title:
The Atacama Cosmology Telescope: Dusty Star-Forming Galaxies and Active
  Galactic Nuclei in the Southern Survey

abstract:
  We present a catalog of 191 extragalactic sources detected by the Atacama
Cosmology Telescope (ACT) at 148 GHz and/or 218 GHz in the 2008 Southern
survey. Flux densities span 14-1700 mJy, and we use source spectral indices
derived using ACT-only data to divide our sources into two sub-populations: 167
radio galaxies powered by central active galactic nuclei (AGN), and 24 dusty
star-forming galaxies (DSFGs). We cross-identify 97% of our sources (166 of the
AGN and 19 of the DSFGs) with those in currently available catalogs. When
combined with flux densities from the Australian Telescope 20 GHz survey and
follow-up observations with the Australia Telescope Compact Array, the
synchrotron-dominated population is seen to exhibit a steepening of the slope
of the spectral energy distribution from 20 to 148 GHz, with the trend
continuing to 218 GHz. The ACT dust-dominated source population has a median
spectral index of 3.7+0.62-0.86, and includes both local galaxies and sources
with redshifts as great as 5.6. Dusty sources with no counterpart in existing
catalogs likely belong to a recently discovered subpopulation of DSFGs lensed
by foreground galaxies or galaxy groups.


title:
Oil droplet behavior at a pore entrance in the presence of crossflow:
  Implications for microfiltration of oil-water dispersions

abstract:
  The behavior of an oil droplet pinned at the entrance of a micropore and
subject to clossflow-induced shear is investigated numerically by solving the
Navier-Stokes equation. We found that in the absence of crossflow, the critical
transmembrane pressure required to force the droplet into the pore is in
excellent agreement with a theoretical prediction based on the Young-Laplace
equation. With increasing shear rate, the critical pressure of permeation
increases, and at sufficiently high shear rates the oil droplet breaks up into
two segments. The results of numerical simulations indicate that droplet
breakup at the pore entrance is facilitated at lower surface tension, higher
oil-to-water viscosity ratio and larger droplet size but is insensitive to the
value of the contact angle. Using simple force and torque balance arguments, an
estimate for the increase in critical pressure due to crossflow and the breakup
capillary number is obtained and validated for different viscosity ratios,
surface tension coefficients, contact angles, and drop-to-pore size ratios.


title:
Asymptotically Optimal Sequential Estimation of the Mean Based on
  Inclusion Principle

abstract:
  A large class of problems in sciences and engineering can be formulated as
the general problem of constructing random intervals with pre-specified
coverage probabilities for the mean. Wee propose a general approach for
statistical inference of mean values based on accumulated observational data.
We show that the construction of such random intervals can be accomplished by
comparing the endpoints of random intervals with confidence sequences for the
mean. Asymptotic results are obtained for such sequential methods.


title: Optimal multi-binding unification for sharing and linearity analysis

abstract:
  In the analysis of logic programs, abstract domains for detecting sharing
properties are widely used. Recently the new domain $\Linp$ has been introduced
to generalize both sharing and linearity information. This domain is endowed
with an optimal abstract operator for single-binding unification. The authors
claim that the repeated application of this operator is also optimal for
multi-binding unification. This is the proof of such a claim.


title: On the scattering over the GKP vacuum

abstract:
  By converting the Asymptotic Bethe Ansatz (ABA) of ${\cal N}=4$ SYM into
non-linear integral equations, we find 2D scattering amplitudes of excitations
on top of the GKP vacuum. We prove that this is a suitable and powerful set-up
for the understanding and computation of the whole S-matrix. We show that all
the amplitudes depend on the fundamental scalar-scalar one.


title:
The Compositional Nature of Verb and Argument Representations in the
  Human Brain

abstract:
  How does the human brain represent simple compositions of objects, actors,and
actions? We had subjects view action sequence videos during neuroimaging (fMRI)
sessions and identified lexical descriptions of those videos by decoding (SVM)
the brain representations based only on their fMRI activation patterns. As a
precursor to this result, we had demonstrated that we could reliably and with
high probability decode action labels corresponding to one of six action videos
(dig, walk, etc.), again while subjects viewed the action sequence during
scanning (fMRI). This result was replicated at two different brain imaging
sites with common protocols but different subjects, showing common brain areas,
including areas known for episodic memory (PHG, MTL, high level visual
pathways, etc.,i.e. the 'what' and 'where' systems, and TPJ, i.e. 'theory of
mind'). Given these results, we were also able to successfully show a key
aspect of language compositionality based on simultaneous decoding of object
class and actor identity. Finally, combining these novel steps in 'brain
reading' allowed us to accurately estimate brain representations supporting
compositional decoding of a complex event composed of an actor, a verb, a
direction, and an object.


title: Smooth attractors for the quintic wave equations with fractional damping

abstract:
  Dissipative wave equations with critical quintic nonlinearity and damping
term involving the fractional Laplacian are considered. The additional
regularity of energy solutions is established by constructing the new
Lyapunov-type functional and based on this, the global well-posedness and
dissipativity of the energy solutions as well as the existence of a smooth
global and exponential attractors of finite Hausdorff and fractal dimension is
verified.


title: Markov random fields factorization with context-specific independences

abstract:
  Markov random fields provide a compact representation of joint probability
distributions by representing its independence properties in an undirected
graph. The well-known Hammersley-Clifford theorem uses these conditional
independences to factorize a Gibbs distribution into a set of factors. However,
an important issue of using a graph to represent independences is that it
cannot encode some types of independence relations, such as the
context-specific independences (CSIs). They are a particular case of
conditional independences that is true only for a certain assignment of its
conditioning set; in contrast to conditional independences that must hold for
all its assignments. This work presents a method for factorizing a Markov
random field according to CSIs present in a distribution, and formally
guarantees that this factorization is correct. This is presented in our main
contribution, the context-specific Hammersley-Clifford theorem, a
generalization to CSIs of the Hammersley-Clifford theorem that applies for
conditional independences.


title: Collective behavior and evolutionary games - An introduction

abstract:
  This is an introduction to the special issue titled "Collective behavior and
evolutionary games" that is in the making at Chaos, Solitons & Fractals. The
term collective behavior covers many different phenomena in nature and society.
From bird flocks and fish swarms to social movements and herding effects, it is
the lack of a central planner that makes the spontaneous emergence of sometimes
beautifully ordered and seemingly meticulously designed behavior all the more
sensational and intriguing. The goal of the special issue is to attract
submissions that identify unifying principles that describe the essential
aspects of collective behavior, and which thus allow for a better
interpretation and foster the understanding of the complexity arising in such
systems. As the title of the special issue suggests, the later may come from
the realm of evolutionary games, but this is certainly not a necessity, neither
for this special issue, and certainly not in general. Interdisciplinary work on
all aspects of collective behavior, regardless of background and motivation,
and including synchronization and human cognition, is very welcome.


title: Universal Nash Equilibrium Strategies for Differential Games

abstract:
  The paper is concerned with a two-player nonzero-sum differential game in the
case when players are informed about the current position. We consider the game
in control with guide strategies first proposed by Krasovskii and Subbotin. The
construction of universal strategies is given both for the case of continuous
and discontinuous value functions. The existence of a discontinuous value
function is established. The continuous value function does not exist in the
general case. In addition, we show the example of smooth value function not
being a solution of the system of Hamilton--Jacobi equation.


title:
Generative Model Selection Using a Scalable and Size-Independent Complex
  Network Classifier

abstract:
  Real networks exhibit nontrivial topological features such as heavy-tailed
degree distribution, high clustering, and small-worldness. Researchers have
developed several generative models for synthesizing artificial networks that
are structurally similar to real networks. An important research problem is to
identify the generative model that best fits to a target network. In this
paper, we investigate this problem and our goal is to select the model that is
able to generate graphs similar to a given network instance. By the means of
generating synthetic networks with seven outstanding generative models, we have
utilized machine learning methods to develop a decision tree for model
selection. Our proposed method, which is named "Generative Model Selection for
Complex Networks" (GMSCN), outperforms existing methods with respect to
accuracy, scalability and size-independence.


title: Protecting OAM Photons from Decoherence in a Turbulent Atmosphere

abstract:
  One of the most important properties of orbital angular momentum (OAM) of
photons is that the Hilbert space required to describe a general quantum state
is infinite dimensional. In principle, this could allow for encoding
arbitrarily large amounts of quantum information per photon, but in practice,
this potential is limited by decoherence and errors. To determine whether
photons with OAM are suitable for quantum communication, we numerically
simulated their passage through a turbulent atmosphere and the resulting
errors. We also proposed an encoding scheme to protect the photons from these
errors, and characterized its effectiveness by the channel fidelity.


title: Lithium Mediated Benzene Adsorption on Graphene and Graphene Nanoribbons

abstract:
  The anchoring of benzene molecules on lithium adsorption sites at the surface
of graphene and nanoribbons thereof are investigated. The effects of adsorbate
densities, specific adsorption locations, and spin states on the structural
stability and electronic properties of the underlying graphene derivatives are
revealed. At sufficiently high densities, bare lithium adsorption turns
armchair graphene nanoribbons metallic and their zigzag counterparts
half-metallic due to charge transfer from the adatom to the {\pi} electronic
system. Upon benzene adsorption, the lithium cation encounters two {\pi}
systems thus drawing charge back towards the benzene molecule. This, in turn,
leads to the opening of a measurable bandgap, whose size and character are
sensitive to the adsorbate density, thus indicating that a chemical detector
based on lithium adsorbed graphene may be devised. Our results are therefore
expected to support the design of novel graphene-based sensing and switching
devices.


title: A note on quantum related-key attacks

abstract:
  In a basic related-key attack against a block cipher, the adversary has
access to encryptions under keys that differ from the target key by bit-flips.
In this short note we show that for a quantum adversary such attacks are quite
powerful: if the secret key is (i) uniquely determined by a small number of
plaintext-ciphertext pairs, (ii) the block cipher can be evaluated efficiently,
and (iii) a superposition of related keys can be queried, then the key can be
extracted efficiently.


title: Background modeling for the GERDA experiment

abstract:
  The neutrinoless double beta (0nubb) decay experiment GERDA at the LNGS of
INFN has started physics data taking in November 2011. This paper presents an
analysis aimed at understanding and modeling the observed background energy
spectrum, which plays an essential role in searches for a rare signal like
0nubb decay. A very promising preliminary model has been obtained, with the
systematic uncertainties still under study. Important information can be
deduced from the model such as the expected background and its decomposition in
the signal region. According to the model the main background contributions
around Qbb come from Bi-214, Th-228, K-42, Co-60 and alpha emitting isotopes in
the Ra-226 decay chain, with a fraction depending on the assumed source
positions.


title: The neutron background of the XENON100 dark matter experiment

abstract:
  The XENON100 experiment, installed underground at the Laboratori Nazionali
del Gran Sasso (LNGS), aims to directly detect dark matter in the form of
Weakly Interacting Massive Particles (WIMPs) via their elastic scattering off
xenon nuclei. This paper presents a study on the nuclear recoil background of
the experiment, taking into account neutron backgrounds from ($\alpha$,n) and
spontaneous fission reactions due to natural radioactivity in the detector and
shield materials, as well as muon-induced neutrons. Based on Monte Carlo
simulations and using measured radioactive contaminations of all detector
components, we predict the nuclear recoil backgrounds for the WIMP search
results published by the XENON100 experiment in 2011 and 2012,
0.11$^{+0.08}_{-0.04}$ events and 0.17$^{+0.12}_{-0.07}$ events, respectively,
and conclude that they do not limit the sensitivity of the experiment.


title: Andromeda's Dust

abstract:
  Spitzer Space Telescope and Herschel Space Observatory imaging of M31 is
used, with a physical dust model, to construct maps of dust surface density,
dust-to-gas ratio, starlight heating intensity, and PAH abundance, out to
R=25kpc. The global dust mass is M_d=5.4x10^7Msol, the global dust/H mass ratio
is M_d/M_H=0.0081, and the global PAH abundance is <q_PAH>=0.039. The dust
surface density has an inner ring at R=5.6kpc, a maximum at R=11.2kpc, and an
outer ring at R=15.1kpc. The dust/gas ratio varies from M_d/M_H=0.026 at the
center to ~0.0027 at R=25kpc. From the dust/gas ratio, we estimate the ISM
metallicity to vary by a factor ~10, from Z/Zsol=3 at R=0 to ~0.3 at R=25kpc.
The dust heating rate parameter <U> peaks at the center, with <U> approx 35,
declining to <U> approx 0.25 at R=20kpc. Within the central kpc, the starlight
heating intensity inferred from the dust modeling is close to what is estimated
from the stars in the bulge. The PAH abundance reaches a peak q_PAH=0.045 at
R=11.2kpc. When allowance is made for the different spectrum of the bulge
stars, q_PAH for the dust in the central kpc is similar to the overall value of
q_PAH in the disk. The silicate-graphite-PAH dust model used here is generally
able to reproduce the observed dust spectral energy distribution across M31,
but overpredicts 500um emission at R=2-6kpc, suggesting that at R=2-6kpc, the
dust opacity varies more steeply with frequency (with beta approx 2.3 between
200 and 600um) than in the model


title: Computing Flowpipe of Nonlinear Hybrid Systems with Numerical Methods

abstract:
  Modern control-command systems often include controllers that perform
nonlinear computations to control a physical system, which can typically be
described by an hybrid automaton containing high-dimensional systems of
nonlinear differential equations. To prove safety of such systems, one must
compute all the reachable sets from a given initial position, which might be
uncertain (its value is not precisely known). On linear hybrid systems,
efficient and precise techniques exist, but they fail to handle nonlinear flows
or jump conditions. In this article, we present a new tool name HySon which
computes the flowpipes of both linear and nonlinear hybrid systems using
guaranteed generalization of classical efficient numerical simulation methods,
including with variable integration step-size. In particular, we present an
algorithm for detecting discrete events based on guaranteed interpolation
polynomials that turns out to be both precise and efficient. Illustrations of
the techniques developed in this article are given on representative examples.


title:
The Tip of the Red Giant Branch Distances to Type Ia Supernova Host
  Galaxies. II. M66 and M96 in the Leo I Group

abstract:
  M66 and M96 in the Leo I Group are nearby spiral galaxies hosting Type Ia
Supernovae (SNe Ia). We estimate the distances to these galaxies from the
luminosity of the tip of the red giant branch (TRGB). We obtain $VI$ photometry
of resolved stars in these galaxies from $F555W$ and $F814W$ images in the {\it
Hubble Space Telescope} archive. From the luminosity function of these red
giants we find the TRGB $I$-band magnitude to be $I_{\rm TRGB}=26.20\pm0.03$
for M66 and $26.21\pm0.03$ for M96. These values yield distance modulus
$(m-M)_0=30.12\pm0.03 ({\rm random})\pm0.12 ({\rm systematic})$ for M66 and
$(m-M)_0=30.15\pm0.03 ({\rm random})\pm0.12 ({\rm systematic})$ for M96. These
results show that they are indeed the members of the same group. With these
results we derive absolute maximum magnitudes of two SNe (SN 1989B in M66 and
SN 1998bu in M96). $V$-band magnitudes of these SNe Ia are $\sim$0.2 mag
fainter than SN 2011fe in M101, the nearest recent SN Ia. We also derive
near-infrared magnitudes for SN 1998bu. Optical magnitudes of three SNe Ia (SN
1989B, SN 1998bu, and SN 2011fe) based on TRGB analysis yield a Hubble
constant, $H_0=67.6\pm1.5 ({\rm random})\pm 3.7({\rm systematic})$ \kmsMpc.
This value is similar to the values derived from recent WMAP9 results,
$H_0=69.32\pm0.80$ \kmsMpc. % and from Planck results, $H_0=67.3\pm1.2$
\kmsMpc, but smaller than other recent determinations based on Cepheid
calibration for SNe Ia luminosity, $H_0 = 74 \pm3$ km s$^{-1}$ Mpc$^{-1}$.


title:
The Hot and Energetic Universe: A White Paper presenting the science
  theme motivating the Athena+ mission

abstract:
  This White Paper, submitted to the recent ESA call for science themes to
define its future large missions, advocates the need for a transformational
leap in our understanding of two key questions in astrophysics: 1) How does
ordinary matter assemble into the large scale structures that we see today? 2)
How do black holes grow and shape the Universe? Hot gas in clusters, groups and
the intergalactic medium dominates the baryonic content of the local Universe.
To understand the astrophysical processes responsible for the formation and
assembly of these large structures, it is necessary to measure their physical
properties and evolution. This requires spatially resolved X-ray spectroscopy
with a factor 10 increase in both telescope throughput and spatial resolving
power compared to currently planned facilities. Feedback from supermassive
black holes is an essential ingredient in this process and in most galaxy
evolution models, but it is not well understood. X-ray observations can
uniquely reveal the mechanisms launching winds close to black holes and
determine the coupling of the energy and matter flows on larger scales. Due to
the effects of feedback, a complete understanding of galaxy evolution requires
knowledge of the obscured growth of supermassive black holes through cosmic
time, out to the redshifts where the first galaxies form. X-ray emission is the
most reliable way to reveal accreting black holes, but deep survey speed must
improve by a factor ~100 over current facilities to perform a full census into
the early Universe. The Advanced Telescope for High Energy Astrophysics
(Athena+) mission provides the necessary performance (e.g. angular resolution,
spectral resolution, survey grasp) to address these questions and revolutionize
our understanding of the Hot and Energetic Universe. These capabilities will
also provide a powerful observatory to be used in all areas of astrophysics.

categories: astro-ph.HE astro-ph.CO astro-ph.EP astro-ph.IM astro-ph.SR


title: Kepler Microlens Planets and Parallaxes

abstract:
  Kepler's quest for other Earths need not end just yet: it remains capable of
characterizing cool Earth-mass planets by microlensing, even given its degraded
pointing control. If Kepler were pointed at the Galactic bulge, it could
conduct a search for microlensing planets that would be virtually
non-overlapping with ground-based surveys. More important, by combining Kepler
observations with current ground-based surveys, one could measure the
"microlens parallax" \pi_E for a large fraction of the known microlensing
events. Such parallax measurements would yield mass and distance determinations
for the great majority of microlensing planets, enabling much more precise
study of the planet distributions as functions of planet and host mass,
planet-host separation, and Galactic position (particularly bulge vs. disk). In
addition, rare systems (such as planets orbiting brown dwarfs or black holes)
that are presently lost in the noise would be clearly identified. In contrast
to Kepler's current primary hunting ground of close-in planets, its
microlensing planets would be in the cool outer parts of solar systems,
generally beyond the snow line. The same survey would yield a spectacular
catalog of brown-dwarf binaries, probe the stellar mass function in a unique
way, and still have plenty of time available for asteroseismology targets.


title: Demystifying the PeV Cascades in IceCube: Less (Energy) is More (Events)

abstract:
  The IceCube neutrino observatory has detected two cascade events with
energies near 1 PeV. Without invoking new physics, we analyze the source of
these neutrinos. We show that atmospheric conventional neutrinos and cosmogenic
neutrinos (those produced in the propagation of ultra-high- energy cosmic rays)
are strongly disfavored. For atmospheric prompt neutrinos or a diffuse
background of neutrinos produced in astrophysical objects, the situation is
less clear. We show that there are tensions with observed data, but that the
details depend on the least-known aspects of the IceCube analysis. Very likely,
prompt neutrinos are disfavored and astrophysical neutrinos are plausible. We
demonstrate that the fastest way to reveal the origin of the observed PeV
neutrinos is to search for neutrino cascades in the range below 1 PeV, for
which dedicated analyses with high sensitivity have yet to appear, and where
many more events could be found.


title:
A Detailed Kinematic Map of Cassiopeia A's Optical Main Shell and Outer
  High-Velocity Ejecta

abstract:
  We present three-dimensional kinematic reconstructions of optically emitting
material in the young Galactic supernova remnant Cassiopeia A (Cas A). These
Doppler maps have the highest spectral and spatial resolutions of any previous
survey of Cas A and represent the most complete catalog of its optically
emitting material to date. We confirm that the bulk of Cas A's optically bright
ejecta populate a torus-like geometry tilted approximately 30 degrees with
respect to the plane of the sky with a -4000 to +6000 km/s radial velocity
asymmetry. Near-tangent viewing angle effects and an inhomogeneous surrounding
CSM/ISM environment suggest that this geometry and velocity asymmetry may not
be faithfully representative of the remnant's true 3D structure or the
kinematic properties of the original explosion. The majority of the optical
ejecta are arranged in several well-defined and nearly circular ring-like
structures with diameters between approximately 30 arcsec (0.5 pc) and 2 arcmin
(2 pc). These ejecta rings appear to be a common phenomenon of young
core-collapse remnants and may be associated with post-explosion input of
energy from plumes of radioactive 56Ni-rich ejecta that rise, expand, and
compress non-radioactive material. Our optical survey also encompassed Cas A's
faint outlying ejecta knots and exceptionally high-velocity NE and SW streams
of S-rich debris often referred to as `jets'. These outer knots, which exhibit
a chemical make-up suggestive of an origin deep within the progenitor star,
appear to be arranged in opposing and wide-angle outflows with opening
half-angles of approximately 40 degrees.


title: Transit observations of the Hot Jupiter HD 189733b at X-ray wavelengths

abstract:
  We present new X-ray observations obtained with Chandra ACIS-S of the HD
189733 system, consisting of a K-type star orbited by a transiting Hot Jupiter
and an M-type stellar companion. We report a detection of the planetary transit
in soft X-rays with a significantly larger transit depth than observed in the
optical. The X-ray data favor a transit depth of 6-8%, versus a broadband
optical transit depth of 2.41%. While we are able to exclude several possible
stellar origins for this deep transit, additional observations will be
necessary to fully exclude the possibility that coronal inhomogeneities
influence the result. From the available data, we interpret the deep X-ray
transit to be caused by a thin outer planetary atmosphere which is transparent
at optical wavelengths, but dense enough to be opaque to X-rays. The X-ray
radius appears to be larger than the radius observed at far-UV wavelengths,
most likely due to high temperatures in the outer atmosphere at which hydrogen
is mostly ionized. We furthermore detect the stellar companion HD 189733B in
X-rays for the first time with an X-ray luminosity of log LX = 26.67 erg/s. We
show that the magnetic activity level of the companion is at odds with the
activity level observed for the planet-hosting primary. The discrepancy may be
caused by tidal interaction between the Hot Jupiter and its host star.


title:
An XMM-Newton Survey of the Soft X-ray Background. III. The Galactic
  Halo X-ray Emission

abstract:
  We present measurements of the Galactic halo's X-ray emission for 110
XMM-Newton sight lines, selected to minimize contamination from solar wind
charge exchange emission. We detect emission from few million degree gas on
~4/5 of our sight lines. The temperature is fairly uniform (median = 2.22e6 K,
interquartile range = 0.63e6 K), while the emission measure and intrinsic
0.5--2.0 keV surface brightness vary by over an order of magnitude (~(0.4-7)e-3
cm^-6 pc and ~(0.5-7)e-12 erg cm^-2 s^-1 deg^-2, respectively, with median
detections of 1.9e-3 cm^-6 pc and 1.5e-12 erg cm^-2 s^-1 deg^-2, respectively).
The high-latitude sky contains a patchy distribution of few million degree gas.
This gas exhibits a general increase in emission measure toward the inner
Galaxy in the southern Galactic hemisphere. However, there is no tendency for
our observed emission measures to decrease with increasing Galactic latitude,
contrary to what is expected for a disk-like halo morphology. The measured
temperatures, brightnesses, and spatial distributions of the gas can be used to
place constraints on models for the dominant heating sources of the halo. We
provide some discussion of such heating sources, but defer comparisons between
the observations and detailed models to a later paper.


title:
Time reversal symmetry breakdown in normal and superconducting states in
  frustrated three-band systems

abstract:
  We discuss the phase diagram and phase transitions in $U(1)\times \groupZ{2}$
three-band superconductors with broken time reversal symmetry. We find that
beyond mean field approximation and for sufficiently strong frustration of
interband interactions there appears an unusual metallic state precursory to a
superconducting phase transition. In that state, the system is not
superconducting. Nonetheless, it features a spontaneously broken $\groupZ{2}$
time reversal symmetry. By contrast, for weak frustration of interband coupling
the energy of a domain wall between different $\groupZ{2}$ states is low and
thus fluctuations restore broken time reversal symmetry in the superconducting
state at low temperatures.


title:
Warm Dark Matter as a solution to the small scale crisis: new
  constraints from high redshift Lyman-alpha forest data

abstract:
  We present updated constraints on the free-streaming of warm dark matter
(WDM) particles derived from an analysis of the Lya flux power spectrum
measured from high-resolution spectra of 25 z > 4 quasars obtained with the
Keck High Resolution Echelle Spectrometer (HIRES) and the Magellan Inamori
Kyocera Echelle (MIKE) spectrograph. We utilize a new suite of high-resolution
hydrodynamical simulations that explore WDM masses of 1, 2 and 4 keV (assuming
the WDM consists of thermal relics), along with different physically motivated
thermal histories. We carefully address different sources of systematic error
that may affect our final results and perform an analysis of the Lya flux power
with conservative error estimates. By using a method that samples the
multi-dimensional astrophysical and cosmological parameter space, we obtain a
lower limit mwdm > 3.3 keV (2sigma) for warm dark matter particles in the form
of early decoupled thermal relics. Adding the Sloan Digital Sky Survey (SDSS)
Lya flux power spectrum does not improve this limit. Thermal relics of masses 1
keV, 2 keV and 2.5 keV are disfavoured by the data at about the 9sigma, 4sigma
and 3sigma C.L., respectively. Our analysis disfavours WDM models where there
is a suppression in the linear matter power spectrum at (non-linear) scales
corresponding to k=10h/Mpc which deviates more than 10% from a LCDM model.
Given this limit, the corresponding "free-streaming mass" below which the mass
function may be suppressed is 2x10^8 Msun/h. There is thus very little room for
a contribution of the free-streaming of WDM to the solution of what has been
termed the small scale crisis of cold dark matter.


title: Xenophobic Dark Matter

abstract:
  We consider models of xenophobic dark matter, in which isospin-violating dark
matter-nucleon interactions significantly degrade the response of xenon direct
detection experiments. For models of near-maximal xenophobia, with
neutron-to-proton coupling ratio $f_n / f_p \approx -0.64$, and dark matter
mass near 8 GeV, the regions of interest for CoGeNT and CDMS-Si and the region
of interest identified by Collar and Fields in CDMS-Ge data can be brought into
agreement. This model may be tested in future direct, indirect, and collider
searches. Interestingly, because the natural isotope abundance of xenon implies
that xenophobia has its limits, we find that this xenophobic model may be
probed in the near future by xenon experiments. Near-future data from the LHC
and Fermi-LAT may also provide interesting alternative probes of xenophobic
dark matter.


title:
Dynamical Versus Stellar Masses in Compact Early-Type Galaxies: Further
  Evidence for Systematic Variation in the Stellar Initial Mass Function

abstract:
  Several independent lines of evidence suggest that the stellar initial mass
function (IMF) in early-type galaxies becomes increasingly `bottom-heavy' with
increasing galaxy mass and/or velocity dispersion, sigma. Here we consider
evidence for IMF variation in a sample of relatively compact early-type
galaxies drawn from the Sloan Digital Sky Survey. These galaxies are of
sufficiently high stellar density that a dark halo likely makes a minor
contribution to the total dynamical mass, Mdyn, within one effective radius. We
fit our detailed stellar population synthesis models to the stacked absorption
line spectra of these galaxies in bins of sigma and find evidence from
IMF-sensitive spectral features for a bottom-heavy IMF at high sigma. We also
apply simple `mass-follows-light' dynamical models to the same data and find
that Mdyn is significantly higher than what would be expected if these galaxies
were stellar dominated and had a universal Milky Way IMF. Adopting Mdyn M_*
therefore implies that the IMF is `heavier' at high sigma. Most importantly,
the quantitative amount of inferred IMF variation is very similar between the
two techniques, agreeing to within 0.1 dex in mass. The agreement between two
independent techniques, when applied to the same data, provides compelling
evidence for systematic variation in the IMF as a function of early-type galaxy
velocity dispersion. Any alternative explanations must reproduce both the
results from dynamical and stellar population-based techniques.


title:
X-ray Outflows and Super-Eddington Accretion in the Ultraluminous X-ray
  Source Holmberg IX X-1

abstract:
  Studies of X-ray continuum emission and flux variability have not
conclusively revealed the nature of ultra-luminous X-ray sources (ULXs) at the
high-luminosity end of the distribution (those with Lx > 1e40 erg/s). These are
of particular interest because the luminosity requires either super-Eddington
accretion onto a black hole of mass ~10 Msun, or more standard accretion onto
an intermediate-mass black hole. Super-Eddington accretion models predict
strong outflowing winds, making atomic absorption lines a key diagnostic of the
nature of extreme ULXs. To search for such features, we have undertaken a long,
500 ks observing campaign on Holmberg IX X-1 with Suzaku. This is the most
sensitive dataset in the iron K bandpass for a bright, isolated ULX to date,
yet we find no statistically significant atomic features in either emission or
absorption; any undetected narrow features must have equivalent widths less
than 15-20 eV at 99% confidence. These limits are far below the >150 eV lines
expected if observed trends between mass inflow and outflow rates extend into
the super-Eddington regime, and in fact rule out the line strengths observed
from disk winds in a variety of sub-Eddington black holes. We therefore cannot
be viewing the central regions of Holmberg IX X-1 through any substantial
column of material, ruling out models of spherical super-Eddington accretion.
If Holmberg IX X-1 is a super-Eddington source, any associated outflow must
have an anisotropic geometry. Finally, the lack of iron emission suggests that
the stellar companion cannot be launching a strong wind, and that Holmberg IX
X-1 must primarily accrete via roche-lobe overflow.


title:
Three-Loop Corrections to the Higgs Boson Mass and Implications for
  Supersymmetry at the LHC

abstract:
  In supersymmetric models with minimal particle content and without left-right
squark mixing, the conventional wisdom is that the 125.6 GeV Higgs boson mass
implies top squark masses of O(10) TeV, far beyond the reach of colliders. This
conclusion is subject to significant theoretical uncertainties, however, and we
provide evidence that it may be far too pessimistic. We evaluate the Higgs
boson mass, including the dominant three-loop terms at O(\alpha_t \alpha_s^2),
in currently viable models. For multi-TeV stops, the three-loop corrections can
increase the Higgs boson mass by as much as 3 GeV and lower the required stop
mass to 3 to 4 TeV, greatly improving prospects for supersymmetry discovery at
the upcoming run of the LHC and its high-luminosity upgrade.


title:
The Hot and Energetic Universe: The evolution of galaxy groups and
  clusters

abstract:
  Major astrophysical questions related to the formation and evolution of
structures, and more specifically of galaxy groups and clusters, will still be
open in the coming decade and beyond: what is the interplay of galaxy,
supermassive black hole, and intergalactic gas evolution in the most massive
objects in the Universe - galaxy groups and clusters? What are the processes
driving the evolution of chemical enrichment of the hot diffuse gas in
large-scale structures? How and when did the first galaxy groups in the
Universe, massive enough to bind more than 10^7 K gas, form? Focussing on the
period when groups and clusters assembled (0.5<z<2.5), we show that, due to the
continuum and line emission of this hot intergalactic gas at X-ray wavelengths,
Athena+, combining high sensitivity with excellent spectral and spatial
resolution, will deliver breakthrough observations in view of the
aforementioned issues. Indeed, the physical and chemical properties of the hot
intra-cluster gas, and their evolution across time, are a key to understand the
co-evolution of galaxy and supermassive black hole within their environments.


title:
Testing the validity of the single-spin approximation in
  inspiral-merger-ringdown waveforms

abstract:
  Gravitational-wave signals from black-hole binaries with non-precessing spins
are described by four parameters -- each black hole's mass and spin. It has
been shown that the dominant spin effects can be modeled by a \emph{single}
spin parameter, leading to the development of several \emph{three-parameter}
waveform models. Previous studies indicate that these models should be adequate
for gravitational-wave detection. In this paper we focus on the systematic
biases that would result from using them to estimate binary parameters, and
consider a one-parameter family of configurations at one choice of mass ratio
and effective single spin. We find that for low-mass binaries within that
family of configurations, where the observable waveform is dominated by the
inspiral, the systematic bias in all physical parameters is smaller than the
parameter uncertainty due to degeneracies between the mass ratio and the spins,
at least up to signal-to-noise ratios (SNRs) of 50. For higher-mass binaries,
where the merger and ringdown make a greater contribution to the observed
signal, the bias in the mass ratio is comparable to its uncertainty at SNRs of
only $\sim$30, and the bias in the measurement of the total spin is
\emph{larger} than the uncertainty defined by the 90% confidence region even at
an SNR of only 10. Although this bias may be mitigated in future models by a
better choice of single-effective-spin parameter, these results suggest that it
may be possible to accurately measure \emph{both} black-hole spins in
intermediate-mass binaries.


title: Drivers of HI Turbulence in Dwarf Galaxies

abstract:
  Neutral hydrogen (HI) velocity dispersions are believed to be set by
turbulence in the interstellar medium (ISM). Although turbulence is widely
believed to be driven by star formation (SF), recent studies have shown that
this driving mechanism may not be dominant in regions of low SF rate surface
density (SFRSD), such as found in dwarf galaxies or the outer regions of
spirals. We have generated average HI line profiles in a number of nearby
dwarfs and low-mass spirals by co-adding HI spectra in regions with either a
common radius or SFRSD. We find that the spatially-resolved superprofiles are
composed of a central narrow peak (5-15 km/s) with higher velocity wings to
either side. With the assumption that the central peak reflects the turbulent
velocity dispersion, we compare HI kinematics to local ISM properties,
including surface mass densities and measures of SF. The HI velocity dispersion
is correlated most strongly with surface mass density, which points at a
gravitational origin for turbulence, but it is unclear which instabilities can
operate efficiently in these systems. SF energy is produced at a level
sufficient to drive HI turbulent motions where SFRSD > 10^-4 Msun yr^-1 kpc^-2.
At low SF intensities, SF does not supply enough energy for turbulence, nor
does it uniquely determine the velocity dispersion. Nevertheless, SF appears to
provide a lower threshold for HI velocity dispersions. We find that coupling
efficiency decreases with increasing SFRSD, consistent with a picture where SF
couples to the ISM with constant efficiency, but that less of that energy is
found in HI at higher SFRSD. We examine a number of potential drivers of HI
turbulence, including SF, gravitational instabilities, the magnetorotational
instability, and accretion, and find that no single mechanism can drive the
observed levels of turbulence at low SFRSD. We discuss possible solutions to
this conundrum.


title:
The Hot and Energetic Universe: The astrophysics of galaxy groups and
  clusters

abstract:
  As the nodes of the cosmic web, clusters of galaxies trace the large-scale
distribution of matter in the Universe. They are thus privileged sites in which
to investigate the complex physics of structure formation. However, the
complete story of how these structures grow, and how they dissipate the
gravitational and non-thermal components of their energy budget over cosmic
time, is still beyond our grasp. Fundamental questions such as How do hot
diffuse baryons accrete and dynamically evolve in dark matter potentials? How
and when was the energy that we observe in the ICM generated and distributed?
Where and when are heavy elements produced and how are they circulated? are
still unanswered. Most of the cluster baryons exists in the form of a diffuse,
hot, metal-enriched plasma that radiates primarily in the X-ray band (the
intracluster medium, ICM), allowing the X-ray observations of the evolving
cluster population to provide a unique opportunity to address these topics.
Athena+ with its large collecting area and unprecedented combination of high
spectral and angular resolution offers the only way to make major advances in
answering these questions. Athena+ will show how the baryonic gas evolves in
the dark matter potential wells by studying the motions and turbulence in the
ICM. Athena+ will be able to resolve the accreting region both spatially and
spectroscopically, probing the true nature and physical state of the X-ray
emitting plasma. Athena+ has the capabilities to permit a definitive
understanding of the formation and evolution of large-scale cosmic structure
through the study of the cluster population.


title:
The Hot and Energetic Universe: AGN feedback in galaxy clusters and
  groups

abstract:
  Mechanical feedback via Active Galactic Nuclei (AGN) jets in the centres of
galaxy groups and clusters is a crucial ingredient in current models of galaxy
formation and cluster evolution. Jet feedback is believed to regulate gas
cooling and thus star formation in the most massive galaxies, but a robust
physical understanding of this feedback mode is currently lacking. The large
collecting area, excellent spectral resolution and high spatial resolution of
Athena+ will provide the breakthrough diagnostic ability necessary to develop
this understanding, via: (1) the first kinematic measurements on relevant
spatial scales of the hot gas in galaxy, group and cluster haloes as it absorbs
the impact of AGN jets, and (2) vastly improved ability to map thermodynamic
conditions on scales well-matched to the jets, lobes and gas disturbances
produced by them. Athena+ will therefore determine for the first time how jet
energy is dissipated and distributed in group and cluster gas, and how a
feedback loop operates in group/cluster cores to regulate gas cooling and AGN
fuelling. Athena+ will also establish firmly the cumulative impact of powerful
radio galaxies on the evolution of baryons from the epoch of group/cluster
formation to the present day.


title:
The Hot and Energetic Universe: The missing baryons and the warm-hot
  intergalactic medium

abstract:
  The backbone of the large-scale structure of the Universe is determined by
processes on a cosmological scale and by the gravitational interaction of the
dominant dark matter. However, the mobile baryon population shapes the
appearance of these structures. Theory predicts that most of the baryons reside
in vast unvirialized filamentary structures that connect galaxy groups and
clusters, but the observational evidence is currently lacking. Because the
majority of the baryons are supposed to exist in a large-scale, hot and dilute
gaseous phase, X-rays provide the ideal tool to progress our understanding.
Observations with the Athena+ X-ray Integral Field Unit will reveal the
location, chemical composition, physical state and dynamics of the active
population of baryons.


title:
The Hot and Energetic Universe: The formation and growth of the earliest
  supermassive black holes

abstract:
  A crucial challenge in astrophysics over the coming decades will be to
understand the origins of supermassive black holes (SMBHs) that lie at the
centres of most, if not all, galaxies. The processes responsible for the
initial formation of these SMBHs and their early growth via accretion - when
they are seen as Active Galactic Nuclei (AGN) - remain unknown. To address this
challenge, we must identify low luminosity and obscured z>6 AGNs, which
represent the bulk of early SMBH growth. Sensitive X-ray observations are a
unique signpost of accretion activity, uncontaminated by star formation
processes, which prevent reliable AGN identification at other wavelengths (e.g.
optical, infrared). The Athena+ Wide Field Imager will enable X-ray surveys to
be carried out two orders of magnitude faster than with Chandra or XMM-Newton,
opening a new discovery space and identifying over 400 z>6 AGN, including
obscured sources. Athena+ will also play a fundamental role to enhance the
scientific return of future multiwavelength facilities that will probe the
physical conditions within the host galaxies of early SMBHs, which is vital for
understanding how SMBHs form, what fuels their subsequent growth, and to assess
their impact on the early Universe. Follow-up of samples of z>6 galaxies with
the Athena+ X-ray Integral Field Unit could also reveal the presence of highly
obscured AGNs, thanks to the detection of strong iron lines. Thus, Athena+ will
enable the first quantitative measurements of the extent and distribution of
SMBH accretion in the early Universe.


title:
Near-infrared Variability among YSOs in the Star Formation Region Cygnus
  OB7

abstract:
  We present an analysis of near-infrared time-series photometry in J, H, and K
bands for about 100 epochs of a 1 square degree region of the Lynds 1003/1004
dark cloud in the Cygnus OB7 region. Augmented by data from the Wide-field
Infrared Survey Explorer (WISE), we identify 96 candidate disk bearing young
stellar objects (YSOs) in the region. Of these, 30 are clearly Class I or
earlier. Using the Wide-Field imaging CAMera (WFCAM) on the United Kingdom
InfraRed Telescope (UKIRT), we were able to obtain photometry over three
observing seasons, with photometric uncertainty better than 0.05 mag down to J
~17. We study detailed light curves and color trajectories of ~50 of the YSOs
in the monitored field. We investigate the variability and periodicity of the
YSOs and find the data are consistent with all YSOs being variable in these
wavelengths on time scales of a few years. We divide the variability into four
observational classes: 1) stars with periodic variability stable over long
timescales, 2) variables which exhibit short-lived cyclic behavior, 3) long
duration variables, and 4) stochastic variables. Some YSO variability defies
simple classification. We can explain much of the observed variability as being
due to dynamic and rotational changes in the disk, including an asymmetric or
changing blocking fraction, changes to the inner disk hole size, as well as
changes to the accretion rate. Overall, we find that the Class I:Class II ratio
of the cluster is consistent with an age of < 1Myr, with at least one
individual, wildly varying, source ~ 100,000 yr old. We have also discovered a
Class II eclipsing binary system with a period of 17.87 days.


title:
An In-Depth View of the Mid-Infrared Properties of Point Sources and the
  Diffuse ISM in the SMC Giant HII Region, N66

abstract:
  (abridged)The focus of this work is to study mid-infrared point sources and
the diffuse interstellar medium (ISM) in the low-metallicity (~0.2 solar) giant
HII region N66 using the Spitzer Space Telescope's Infrared Spectrograph. We
study 14 targeted infrared point sources as well as spectra of the diffuse ISM
that is representative of both the photodissociation regions (PDRs) and the HII
regions. Among the point source spectra, we spectroscopically confirm that the
brightest mid-infrared point source is a massive embedded young stellar object,
we detect silicates in emission associated with two young stellar clusters, and
we observe spectral features of a known B[e] supergiant that are more commonly
associated with Herbig Be stars. In the diffuse ISM, we provide additional
evidence that the very small grain population is being photodestroyed in the
hard radiation field. The 11.3 um PAH complex emission exhibits an unexplained
centroid shift in both the point source and ISM spectra that should be
investigated at higher signal-to-noise and resolution. Unlike studies of other
regions, the 6.2 um and 7.7 um band fluxes are decoupled; the data points cover
a large range of I7.7/I11.3 PAH ratio values within a narrow band of I6.2/I11.3
ratio values. Furthermore, there is a spread in PAH ionization, being more
neutral in the dense PDR where the radiation field is relatively soft, but
ionized in the diffuse ISM/PDR. By contrast, the PAH size distribution appears
to be independent of local ionization state. Important to unresolved studies of
extragalactic low-metallicity star-forming regions, we find that emission from
the infrared-bright point sources accounts for only 20-35% of the PAH emission
from the entire region. These results make a comparative dataset to other
star-forming regions with similarly hard and strong radiation fields.


title:
The Hot and Energetic Universe: Understanding the build-up of
  supermassive black holes and galaxies at the heyday of the Universe

abstract:
  Observations in the last decade have provided strong evidence that the growth
of supermassive black holes at the centres of galaxies is among the most
influential processes in galaxy evolution. Open questions that relate to our
current understanding of black hole growth and its relation to the build-up of
galaxies at redshifts z=1-4, when most black holes and stars we see in
present-day galaxies were put in place, include: what is the nature of AGN
feedback and whether it plays a significant role in the evolution of galaxies?
what is the dominant population of accreting AGN at that critical epoch? is it
dominated by obscured objects as required by many current observations and
models? The Athena+ mission concept will provide the technological leap
required for a breakthrough in our understanding of AGN and galaxy evolution at
the heyday of the Universe. The high throughput of Athena+ will allow the
systematic study of the incidence, nature and energetics of AGN feedback
processes to z~4 via the identification and measurement of blue-shifted X-ray
absorption lines. The excellent survey and spectral capabilities of the Athena+
Wide Field Imager will complete the census of black hole growth by yielding
samples of up to 100 times larger than is currently possible of the most
heavily obscured, including Compton thick, AGN to redshifts z~4. The
demographics of this population relative to their hosts is fundamental for
understanding how major black hole growth events relate to the build-up of
galaxies.


title: Dynamical generation of the weak and Dark Matter scale

abstract:
  Assuming that naturalness should be modified by ignoring quadratic
divergences, we propose a simple extension of the Standard Model where the weak
scale is dynamically generated together with an automatically stable vector.
Identifying it as thermal Dark Matter, the model has one free parameter. It
predicts one extra scalar, detectable at colliders, which triggers a
first-order dark/electroweak cosmological phase transition with production of
gravitational waves. Vacuum stability holds up to the Planck scale.


title: The Hot and Energetic Universe: Astrophysics of feedback in local AGN

abstract:
  Understanding the astrophysics of feedback in active galactic nuclei (AGN) is
key to understanding the growth and co-evolution of supermassive black holes
and galaxies. AGN-driven winds/outflows are potentially the most effective way
of transporting energy and momentum from the nuclear scales to the host galaxy,
quenching star formation by sweeping away the gas reservoir. Key questions in
this field are: 1) how do accretion disks around black holes launch
winds/outflows, and how much energy do these carry? 2) How are the energy and
metals accelerated in winds/outflows transferred and deposited into the
circumgalactic medium? X-ray observations are a unique way to address these
questions because they probe the phase of the outflows which carries most of
the kinetic energy. We show how a high throughput, high spectral resolution
instrument like the X-ray Integral Field Unit (X-IFU) on Athena+ will allow us
to address these questions by determining the physical parameters (ionization
state, density, temperature, abundances, velocities, geometry, etc.) of the
outflows on a dynamical time-scale, in a broad sample of nearby bright AGN. The
X-IFU will also allow direct spectral imaging of the impact of these winds on
the host galaxy for local AGN, forming a template for understanding AGN at
higher redshifts where wind shocks cannot be resolved.


title:
The Hot and Energetic Universe: The close environments of supermassive
  black holes

abstract:
  Most of the action in Active Galactic Nuclei (AGN) occurs within a few tens
of gravitational radii from the supermassive black hole, where matter in the
accretion disk may lose up to almost half of its energy with a copious
production of X-rays, emitted via Comptonization of the disk photons by hot
electrons in a corona and partly reflected by the accretion disk. Thanks to its
large effective area and excellent energy resolution, Athena+ contributions in
the understanding of the physics of accretion in AGN will be fundamental - and
unique - in many respects. It will allow us to map the disk-corona system -
which is crucial to understand the mechanism of energy extraction and the
relation of the corona with winds and jets - by studying the time lags between
reflected and primary photons. These lags have been recently discovered by
XMM-Newton, but only Athena+ will have the sensitivity required to fully
exploit this technique. Athena+ will also be able e.g. to determine robustly
the spin of the black hole in nearby sources (and to extend these measurements
beyond the local Universe), to establish the nature of the soft X-ray
components, and to map the circumnuclear matter within the AGN inner parsec
with unprecedented details.


title: The Hot and Energetic Universe: Solar system and exoplanets

abstract:
  The high resolution non-dispersive spectroscopy and unprecedented sensitivity
of Athena+ will revolutionize solar system observing: the origin of the ions
producing Jupiter's X-ray aurorae via charge exchange will be conclusively
established, as well as their dynamics, giving clues to their acceleration
mechanisms. X-ray aurorae on Saturn will be searched for to a depth
unattainable by current Earth-bound observatories. The X-ray Integral Field
Unit of Athena+ will map Mars' expanding exosphere, which has a line-rich solar
wind charge exchange spectrum, under differing solar wind conditions and
through the seasons; relating Mars' X-ray emission to its atmospheric loss will
have significant impact also on the study of exoplanet atmospheres. Spectral
mapping of cometary comae, which are spectacular X-ray sources with extremely
line-rich spectra, will probe solar wind composition and speed at varying
distances from the Sun. Athena+ will provide unique contributions also to
exoplanetary astrophysics. Athena+ will pioneer the study of
ingress/eclipse/egress effects during planetary orbits of hot-Jupiters, and
will confirm/improve the evidence of Star-Planet Interactions (SPI) in a wider
sample of planetary systems. Finally Athena+ will drastically improve the
knowledge of the X-ray incident radiation on exoplanets, a key element for
understanding the effects of atmospheric mass loss and of the chemical and
physical evolution of planet atmospheres, particularly relevant in the case of
young systems.


title: The Hot and Energetic Universe: Star formation and evolution

abstract:
  Stars over a wide range of masses and evolutionary stages are nowadays known
to emit X-rays. This X-ray emission is a unique probe of the most energetic
phenomena occurring in the circumstellar environment of these stars, and
provides precious insight on magnetic phenomena or hydrodynamic shocks. Owing
to its large collecting area, Athena+ will open up an entirely new window on
these phenomena. Indeed, Athena+ will not only allow us to study many more
objects with an unprecedented spectral resolution, but will also pioneer the
study of the dynamics of these objects via time-resolved high-resolution
spectroscopy. In this way, Athena+ will be a unique tool to study accretion
processes in TTauri stars, flaring activity in young stars, dynamos in
ultra-cool dwarfs, small and large-scale structures in the winds of single
massive stars, wind interactions in massive binary systems, hot bubbles in
planetary nebula... All these studies will lead to a deeper understanding of
yet poorly understood processes which have profound impact in star and
planetary system formation as well as in feedback processes on Galactic scale.


title: The Hot and Energetic Universe: End points of stellar evolution

abstract:
  White dwarfs, neutron stars and stellar mass black holes are key laboratories
to study matter in most extreme conditions of gravity and magnetic field. The
unprecedented effective area of Athena+ will allow us to advance our
understanding of emission mechanisms and accretion physics over a wide range of
mass accretion rates, starting from lower and sub-luminous quiescent X-ray
binaries up to super-Eddington ultra-luminous sources. Athena+ will measure
stellar black hole spins in a much higher number of binaries than achievable
now, opening the possibility to study how spin varies with black hole history.
The high throughput and energy resolution of the X-IFU will be instrumental in
establishing how disc wind properties depend on accretion state, in determining
wind launching mechanism and in quantifying the impact of the wind induced mass
loss on binary evolution and environment. Triggers and high quality optical and
radio data originating from large wide field contemporaneous instruments will
provide essential complementary information on jet launching mechanisms and on
the physics of rotation powered pulsars, for instance. In addition, Athena+
will furnish multiple, independent measurements of the neutron star mass/radius
relation in a wide range of environments and conditions so as to constrain the
debated equation of state.


title:
The Hot and Energetic Universe: The astrophysics of supernova remnants
  and the interstellar medium

abstract:
  The study of both supernova remnants and the hot and cold phases of the
interstellar medium are essential for understanding the final stages of stellar
evolution and their feedback on the evolution of galaxies through injection of
energy and heavy elements. These studies are also crucial for understanding the
physics of supernovae, their cosmological implication, and the origin of
galactic cosmic rays. The unique capabilities of Athena+ will allow us to
explore a new parameter space. Spatially-resolved high-resolution spectroscopy
using Athena+ X-IFU of young remnants will allow to characterize individual
parcels of ejected material in the line of sight in terms of kinematics,
ionization and composition, providing access to the three dimensional geometry
of the explosion. Athena+ will also allow studying shock physics and particle
acceleration in supernova remnants, as well as their interaction with their
environment. Athena+ X-IFU will also characterize the ionization mechanisms
competing in forming the complex structures of the hot interstellar medium,
likely to keep the echo of past star formation activity, both in our Galaxy and
nearby ones. For the first time the dust and gas of the densest cold medium,
like in the Galactic Centre environment, will be studied. Athena+ X-IFU will
observe, along with the Mg K and Si K edges, which are the main tracers of the
silicates content of the ISM, the Fe K edge with unprecedented sensitivity and
energy-resolution. This will allow us to study for the first time the nature of
Fe-bearing dust in such regions.


title: The Hot and Energetic Universe: Luminous extragalactic transients

abstract:
  We discuss the importance and potential contribution of Athena+ to the
science questions related to gamma-ray bursts, tidal disruption events and
supernova shock break-out. Athena+ will allow breakthrough observations
involving high-resolution X-ray spectroscopic observations of high-z gamma-ray
bursts, observations of tidal disruption events tailored to determine the mass
and potentially the spin of the black hole responsible for the tidal disruption
and observations of X-rays from the supernova shock breakout providing a
measure of the radius of the exploding star or of the companion in the case of
type Ia supernovae. We briefly discuss survey facilities that will provide
triggers to these events envisaged to be operational around 2028.


title: The Fast and Furious Decay of the Peculiar Type Ic Supernova 2005ek

abstract:
  We present extensive multi-wavelength observations of the extremely rapidly
declining Type Ic supernova, SN 2005ek. Reaching a peak magnitude of M_R =
-17.3 and decaying by ~3 mag in the first 15 days post-maximum, SN 2005ek is
among the fastest Type I supernovae observed to date. The spectra of SN 2005ek
closely resemble those of normal SN Ic, but with an accelerated evolution.
There is evidence for the onset of nebular features at only nine days
post-maximum. Spectroscopic modeling reveals an ejecta mass of ~0.3 Msun that
is dominated by oxygen (~80%), while the pseudo-bolometric light curve is
consistent with an explosion powered by ~0.03 Msun of radioactive Ni-56.
Although previous rapidly evolving events (e.g., SN 1885A, SN 1939B, SN 2002bj,
SN 2010X) were hypothesized to be produced by the detonation of a helium shell
on a white dwarf, oxygen-dominated ejecta are difficult to reconcile with this
proposed mechanism. We find that the properties of SN 2005ek are consistent
with either the edge-lit double detonation of a low-mass white dwarf or the
iron-core collapse of a massive star, stripped by binary interaction. However,
if we assume that the strong spectroscopic similarity of SN 2005ek to other SN
Ic is an indication of a similar progenitor channel, then a white-dwarf
progenitor becomes very improbable. SN 2005ek may be one of the lowest mass
stripped-envelope core-collapse explosions ever observed. We find that the rate
of such rapidly declining Type I events is at least 1-3% of the normal SN Ia
rate.


title:
Nebular emission and the Lyman continuum photon escape fraction in
  CALIFA early-type galaxies

abstract:
  We use deep integral field spectroscopy data from the CALIFA survey to study
the warm interstellar medium (WIM) of 32 nearby early-type galaxies (ETGs). We
propose a tentative subdivision of our sample ETGs into two groups, according
to their Ha equivalent width (EW) and Lyman continuum (LyC) photon escape
fraction (PLF). Type i ETGs show nearly constant EWs and a PLF~0, suggesting
that photoionization by post-AGB stars is the main driver of their faint
extranuclear nebular emission. Type ii ETGs are characterized by very low,
outwardly increasing EWs, and a PLF as large as ~0.9 in their centers. Such
properties point to a low, and inwardly decreasing WIM density and/or volume
filling factor. We argue that, because of extensive LyC photon leakage,
emission-line luminosities and EWs are reduced in type ii ETG nuclei by at
least one order of magnitude. Consequently, the line weakness of these ETGs is
by itself no compelling evidence for their containing merely "weak"
(sub-Eddington accreting) active galactic nuclei (AGN). In fact, LyC photon
escape, which has heretofore not been considered, may constitute a key element
in understanding why many ETGs with prominent signatures of AGN activity in
radio continuum and/or X-ray wavelengths show only faint emission lines and
weak signatures of AGN activity in their optical spectra. The LyC photon
escape, in conjunction with dilution of nuclear EWs by line-of-sight
integration through a triaxial stellar host, can systematically impede
detection of AGN in gas-poor galaxy spheroids through optical emission-line
spectroscopy. We further find that type i and ii ETGs differ little (~0.4 dex)
in their mean BPT line ratios, which in both cases are characteristic of
LINERs. This potentially hints at a degeneracy of the projected,
luminosity-weighted BPT ratios for the specific 3D properties of the WIM in
ETGs. (abridged)


title:
Spin Transfer of Quantum Information between Majorana Modes and a
  Resonator

abstract:
  We show that resonant coupling and entanglement between a mechanical
resonator and majorana bound states can be achieved via spin currents in a 1D
quantum wire with strong spin-orbit interactions. The bound states induced by
vibrating and stationary magnets can hybridize thus resulting in spin-current
induced $4\pi$-periodic torque, as a function of the relative field angle,
acting on the resonator. We study the feasibility of detecting and manipulating
majorana bound states with the use of magnetic resonance force microscopy
techniques.


title: Perturbations of quadratic Hamiltonian two-saddle cycles

abstract:
  We prove that the number of limit cycles, which bifurcate from a two-saddle
loop of a planar quadratic Hamiltonian system, under an arbitrary quadratic
deformation, is less than or equal to three.


title:
An emission mechanism explaining off-pulse emission originating in the
  outer magnetosphere of pulsars

abstract:
  We have examined the cyclotron resonance instability developing in the
relativistic out-flowing plasma in the pulsar magnetosphere. The instability
condition leads to radio emission in the sub-GHz frequency regime which is
likely to be seen as off-pulse emission. Recent studies have shown the presence
of off-pulse emission in long period pulsars, and we demonstrate this plasma
process to be an energetically viable mechanism.


title:
Probing Heavy-Light Neutrino Mixing in Left-Right Seesaw Models at the
  LHC

abstract:
  We show that in TeV-scale left-right (L-R) symmetric seesaw models, there are
new dominant contributions to the collider signals of heavy Majorana neutrinos
arising from the heavy-light neutrino mixing, which directly probe the seesaw
matrix in a certain class of models. We propose a way to distinguish this
contribution from the widely discussed one that only probes the Majorana nature
of the heavy right-handed neutrinos, by analyzing some simple kinematical
variables. We find that in this class of L-R seesaw models the existing LHC
data already yield slightly stronger constraints on the heavy-light neutrino
mixing than those derived for standard seesaw models, and the improvement will
be significant as more data are collected.


title:
Flavor Violating Higgs signals in the Texturized Two-Higgs Doublet Model
  (2HDM-Tx)

abstract:
  Flavor violating Higgs signals, such as the top FCNC decay $t\to ch^0$ and
the LFV Higgs decay $h^0\to \tau\mu$, have been studied at the LHC. These
signals can arise within the general Two-Higgs doublet model (THDM), where each
Higgs doublet couples to all fermions types through Yukawa matrices $Y^f_1$ and
$Y^f_2$. The Yukawa matrices can be assumed to have the same form or they could
have different structures. In this paper we study the case when both $Y^f_1$
and $Y^f_2$ have completely different forms, but in such a way that they
complement to produce a specific hermitian mass matrix. We find that for
specific four-zero textures, the Flavor Violating Higgs couplings depend only
on the free parameters $\tan \beta$, $\gamma_f$ and the fermion masses. We use
the current bounds on the low energy processes, to derive constraints on the
Heavy Higgs boson mass, $\tan \beta$ and $\gamma_f$. Then, we use these
constraints to evaluate the LFV Higgs decays, which reach Branching ratios that
could be tested at the LHC.


title:
Effects of shocks in stellar atmosphere models on the emission line
  spectrum of surrounding Hii regions

abstract:
  Emission line studies from Hii regions in galaxies require tools for the
inversion of line ratios into desired physical properties. These tools
generally come in form of diagnostic ratios/diagrams that are based on grids of
photoionisation models. An important input to the photoionisation models is the
stellar atmosphere spectrum of the ionising sources. The current omission of
shocks in the calculation of the former set of models could threaten the
accuracy of the physical interpretation of emission line ratios from Hii
regions. Current stellar atmosphere models that are crucial inputs to the grid
of photoionisation models used to generate nebular emission line diagnostic
diagrams might produce significant biases due to the omission of shocks. We
investigate whether a new generation of photoionisation model grids, taking
shocks into account, is required to compensate for the biases. We make use of
the WM-Basic stellar atmosphere code, which can account for the extra energetic
emission in the stellar spectral energy distribution produced by shocks, in
conjunction with the photoionisation code MOCASSIN to determine whether shocks
produce significant biases in the determination of the physical parameters of
the interstellar medium and/or ionising stellar parameters. We conclude that
these effects are only important for stellar sources with effective
temperatures lower than 30kK and in this case they yield artificially high
stellar temperatures, electron temperatures and nebular ionisation parameters.
The magnitude of the effect is also obviously dependent on the strength of the
shock and is likely to be unimportant for the majority of stellar sources.
Nevertheless, we find our 20kK and 30kK shock models to strongly enhance the He
ii 4686 nebular emission line. This result is however not strong enough to
explain previously observed He ii 4686 line emission in the spectra of Hii
galaxies.


title:
Continued Neutron Star Crust Cooling of the 11 Hz X-Ray Pulsar in Terzan
  5: A Challenge to Heating and Cooling Models?

abstract:
  The transient neutron star low-mass X-ray binary and 11 Hz X-ray pulsar IGR
J17480-2446 in the globular cluster Terzan 5 exhibited an 11-week accretion
outburst in 2010. Chandra observations performed within five months after the
end of the outburst revealed evidence that the crust of the neutron star became
substantially heated during the accretion episode and was subsequently cooling
in quiescence. This provides the rare opportunity to probe the structure and
composition of the crust. Here, we report on new Chandra observations of Terzan
5 that extend the monitoring to ~2.2 yr into quiescence. We find that the
thermal flux and neutron star temperature have continued to decrease, but
remain significantly above the values that were measured before the 2010
accretion phase. This suggests that the crust has not thermally relaxed yet,
and may continue to cool. Such behavior is difficult to explain within our
current understanding of heating and cooling of transiently accreting neutron
stars. Alternatively, the quiescent emission may have settled at a higher
observed equilibrium level (for the same interior temperature), in which case
the neutron star crust may have fully cooled.


title:
Necessary Conditions for the Generic Global Rigidity of Frameworks on
  Surfaces

abstract:
  A result due in its various parts to Hendrickson, Connelly, and Jackson and
Jord\'an, provides a purely combinatorial characterisation of global rigidity
for generic bar-joint frameworks in $\mathbb{R}^2$. The analogous conditions
are known to be insufficient to characterise generic global rigidity in higher
dimensions. Recently Laman-type characterisations of rigidity have been
obtained for generic frameworks in $\mathbb{R}^3$ when the vertices are
constrained to lie on various surfaces, such as the cylinder and the cone. In
this paper we obtain analogues of Hendrickson's necessary conditions for the
global rigidity of generic frameworks on the cylinder, cone and ellipsoid.


title: Auditing: Active Learning with Outcome-Dependent Query Costs

abstract:
  We propose a learning setting in which unlabeled data is free, and the cost
of a label depends on its value, which is not known in advance. We study binary
classification in an extreme case, where the algorithm only pays for negative
labels. Our motivation are applications such as fraud detection, in which
investigating an honest transaction should be avoided if possible. We term the
setting auditing, and consider the auditing complexity of an algorithm: the
number of negative labels the algorithm requires in order to learn a hypothesis
with low relative error. We design auditing algorithms for simple hypothesis
classes (thresholds and rectangles), and show that with these algorithms, the
auditing complexity can be significantly lower than the active label
complexity. We also discuss a general competitive approach for auditing and
possible modifications to the framework.


title: Robust Extraction of Tomographic Information via Randomized Benchmarking

abstract:
  We describe how randomized benchmarking can be used to reconstruct the unital
part of any trace-preserving quantum map, which in turn is sufficient for the
full characterization of any unitary evolution, or more generally, any unital
trace-preserving evolution. This approach inherits randomized benchmarking's
robustness to preparation, measurement, and gate imperfections, therefore
avoiding systematic errors caused by these imperfections. We also extend these
techniques to efficiently estimate the average fidelity of a quantum map to
unitary maps outside of the Clifford group. The unitaries we consider
correspond to large circuits commonly used as building blocks to achieve
scalable, universal, and fault-tolerant quantum computation. Hence, we can
efficiently verify all such subcomponents of a circuit-based universal quantum
computer. In addition, we rigorously bound the time and sampling complexities
of randomized benchmarking procedures, proving that the required non-linear
estimation problem can be solved efficiently.


title:
A Spin-Dependent Interpretation for Possible Signals of Light Dark
  Matter

abstract:
  Signals broadly compatible with light (7-10 GeV) dark matter have been
reported in three direct detection experiments: CoGeNT, DAMA/LIBRA, and CDMS-II
silicon. These possible signals have been interpreted in the context of
spin-independent interactions between the target nuclei and dark matter,
although there is tension with null results, particularly from xenon-based
experiments. In this paper, we demonstrate that the CoGeNT and CDMS-II silicon
results are also compatible assuming a spin-dependent neutron interaction,
though this is in tension with xenon-based experiments and PICASSO. The tension
with the null results from XENON100 and XENON10 is approximately the same as
for the spin-independent coupling. All three experimental signals can be made
compatible through a combination of spin-dependent interactions with both the
proton and neutron, although such a scenario increases the conflict with the
null results of other experiments.


title:
Transverse Momentum of Protons, Pions and Kaons in High Multiplicity pp
  and pA Collisions: Evidence for the Color Glass Condensate?

abstract:
  The CMS experiment at the Large Hadron Collider has recently presented data
on the average transverse momentum of protons, kaons and pions as a function of
particle multiplicity. We relate the particle multiplicity to saturation
momentum using recently published computations of the interaction radius
determined from the theory of the Color Glass Condensate. We show that the pp
and the pA experimental data scale in terms of these saturation momenta.
Computing transverse momentum spectra for identified particles using
Boltzmann-type distributions and relating different associated multiplicities
using geometric scaling, these simple distributions reproduce the observed
dependence of the mean transverse momentum on particle multiplicities seen in
both pp and pA interactions for pions to good accuracy, and to fair agreement
for protons and kaons.


title: Negative Refraction Does Not Make Perfect Lenses

abstract:
  The widely-accepted theoretical treatment of the electromagnetic boundary
problem of evanescent wave transfer at an interface between a normal medium of
n=1 and an ideal negative index medium of n=-1 neglects the non-zero induced
surface current and charge densities at the interface and is self-inconsistent.
We re-solve the electromagnetic boundary problem by taking into account the
non-zero induced surface current and charge densities that have been neglected
so far by others. We give the exact induced surface current and charge
distributions for this special case and solve the refracted and reflected
fields analytically using Green's function method. The self-consistent solution
yields a transmission coefficient of 1 and reflection coefficient of 0 for all
evanescent waves. Accordingly, we found that, on the contrary to the popular
belief, negative index of refraction does not make perfect lenses.


title:
Quantum criticality in the pseudogap Bose-Fermi Anderson and Kondo
  models: Interplay between fermion- and boson-induced Kondo destruction

abstract:
  We address the phenomenon of critical Kondo destruction in pseudogap
Bose-Fermi Anderson and Kondo quantum impurity models. These models describe a
localized level coupled both to a fermionic bath having a density of states
that vanishes like |\epsilon|^r at the Fermi energy (\epsilon=0) and, via one
component of the impurity spin, to a bosonic bath having a sub-Ohmic spectral
density proportional to |\omega|^s. Each bath is capable by itself of
suppressing the Kondo effect at a continuous quantum phase transition. We study
the interplay between these two mechanisms for Kondo destruction using
continuous-time quantum Monte Carlo for the pseudogap Bose-Fermi Anderson model
with 0<r<1/2 and 1/2<s<1, and applying the numerical renormalization-group to
the corresponding Kondo model. At particle-hole symmetry, the models exhibit a
quantum critical point between a Kondo (fermionic strong-coupling) phase and a
localized (Kondo-destroyed) phase. The two solution methods, which are in good
agreement in their domain of overlap, provide access to the many-body spectrum,
as well as to correlation functions including, in particular, the
single-particle Green's function and the static and dynamical local spin
susceptibilities. The quantum-critical regime exhibits the hyperscaling of
critical exponents and \omega/T scaling in the dynamics that characterize an
interacting critical point. The (r,s) plane can be divided into three regions:
one each in which the calculated critical properties are dominated by the
bosonic bath alone or by the fermionic bath alone, and between these two
regions, a third in which the bosonic bath governs the critical spin response
but both baths influence the renormalization-group flow near the quantum
critical point.


title: Modeling the dynamics of bivalent histone modifications

abstract:
  Epigenetic modifications to histones may promote either activation or
repression of the transcription of nearby genes. Recent experimental studies
show that the promoters of many lineage-control genes in stem cells have
"bivalent domains" in which the nucleosomes contain both active (H3K4me3) and
repressive (H3K27me3) marks. It is generally agreed that bivalent domains play
an important role in stem cell differentiation, but the underlying mechanisms
remain unclear. Here we formulate a mathematical model to investigate the
dynamic properties of histone modification patterns. We then illustrate that
our modeling framework can be used to capture key features of experimentally
observed combinatorial chromatin states.


title:
Complete history of the observable 21-cm signal from the first stars
  during the pre-reionization era

abstract:
  We present the first complete calculation of the history of the inhomogeneous
21-cm signal from neutral hydrogen during the era of the first stars. We use
hybrid computational methods to capture the large-scale distribution of the
first stars, whose radiation couples to the neutral hydrogen emission, and to
evaluate the 21-cm signal from z ~ 15-35. In our realistic picture large-scale
fluctuations in the 21-cm signal are sourced by the inhomogeneous density field
and by the Ly-alpha and X-ray radiative backgrounds. The star formation is
suppressed by two spatially varying effects: negative feedback provided by the
Lyman-Werner radiative background, and supersonic relative velocities between
the gas and dark matter. Our conclusions are quite promising: we find that the
fluctuations imprinted by the inhomogeneous Ly-alpha background in the 21-cm
signal at z ~ 25 should be detectable with the Square Kilometer Array.


title:
Reference Distribution Functions for Magnetically Confined Plasmas from
  the Minimum Entropy Production Theorem and the MaxEnt Principle, subject to
  the Scale-Invariant Restrictions

abstract:
  We derive the expression of the reference distribution function for
magnetically confined plasmas far from the thermodynamic equilibrium. The local
equilibrium state is fixed by imposing the minimum entropy production theorem
and the maximum entropy (MaxEnt) principle, subject to scale invariance
restrictions. After a short time, the plasma reaches a state close to the local
equilibrium. This state is referred to as the reference state. The aim of this
letter is to determine the reference distribution function (RDF) when the local
equilibrium state is defined by the above mentioned principles. We prove that
the RDF is the stationary solution of a generic family of stochastic processes
corresponding to an universal Landau-type equation with white parametric noise.
As an example of application, we consider a simple, fully ionized, magnetically
confined plasmas, with auxiliary Ohmic heating. The free parameters are linked
to the transport coefficients of the magnetically confined plasmas, by the
kinetic theory.


title:
Anticipatory Mobile Computing: A Survey of the State of the Art and
  Research Challenges

abstract:
  Today's mobile phones are far from mere communication devices they were ten
years ago. Equipped with sophisticated sensors and advanced computing hardware,
phones can be used to infer users' location, activity, social setting and more.
As devices become increasingly intelligent, their capabilities evolve beyond
inferring context to predicting it, and then reasoning and acting upon the
predicted context. This article provides an overview of the current state of
the art in mobile sensing and context prediction paving the way for
full-fledged anticipatory mobile computing. We present a survey of phenomena
that mobile phones can infer and predict, and offer a description of machine
learning techniques used for such predictions. We then discuss proactive
decision making and decision delivery via the user-device feedback loop.
Finally, we discuss the challenges and opportunities of anticipatory mobile
computing.


title:
Measurement of the Differential Cross Section d{\sigma}/d(cos {\theta}t)
  for Top-Quark Pair Production in p-pbar Collisions at sqrt{s} = 1.96 TeV

abstract:
  We report a measurement of the differential cross section, d{\sigma}/d(cos
{\theta}t), for top-quark-pair production as a function of the top-quark
production angle in proton-antiproton collisions at sqrt{s} = 1.96 TeV. This
measurement is performed using data collected with the CDF II detector at the
Tevatron, corresponding to an integrated luminosity of 9.4/fb. We employ the
Legendre polynomials to characterize the shape of the differential cross
section at the parton level. The observed Legendre coefficients are in good
agreement with the prediction of the next-to-leading-order standard-model
calculation, with the exception of an excess linear-term coefficient, a1 = 0.40
+- 0.12, compared to the standard-model prediction of a1 =
0.15^{+0.07}_{-0.03}.


title: Trimaximal TM1 neutrino mixing in S4 with spontaneous CP violation

abstract:
  The measurement of the reactor angle by the Daya Bay and RENO experiments in
2012 has ruled out the tri-bimaximal paradigm. Adopting an S4 family symmetry,
we propose direct models of the trimaximal type TM1 in which the tri-bimaximal
Klein symmetry of the neutrino sector is broken to a residual Z2 symmetry. In
such a scenario, the solar mixing angle is decreased compared to its
tri-bimaximal value by about one degree, thus bringing it in excellent
agreement with experimental observation. The atmospheric mixing angle, on the
other hand, depends on the CP violating Dirac phase delta. Imposing CP
conservation in the family symmetry limit, we show how to break the CP symmetry
via flavon VEVs with well-defined complex phases, so that sizable deviations of
the atmospheric angle from maximal mixing, consistent with the latest global
fits, are produced.


title:
Simple proof of Dynkin's formula for single-server systems and
  polynomial convergence rates

abstract:
  An elementary and rigorous justification of Dynkin's identity with an
extended infinitesimal operator based on the idea of a complete probability
formula is given for queueing systems with a single server and discontinuous
intensities of arrivals and serving.


title: Capacity and Scheduling of Access Points for Multiple Live Video Streams

abstract:
  This paper studies the problem of serving multiple live video streams to
several different clients from a single access point over unreliable wireless
links, which is expected to be major a consumer of future wireless capacity.
This problem involves two characteristics. On the streaming side, different
video streams may generate variable-bit-rate traffic with different traffic
patterns. On the network side, the wireless transmissions are unreliable, and
the link qualities differ from client to client. In order to alleviate the
above stochastic aspects of both video streams and link unreliability, each
client typically buffers incoming packets before playing the video. The quality
of the video playback subscribed to by each flow depends, among other factors,
on both the delay of packets as well as their throughput.
  In this paper we characterize precisely the capacity of the wireless video
server in terms of what combination of joint per-packet-delays and throughputs
can be supported for the set of flows, as a function of the buffering delay
introduced at the server.
  We also address how to schedule packets at the access point to satisfy the
joint per-packet-delay-throughput performance measure. We test the designed
policy on the traces of three movies. From our tests, it appears to outperform
other policies by a large margin.


title:
Joint Transmit Diversity Optimization and Relay Selection for
  Cooperative MIMO Systems using Discrete Stochastic Algorithms

abstract:
  We propose a joint discrete stochastic optimization based transmit diversity
selection (TDS) and relay selection (RS) algorithm for decode-and-forward (DF),
cooperative MIMO systems with a non-negligible direct path. TDS and RS are
performed jointly with continuous least squares channel estimation (CE), linear
minimum mean square error (MMSE) receivers are used at all nodes and no
inter-relay communication is required. The performance of the proposed scheme
is evaluated via bit-error rate (BER) comparisons and diversity analysis, and
is shown to converge to the optimum exhaustive solution.


title:
Bidirectional MMSE Algorithms for Interference Mitigation in CDMA
  Systems over Fast Fading Channels

abstract:
  This paper presents adaptive bidirectional minimum mean-square error (MMSE)
parameter estimation algorithms for fast-fading channels. The time correlation
between successive channel gains is exploited to improve the estimation and
tracking capabilities of adaptive algorithms and provide robustness against
time-varying channels. Bidirectional normalized least mean-square (NLMS) and
conjugate gradient (CG) algorithms are devised along with adaptive mixing
parameters that adjust to the time-varying channel correlation properties. An
analysis of the proposed algorithms is provided along with a discussion of
their performance advantages. Simulations for an application to interference
suppression in DS-CDMA systems show the advantages of the proposed algorithms.


title:
Free energy barrier for melittin reorientation from a membrane-bound
  state to a transmembrane state

abstract:
  An important step in a phospholipid membrane pore formation by melittin
antimicrobial peptide is a reorientation of the peptide from a surface into a
transmembrane conformation. In this work we perform umbrella sampling
simulations to calculate the potential of mean force (PMF) for the
reorientation of melittin from a surface-bound state to a transmembrane state
and provide a molecular level insight into understanding peptide and lipid
properties that influence the existence of the free energy barrier. The PMFs
were calculated for a peptide to lipid (P/L) ratio of 1/128 and 4/128. We
observe that the free energy barrier is reduced when the P/L ratio increased.
In addition, we study the cooperative effect; specifically we investigate if
the barrier is smaller for a second melittin reorientation, given that another
neighboring melittin was already in the transmembrane state. We observe that
indeed the barrier of the PMF curve is reduced in this case, thus confirming
the presence of a cooperative effect.


title: Revisiting the Faddeev-Skyrme Model and Hopf Solitons

abstract:
  We observe that the Faddeev-Skyrme model emerges as a low-energy limit of
scalar QED with two charged scalar fields and a selfinteraction potential of a
special form (inspired by supersymmetric QCD). Then we discuss possible Hopf
solitons of the "twisted-toroidal" type.


title: Bayesian Solution Uncertainty Quantification for Differential Equations

abstract:
  We explore probability modelling of discretization uncertainty for system
states defined implicitly by ordinary or partial differential equations.
Accounting for this uncertainty can avoid posterior under-coverage when
likelihoods are constructed from a coarsely discretized approximation to system
equations. A formalism is proposed for inferring a fixed but a priori unknown
model trajectory through Bayesian updating of a prior process conditional on
model information. A one-step-ahead sampling scheme for interrogating the model
is described, its consistency and first order convergence properties are
proved, and its computational complexity is shown to be proportional to that of
numerical explicit one-step solvers. Examples illustrate the flexibility of
this framework to deal with a wide variety of complex and large-scale systems.
Within the calibration problem, discretization uncertainty defines a layer in
the Bayesian hierarchy, and a Markov chain Monte Carlo algorithm that targets
this posterior distribution is presented. This formalism is used for inference
on the JAK-STAT delay differential equation model of protein dynamics from
indirectly observed measurements. The discussion outlines implications for the
new field of probabilistic numerics.


title:
Symmetry breaking in optimal timing of traffic signals on an idealized
  two-way street

abstract:
  Simple physical models based on fluid mechanics have long been used to
understand the flow of vehicular traffic on freeways; analytically tractable
models of flow on an urban grid, however, have not been as extensively
explored. In an ideal world, traffic signals would be timed such that
consecutive lights turned green just as vehicles arrived, eliminating the need
to stop at each block. Unfortunately, this "green wave" scenario is generally
unworkable due to frustration imposed by competing demands of traffic moving in
different directions. Until now this has typically been resolved by numerical
simulation and optimization. Here, we develop a theory for the flow in an
idealized system consisting of a long two-way road with periodic intersections.
We show that optimal signal timing can be understood analytically and that
there are counter-intuitive asymmetric solutions to this signal coordination
problem. We further explore how these theoretical solutions degrade as traffic
conditions vary and automotive density increases.

categories: physics.soc-ph cond-mat.other cond-mat.stat-mech nlin.SI


title:
Time Transfer functions as a way to validate light propagation solutions
  for space astrometry

abstract:
  Given the extreme accuracy of modern space astrometry, a precise relativistic
modeling of observations is required. Concerning light propagation, the
standard procedure is the solution of the null-geodesic equations. However,
another approach based on the Time Transfer Functions (TTF) has demonstrated
its capability to give access to key quantities such as the time of flight of a
light signal between two point-events and the tangent vector to its
null-geodesic in a weak gravitational field using an integral-based method. The
availability of several models, formulated in different and independent ways,
must not be considered like an oversized relativistic toolbox. Quite the
contrary, they are needed as validation to put future experimental results on
solid ground. The objective of this work is then twofold. First, we build the
time of flight and tangent vectors in a closed form within the TTF formalism
giving the case of a time dependent metric. Second, we show how to use this new
approach to obtain a comparison of the TTF with two existing modelings, namely
GREM and RAMOD. In this way, we evidentiate the mutual consistency of the three
models, opening the basis for further links between all the approaches, which
is mandatory for the interpretation of future space missions data. This will be
illustrated through two recognized cases: a static gravitational field and a
system of monopoles in uniform motion.


title: Probing Vector Mesons in Deuteron Break-up Reactions

abstract:
  We study vector meson photoproduction from the deuteron at high momentum
transfer, accompanied by break-up of the deuteron into a proton and neutron.
The large $-t$ involved allows one of the nucleons to be identified as struck,
and the other as a spectator to the $\gamma N\rightarrow VN$ subprocess.
Corrections to the plane wave impulse approximation involve final state
interactions (FSIs) between the struck nucleon or the vector meson, either of
which is energetic, with the slow spectator nucleon. In this regime, the
eikonal approximation is valid, so is employed to calculate the cross-section
for the reaction. Due to the high-energy nature of the FSIs, the maxima of the
rescatterings are located at nearly transverse directions of the fast hadrons.
This results in two peaks in the angular distribution of the spectator nucleon,
each corresponding to either the $V$-$N$ or the $p$-$n$ rescattering. The
$V$-$N$ peak provides a new means of probing the $V$-$N$ interaction. This is
checked for near-threshold $\phi$ and $J/\Psi$ photoproduction reactions which
demonstrate that the $V$-$N$ peak can be used to extract the largely unknown
amplitudes of $\phi$-$N$ and $J/\Psi$-$N$ interactions.
  Two additional phenomena are observed when extending the calculation of
$J/\Psi$ photoproduction to the sub-threshold and high-energy domains. In the
first case we observe overall suppression of FSI effects due to a restricted
phase space for sub-threshold production in the rescattering amplitude. In the
second, we observe cancellation of the $V$-$N$ rescattering amplitudes for
vector mesons produced off of different nucleons in the deuteron.


title:
Proton-proton and electron-positron collider in a 100 km ring at
  Fermilab

abstract:
  The discovery of a Higgs-like boson with mass near 126 GeV, at the LHC, has
reignited interest in future energy frontier colliders. We propose here a
proton-proton (pp) collider in a 100 km ring, with center of mass (CM) energy
of ~100 TeV which would have substantial discovery potential for new heavy
particles and new physics beyond the Standard Model. In the case that LHC
experiments have already found exotic resonances or heavy "partner" particles,
this collider could fill out the "tower" of resonances (thus e.g. confirming an
extra dimension) or the full suite of partner particles (e.g. for
supersymmetry). The high luminosity of the new collider would enable unique
precision studies of the Higgs boson (including Higgs self coupling and rare
Higgs decays), and its higher energy would allow more complete measurements of
vector boson scattering to help elucidate electroweak symmetry breaking. We
also discuss an e+e- collider in the same 100 km ring with CM energies from 90
to 350 GeV. This collider would enable precision electroweak measurements up to
the ttbar threshold, and serve as a Higgs factory.


title:
Implications of the Planck bispectrum constraints for the primordial
  trispectrum

abstract:
  The new Planck constraints on the local bispectrum parameter fnl are about
10^5 times tighter than the current constraints on the trispectrum parameter
gnl, which means that the allowed numerical values of the second and third
order terms in the perturbative expansion of the curvature perturbation are
comparable. We show that a consequence of this is that if gnl is large enough
to be detectable, then it will induce a large variation between the observable
value of fnl and its value in a larger inflated volume. Even if there were only
a few extra efoldings between the beginning of inflation and horizon crossing
of our Hubble horizon, an observably large gnl means that fnl is unlikely to be
as small as its current constraint, regardless of its true background value.
This result is very general, it holds regardless of how many fields contributed
to the curvature perturbation. We also generalise this result to other shapes
of non-Gaussianity, beyond the local model. We show that the variance of the
3-point function in the squeezed limit is bounded from below by the square of
the squeezed limit of the 4-point function.