principle, the angular anisotropy in the extragalactic gamma-ray
background (EGRB) places severe constraints upon putative populations of
unresolved gamma-ray point sources. Existing estimates of the EGRB anisotropy
have been constructed by excising known point sources, e.g., taken from the
First or 2 Year Fermi-LAT Source Catalog (1FGL or 2FGL, respectively) and
statistically analyzing the residual gamma-ray sky maps. We perform an
independent check of the EGRB anisotropy limits by comparing the values
obtained from the 1FGL-masked sky maps to the signal implied by sources that
lie below the 1FGL detection threshold in the more sensitive 2FGL and 1FHL
(First Fermi-LAT catalog of >10 GeV sources). As such, our analysis provides an
internal consistency check of implications for source counts and spectral index
distributions of gamma-ray bright active galactic nuclei obtained from
Fermi-LAT data. Based on this, we find evidence for substantially larger
anisotropies than those previously reported at energies above 5 GeV, where BL
Lac objects are likely to provide the bulk of their contribution to the EGRB.
This uncertainty in the EGRB anisotropy cautions against using it as an
independent constraint for the high-redshift gamma-ray universe. Moreover, this
would suggest that contrary to previous claims, smooth extensions of the
resolved point-source population may be able to simultaneously explain both the
isotropic and anisotropic components of the EGRB.


title:
It takes a village to raise a tide: nonlinear multiple-mode coupling and
  mode identification in KOI-54

abstract:
  We explore the tidal excitation of stellar modes in binary systems using
Kepler observations of the remarkable eccentric binary KOI-54 (HD 187091; KIC
8112039), which displays strong ellipsoidal variation as well as a variety of
linear and nonlinear pulsations. We report the amplitude and phase of over 120
harmonic and anharmonic pulsations in the system. We use pulsation phases to
determine that the two largest-amplitude pulsations, the 90th and 91st
harmonics, most likely correspond to axisymmetric m=0 modes in both stars, and
thus cannot be responsible for resonance locks as had been recently proposed.
We find evidence that the amplitude of at least one of these two pulsations is
decreasing with a characteristic timescale of ~100 yr. We also use the
pulsations' phases to confirm the onset of the traveling wave regime for
harmonic pulsations with frequencies <~50 Omega_orbit, in agreement with
theoretical expectations. We present evidence that many pulsations that are not
harmonics of the orbital frequency correspond to modes undergoing simultaneous
nonlinear coupling to multiple linearly driven parent modes. Since coupling
among multiple modes can lower the threshold for nonlinear interactions,
nonlinear phenomena may be easier to observe in highly eccentric systems, where
broader arrays of driving frequencies are available. This may help to explain
why the observed amplitudes of the linear pulsations are much smaller than the
theoretical threshold for decay via three-mode coupling.


title:
Superconducting Proximity Effect in Silicene: Spin-Valley Polarized
  Andreev Reflection, Non-Local Transport, and Supercurrent

abstract:
  We theoretically study the superconducting proximity effect in silicene,
which features massive Dirac fermions with a tunable mass (band gap), and
compute the conductance across a normal/superconductor (N/S) silicene junction,
the non-local conductance of an N/S/N junction, and the supercurrent flowing in
an S/N/S junction. It is demonstrated that the transport processes consisting
of local and non-local Andreev reflection may be efficiently controlled via an
external electric field owing to the buckled structure of silicene. In
particular, we demonstrate that it is possible to obtain a fully spin-valley
polarized crossed Andreev reflection process without any contamination of
elastic cotunneling or local Andreev reflection, in stark contrast to ordinary
metals. It is also shown that the supercurrent flowing in the S/N/S junction
can be fully spin-valley polarized and that it is controllable by an external
electric field.


title: Absorption of planar massless scalar waves by Kerr black holes

abstract:
  We consider planar massless scalar waves impinging upon a Kerr black hole,
for general angles of incidence. We compute the absorption cross section via
the partial wave approach, and present a gallery of results. In the
low-frequency regime, we show that the cross section approaches the horizon
area; in the high-frequency regime, we show that the cross section approaches
the geodesic capture cross section. In the aligned case, we extend the complex
angular momentum method to obtain a `sinc' approximation, which relates the
regular high-frequency oscillations in the cross section to the properties of
the polar null orbit. In the non-aligned case, we show, via a semi-analytic
approximation, that the reduction in symmetry generates a richer, less regular
absorption cross section. We separate the absorption cross section into
corotating and counterrotating contributions, showing that the absorption is
larger for counterrotating waves, as expected.


title: Quantum key distribution session with 16-dimensional photonic states

abstract:
  The secure transfer of information is an important problem in modern
telecommunications. Quantum key distribution (QKD) provides a solution to this
problem by using individual quantum systems to generate correlated bits between
remote parties, that can be used to extract a secret key. QKD with
D-dimensional quantum channels provides security advantages that grow with
increasing D. However, the vast majority of QKD implementations has been
restricted to two dimensions. Here we demonstrate the feasibility of using
higher dimensions for real-world quantum cryptography by performing, for the
first time, a fully automated QKD session based on the BB84 protocol with
16-dimensional quantum states. Information is encoded in the single-photon
transverse momentum and the required states are dynamically generated with
programmable spatial light modulators. Our setup paves the way for future
developments in the field of experimental high-dimensional QKD.


title: Conformal window in QCD for large numbers of colours and flavours

abstract:
  We conjecture that the phase transitions in QCD at large number of colours
N\gg 1 is triggered by the drastic change in the instanton density. As a result
of it, all physical observables also experience some sharp modification in the
\theta behaviour. This conjecture is motivated by the holographic model of QCD
where confinement -deconfinement phase transition indeed happens precisely at
temperature T=T_c where $\theta$ dependence of the vacuum energy experiences a
sudden change in behaviour: from N^2\cos(\theta/N) at T<T_c to
\cos\theta\exp(-N) at T>T_c. This conjecture is also supported by recent
lattice studies. We employ this conjecture to study a possible phase transition
as a function of \kappa\equiv N_f/N from confinement to conformal phase in the
Veneziano limit N_f\sim N when number of flavours and colours are large, but
the ratio \kappa is finite. Technically, we consider an operator which gets its
expectation value solely from nonperturbative instaton effects. When \kappa
exceeds some critical value \kappa> \kappa_c the integral over instanton size
is dominated by small-size instatons, making the instanton computations
reliable with expected \exp(-N) behaviour. However, when \kappa<\kappa_c, the
integral over instaton size is dominated by large-size instantons, and the
instanton expansion breaks down. This regime with \kappa<\kappa_c corresponds
to the confinement phase. We also compute the variation of the critical
\kappa_c(T, \mu) when the temperature and chemical potential T, \mu \ll
\Lambda_{QCD} slightly vary. We also discuss the scaling
(x_i-x_j)^{-\gamma_{\rm det}} in the conformal phase.


title: Co-Evolution of Galactic Nuclei and Globular Cluster Systems

abstract:
  We revisit the hypothesis that dense galactic nuclei are formed from
inspiraling globular clusters. Recent advances in understanding of the
continuous formation of globular clusters over cosmic time and the concurrent
evolution of the galaxy stellar distribution allow us to construct a simple
model that matches the observed spatial and mass distributions of clusters in
the Galaxy and the giant elliptical galaxy M87. In order to compare with
observations, we model the effects of dynamical friction and dynamical
evolution, including stellar mass loss, tidal stripping of stars, and tidal
disruption of clusters by the growing galactic nucleus. We find that
inspiraling globular clusters form a dense central structure, with mass and
radius comparable to the typical values in observed nuclear star clusters
(NSCs) in late-type and low-mass early-type galaxies. The density contrast
associated with the NSC is less pronounced in giant elliptical galaxies. Our
results indicate that the NSC mass as a fraction of mass of the galaxy stellar
spheroid scales as M_NSC/M_* = 0.0025 M_{*,11}^{-0.5}. Thus disrupted globular
clusters could contribute most of the mass of NSCs in galaxies with stellar
mass below 10^{11} Msun. The inner part of the accumulated cluster may seed the
growth of a central black hole via stellar dynamical core collapse, thereby
relieving the problem of how to form luminous quasars at high redshift. The
seed black hole may reach about 10^5 Msun within 1 Gyr of the beginning of
globular cluster formation.


title:
A classification of homogeneous K\"{a}hler manifolds with discrete
  isotropy and top nonvanishing homology in codimension two

abstract:
  Suppose $G$ is a connected complex Lie group and $\Gamma$ is a discrete
subgroup such that $X := G/\Gamma$ is K\"ahler and the codimension of the top
non--vanishing homology group of $X$ with coefficients in $\mathbb Z_2$ is less
than or equal to two. We show that $G$ is solvable and a finite covering of $X$
is biholomorphic to a product $C\times A$, where $C$ is a Cousin group and $A$
is $\{e \}$, $\mathbb C$, $\mathbb C^*$, or $\mathbb C^*\times\mathbb C^*$.


title: Constraining Minimal $U(1)_{B-L}$ model from Dark Matter Observations

abstract:
  We study the $B-L$ gauge extension of the Standard Model which contains a
singlet scalar and three right-handed neutrinos. The vacuum expectation value
of the singlet scalar breaks the $U(1)_{B-L}$ symmetry. Here the third
generation right-handed neutrino is qualified as the dark matter candidate, as
an artifact of $Z_2$-charge assignment. Relic abundance of the dark matter is
consistent with WMAP9 and PLANCK data, only near scalar resonances where dark
matter mass is almost half of the scalar boson masses. Requiring correct relic
abundance, we restrict the parameter space of the scalar mixing angle and mass
of the heavy scalar boson of this model. Besides this, the maximum value of
spin-independent scattering cross-section off nucleon is well-below the {\sc
Xenon100} and recent LUX exclusion limits and can be probed by future {\sc
Xenon1T} experiment. In addition, we compute the annihilation of the dark
matter into two photon final state in detail and compare with the Fermi-LAT
upper bound on $\langle\sigma v\rangle_{\gamma \gamma}$ for NFW and Einasto
profile.


title: Before the Bang

abstract:
  While inflation has been an extremely successful cosmological paradigm,
almost certainly something have had to have happened before it began. Can the
pre-inflationary phase be of any theoretical or phenomenological significance?
Could Quantum Gravity have played any interesting role in this story? These are
some of the questions we want to explore in this essay written for the Gravity
Research Foundation 2013 "Awards for Essays on Gravitation" competition.


title: Higgs mass naturalness and scale invariance in the UV

abstract:
  It has been suggested that electroweak symmetry breaking in the Standard
Model may be natural if the Standard Model merges into a conformal field theory
(CFT) at short distances. In such a scenario the Higgs mass would be protected
from quantum corrections by the scale invariance of the CFT. In order for the
Standard Model to merge into a CFT at least one new ultraviolet (UV) scale is
required at which the couplings turn over from their usual Standard Model
running to the fixed point behavior. We argue that the Higgs mass is sensitive
to such a turn-over scale even if there are no associated massive particles and
the scale arises purely from dimensional transmutation. We demonstrate this
sensitivity to the turnover scale explicitly in toy models. Thus if scale
invariance is responsible for Higgs mass naturalness, then the transition to
CFT dynamics must occur near the TeV scale with observable consequences at
colliders. In addition, the UV fixed point theory in such a scenario must be
interacting because logarithmic running near a free fixed point constitutes
hard breaking of scale invariance and spoils the Higgs mass protection.


title:
Searching for new gamma-ray blazar candidates in the 3rd Palermo BAT
  Hard X-ray Catalog with WISE

abstract:
  We searched for gamma-ray blazar candidates among the 382 unidentified hard
X-ray sources of the 3rd Palermo BAT Catalog (3PBC) obtained from the analysis
of 66 months of SWIFT-BAT survey data and listing 1586 sources. We adopted a
recently developed association method based on the peculiar infrared colors
which characterize the gamma-ray blazars included in the second catalog of
active galactic nuclei detected by the Fermi Large Area Telescope (2LAC). We
used this method exploiting the data of the all-sky survey performed by the
Wide-Field Infrared Survey Explorer (WISE) to establish correspondences between
unidentified 3PBC sources and WISE gamma-ray blazar candidates located within
the BAT positional uncertainty region at 99% confidence level. We obtained a
preliminary list of candidates for which we analysed all the available data in
the SWIFT archive to complement the information in the literature and in the
radio, infrared and optical catalogs with the information on their optical-UV
and soft X-ray emission. Requiring the presence of radio and soft X-ray
counterparts consistent with the infrared positions of the selected WISE
sources, as well as a blazar-like radio morphology, we finally obtained a list
of 24 gamma-ray blazar candidates.


title:
The abelian confinement mechanism revisited: new aspects of the
  Georgi-Glashow model

abstract:
  The confinement problem remains one of the most difficult problems in
theoretical physics. An important step toward the solution of this problem is
the Polyakov's work on abelian confinement. The Georgi-Glashow model is a
natural testing ground for this mechanism which has been surprising us by its
richness and wide applicability. In this work, we shed light on two new aspects
of this model in 2+1 D. First, we develop a many-body description of the
effective degrees of freedom. Namely, we consider a non-relativistic gas of
W-bosons in the background of monopole-instanton plasma. Many-body treatment is
a standard toolkit in condensed matter physics. However, we add a new twist by
supplying the monopole-instantons as external background field. Using this
construction, we calculate the exact form of the potential between two electric
probes as a function of their separation. This potential is expressed in terms
of the Meijer-G function which interpolates between logarithmic and linear
behavior at small and large distances, respectively. Second, we develop a
systematic approach to integrate out the effect of the W-bosons at finite
temperature in the range 0<T<M_W, where M_W is the W-boson mass, starting from
the full relativistic partition function of the Georgi-Glashow model. Using a
heat kernel expansion that takes into account the non-trivial thermal holonomy,
we show that the partition function describes a three-dimensional two-component
Coulomb gas. We repeat our analysis using the many-body description which
yields the same result and provides a check on our formalism. At temperatures
close to the deconfinement temperature, the gas becomes essentially
two-dimensional recovering the partition function of the dual sine-Gordon model
that was considered in a previous work.


title:
A Radiation-Hard Dual Channel 4-bit Pipeline for a 12-bit 40 MS/s ADC
  Prototype with extended Dynamic Range for the ATLAS Liquid Argon Calorimeter
  Readout Electronics Upgrade at the CERN LHC

abstract:
  The design of a radiation-hard dual channel 12-bit 40 MS/s pipeline ADC with
extended dynamic range is presented, for use in the readout electronics upgrade
for the ATLAS Liquid Argon Calorimeters at the CERN Large Hadron Collider. The
design consists of two pipeline A/D channels with four Multiplying
Digital-to-Analog Converters with nominal 12-bit resolution each. The design,
fabricated in the IBM 130 nm CMOS process, shows a performance of 68 dB SNDR at
18 MHz for a single channel at 40 MS/s while consuming 55 mW/channel from a 2.5
V supply, and exhibits no performance degradation after irradiation. Various
gain selection algorithms to achieve the extended dynamic range are implemented
and tested.


title: Hierarchical self-organization of non-cooperating individuals

abstract:
  Hierarchy is one of the most conspicuous features of numerous natural,
technological and social systems. The underlying structures are typically
complex and their most relevant organizational principle is the ordering of the
ties among the units they are made of according to a network displaying
hierarchical features. In spite of the abundant presence of hierarchy no
quantitative theoretical interpretation of the origins of a multi-level,
knowledge-based social network exists. Here we introduce an approach which is
capable of reproducing the emergence of a multi-levelled network structure
based on the plausible assumption that the individuals (representing the nodes
of the network) can make the right estimate about the state of their changing
environment to a varying degree. Our model accounts for a fundamental feature
of knowledge-based organizations: the less capable individuals tend to follow
those who are better at solving the problems they all face. We find that
relatively simple rules lead to hierarchical self-organization and the specific
structures we obtain possess the two, perhaps most important features of
complex systems: a simultaneous presence of adaptability and stability. In
addition, the performance (success score) of the emerging networks is
significantly higher than the average expected score of the individuals without
letting them copy the decisions of the others. The results of our calculations
are in agreement with a related experiment and can be useful from the point of
designing the optimal conditions for constructing a given complex social
structure as well as understanding the hierarchical organization of such
biological structures of major importance as the regulatory pathways or the
dynamics of neural networks.


title:
A brief discussion on the possible bound states for a class of singular
  potentials

abstract:
  The one-dimensional Schr\"{o}dinger equation for a class of potentials
$V(|x|)$ which vanish at infinity and present dominant singularity at the
origin in the form $\alpha /|x|^{\beta}$ ($0<\beta \leq 2$) is investigated.
The Hermiticity of the operators related to observable physical quantities is
used to determinate the proper boundary conditions. Double degeneracy and
exclusion of symmetric solutions, consonant the value of $\beta $, are
discussed. Explicit solutions for the hydrogen atom and the Kratzer potential
are presented.


title: Efficacy of crustal superfluid neutrons in pulsar glitch models

abstract:
  In order to assess the ability of purely crust-driven glitch models to match
the observed glitch activity in the Vela pulsar, we conduct a systematic
analysis of the dependence of the fractional moment of inertia of the inner
crustal neutrons on the stiffness of the nuclear symmetry energy at saturation
density $L$. We take into account both crustal entrainment and the fact that
only a fraction $Y_{\rm g}$ of the core neutrons may couple to the crust on the
glitch-rise timescale. We use a set of consistently-generated crust and core
compositions and equations-of-state which are fit to results of low-density
pure neutron matter calculations. When entrainment is included at the level
suggested by recent microscopic calculations and the core is fully coupled to
the crust, the model is only able to account for the Vela glitch activity for a
1.4$M_{\odot}$ star if the equation of state is particularly stiff $L>100$ MeV.
However, an uncertainty of about 10\% in the crust-core transition density and
pressure allows for the Vela glitch activity to be marginally accounted for in
the range $L\approx30-60$MeV consistent with a range of experimental results.
Alternatively, only a small amount of core neutrons need be involved. If less
than 50\% of the core neutrons are coupled to the crust during the glitch, we
can also account for the Vela glitch activity using crustal neutrons alone for
EOSs consistent with the inferred range of $L$. We also explore the possibility
of Vela being a high-mass neutron star, and of crustal entrainment being
reduced or enhanced relative to its currently predicted values.


title:
An Age Difference of 2 Gyr between a Metal-Rich and a Metal-Poor
  Globular Cluster

abstract:
  Globular clusters trace the formation history of the spheroidal components of
both our Galaxy and others, which represent the bulk of star formation over the
history of the universe. They also exhibit a range of metallicities, with
metal-poor clusters dominating the stellar halo of the Galaxy, and higher
metallicity clusters found within the inner Galaxy, associated with the stellar
bulge, or the thick disk. Age differences between these clusters can indicate
the sequence in which the components of the Galaxy formed, and in particular
which clusters were formed outside the Galaxy and later swallowed along with
their original host galaxies, and which were formed in situ. Here we present an
age determination of the metal-rich globular cluster 47 Tucanae by fitting the
properties of the cluster white dwarf population, which implies an absolute age
of 9.9 (0.7) Gyr at 95% confidence. This is about 2.0 Gyr younger than inferred
for the metal-poor cluster NGC 6397 from the same models, and provides
quantitative evidence that metal-rich clusters like 47 Tucanae formed later
than the metal-poor halo clusters like NGC 6397.


title: Density of rational points on a certain smooth bihomogeneous threefold

abstract:
  We establish sharp upper and lower bounds for the number of rational points
of bounded anticanonical height on a smooth bihomogeneous threefold defined
over Q and of bidegree (1, 2). These bounds are in agreement with Manin's
conjecture.


title:
Robustness of partially interdependent network formed of clustered
  networks

abstract:
  Clustering, or transitivity has been observed in real networks and its
effects on their structure and function has been discussed extensively. The
focus of these studies has been on clustering of single networks while the
effect of clustering on the robustness of coupled networks received very little
attention. Only the case of a pair of fully coupled networks with clustering
has been studied recently. Here we generalize the study of clustering of a
fully coupled pair of networks to the study of partially interdependent network
of networks with clustering within the network components. We show both
analytically and numerically, how clustering within the networks, affects the
percolation properties of interdependent networks, including percolation
threshold, size of giant component and critical coupling point where first
order phase transition changes to second order phase transition as the coupling
between the networks reduces. We study two types of clustering: one type
proposed by Newman where the average degree is kept constant while changing the
clustering and the other proposed by Hackett $et$ $al.$ where the degree
distribution is kept constant. The first type of clustering is treated both
analytically and numerically while the second one is treated only numerically.


title: Intrabeam Scattering Studies at CesrTA

abstract:
  Intrabeam scattering (IBS) limits the emittance and single-bunch current that
can be achieved in electron or positron storage ring colliders, damping rings,
and light sources. Much theoretical work on IBS exists, and while the theories
have been validated in hadron and ion machines, the presence of strong damping
makes IBS in lepton machines a different phenomenon. We present the results of
measurements at CesrTA of IBS dominated beams, and compare the data with
theory. The beams we study have parameters typical of those specified for the
next generation of wiggler dominated storage rings: low emittance, small bunch
length, and few GeV energy. Our measurements are in good agreement with IBS
theory, provided a tail-cut procedure is applied.


title: Highly efficient, dual state emission from an organic semiconductor

abstract:
  We report highly efficient, simultaneous fluorescence and phosphorescence
(74% yield) at room temperature from a single molecule ensemble of (BzP)PB
dispersed into a polymer host. The slow phosphorescence (208 ms lifetime) is
very efficient (50%) at room temperature and only possible because the
non-radiative rate for the triplet state is extremely low. The ability of an
organic molecule to function as an efficient dual state emitter at room
temperature is unusual and opens new fields of applications including the use
as broadband down-conversion emitters, optical sensors and attenuators, exciton
probes, and spin-independent intermediates for F\"orster resonant energy
transfer.


title: Route Swarm: Wireless Network Optimization through Mobility

abstract:
  In this paper, we demonstrate a novel hybrid architecture for coordinating
networked robots in sensing and information routing applications. The proposed
INformation and Sensing driven PhysIcally REconfigurable robotic network
(INSPIRE), consists of a Physical Control Plane (PCP) which commands agent
position, and an Information Control Plane (ICP) which regulates information
flow towards communication/sensing objectives. We describe an instantiation
where a mobile robotic network is dynamically reconfigured to ensure high
quality routes between static wireless nodes, which act as source/destination
pairs for information flow. The ICP commands the robots towards evenly
distributed inter-flow allocations, with intra-flow configurations that
maximize route quality. The PCP then guides the robots via potential-based
control to reconfigure according to ICP commands. This formulation, deemed
Route Swarm, decouples information flow and physical control, generating a
feedback between routing and sensing needs and robotic configuration. We
demonstrate our propositions through simulation under a realistic wireless
network regime.


title: The Casimir Forces in a Single Conducting Cylindrical Cavity

abstract:
  We want to study the Casimir effect for a single conducting microscopic
cylindrical cavity. The mathematical technique is based on the Green function
of the geometry of the inside of the cavity, and the integral regularization is
based on the plasma frequency cutoff for real conductors. Using the symmetric
electromagnetic energy-momentum tensor, in terms of four potential, the total
Casimir energy for the inside of the Cavity is calculated. Neglecting the
contribution of the external (outside of the cavity) Casimir energy based on
the reason recently presented in [1], the forces experienced by the lateral
surface of the cavity and its circular bases are calculated. The resulting
expressions show that these forces are repulsive. The numerical computation is
done for the real problem of a cavity with a basis of a radius in the same
order of its height at the scale of 100 nanometers made of the best conducting
materials already known.


title:
Optimal Switching On and Off the Entire Service Capacity of a Parallel
  Queue

abstract:
  This paper studies optimal switching on and o? of the entire service capacity
of an M/M/Infinity queue with holding, running and switching costs where the
running costs depend only on whether the system is running or not. The goal is
to minimize average costs per unit time. The main result is that an
average-optimal policy either always runs the system or is an (M, N)-policy
defined by two thresholds M and N, such that the system is switched on upon an
arrival epoch when the system size accumulates to N and is switched off upon a
departure epoch when the system size decreases to M. It is shown that this
optimization problem can be reduced to a problem with a finite number of states
and actions, and an average-optimal policy can be computed via linear
programming. An example, in which the optimal (M, N)-policy outperforms the
best (0, N)-policy, is provided. Thus, unlike the case of single-server queues
studied in the literature, (0, N)-policies may not be average-optimal.


title: Spinning geometry = Twisted geometry

abstract:
  It is well known that the SU(2)-gauge invariant phase space of loop gravity
can be represented in terms of twisted geometries. These are
piecewise-linear-flat geometries obtained by gluing together polyhedra, but the
resulting geometries are not continuous across the faces. Here we show that
this phase space can also be represented by continuous, piecewise-flat
three-geometries called spinning geometries. These are composed of metric-flat
three-cells glued together consistently. The geometry of each cell and the
manner in which they are glued is compatible with the choice of fluxes and
holonomies.
  We first remark that the fluxes provide each edge with an angular momentum.
By studying the piecewise-flat geometries which minimize edge lengths, we show
that these angular momenta can be literally interpreted as the spin of the
edges: the geometries of all edges are necessarily helices. We also show that
the compatibility of the gluing maps with the holonomy data results in the same
conclusion. This shows that a spinning geometry represents a way to glue
together the three-cells of a twisted geometry to form a continuous geometry
which represents a point in the loop gravity phase space.


title:
A Tractable Model for Non-Coherent Joint-Transmission Base Station
  Cooperation

abstract:
  This paper presents a tractable model for analyzing non-coherent joint
transmission base station (BS) cooperation, taking into account the irregular
BS deployment typically encountered in practice. Besides cellular-network
specific aspects such as BS density, channel fading, average path loss and
interference, the model also captures relevant cooperation mechanisms including
user-centric BS clustering and channel-dependent cooperation activation. The
locations of all BSs are modeled by a Poisson point process. Using tools from
stochastic geometry, the signal-to-interference-plus-noise ratio
($\mathtt{SINR}$) distribution with cooperation is precisely characterized in a
generality-preserving form. The result is then applied to practical design
problems of recent interest. We find that increasing the network-wide BS
density improves the $\mathtt{SINR}$, while the gains increase with the path
loss exponent. For pilot-based channel estimation, the average spectral
efficiency saturates at cluster sizes of around $7$ BSs for typical values,
irrespective of backhaul quality. Finally, it is shown that intra-cluster
frequency reuse is favorable in moderately loaded cells with generous
cooperation activation, while intra-cluster coordinated scheduling may be
better in lightly loaded cells with conservative cooperation activation.


title: Equations of tropical varieties

abstract:
  We introduce a scheme-theoretic enrichment of the principal objects of
tropical geometry. Using a category of semiring schemes, we construct tropical
hypersurfaces as schemes over idempotent semirings such as $\mathbb{T} =
(\mathbb{R}\cup \{-\infty\}, \mathrm{max}, +)$ by realizing them as solution
sets to explicit systems of tropical equations that are uniquely determined by
idempotent module theory. We then define a tropicalization functor that sends
closed subschemes of a toric variety over a ring R with non-archimedean
valuation to closed subschemes of the corresponding tropical toric variety.
Upon passing to the set of $\mathbb{T}$-points this reduces to Kajiwara-Payne's
extended tropicalization, and in the case of a projective hypersurface we show
that the scheme structure determines the multiplicities attached to the
top-dimensional cells. By varying the valuation, these tropicalizations form
algebraic families of $\mathbb{T}$-schemes parameterized by a moduli space of
valuations on R that we construct. For projective subschemes, the Hilbert
polynomial is preserved by tropicalization, regardless of the valuation. We
conclude with some examples and a discussion of tropical bases in the
scheme-theoretic setting.


title:
Complex-band-structure eigenvalue method adapted to Floquet systems:
  topological superconducting wires as a case study

abstract:
  For systems that can be modeled as a single-particle lattice extended along a
privileged direction as, e.g., quantum wires, the so-called eigenvalue method
provides full information about the propagating and evanescent modes as a
function of energy. This complex-band structure method can be applied either to
lattices consisting of an infinite succession of interconnected layers
described by the same local Hamiltonian or to superlattices: Systems in which
the spatial periodicity involves more than one layer. Here, for time-dependent
systems subject to a periodic driving, we present an adapted version of the
superlattice scheme capable of obtaining the Floquet states and the Floquet
quasienergy spectrum. Within this scheme the time periodicity is treated as
existing along spatial dimension added to the original system. The solutions at
a single energy for the enlarged artificial system provide the solutions of the
original Floquet problem. The method is suited for arbitrary periodic
excitations including strong and anharmonic drivings. We illustrate the
capabilities of the methods for both time-independent and time-dependent
systems by discussing: (a) topological superconductors in multimode quantum
wires with spin-orbit interaction and (b) microwave driven quantum dot in
contact with a topological superconductor.


title: Dark Matter Direct Detection With Low Temperature Detectors

abstract:
  Low Temperature Detectors (LTDs) offer the best signal-to-noise performance
and thus, lowest energy threshold among other particle detection technologies
available today. The excellent background rejection provided by these detectors
is essential to search for very rare and very low energy recoils expected from
dark matter interactions. Furthermore, due to their very good event-by-event
background rejection capabilities, LTDs do not heavily rely on self-shielding
in order to mitigate radioactive backgrounds (in contrast with the monolithic
liquid Noble Gas detectors) thus they can be more easily prototyped and tested
for basic detector performance. A review of the status and prospects of the
major Dark Matter search experiments using LTD technologies is presented here.

categories: astro-ph.IM astro-ph.CO hep-ph physics.ins-det


title:
A non-perturbative expression for the transmission through a leaky
  chiral edge mode

abstract:
  Chiral edge modes of topological insulators and Hall states exhibit
non-trivial behavior of conductance in the presence of impurities or additional
channels. We will present a simple formula for the conductance through a chiral
edge mode coupled to a disordered bulk. For a given coupling matrix between the
chiral mode and bulk modes, and a Green function matrix of bulk modes in real
space, the renormalized Green function of the chiral mode is expressed in
closed form as a ratio of determinants. We demonstrate the usage of the formula
in two systems: i) a 1d wire with random onsite impurity potentials for which
we found the disorder averaging is made simpler with the formula, and ii) a
quantum Hall fluid with impurities in the bulk for which the phase picked up by
the chiral mode due to the scattering with the impurities can be conveniently
estimated.


title: Mass sensitivity in the radio lateral distribution function

abstract:
  Measuring the mass composition of ultra-high energy cosmic rays is one of the
main tasks in the cosmic rays field. Here we are exploring the composition
signature in the coherent electromagnetic emission from extensive air showers,
detected in the MHz frequency range. One of the experiments that successfully
detects radio events in the frequency band of 40-80 MHz is the LOPES experiment
at KIT. It is a digital interferometric antenna array and has the important
advantage of taking data in coincidence with the particle detector array
KASCADE-Grande. A possible method to look at the composition signature in the
radio data, predicted by simulations, concerns the radio lateral distribution
function, since its slope is strongly correlated with Xmax. Recent comparison
between REAS3 simulations and LOPES data showed a significantly improved
agreement in the lateral distribution function and for this reason an analysis
on a possible LOPES mass signature through the slope method is promising.
Trying to reproduce a realistic case, proton and iron showers are simulated
with REAS3 using the LOPES selection information as input parameters. The
obtained radio lateral distribution slope is analyzed in detail. The lateral
slope method to look at the composition signature in the radio data is shown
here and a possible signature of mass composition in the LOPES data is
discussed.


title: On Lattices and the Dualities of Information Measures

abstract:
  Measures of dependence among variables, and measures of information content
and shared information have become valuable tools of multi-variable data
analysis. Information measures, like marginal entropies, mutual and
multi-information, have a number of significant advantages over more standard
statistical methods, like their reduced sensitivity to sampling limitations
than statistical estimates of probability densities. There are also interesting
applications of these measures to the theory of complexity and to statistical
mechanics. Their mathematical properties and relationships are therefore of
interest at several levels.
  Of the interesting relationships between common information measures, perhaps
none are more intriguing and as elegant as the duality relationships based on
Mobius inversions. These inversions are directly related to the lattices
(posets) that describe these sets of variables and their multi-variable
measures. In this paper we describe extensions of the duality previously noted
by Bell to a range of measures, and show how the structure of the lattice
determines fundamental relationships of these functions. Our major result is a
set of interlinked duality relations among marginal entropies, interaction
information, and conditional interaction information. The implications of these
results include a flexible range of alternative formulations of
information-based measures, and a new set of sum rules that arise from
path-independent sums on the lattice. Our motivation is to advance the
fundamental integration of this set of ideas and relations, and to show
explicitly the ways in which all these measures are interrelated through
lattice properties. These ideas can be useful in constructing theories of
complexity, descriptions of large scale stochastic processes and systems, and
in devising algorithms and approximations for computations in multi-variable
data analysis.


title: Fifty Years of Breakthrough Discoveries in Fluid Criticality

abstract:
  Fifty years ago two scientists, who celebrate their 80th birthdays in 2011,
Alexander V. Voronel and Johannes V. Sengers performed breakthrough experiments
that challenged the commonly accepted views on critical phenomena in fluids.
Voronel discovered that the isochoric heat capacity of argon becomes infinite
at the vapor-liquid critical point. Almost simultaneously, Sengers observed a
similar anomaly for the thermal conductivity of near-critical carbon dioxide.
The existence of these singularities was later proved to be universal for all
fluids. These experiments had a profound effect on the development of the
modern (scaling) theory of phase transitions, which is based on the diverging
fluctuations of the order parameter. In particular, the discovery of the
heat-capacity divergence at the critical point was a keystone for the
formulation of static scaling theory, while the discovery of the divergence of
the thermal conductivity played an important role in the formulation of dynamic
scaling and mode-coupling theory. Moreover, owing to the discoveries made by
Voronel and Sengers 50 years ago, critical phenomena in fluids have become an
integral part of contemporary condensed-matter physics.


title:
A composite likelihood approach to computer model calibration using
  high-dimensional spatial data

abstract:
  Computer models are used to model complex processes in various disciplines.
Often, a key source of uncertainty in the behavior of complex computer models
is uncertainty due to unknown model input parameters. Statistical computer
model calibration is the process of inferring model parameter values, along
with associated uncertainties, from observations of the physical process and
from model outputs at various parameter settings. Observations and model
outputs are often in the form of high-dimensional spatial fields, especially in
the environmental sciences. Sound statistical inference may be computationally
challenging in such situations. Here we introduce a composite likelihood-based
approach to perform computer model calibration with high-dimensional spatial
data. While composite likelihood has been studied extensively in the context of
spatial statistics, computer model calibration using composite likelihood poses
several new challenges. We propose a computationally efficient approach for
Bayesian computer model calibration using composite likelihood. We also develop
a methodology based on asymptotic theory for adjusting the composite likelihood
posterior distribution so that it accurately represents posterior
uncertainties. We study the application of our new approach in the context of
calibration for a climate model.


title: VERITAS Observations of TeV Binaries

abstract:
  Since the commissioning of the array in Spring 2007, the VERITAS array
(sensitive in the 0.1-50 TeV energy range) has acquired over 300 hours of
observations investigating the TeV emission from X-ray binary star systems, in
particular focusing on the known TeV binary targets LS I +61 303 and HESS
J0632+057. Both TeV binaries have been monitored by VERITAS for several years
and the resulting dataset is continuing to yield important results in the
characterization of these poorly understood systems. We present these results,
as well as the contemporaneous observations of these sources taken with
Fermi-LAT and Swift-XRT. In the case of LS I +61 303, simultaneous observations
taken with VERITAS and Fermi-LAT reveal a break in emission in the 10-200 GeV
range. For HESS J0632 057, the extended VERITAS observations have allowed for
the first identification of a binary system through TeV gamma-ray observations.


title:
Noncommutative polynomials nonnegative on a variety intersect a convex
  set

abstract:
  By a result of Helton and McCullough, open bounded convex free semialgebraic
sets are exactly open (matricial) solution sets D_L of a linear matrix
inequality (LMI) L(X)>0. This paper gives a precise algebraic certificate for a
polynomial being nonnegative on a convex semialgebraic set intersect a variety,
a so-called "Perfect" Positivstellensatz.
  For example, given a generic convex free semialgebraic set D_L we determine
all "(strong sense) defining polynomials" p for D_L. This follows from our
general result for a given linear pencil L and a finite set I of rows of
polynomials. A matrix polynomial p is positive where L is positive and I
vanishes if and only if p has a weighted sum of squares representation module
the "L-real radical" of I. In such a representation the degrees of the
polynomials appearing depend in a very tame way only on the degree of p and the
degrees of the elements of I. Further, this paper gives an efficient algorithm
for computing the L-real radical of I.
  Our Positivstellensatz has a number of additional consequences which are
presented.


title:
Scrutinizing h(125) in Two Higgs Doublet Models at the LHC, ILC, and
  Muon Collider

abstract:
  The discovery at the LHC of a scalar particle with properties that are so far
consistent with the SM Higgs boson is one of the most important advances in the
history of particle physics. The challenge of future collider experiments is to
determine whether its couplings will show deviations from the SM Higgs, as this
would indicate new physics at the TeV scale, and also to probe the flavor
structure of the Yukawa couplings. As a benchmark alternative to the SM Higgs,
we consider a generic two Higgs doublet model (2HDM) and analyze the precision
to which the LHC14, an ILC250, 500, 1000 GeV and a 125 GeV Muon Collider (MC)
can determine the gauge and Yukawa couplings. We allow for correlations among
the couplings. We include the impact of a Higgs total width measurement,
indirectly at the LHC and ILC and by a direct scan at the MC. We also discuss
pattern relations among the couplings that can test for singlet or doublet
Higgs extensions of 2HDMs.


title:
Reconstructing energy and Xmax of cosmic ray air showers using the radio
  lateral distribution measured with LOPES

abstract:
  The LOPES experiment, a digital radio interferometer located at KIT
(Karlsruhe Institute of Technology), obtained remarkable results for the
detection of radio emission from extensive air showers at MHz frequencies.
Features of the radio lateral distribution function (LDF) measured by LOPES are
explored in this work for a precise reconstruction of two fundamental air
shower parameters: the primary energy and the shower Xmax. The method presented
here has been developed on (REAS3-)simulations, and is applied to LOPES
measurements. Despite the high human-made noise at the LOPES site, it is
possible to reconstruct both the energy and Xmax for individual events. On the
one hand, the energy resolution is promising and comparable to the one of the
co-located KASCADE-Grande experiment. On the other hand, Xmax values are
reconstructed with the LOPES measurements with a resolution of 90 g/cm2 . A
precision on Xmax better than 30 g/cm2 is predicted and achievable in a region
with a lower human-made noise level.


title: A new population of recently quenched elliptical galaxies in the SDSS

abstract:
  We use the Sloan Digital Sky Survey to investigate the properties of massive
elliptical galaxies in the local Universe (z\leq0.08) that have unusually blue
optical colors. Through careful inspection, we distinguish elliptical from
non-elliptical morphologies among a large sample of similarly blue galaxies
with high central light concentrations (c_r\geq2.6). These blue ellipticals
comprise 3.7 per cent of all c_r\geq2.6 galaxies with stellar masses between
10^10 and 10^11 h^{-2} {\rm M}_{\sun}. Using published fiber spectra
diagnostics, we identify a unique subset of 172 non-star-forming ellipticals
with distinctly blue urz colors and young (< 3 Gyr) light-weighted stellar
ages. These recently quenched ellipticals (RQEs) have a number density of
2.7-4.7\times 10^{-5}\,h^3\,{\rm Mpc}^{-3} and sufficient numbers above
2.5\times10^{10} h^{-2} {\rm M}_{\sun} to account for more than half of the
expected quiescent growth at late cosmic time assuming this phase lasts 0.5
Gyr. RQEs have properties that are consistent with a recent merger origin
(i.e., they are strong `first-generation' elliptical candidates), yet few
involved a starburst strong enough to produce an E+A signature. The preferred
environment of RQEs (90 per cent reside at the centers of < 3\times
10^{12}\,h^{-1}{\rm M}_{\sun} groups) agrees well with the `small group scale'
predicted for maximally efficient spiral merging onto their halo center and
rules out satellite-specific quenching processes. The high incidence of Seyfert
and LINER activity in RQEs and their plausible descendents may heat the
atmospheres of small host halos sufficiently to maintain quenching.


title: VER J2019+407 and the Cygnus Cocoon

abstract:
  Current gamma-ray observatories have made substantial advances in the study
of potential cosmic ray accelerators such as supernova remnants (SNRs), but the
study of cosmic rays in flight from their parent accelerators remains a topic
of great interest. The Fermi Gamma-ray Space Telescope (FGST) discovered a four
square degree region of gamma-ray emission between 3 GeV and 100 GeV. This
structure lies between the Cygnus OB2 association and the gamma-Cygni SNR,
which is bright in gamma rays above 10 GeV. The atmospheric Cherenkov
observatory VERITAS also sees VHE (> 100 GeV) gamma-ray emission from the
direction gamma-Cygni (VER J2019+407). We discuss the relationship of VER
J2019+407 to both the gamma-Cygni SNR and the cocoon. Toy model simulations are
used to evaluate prospects for detecting the cocoon at very high energies with
VERITAS, as well as ways in which cocoon emission at these energies could
impact measurements of the morphology and spectrum of VER J2019+407.


title: SDN-like: The Next Generation of Pub/Sub

abstract:
  Software-Defined Networking (SDN) has raised the boundaries of cloud
computing by offering unparalleled levels of control and flexibility to system
administrators over their virtualized environments. To properly embrace this
new era of SDN-driven network architectures, the research community must not
only consider the impact of SDN over the protocol stack, but also on its
overlying networked applications. In this big ideas paper, we study the impact
of SDN on the design of future message-oriented middleware, specifically
pub/sub systems. We argue that key concepts put forth by SDN can be applied in
a meaningful fashion to the next generation of pub/sub systems. First, pub/sub
can adopt a logically centralized controller model for maintenance, monitoring,
and control of the overlay network. We establish a parallel with existing work
on centralized pub/sub routing and discuss how the logically centralized
controller model can be implemented in a distributed manner. Second, we
investigate the separation of the control and data plane, which is integral to
SDN, which can be adopted to raise the level of decoupling in pub/sub. We
introduce a new model of pub/sub which separates the traditional publisher and
subscriber roles into flow regulators and producer/consumers of data. We then
present use cases that benefit from this approach and study the impact of
decoupling for performance.


title: On the accuracy of N-body simulations at very large scales

abstract:
  We examine the deviation of Cold Dark Matter particle trajectories from the
Newtonian result as the size of the region under study becomes comparable to or
exceeds the particle horizon. To first order in the gravitational potential,
the general relativistic result coincides with the Zel'dovich approximation and
hence the Newtonian prediction on all scales. At second order, General
Relativity predicts corrections which overtake the corresponding second order
Newtonian terms above a certain scale of the order of the Hubble radius.
However, since second order corrections are very much suppressed on such
scales, we conclude that simulations which exceed the particle horizon but use
Newtonian equations to evolve the particles, reproduce the correct trajectories
very well. The dominant relativistic corrections to the power spectrum on
scales close to the horizon are at most of the order of $\sim 10^{-5}$ at
$z=49$ and $\sim 10^{-3}$ at $z=0$. The differences in the positions of real
space features are affected at a level below $10^{-6}$ at both redshifts. Our
analysis also clarifies the relation of N-body results to relativistic
considerations.


title:
Momentum density and phase maps of a two-dimensional trapped
  Bose-Einstein condensate excited by a red laser

abstract:
  We investigate numerically the momentum density and phase maps $-$in
coordinate and momentum space$-$ of a two dimensional Bose-Einstein condensate
(BEC) excited by a moving red-detuned laser potential. The BEC is confined in a
harmonic trap cutoff by hard walls. The system and excitation scheme are as in
our previous work (Roger R. Sakhel {\it et al.} to appear in J. Low Temp. Phys.
(2013)); but with twice the number of particles and interaction strength. We
solve the time-dependent Gross-Pitaevskii equation numerically using the
split-step Crank-Nicolson method in real time. It is demonstrated that the
red-detuned laser has a phase-imprinting effect like a repulsive potential
barrier. Signatures of excitations are extracted from the dynamics of the
momentum densities and phase maps. Further, a new phase is defined in momentum
space, which is used to reveal excitations. Therefore, phase maps in coordinate
space and momentum space are compared for different BEC evolution times. We
argue, that this momentum-space phase is especially important with regard to
the studies of BEC momentum distributions. In addition, this work presents a
new method of BEC interferometry and should contribute to the ongoing research
in that field. One of our significant findings is the presence of substantial
differences betwteen the momentum density obtained by a Fourier transform (FT)
of the spatial density distribution and the one obtained from the modulus of
the wavefunction in momentum space; the latter is obtained by a FT of the
spatial wavefunction.


title: The ANDES Deep Underground Laboratory

abstract:
  ANDES (Agua Negra Deep Experiment Site) is a unique opportunity to build a
deep underground laboratory in the southern hemisphere. It will be built in the
Agua Negra tunnel planned between Argentina and Chile, and operated by the
CLES, a Latin American consortium. With 1750m of rock overburden, and no close-
by nuclear power plant, it will provide an extremely radiation quiet
environment for neutrino and dark matter experiments. In particular, its
location in the southern hemisphere should play a major role in understanding
dark matter modulation signals.


title:
Integral points on quadratic twists and linear growth for certain
  elliptic fibrations

abstract:
  We prove that the number of rational points of bounded height on certain del
Pezzo surfaces of degree 1 defined over Q grows linearly, as predicted by
Manin's conjecture. Along the way, we investigate the average number of
integral points of small naive height on quadratic twists of a fixed elliptic
curve with full rational 2-torsion.


title:
Negative differential resistance in graphene-nanoribbon/carbon-nanotube
  crossbars: A first-principles multiterminal quantum transport study

abstract:
  We simulate quantum transport between a graphene nanoribbon (GNR) and a
single-walled carbon nanotube (CNT) where electrons traverse vacuum gap between
them. The GNR covers CNT over a nanoscale region while their relative rotation
is 90 degrees, thereby forming a four-terminal crossbar where the bias voltage
is applied between CNT and GNR terminals. The CNT and GNR are chosen as either
semiconducting (s) or metallic (m) based on whether their two-terminal
conductance exhibits a gap as a function of the Fermi energy or not,
respectively. We find nonlinear current-voltage (I-V) characteristics in all
three investigated devices---mGNR-sCNT, sGNR-sCNT and mGNR-mCNT
crossbars---which are asymmetric with respect to changing the bias voltage from
positive to negative. Furthermore, the I-V characteristics of mGNR-sCNT
crossbar exhibits negative differential resistance (NDR) with low onset voltage
$V_\mathrm{NDR} \simeq 0.25$ V and peak-to-valley current ratio $\simeq 2.0$.
The overlap region of the crossbars contains only $\simeq 460$ carbon and
hydrogen atoms which paves the way for nanoelectronic devices ultrascaled well
below the smallest horizontal length scale envisioned by the international
technology roadmap for semiconductors. Our analysis is based on the
nonequilibrium Green function formalism combined with density functional theory
(NEGF-DFT), where we also provide an overview of recent extensions of NEGF-DFT
framework (originally developed for two-terminal devices) to multiterminal
devices.


title:
Upper bounds for Bergman kernels associated to positive line bundles
  with smooth Hermitian metrics

abstract:
  Off-diagonal upper bounds are established away from the diagonal for the
Bergman kernels associated to high powers of holomorphic line bundles over
compact complex manifolds, asymptotically as the power tends to infinity. The
line bundle is assumed to be equipped with a Hermitian metric with positive
curvature form, which is infinitely differentiable but not necessarily real
analytic. The bounds obtained are the best possible for this class of metrics.


title: CLASH: Photometric redshifts with 16 HST bands in galaxy cluster fields

abstract:
  The Cluster Lensing And Supernovae survey with Hubble (CLASH) is an Hubble
Space Telescope (HST) Multi-Cycle Treasury program observing 25 massive galaxy
clusters. CLASH observations are carried out in 16 bands from UV to NIR to
derive accurate and reliable estimates of photometric redshifts. We present the
CLASH photometric redshifts and study the photometric redshift accuracy of the
arcs in more detail for the case of MACS1206.2-0847. We use the publicly
available Le Phare and BPZ photometric redshift codes on 17 CLASH galaxy
clusters. Using Le Phare code for objects with StoN>=10, we reach a precision
of 3%(1+z) for the strong lensing arcs, which is reduced to 2.4%(1+z) after
removing outliers. For galaxies in the cluster field the corresponding values
are 4%(1+z) and 3%(1+z). Using mock galaxy catalogues, we show that 3%(1+z)
precision is what one would expect from the CLASH photometry when taking into
account extinction from dust, emission lines and the finite range of SEDs
included in the photo-z template library. We study photo-z results for
different aperture photometry and find that the SExtractor isophotal photometry
works best. Le Phare and BPZ give similar photo-z results for the strong
lensing arcs as well as galaxies of the cluster field. Results are improved
when optimizing the photometric aperture shape showing an optimal aperture size
around 1" radius giving results which are equivalent to isophotal photometry.
Tailored photometry of the arcs improve the photo-z results.


title: Dynamical Supersymmetry Breaking with T_N Theory

abstract:
  We demonstrate that the supersymmetry is dynamically broken in the
four-dimensional SU(N) gauge theory coupled to a strongly-coupled
superconformal theory T_N. This is a direct generalization of the model of
supersymmetry breaking on deformed moduli space in supersymmetric QCD with an
SU(2) gauge group.


title:
Zeros of partial sums of the Dedekind zeta function of a cyclotomic
  field

abstract:
  In this article, we study the zeros of the partial sums of the Dedekind zeta
function of a cyclotomic field $K$ defined by the truncated Dirichlet series \[
\zeta_{K, X} (s)
  = \sum_{\|\mathfrak{a}\| \leq X} \frac{1}{\|\mathfrak{a}\|^{s}}, \] where the
sum is to be taken over nonzero integral ideals $\mathfrak{a}$ of $K$ and
$\|\mathfrak{a}\|$ denotes the absolute norm of $\mathfrak{a}$. Specifically,
we establish the zero-free regions for $\zeta_{K, X} (s)$ and estimate the
number of zeros of $\zeta_{K, X} (s)$ up to height $T$.


title: Drawing Arrangement Graphs In Small Grids, Or How To Play Planarity

abstract:
  We describe a linear-time algorithm that finds a planar drawing of every
graph of a simple line or pseudoline arrangement within a grid of area
O(n^{7/6}). No known input causes our algorithm to use area
\Omega(n^{1+\epsilon}) for any \epsilon>0; finding such an input would
represent significant progress on the famous k-set problem from discrete
geometry. Drawing line arrangement graphs is the main task in the Planarity
puzzle.


title:
Collider Constraints on the Dark Matter Interpretation of the CDMS II
  Results

abstract:
  The recent observation of three events by the CDMS II experiment can be
interpreted as a 8.6 GeV dark matter scatters elastically with the nucleons
inside the silicon detectors with a spin-independent cross section of 1.9 x
10^-41 cm^2. We employ the effective dark matter interaction approach to fit to
the interpreted cross section, and make predictions for monojet and monophoton
production at the LHC with the fitted parameters. We show that some of the
operators are already ruled out by current data while the others can be further
probed in the upcoming 14 TeV run of the LHC.


title:
Communication lower bounds and optimal algorithms for programs that
  reference arrays -- Part 1

abstract:
  The movement of data (communication) between levels of a memory hierarchy, or
between parallel processors on a network, can greatly dominate the cost of
computation, so algorithms that minimize communication are of interest.
Motivated by this, attainable lower bounds for the amount of communication
required by algorithms were established by several groups for a variety of
algorithms, including matrix computations. Prior work of
Ballard-Demmel-Holtz-Schwartz relied on a geometric inequality of Loomis and
Whitney for this purpose. In this paper the general theory of discrete
multilinear Holder-Brascamp-Lieb (HBL) inequalities is used to establish
communication lower bounds for a much wider class of algorithms. In some cases,
algorithms are presented which attain these lower bounds.
  Several contributions are made to the theory of HBL inequalities proper. The
optimal constant in such an inequality for torsion-free Abelian groups is shown
to equal one whenever it is finite. Bennett-Carbery-Christ-Tao had
characterized the tuples of exponents for which such an inequality is valid as
the convex polyhedron defined by a certain finite list of inequalities. The
problem of constructing an algorithm to decide whether a given inequality is on
this list, is shown to be equivalent to Hilbert's Tenth Problem over the
rationals, which remains open. Nonetheless, an algorithm which computes the
polyhedron itself is constructed.


title: Spectral compression of single photons

abstract:
  Photons are critical to quantum technologies since they can be used for
virtually all quantum information tasks: in quantum metrology, as the
information carrier in photonic quantum computation, as a mediator in hybrid
systems, and to establish long distance networks. The physical characteristics
of photons in these applications differ drastically; spectral bandwidths span
12 orders of magnitude from 50 THz for quantum-optical coherence tomography to
50 Hz for certain quantum memories. Combining these technologies requires
coherent interfaces that reversibly map centre frequencies and bandwidths of
photons to avoid excessive loss. Here we demonstrate bandwidth compression of
single photons by a factor 40 and tunability over a range 70 times that
bandwidth via sum-frequency generation with chirped laser pulses. This
constitutes a time-to-frequency interface for light capable of converting
time-bin to colour entanglement and enables ultrafast timing measurements. It
is a step toward arbitrary waveform generation for single and entangled
photons.


title:
Optical spectral index - luminosity relation for the 17 mapped
  Palomar-Green quasars

abstract:
  In this paper, the optical spectra index - luminosity relationship is checked
for the well-known 17 individual mapped QSOs, in order to give one more clearer
conclusion on the so far conflicting dependence of the spectral index on the
luminosity for AGN. Different from the global relationships based on the color
difference (photometry parameters) for samples of AGN, the more reliable
relationship is determined for the multi-epoch observed individual mapped QSOs
with no contamination from the host galaxies, the line variabilities and the
much different central properties. The final confirmed results are as follows.
(1): No strong dependence of the optical spectral index on the continuum
luminosity can be found for all the 17 QSOs, besides two objects (PG 0026 and
PG 1613) having some weak trends (with $3\sigma$ confidence level) for the
relationship. In other words, the common sense 'AGNs get bluer when they get
brighter' is not so common. (2): There are much different damped intrinsic
variability time scales for the variability modes of the optical spectral index
and the continuum emission, through the well applied Damped Random Walk method
for the AGN variability. In other words, there are some different intrinsic
mechanisms controlling the variabilities of the optical spectral index and the
power law AGN continuum emission. Therefore, the much weak dependence of the
optical spectral index on the continuum luminosity can be further confirmed.


title: Power dependence of electric dipole spin resonance

abstract:
  We develop a formalism of electric dipole spin resonance (EDSR) based on
slanting magnetic field, where we especially investigate the microwave
amplitude dependence. With increasing microwave amplitude, the Rabi frequency
increases linearly for a spin confined in a harmonic potential. How- ever, when
the spin is confined in the double-well potential, the Rabi frequency shows
sub-linear dependence with increasing the microwave amplitude.


title:
Joint DOA and Polarization Estimation with Sparsely Distributed and
  Spatially Non-Collocating Dipole/Loop Triads

abstract:
  This paper introduces an ESPRIT-based algorithm to estimate the
directions-of-arrival and polarizations for multiple sources. The investigated
algorithm is based on new sparse array geometries, which are composed of three
non-collocating dipole triads or three non-collocating loop triads. Both the
inter-triad spacings and the inter-sensor spacings in the same triad can be far
larger than a half-wavelength of the incident sources. By adopting the ESPRIT
algorithm, the eigenvalues of the data-correlation matrix offer the fine but
ambiguous estimates of the direction-cosines for each source, and the
eigenvectors provide the estimates of each source's steering vector. Based on
the constrained array geometries, the fine and unambiguous estimates of
directions-of-arrival and polarizations are obtained. Simulation results verify
the efficacy of the investigated approach and also verify the aperture
extension property of the proposed array geometries.


title: Liouville theorems for the polyharmonic Henon-Lane-Emden system

abstract:
  We study Liouville theorems for the following polyharmonic
H\'{e}non-Lane-Emden system \begin{eqnarray*}
  \left\{\begin{array}{lcl} (-\Delta)^m u&=& |x|^{a}v^p \ \ \text{in}\ \
\mathbb{R}^n,\\ (-\Delta)^m v&=& |x|^{b}u^q \ \ \text{in}\ \ \mathbb{R}^n,
\end{array}\right.
  \end{eqnarray*} when $m,p,q \ge 1,$ $pq\neq1$, $a,b\ge0$. The main conjecture
states that $(u,v)=(0,0)$ is the unique nonnegative solution of this system
whenever $(p,q)$ is {\it under} the critical Sobolev hyperbola, i.e. $
\frac{n+a}{p+1}+\frac{n+b}{q+1}>{n-2m}$. We show that this is indeed the case
in dimension $n=2m+1$ for bounded solutions. In particular, when $a=b$ and
$p=q$, this means that $u=0$ is the only nonnegative bounded solution of the
polyharmonic H\'{e}non equation
  \begin{equation*}
  (-\Delta)^m u= |x|^{a}u^p \ \ \text{in}\ \ \mathbb{R}^{n}
  \end{equation*} in dimension $n=2m+1$ provided $p$ is the subcritical Sobolev
exponent, i.e., $1<p<{1+4m+2a}$. Moreover, we show that the conjecture holds
for radial solutions in any dimensions. It seems the power weight functions
$|x|^a$ and $|x|^b$ make the problem dramatically more challenging when dealing
with nonradial solutions.


title: Are there infinitely many decompositions of the nucleon spin ?

abstract:
  We argue against the rapidly spreading idea of gauge-invariant-extension
(GIE) approach in the nucleon spin decomposition problem, which implies the
existence of infinitely many gauge-invariant decomposition of the nucleon spin.


title:
Polynomial-Phase Signal Direction-Finding & Source-Tracking with an
  Acoustic Vector Sensor

abstract:
  A new ESPRIT-based algorithm is proposed to estimate the direction-of-arrival
of an arbitrary degree polynomial-phase signal with a single acoustic vector
sensor. The proposed approach requires neither a priori knowledge of the
polynomial-phase signal's coefficients nor a priori knowledge of the
polynomial-phase signal's frequency-spectrum. A pre-processing technique is
also proposed to incorporate the single-forgetting-factor algorithm and
multiple-forgetting-factor adaptive tracking algorithm to track a
polynomial-phase signal using one acoustic vector sensor. Simulation results
verify the efficacy of the proposed direction finding and source tracking
algorithms.