title: Ambitwistor strings and the scattering equations

abstract:
  We show that string theories admit chiral infinite tension analogues in which
only the massless parts of the spectrum survive. Geometrically they describe
holomorphic maps to spaces of complex null geodesics, known as ambitwistor
spaces. They have the standard critical space--time dimensions of string theory
(26 in the bosonic case and 10 for the superstring). Quantization leads to the
formulae for tree--level scattering amplitudes of massless particles found
recently by Cachazo, He and Yuan. These representations localize the vertex
operators to solutions of the same equations found by Gross and Mende to govern
the behaviour of strings in the limit of high energy, fixed angle scattering.
Here, localization to the scattering equations emerges naturally as a
consequence of working on ambitwistor space. The worldsheet theory suggests a
way to extend these amplitudes to spinor fields and to loop level. We argue
that this family of string theories is a natural extension of the existing
twistor string theories.


title:
Stability of nonspinning effective-one-body model in approximating
  two-body dynamics and gravitational-wave emission

abstract:
  The detection of gravitational waves and the extraction of physical
information from them requires the prediction of accurate waveforms to be used
in template banks. For that purpose, the accuracy of effective-one-body (EOB)
waveforms has been improved over the last years by calibrating them to
numerical-relativity (NR) waveforms. So far, the calibration has employed a
handful of NR waveforms with a total length of ~30 cycles, the length being
limited by the computational cost of NR simulations. Here we address the
outstanding problem of the stability of the EOB calibration with respect to the
length of NR waveforms. Performing calibration studies against NR waveforms of
nonspinning black-hole binaries with mass ratios 1, 1.5, 5, and 8, and with a
total length of ~60 cycles, we find that EOB waveforms calibrated against
either 30 or 60 cycles will be indistinguishable by the advanced detectors LIGO
and Virgo when the signal-to-noise ratio (SNR) is below 110. When extrapolating
to a very large number of cycles, using very conservative assumptions, we can
conclude that state-of-the-art nonspinning EOB waveforms of any length are
sufficiently accurate for parameter estimation with advanced detectors when the
SNR is below 20, the mass ratio is below 5 and total mass is above 20 Msun. The
results are not conclusive for the entire parameter space because of current NR
errors.


title:
Equations for the third secant variety of the Segre product of n
  projective spaces

abstract:
  We determine set theoretic defining equations for the third secant variety of
the Segre product of $n$ projective spaces, and from the proof of the main
statement we derive an upper bound for the degrees of these equations.


title: Snowmass Computing Frontier: Software Development, Staffing and Training

abstract:
  Report of the Snowmass CpF-I4 subgroup on Software Development, Staffing and
Training


title:
Modeling and Simulation of the Effects of Cyclic Loading on Articular
  Cartilage Lesion Formation

abstract:
  We present a model of articular cartilage lesion formation to simulate the
effects of cyclic loading. This model extends and modifies the
reaction-diffusion-delay model by Graham et al. 2012 for the spread of a lesion
formed though a single traumatic event. Our model represents "implicitly" the
effects of loading, meaning through a cyclic sink term in the equations for
live cells.
  Our model forms the basis for in silico studies of cartilage damage relevant
to questions in osteoarthritis, for example, that may not be easily answered
through in vivo or in vitro studies.
  Computational results are presented that indicate the impact of differing
levels of EPO on articular cartilage lesion abatement.


title:
First determination of $f_+(0) |V_{us}|$ from a combined analysis of
  $\tau\to K\pi \nu_\tau$ decay and $\pi K$ scattering with constraints from
  $K_{\ell3}$ decays

abstract:
  We perform a combined analysis of $\tau\to K\pi \nu_\tau$ decay and $\pi K$
scattering with constraints from $K_{\ell3}$ data using a $N/D$ approach that
fulfills requirements from unitarity and analyticity. We obtain a good fit of
the $I=1/2$ $\pi K$ amplitude in the $P$ wave using the LASS data above the
elastic region while in this region data are generated via Monte Carlo using
the FOCUS results based on $D_{\ell 4}$ decay. The spectrum and branching ratio
of $\tau\to K\pi \nu_\tau$ constrained by $K_{\ell3}$ decays are also well
reproduced leading to $f_+(0) |V_{us}|= 0.2163 \pm 0.0014 $. Furthermore, we
obtain the slope of the vector form factor $\lambda_+=(25.56 \pm 0.40) \times
10^{-3} $ while the value of the scalar form factor at the Callan-Treiman point
is $\ln C=0.2062 \pm 0.0089$. Given the experimental precision our results are
compatible with the Standard model.


title:
Horava-Lifshitz Gravity Effects on Casimir Energy in Weak Field
  Approximation and Infrared Regime

abstract:
  We calculate the renormalized vacuum energy of a massless scalar field
confined between two nearby parallel plates formed by ideal uncharged
conductors, placed tangentially to the surface of a sphere with mass M and
radius R. This study will take into account the static and spherically
symmetric solution of Horava-Lifshitz gravity found by Kehagias-Sfetsos (KS),
in both weak field and infrared limits. A slight amplification of the Casimir
force between the conducting plates is found. Thermal corrections to the
Casimir energy are analyzed. Based on current Casimir effect measurements, a
constraint on the $\omega$ parameter of KS metric is also obtained.


title:
Exponential lower bounds on fixed-size psd rank and semidefinite
  extension complexity

abstract:
  There has been a lot of interest recently in proving lower bounds on the size
of linear programs needed to represent a given polytope P. In a breakthrough
paper Fiorini et al. [Proceedings of 44th ACM Symposium on Theory of Computing
2012, pages 95-106] showed that any linear programming formulation of
maximum-cut must have exponential size. A natural question to ask is whether
one can prove such strong lower bounds for semidefinite programming
formulations. In this paper we take a step towards this goal and we prove
strong lower bounds for a certain class of SDP formulations, namely SDPs over
the Cartesian product of fixed-size positive semidefinite cones. In practice
this corresponds to semidefinite programs with a block-diagonal structure and
where blocks have constant size d. We show that any such extended formulation
of the cut polytope must have exponential size (when d is fixed). The result of
Fiorini et al. for LP formulations is obtained as a special case when d=1. For
blocks of size d=2 the result rules out any small formulations using
second-order cone programming. Our study of SDP lifts over Cartesian product of
fixed-size positive semidefinite cones is motivated mainly from practical
considerations where it is well known that such SDPs can be solved more
efficiently than general SDPs. The proof of our lower bound relies on new
results about the sparsity pattern of certain matrices with small psd rank,
combined with an induction argument inspired from the recent paper by Kaibel
and Weltge [arXiv:1307.3543] on the LP extension complexity of the correlation
polytope.


title: Regularity bounds for complexes and their homology

abstract:
  Let $R$ be a standard graded algebra over a field $k$. We prove an
Auslander-Buchsbaum formula for the absolute Castelnuovo-Mumford regularity,
extending important cases of previous works of Chardin and R\"omer. For a
bounded complex of finitely generated graded $R$-modules $L$, we prove the
equality $\text{reg}~ L=\max_{i\in \mathbb Z} \{\text{reg}~ H_i(L)-i\}$ given
the condition $\text{depth}~ H_i(L)\ge \dim H_{i+1}(L)-1$ for all $i<\sup L$.
As applications, we recover previous bounds on regularity of Tor due to
Caviglia, Eisenbud-Huneke-Ulrich, among others. We also obtain strengthened
results on regularity bounds for Ext and for the quotient by a linear form of a
module.


title:
Accelerating anisotropic cosmologies in Brans-Dicke gravity coupled to a
  mass-varying vector field

abstract:
  The field equations of Brans-Dicke gravity coupled to a mass-varying vector
field are derived. Anisotropic cosmological solutions with a locally
rotationally symmetric Bianchi type I metric and time-dependent scalar and
electric vector fields are studied. A particular class of exact solutions for
which all the variable parameters have a power-law time dependence is given.
The universe expands with a constant expansion anisotropy within this class of
solutions. We show that the accelerating expansion is driven by the scalar
field and the electric vector field can be interpreted as an anisotropic dark
matter source.


title: Realistic Implementation of Chiral Magnetic Wave in Heavy Ion Collisions

abstract:
  Chiral Magnetic Wave (CMW) is a gapless collective excitation of chiral
charges along the direction of magnetic field in the Quark-Gluon Plasma that
arises from the triangle anomaly of QCD. We perform reliable study of the CMW
in the realistic simulation of heavy ion collisions, and find that the CMW
contributions to the charge dependent elliptic flow of pions, $\Delta v_2 =
v_2(\pi^-)-v_2(\pi^+)$, linearly depending on the net charge asymmetry
$A_\pm\equiv (N_+-N_-)/(N_++N_-)$ with a positive slope $r$, is comparable to
the recent experimental results from RHIC. We identify "Freezeout Hole Effect",
which is a direct consequence of the propagation of CMW during the realistic
evolution of fireball, as the dominant physics effect responsible for a sizable
contribution from the CMW to the slope parameter $r$, and emphasize that a
proper treatment of the freeze out condition is crucial in any reliable
computation of the CMW contribution to the slope parameter $r$. We also
implement chiral phase transition effect in our study, which illustrates the
sensitivity of the results to chiral phase transition temperature, and suggest
that the CMW can be an important probe of QCD chiral phase transition. Our
results on the impact parameter dependence compare well with the RHIC
experiments. We also give predictions for the LHC energy.


title:
Impact on Astrophysics and Elementary Particle Physics of recent and
  future solar neutrino data

abstract:
  The study of neutrinos is fundamental to connect astrophysics and elementary
particle physics. In this last decade solar neutrino experiments and KamLAND
confirmed the LMA solution and further clarified the mass and oscillation
pattern. Borexino attacked also the study of the low energy neutrino spectrum.
However, important points still need clarification, like the apparent anomaly
in the vacuum to matter transition region. Besides, a more detailed study of
the low energy components of the pp cycle, combined with a measurement of CNO
fluxes, is compulsory, also to discriminate between the low and the high Z
versions of the Solar Standard Models and solve the metallicity problem. We
discuss the main recent advancements and the possibilities of studying these
open problems with Borexino, SNO+ and the future experiments, like the next
generation of scintillators.


title: Mottness-induced healing in strongly correlated superconductors

abstract:
  We study impurity healing effects in models of strongly correlated
superconductors. We show that in general both the range and the amplitude of
the spatial variations caused by nonmagnetic impurities are significantly
suppressed in the superconducting as well as in the normal states. We
explicitly quantify the weights of the local and the non-local responses to
inhomogeneities and show that the former are overwhelmingly dominant over the
latter. By quantifying the spatial range of the local response, we show that it
is restricted to only a few lattice spacings over a significant range of
dopings in the vicinity of the Mott insulating state. We demonstrate that this
healing effect is ultimately due to the suppression of charge fluctuations
induced by Mottness. We also define and solve analytically a simplified yet
accurate model of healing, within which we obtain simple expressions for
quantities of direct experimental relevance.


title: On Chiral Mesons in AdS/CFT

abstract:
  We analyze the spectra of non-chiral and chiral bifundamental mesons arising
on intersecting D7-branes in $AdS_{5}\times S^{5}$. In the absence of magnetic
flux on the curve of intersection, the spectrum is non-chiral, and the dual
gauge theory is conformal in the quenched/probe approximation. For this case we
calculate the dimensions of the bifundamental mesonic operators. We then
consider magnetization of the D7-branes, which deforms the dual theory by an
irrelevant operator and renders the mesons chiral. The magnetic flux spoils the
conformality of the dual theory, and induces a D3-brane charge that becomes
large in the ultraviolet, where the non-normalizable bifundamental modes are
rapidly divergent. An ultraviolet completion is therefore necessary to
calculate the correlation functions in the chiral case. On the other hand, the
normalizable modes are very well localized in the infrared, leading to new
possibilities for local model-building on intersecting D7-branes in warped
geometries.


title: Primal Beats Dual on Online Packing LPs in the Random-Order Model

abstract:
  We study packing LPs in an online model where the columns are presented to
the algorithm in random order. This natural problem was investigated in various
recent studies motivated, e.g., by online ad allocations and yield management
where rows correspond to resources and columns to requests specifying demands
for resources. Our main contribution is a $1-O(\sqrt{(\log{d})/B})$-competitive
online algorithm, where $d$ denotes the column sparsity, i.e., the maximum
number of resources that occur in a single column, and $B$ denotes the capacity
ratio $B$, i.e., the ratio between the capacity of a resource and the maximum
demand for this resource. In other words, we achieve a $(1 -
\epsilon)$-approximation if the capacity ratio satisfies $B=\Omega((\log
d)/\epsilon^2)$, which is known to be best-possible for any (randomized) online
algorithms.
  Our result improves exponentially on previous work with respect to the
capacity ratio. In contrast to existing results on packing LP problems, our
algorithm does not use dual prices to guide the allocation of resources.
Instead, it simply solves, for each request, a scaled version of the partially
known primal program and randomly rounds the obtained fractional solution to
obtain an integral allocation for this request. We show that this simple
algorithmic technique is not restricted to packing LPs with large capacity
ratio: We prove an upper bound on the competitive ratio of
$\Omega(d^{-1/(B-1)})$, for any $B \ge 2$. In addition, we show that our
approach can be combined with VCG payments and obtain an incentive compatible
$(1-\epsilon)$-competitive mechanism for packing LPs with $B=\Omega((\log
m)/\epsilon^2)$, where $m$ is the number of constraints. Finally, we apply our
technique to the generalized assignment problem for which we obtain the first
online algorithm with competitive ratio $O(1)$.


title: General virial theorem for modified-gravity MOND

abstract:
  An important and useful relation is known to hold in two specific MOND
theories. It pertains to low-acceleration, isolated systems of pointlike
masses, m_p, at positions r_p, subject to gravitational forces F_p. It reads
sum_p r_p.F_p=-(2/3)(Ga0)^{1/2}[(\sum_p m_p)^{3/2}-\sum_p m_p^{3/2}]; a0 is the
MOND acceleration constant. Here I show that this relation holds in the
nonrelativistic limit of any modified-gravity MOND theory. It follows from only
the basic tenets of MOND (as applied to such theories): departure from standard
dynamics at accelerations below a0, and space-time scale invariance in the
nonrelativistic, low-acceleration limit. This implies space-dilatation
invariance of the static, gravitational-field equations, which, in turn, leads
to the above point-mass virial relation. Thus, the various MOND predictions and
tests based on this relation hold in any modified-gravity MOND theory. Since we
do not know that any of the existing MOND theories point in the right
direction, it is important to identify such predictions that hold in a much
larger class of theories. Among these predictions are the MOND two-body force
for arbitrary masses, and a general mass-velocity-dispersion relation of the
form sigma^2=(2/3)(MGa0)^{1/2}[1-\sum_p (m_p/M)^{3/2}], where M is the total
mass.


title: A Periodic Solution to Impulsive Logistic Equation

abstract:
  In this paper is provided a new representation of periodic solution to the
impulsive Logistic equation considered in [7].


title: Annotations regarding the Oxford Questions

abstract:
  The recently published "Oxford Questions" are supplemented with annotations
concerning: doctrine of wave packets collapse (and sub- sidiarily Schrodinger's
cat thought experiment), description of quan- tum measurements respectively
interpretation of uncertainty relations.


title: A spectroscopic binary in the Hercules dwarf spheroidal galaxy

abstract:
  We present the radial velocity curve of a single-lined spectroscopic binary
in the faint Hercules dwarf spheroidal (dSph) galaxy, based on 34 individual
spectra covering more than two years of observations. This is the first time
that orbital elements could be derived for a binary in a dSph. The system
consists of a metal-poor red giant and a low-mass companion, possibly a white
dwarf, with a 135-days period in a moderately eccentric ($e=0.18$) orbit. Its
period and eccentricity are fully consistent with metal-poor binaries in the
Galactic halo, while the projected semimajor axis is small, at $a_p$ sin$i$ =
38 R$_{sun}$. In fact, a very close orbit could inhibit the production of
heavier elements through $s$-process nucleosynthesis, leading to the very low
abundances of neutron-capture elements that are found in this star. We discuss
the further implications for the chemical enrichment history of the Hercules
dSph, but find no compelling binary scenario that could reasonably explain the
full, peculiar abundance pattern of the Hercules dSph galaxy.


title:
Mapping Compound Cosmic Telescopes Containing Multiple, Projected
  Cluster-Scale Halos

abstract:
  Lines of sight with multiple, projected, cluster-scale halos have high total
masses and complex lens plane interactions that can boost the area of
magnification, or etendue, making detection of faint background sources more
likely than elsewhere. To identify these new "compound" cosmic telescopes, we
have found lines-of-sight with the highest integrated mass densities, as traced
by the projected concentrations of Luminous Red Galaxies (LRGs). We use 1151
MMT Hectospec spectra to derive preliminary magnification maps for two such
lines of sight with total mass exceeding ~ 3 x 10$^{15}$ Msun -- J0850+3604
(0850) and J1306+4632 (1306). We identify 2-3 group- and cluster-scale halos in
each beam over 0.1 < z < 0.7, all of which are well-traced by LRGs. In Subaru
Suprime-Cam imaging of beam 0850, we discover serendipitously a candidate
multiply-imaged V-dropout source at z = 5.03, whose location is consistent with
the critical curves for a source plane of $z_s$ = 5.03 predicted by our mass
model. Incorporating the position of the candidate multiply-imaged galaxy as a
constraint on the critical curve location in 0850 narrows the 68% confidence
band on lens plane area with mu > 10 for a source plane of $z_s$ = 10 to [1.8,
4.2] square arcminutes, comparable to that of MACS 0717+3745 and El Gordo, two
of the most powerful known single cluster lenses. The 68% confidence intervals
on the lens plane area with mu > 10 for 1306 are [2.3, 6.7] square arcminutes.
The significant lensing power of our beams makes them powerful probes of
reionization and galaxy formation in the early Universe.


title:
Constraints on the multi-lognormal magnetic fields from the observations
  of the cosmic microwave background and the matter power spectrum

abstract:
  Primordial magnetic fields (PMFs), which were generated in the early Universe
before recombination, affect the motion of plasma and then the cosmic microwave
background and the matter power spectrum. We consider constraints on PMFs with
a characteristic correlation length from the observations of the anisotropies
of the cosmic microwave background and the matter power spectrum. The spectrum
of PMFs is modeled with multi-lognormal distributions, rather than power-law
distribution, and we derive constraints on the strength $|\mathbf{B}_k|$ at
each wave number $k$ along with the standard cosmological parameters in the
flat Universe and the foreground sources. We obtain upper bounds on the field
strengths at $k=10^{-1}, 10^{-2}, 10^{-4}$, and $10^{-5}$ Mpc$^{-1}$ as 4.7 nG,
2.1 nG, 5.3 nG, and 10.9 nG ($2\sigma$ C.L.) respectively, while the field
strength at $k=10^{-3} $Mpc$^{-1}$ turns out to have a finite value as
$|\mathbf{B}_{k = 10^{-3}}| = 6.2 \pm 1.3 $ nG ($1\sigma$ C.L.). This finite
value is attributed to the finite values of BB mode data at $\ell > 300$
obtained from the QUAD experiment. If we do not include the BB mode data, we
obtain only the upper bound on $B_{k=10^{-3}}$.


title:
Constraining isocurvature perturbations with the 21cm emission from
  minihaloes

abstract:
  We investigate the effects of isocurvature perturbations on the 21cm
radiation from minihaloes (MHs) at high redshifts and examine constraints on
the isocurvature amplitude and power spectrum using the next generation of
radio telescopes such as the Square Kilometre Array. We find that there is a
realistic prospect of observing the isocurvature imprints in the 21cm emission
from MHs, but only if the isocurvature spectral index is close to $3$ (i.e.,
the spectrum is blue). When the isocurvature fraction increases beyond $\sim
10\%$ of the adiabatic component, we observe an unexpected decline in the 21cm
fluctuations from small-mass MHs, which can be explained by the incorporation
small MHs into larger haloes. We perform a detailed Fisher-matrix analysis, and
conclude that the combination of future CMB and 21cm experiments (such as
CMBPol and the Fast-Fourier-Transform Telescope) is ideal in constraining the
isocurvature parameters, but will stop short of distinguishing between CDM and
baryon types of isocurvature perturbations, unless the isocurvature fraction is
large and the spectrum is blue.


title: Compactifying de Sitter Naturally Selects a Small Cosmological Constant

abstract:
  We study compactifications of $D$-dimensional de Sitter space with a $q$-form
flux down to $D-Nq$ dimensions. We show that for $(N-1)(q-1)\geq 2$ there are
double-exponentially or even infinitely many compact de Sitter vacua, and that
their effective cosmological constants accumulate at zero. This population
explosion of $\Lambda \ll 1$ de Sitters arises by a mechanism analogous to
natural selection.


title:
Dissecting galaxy formation models with Sensitivity Analysis -- A new
  approach to constrain the Milky Way formation history

abstract:
  [Abridged] We present an application of a statistical tool known as
Sensitivity Analysis to characterize the relationship between input parameters
and observational predictions of semi-analytic models of galaxy formation
coupled to cosmological $N$-body simulations. We show how a sensitivity
analysis can be performed on our chemo-dynamical model, ChemTreeN, to
characterize and quantify its relationship between model input parameters and
predicted observable properties. The result of this analysis provides the user
with information about which parameters are most important and most likely to
affect the prediction of a given observable. It can also be used to simplify
models by identifying input parameters that have no effect on the outputs of
interest. Conversely, it allows us to identify what model parameters can be
most efficiently constrained by the given observational data set. We have
applied this technique to real observational data sets associated with the
Milky Way, such as the luminosity function of satellite galaxies. A statistical
comparison of model outputs and real observables is used to obtain a
"best-fitting" parameter set. We consider different Milky Way-like dark matter
halos to account for the dependence of the best-fitting parameters selection
process on the underlying merger history of the models. For all formation
histories considered, running ChemTreeN with best-fitting parameters produced
luminosity functions that tightly fit their observed counterpart. However, only
one of the resulting stellar halo models was able to reproduce the observed
stellar halo mass within 40 kpc of the Galactic center. On the basis of this
analysis it is possible to disregard certain models, and their corresponding
merger histories, as good representations of the underlying merger history of
the Milky Way.


title:
Cosmic Degeneracies I: Joint N-body Simulations of Modified Gravity and
  Massive Neutrinos

abstract:
  We present the first suite of cosmological N-body simulations that
simultaneously include the effects of two different and theoretically
independent extensions of the standard $\Lambda$CDM cosmological scenario -
namely an $f(R)$ theory of Modified Gravity (MG) and a cosmological background
of massive neutrinos - with the aim to investigate their possible observational
degeneracies. We focus on three basic statistics of the large-scale matter
distribution, more specifically the nonlinear matter power spectrum, the halo
mass function, and the halo bias, for which we determine the deviation with
respect to the fiducial $\Lambda$CDM cosmology in the context of both separate
and combined simulations of $f(R)$ MG and massive neutrinos scenarios. Our
results show that while these two extended models separately determine very
prominent and potentially detectable features in all the three statistics, when
we allow them to be simultaneously at work these features are strongly
suppressed, resulting in much weaker deviations from the standard model's
predictions. In particular, when an $f(R)$ gravity model with $f_{R0}=-1\times
10^{-4}$ is combined with a total neutrino mass of $\Sigma _{i}m_{\nu
_{i}}=0.4$ eV, the resulting matter power spectrum, halo mass function, and
bias at z=0 are found to be consistent with the standard model's predictions at
the 10%, 20%, and 5% accuracy levels, respectively. Therefore, our results
imply an intrinsic theoretical limit to the effective discriminating power of
present and future observational data sets with respect to these widely
considered extensions of the standard cosmological scenario in the absence of
independent measurements of the neutrino masses from laboratory experiments,
even though the high-redshift evolution might still allow to partially break
the degeneracy [Abridged].


title: Terzan 8: a Sagittarius-flavoured globular cluster

abstract:
  Massive globular clusters (GCs) contain at least two generations of stars
with slightly different ages and clearly distinct light elements abundances.
The Na-O anticorrelation is the best studied chemical signature of multiple
stellar generations. Low-mass clusters appear instead to be usually chemically
homogeneous. We are investigating low-mass GCs to understand what is the lower
mass limit where multiple populations can form, mainly using the Na and O
abundance distribution. We used VLT/FLAMES spectra of giants in the low-mass,
metal-poor GC Terzan 8, belonging to the Sagittarius dwarf galaxy, to determine
abundances of Fe, O, Na, alpha-, Fe-peak, and neutron-capture elements in six
stars observed with UVES and 14 observed with GIRAFFE. The average metallicity
is [Fe/H]=-2.27+/-0.03 (rms=0.08), based on the six high-resolution UVES
spectra. Only one star, observed with GIRAFFE, shows an enhanced abundance of
Na and we tentatively assign it to the second generation. In this cluster, at
variance with what happens in more massive GCs, the second generation seems to
represent at most a small minority fraction. We discuss the implications of our
findings, comparing Terzan 8 with the other Sgr dSph GCs, to GCs and field
stars in the Large Magellanic Cloud, Fornax, and in other dwarfs galaxies.


title: An ansatz for one dimensional steady state configurations

abstract:
  We conjecture a universal formula for the heat current of a steady state
connecting two asymptotic equilibrium systems in d-dimensional conformal field
theories. Our proposal is verified by comparing it to exact expressions in 1+1
dimensions and linear hydrodynamics as well as numerical simulations in an
Israel-Stewart like theory of second order viscous hydrodynamics.


title: MadMax, or Where Boosted Significances Come From

abstract:
  In an era of increasingly advanced experimental analysis techniques it is
crucial to understand which phase space regions contribute a signal extraction
from backgrounds. Based on the Neyman-Pearson lemma we compute the maximum
significance for a signal extraction as an integral over phase space regions.
We then study to what degree boosted Higgs strategies benefit ZH and ttH
searches and which transverse momenta of the Higgs are most promising. We find
that Higgs and top taggers are the appropriate tools, but would profit from a
targeted optimization towards smaller transverse momenta. MadMax is available
as an add-on to Madgraph5.


title:
Atmospheric Parameters and Metallicities for 2191 stars in the Globular
  Cluster M4

abstract:
  We report new metallicities for stars of Galactic globular cluster M4 using
the largest number of stars ever observed at high spectral resolution in any
cluster. We analyzed 7250 spectra for 2771 cluster stars gathered with the VLT
FLAMES+GIRAFFE spectrograph at VLT. These medium resolution spectra cover by a
small wavelength range, and often have very low signal-to-noise ratios. We
attacked this dataset by reconsidering the whole method of abundance analysis
of large stellar samples from beginning to end. We developed a new algorithm
that automatically determines the atmospheric parameters of a star. Nearly all
data preparation steps for spectroscopic analyses are processed on the
syntheses, not the observed spectra. For 322 Red Giant Branch stars with $V
\leq 14.7$ we obtain a nearly constant metallicity, $<[{\rm Fe}/{\rm H}]> =
-1.07$ ($\sigma$ = 0.02). No difference in the metallicity at the level of
$0.01 ~\textrm{dex}$ is observed between the two RGB sequences identified by
\cite{Monelli:2013us}. For 1869 Subgiant and Main Sequence Stars $V > 14.7$ we
obtain $<[{\rm Fe}/{\rm H}]> = -1.16$ ($\sigma$ = 0.09) after fixing the
microturbulent velocity. These values are consistent with previous studies that
have performed detailed analyses of brighter RGB stars at higher spectroscopic
resolution and wavelength coverage. It is not clear if the small mean
metallicity difference between brighter and fainter M4 members is real or is
the result of the low signal-to-noise characteristics of the fainter stars. The
strength of our approach is shown by recovering a metallicity close to a single
value for more than two thousand stars, using a dataset that is non-optimal for
atmospheric analyses. This technique is particularly suitable for noisy data
taken in difficult observing conditions.


title: Non-relativistic leptogenesis

abstract:
  In many phenomenologically interesting models of thermal leptogenesis the
heavy neutrinos are non-relativistic when they decay and produce the baryon
asymmetry of the Universe. We propose a non-relativistic approximation for the
corresponding rate equations in the non-resonant case, and a systematic way for
computing relativistic corrections. We determine the leading order coefficients
in these equations, and the first relativistic corrections. The
non-relativistic approximation works remarkably well. It appears to be
consistent with results obtained using a Boltzmann equation taking into account
the momentum distribution of the heavy neutrinos, while being much simpler. We
also compute radiative corrections to some of the coefficients in the rate
equations. Their effect is of order 1% in the regime favored by neutrino
oscillation data. We obtain the correct leading order lepton number washout
rate in this regime, which leads to large (~ 20%) effects compared to previous
computations.


title: Recombination clumping factor during cosmic reionization

abstract:
  We discuss the role of recombinations in the IGM, and the related concept of
the clumping factor, during cosmic reionization. The clumping factor is, in
general, a local quantity that depends on the local over-density and the scale
below which the baryon density field can be assumed smooth. That scale, called
the filtering scale, is itself depended on over-density and local thermal
history. We present a method for building a self-consistent analytical model of
inhomogeneous reionization assuming the linear growth rate of the density
fluctuation, which accounts for these effects simultaneously. We show that
taking into account the local clumping factor introduces significant
corrections to the total recombination rate, comparing to the model with a
globally uniform clumping factor.


title:
Massive Molecular Outflows and Evidence for AGN Feedback from CO
  Observations

abstract:
  We study the properties of massive, galactic-scale outflows of molecular gas
and investigate their impact on galaxy evolution. We present new IRAM PdBI
CO(1-0) observations of local ULIRGs and QSO hosts: clear signature of massive
and energetic molecular outflows, extending on kpc scales, is found in the
CO(1-0) kinematics of four out of seven sources, with measured outflow rates of
several 100 Msun/yr. We combine these new observations with data from the
literature, and explore the nature and origin of massive molecular outflows
within an extended sample of 19 local galaxies. We find that
starburst-dominated galaxies have an outflow rate comparable to their SFR, or
even higher by a factor of ~ 2-4, implying that starbursts can indeed be
effective in removing cold gas from galaxies. Nevertheless, our results suggest
that the presence of an AGN can boost the outflow rate by a large factor, which
is found to increase with the L_AGN/L_bol ratio. The gas depletion time-scales
due to molecular outflows are anti-correlated with the presence and luminosity
of an AGN in these galaxies, and range from a few hundred million years in
starburst galaxies, down to just a few million years in galaxies hosting
powerful AGNs. In quasar hosts the depletion time-scales due to the outflow are
much shorter than the depletion time-scales due to star formation. We estimate
the outflow kinetic power and find that, for galaxies hosting powerful AGNs, it
corresponds to about 5% of the AGN luminosity, as expected by models of AGN
feedback. Moreover, we find that momentum rates of about 20 L_AGN/c are common
among the AGN-dominated sources in our sample. For "pure" starburst galaxies
our data tentatively support models in which outflows are mostly
momentum-driven by the radiation pressure from young stars onto dusty clouds.


title:
The SINS/zC-SINF survey of z~2 galaxy kinematics: Evidence for powerful
  AGN-driven nuclear outflows in massive star-forming galaxies

abstract:
  We report the detection of ubiquitous powerful nuclear outflows in massive (>
10^11 Msun) z~2 star-forming galaxies (SFGs), which are plausibly driven by an
Active Galactic Nucleus (AGN). The sample consists of the eight most massive
SFGs from our SINS/zC-SINF survey of galaxy kinematics with the imaging
spectrometer SINFONI, six of which have sensitive high-resolution adaptive
optics (AO) assisted observations. All of the objects are disks hosting a
significant stellar bulge. The spectra in their central regions exhibit a broad
component in Halpha and forbidden [NII] and [SII] line emission, with typical
velocity FWHM ~ 1500 km/s, [NII]/Halpha ratio ~ 0.6, and intrinsic extent of 2
- 3 kpc. These properties are consistent with warm ionized gas outflows
associated with Type 2 AGN, the presence of which is confirmed via independent
diagnostics in half the galaxies. The data imply a median ionized gas mass
outflow rate of ~ 60 Msun/yr and mass loading of ~ 3. At larger radii, a weaker
broad component is detected but with lower FWHM ~ 485 km/s and [NII]/Halpha ~
0.35, characteristic for star formation-driven outflows as found in the
lower-mass SINS/zC-SINF galaxies. The high inferred mass outflow rates and
frequent occurrence suggest the nuclear outflows efficiently expel gas out of
the centers of the galaxies with high duty cycles, and may thus contribute to
the process of star formation quenching in massive galaxies. Larger samples at
high masses will be crucial to confirm the importance and energetics of the
nuclear outflow phenomenon, and its connection to AGN activity and bulge
growth.


title:
Sloan Digital Sky Survey III Photometric Quasar Clustering: Probing the
  Initial Conditions of the Universe using the Largest Volume

abstract:
  The Sloan Digital Sky Survey has surveyed 14,555 square degrees of the sky,
and delivered over a trillion pixels of imaging data. We present the
large-scale clustering of 1.6 million quasars between z = 0.5 and z = 2.5 that
have been classified from this imaging, representing the highest density of
quasars ever studied for clustering measurements. This data set spans ~11,000
square degrees and probes a volume of 80(Gpc/h)^3. In principle, such a large
volume and medium density of tracers should facilitate high-precision
cosmological constraints. We measure the angular clustering of photometrically
classified quasars using an optimal quadratic estimator in four redshift slices
with an accuracy of ~25% over a bin width of l ~10 - 15 on scales corresponding
to matter-radiation equality and larger (l ~ 2 - 30). Observational systematics
can strongly bias clustering measurements on large scales, which can mimic
cosmologically relevant signals such as deviations from Gaussianity in the
spectrum of primordial perturbations. We account for systematics by employing a
new method recently proposed by Agarwal et al. (2014) to the clustering of
photometrically classified quasars. We carefully apply our methodology to
mitigate known observational systematics and further remove angular bins that
are contaminated by unknown systematics. Combining quasar data with the
photometric luminous red galaxy (LRG) sample of Ross et al. (2011) and Ho et
al. (2012), and marginalizing over all bias and shot noise-like parameters, we
obtain a constraint on local primordial non-Gaussianity of fNL = -113+/-154
(1\sigma error). [Abridged]


title: Geometric Structure of Higher-Dimensional Spheres

abstract:
  We explain in some detail the geometric structure of spheres in any
dimension. Our approach may be helpful for other homogeneous spaces (with other
signatures) such as the de Sitter and anti-de Sitter spaces. We apply the
procedure to the recently proposed division-algebras/Poincar\'e-conjecture
correspondence. Moreover, we explore the possibility of a connection between
N-qubit system and the Hopf maps. We also discuss the possible links of our
work with squashed-spheres in supergravity and pseudo-spheres in oriented
matroid theory.


title:
Resolving the problem of galaxy clustering on small scales: any new
  physics needed?

abstract:
  Galaxy clustering sets strong constraints on the physics governing galaxy
formation and evolution. However, most current models fail to reproduce the
clustering of low-mass galaxies on small scales ($r<1Mpc/h$). In this paper we
study the galaxy clusterings predicted from a few semi-analytical models. We
firstly compare two Munich versions, Guo et al. (2011, Guo11) and De Lucia \&
Blazoit (2007, DLB07). The Guo11 model well reproduces the galaxy stellar mass
function, but over-predicts the clustering of low-mass galaxies on small
scales. The DLB07 model provides a better fit to the clustering on small
scales, but over-predicts the stellar mass function. These seem to be puzzling.
We find that there is slightly more fraction of satellite galaxies residing in
massive haloes in the Guo11 model, which is the dominant contribution to the
clustering discrepancy between the two models. However, both models still
over-predict the clustering at $0.1Mpc/h<r<10Mpc/h$ for low mass galaxies. This
is because both models over-predict the number of satellites by $30\%$ in
massive halos than the data. Actually, the better agreement of DLB07 model with
the data on small scales comes as a coincidence as it predicts too many
low-mass central galaxies which are less clustered and thus bring down the
total clustering. Finally, we show the predictions from the semi-analytical of
Kang et al. (2012). We find that this model can simultaneously fit the stellar
mass function and galaxy clustering if the supernova feedback in satellite
galaxies is stronger. We conclude that semi-analytical models are now able to
solve the small-scales clustering problem, without invoking of any other new
physics or changing the dark matter properties, such as the recent favored warm
dark matter.


title:
Dark Radiation constraints on minicharged particles in models with a
  hidden photon

abstract:
  We compute the thermalization of a hidden sector consisting of minicharged
fermions (MCPs) and massless hidden photons in the early Universe. The precise
measurement of the anisotropies of the cosmic microwave background (CMB) by
Planck and the relic abundance of light nuclei produced during big bang
nucleosynthesis (BBN) constrain the amount of dark radiation of this hidden
sector through the effective number of neutrino species, Neff. This study
presents novel and accurate predictions of dark radiation in the strongly and
weakly coupled regime for a wide range of model parameters. We give the value
of Neff for MCP masses between 100 keV and 10 GeV and minicharges in the range
10^(-11)-1. Our results can be used to constrain MCPs with the current data and
they are also a valuable indicator for future experimental searches, should the
hint for dark radiation manifest itself in the next release of Planck's data.


title:
Deep inelastic scattering structure functions of holographic spin-1
  hadrons with $N_f \geq 1$

abstract:
  Two-point current correlation functions of the large $N$ limit of
supersymmetric and non-supersymmetric Yang-Mills theories at strong coupling
are investigated in terms of their string theory dual models with quenched
flavors. We consider non-Abelian global symmetry currents, which allow one to
investigate vector mesons with $N_f > 1$. From the correlation functions we
construct the deep inelastic scattering hadronic tensor of spin-one mesons,
obtaining the corresponding eight structure functions for polarized vector
mesons. We obtain several relations among the structure functions. Relations
among some of their moments are also derived. Aspects of the sub-leading
contributions in the $1/N$ and $N_f/N$ expansions are discussed. At leading
order we find a universal behavior of the hadronic structure functions.


title: Robust Stability Analysis of Sparsely Interconnected Uncertain Systems

abstract:
  In this paper, we consider robust stability analysis of large-scale sparsely
interconnected uncertain systems. By modeling the interconnections among the
subsystems with integral quadratic constraints, we show that robust stability
analysis of such systems can be performed by solving a set of sparse linear
matrix inequalities. We also show that a sparse formulation of the analysis
problem is equivalent to the classical formulation of the robustness analysis
problem and hence does not introduce any additional conservativeness. The
sparse formulation of the analysis problem allows us to apply methods that rely
on efficient sparse factorization techniques, and our numerical results
illustrate the effectiveness of this approach compared to methods that are
based on the standard formulation of the analysis problem.


title: Short-Duration Gamma-Ray Bursts

abstract:
  Gamma-ray bursts (GRBs) display a bimodal duration distribution, with a
separation between the short- and long-duration bursts at about 2 sec. The
progenitors of long GRBs have been identified as massive stars based on their
association with Type Ic core-collapse supernovae, their exclusive location in
star-forming galaxies, and their strong correlation with bright ultraviolet
regions within their host galaxies. Short GRBs have long been suspected on
theoretical grounds to arise from compact object binary mergers (NS-NS or
NS-BH). The discovery of short GRB afterglows in 2005, provided the first
insight into their energy scale and environments, established a cosmological
origin, a mix of host galaxy types, and an absence of associated supernovae. In
this review I summarize nearly a decade of short GRB afterglow and host galaxy
observations, and use this information to shed light on the nature and
properties of their progenitors, the energy scale and collimation of the
relativistic outflow, and the properties of the circumburst environments. The
preponderance of the evidence points to compact object binary progenitors,
although some open questions remain. Based on this association, observations of
short GRBs and their afterglows can shed light on the on- and off-axis
electromagnetic counterparts of gravitational wave sources from the Advanced
LIGO/Virgo experiments.


title:
An ALMA survey of sub-millimeter galaxies in the Extended Chandra Deep
  Field South: Sub-millimeter properties of color-selected galaxies

abstract:
  We study the sub-mm properties of color-selected galaxies via a stacking
analysis applied for the first time to interferometric data at sub-mm
wavelengths. We base our study on 344 GHz ALMA continuum observations of
~20''-wide fields centered on 86 sub-mm sources detected in the LABOCA Extended
Chandra Deep Field South Sub-mm Survey (LESS). We select various classes of
galaxies (K-selected, star-forming sBzK galaxies, extremely red objects and
distant red galaxies) according to their optical/NIR fluxes. We find clear,
>10-sigma detections in the stacked images of all these galaxy classes. We
include in our stacking analysis Herschel/SPIRE data to constrain the dust SED
of these galaxies. We find that their dust emission is well described by a
modified black body with Tdust~30 K and beta=1.6 and IR luminosities of
(5-11)x10^{11} Lsun, or implied star formation rates of 75-140 Msun/yr. We
compare our results with those of previous studies based on single-dish
observations at 870 micron and find that our flux densities are a factor 2-3
higher than previous estimates. The discrepancy is observed also after removing
sources individually detected in ALESS maps. We report a similar discrepancy by
repeating our analysis on 1.4\,GHz observations of the whole ECDFS. Hence we
find tentative evidence that galaxies that are associated in projected and
redshift space with sub-mm bright sources are brighter than the average
population. Finally, we put our findings in the context of the cosmic star
formation rate density as a function of redshift.


title:
Three-dimensional relativistic pair plasma reconnection with radiative
  feedback in the Crab Nebula

abstract:
  The discovery of rapid synchrotron gamma-ray flares above 100 MeV from the
Crab Nebula has attracted new interest in alternative particle acceleration
mechanisms in pulsar wind nebulae. Diffuse shock-acceleration fails to explain
the flares because particle acceleration and emission occur during a single or
even sub-Larmor timescale. In this regime, the synchrotron energy losses induce
a drag force on the particle motion that balances the electric acceleration and
prevents the emission of synchrotron radiation above 160 MeV. Previous
analytical studies and 2D particle-in-cell (PIC) simulations indicate that
relativistic reconnection is a viable mechanism to circumvent the above
difficulties. The reconnection electric field localized at X-points linearly
accelerates particles with little radiative energy losses. In this paper, we
check whether this mechanism survives in 3D, using a set of large PIC
simulations with radiation reaction force and with a guide field. In agreement
with earlier works, we find that the relativistic drift kink instability
deforms and then disrupts the layer, resulting in significant plasma heating
but few non-thermal particles. A moderate guide field stabilizes the layer and
enables particle acceleration. We report that 3D magnetic reconnection can
accelerate particles above the standard radiation reaction limit, although the
effect is less pronounced than in 2D with no guide field. We confirm that the
highest energy particles form compact bunches within magnetic flux ropes, and a
beam tightly confined within the reconnection layer, which could result in the
observed Crab flares when, by chance, the beam crosses our line of sight.


title:
Constraining the initial conditions of the Universe using large scale
  structure

abstract:
  Primordial non-Gaussianity induces a scale-dependent bias in large scale
structure (LSS) data, proportional to $f_{\rm NL}/k^2$ for the exact local
ansatz. Recent work has shown that models of inflation that predict a large
squeezed limit bispectrum, such as multi-field models and single field
inflation with a modified initial state, typically give rise to a generalized
local ansatz, with the scale-dependent bias now proportional to ${\cal A}_{\rm
NL}/k^\alpha$. We use photometric measurements of the angular power spectrum of
luminous red galaxies and quasars in the Sloan Digital Sky Survey Data Release
Eight (SDSS DR8) with the above parameterization to constrain the amplitude
${\cal A}_{\rm NL}$ and scale-dependence $\alpha$. We find that the
marginalized upper limit on $\alpha$ is 2.0 at the $95\%$ confidence level,
consistent with the local ansatz. We also present Fisher forecasts for a survey
of the same size as DR8 to assess the role of systematics in current
photometric LSS data. Moreover, we present analytic results on the expected
mass dependence of ${\cal A}_{\rm NL}$ for different inflationary models, which
can be an important observable for future surveys, if primordial
non-Gaussianity is non-zero.


title:
Coupling layers regularizes wave propagation in laminar stochastic
  neural fields

abstract:
  We study the effects of coupling between layers of stochastic neural field
models with laminar structure. In particular, we focus on how the propagation
of waves of neural activity in each layer is affected by the coupling. Synaptic
connectivities within and between each layer are determined by integral kernels
of an integrodifferential equation describing the temporal evolution of neural
activity. Excitatory neural fields, with purely positive connectivities,
support traveling fronts in each layer, whose speeds are increased when
coupling between layers is considered. Studying the effects of noise, we find
coupling also serves to reduce the variance in the position of traveling
fronts, as long as the noise sources to each layer are not completely
correlated. Neural fields with asymmetric connectivity support traveling pulses
whose speeds are decreased by interlaminar coupling. Again, coupling reduces
the variance in traveling pulse position, when noise is considered that is not
totally correlated between layers. To derive our stochastic results, we employ
a small-noise expansion, also assuming interlaminar connectivity scales
similarly. Our asymptotic results agree reasonably with accompanying numerical
simulations.


title: Some restrictions on normalizers or centralizers in finite p-groups

abstract:
  We study three restrictions on normalizers or centralizers in finite
p-groups, namely: (i) |N_G(H) : H| <= p^k for every H non-normal in G, (ii)
|N_G(<g>) : <g>| <= p^k for every <g> non-normal in G, and (iii) |C_G(g) : <g>|
<= p^k for every <g> non-normal in G. We prove that (i) and (ii) are
equivalent, and that the order of a non-Dedekind finite p-group satisfying any
of these three conditions is bounded for p>2. More precisely, we get the best
possible bound for the order of G in all three cases, which is |G| <= p^{2k+2}.
The order of the group cannot be bounded for p=2, but we are able to identify
two infinite families of 2-groups out of which |G| <= 2^{f(k)} for some
function f(k) depending only on k.


title: Secular Evolution in Disk Galaxies

abstract:
  Self-gravitating systems evolve toward the most tightly bound configuration
that is reachable via available evolution processes. The inner parts shrink and
the outer parts expand, provided that some physical process transports energy
or angular momentum outward. The evolution of stars, star clusters,
protostellar and protoplanetary disks, black hole accretion disks, and galaxy
disks are all fundamentally similar. These processes for galaxy disks are the
subjects of my lectures and of this Canary Islands Winter School. Part 1
discusses formation, growth, and death of bars. Part 2 details the slow
("secular") rearrangement of angular momentum that results from interactions
between stars or gas and nonaxisymmetries such as bars. We have a heuristic
understanding of how this forms outer rings, inner rings, and stuff dumped into
the center. Observations show that barred galaxies have central concentrations
of gas and star formation. Timescales imply that they grow central
"pseudobulges" that get mistaken for elliptical-galaxy-like classical bulges
but that formed gently out of disks. Part 3 shows how we distinguish between
classical and pseudo bulges. Part 4 reviews how environmental secular evolution
transforms gas-rich, star-forming spirals and irregulars into gas-poor, red and
dead S0 and spheroidal ("Sph") galaxies. Sphs are not ellipticals; they have
structural parameters like those of low-luminosity S+Im galaxies. So Sphs are
bulgeless S0s. Part 5 combines hierarchical clustering and secular evolution
into a comprehensive picture.


title: Joint Mean and Covariance Modeling of Multiple Health Outcome Measures

abstract:
  Health exams determine a patient's health status by comparing the patient's
measurement with a population reference range, a 95% interval derived from a
homogeneous reference population. Similarly, most of the established relation
among health problems are assumed to hold for the entire population. We use
data from the 2009 - 2010 National Health and Nutrition Examination Survey
(NHANES) on four major health problems in the U.S. and apply a joint mean and
covariance model to study how the reference ranges and associations of those
health outcomes could vary among subpopulations. We discuss guidelines for
model selection and evaluation, using standard criteria such as AIC in
conjunction with posterior predictive checks. The results from the proposed
model can help identify subpopulations in which more data need to be collected
to refine the reference range and to study the specific associations among
those health problems.


title: The confining trailing string

abstract:
  We extend the holographic trailing string picture of a heavy quark to the
case of a bulk geometry dual to a confining gauge theory. We compute the
classical trailing confining string solution for a static as well as a
uniformly moving quark. The trailing string is infinitely extended and
approaches a confining horizon, situated at a critical value of the radial
coordinate, along one of the space-time directions, breaking boundary
rotational invariance. We compute the equations for the fluctuations around the
classical solutions, which are used to obtain boundary force correlators
controlling the Langevin dynamics of the quark. The imaginary part of the
correlators has a non-trivial low-frequency limit, which gives rise to a
viscous friction coefficient induced by the confining vacuum. The vacuum
correlators are used to define finite-temperature dressed Langevin correlators
with an appropriate high-frequency behavior.


title: What dynamics can be expected for mixed states in two-slit experiments?

abstract:
  Weak-measurement-based experiments [Kocsis et al., Science 332 (2011) 1170]
have shown that, at least for pure states, the average evolution of independent
photons in Young's two-slit experiment is in compliance with the trajectories
prescribed by the Bohmian formulation of quantum mechanics. But, what happens
if the same experiment is repeated assuming that the wave function associated
with each particle is different, i.e., in the case of mixed (incoherent)
states? This question is investigated here by means of two alternative
numerical simulations of Young's experiment, purposely devised to be easily
implemented and tested in the laboratory. Contrary to what could be expected a
priori, it is found that even for conditions of maximal mixedness or
incoherence (total lack of interference fringes), experimental data will render
a puzzling and challenging outcome: the average particle trajectories will
still display features analogous to those for pure states, i.e., independently
of how mixedness arises, the associated dynamics is influenced by both slits at
the same time. Physically this simply means that weak measurements are not able
to discriminate how mixedness arises in the experiment, since they only provide
information about the averaged system dynamics.


title:
On the Finite-Time Blowup of a 1D Model for the 3D Incompressible Euler
  Equations

abstract:
  We study a 1D model for the 3D incompressible Euler equations in axisymmetric
geometries, which can be viewed as a local approximation to the Euler equations
near the solid boundary of a cylindrical domain. We prove the local
well-posedness of the model in spaces of zero-mean functions, and study the
potential formation of a finite-time singularity under certain convexity
conditions for the velocity field. It is hoped that the results obtained on the
1D model will be useful in the analysis of the full 3D problem, whose loss of
regularity in finite time has been observed in a recent numerical study (Luo
and Hou, 2013).


title: Low-scale seesaw models versus $N_{\rm eff}$

abstract:
  We consider the contribution of the extra sterile states in generic low-scale
seesaw models to extra radiation, parametrized by $N_{\rm eff}$. We find that
the value of $N_{\rm eff}$ is roughly independent of the seesaw scale within a
wide range. We explore the full parameter space in the case of two extra
sterile states and find that these models are strongly constrained by
cosmological data for any value of the seesaw scale below ${\mathcal
O}(100$MeV).


title: Out-of-equilibrium dynamics and thermalization of string order

abstract:
  We investigate the equilibration dynamics of string order in one-dimensional
quantum systems. After initializing a spin-1 chain in the Haldane phase, the
time evolution of non-local correlations following a sudden quench is studied
by means of matrix-product-state-based algorithms. Thermalization occurs only
for scales up to a horizon growing at a well defined speed, due to the finite
maximal velocity at which string correlations can propagate, related to a
Lieb-Robinson bound. The persistence of string ordering at finite times is
non-trivially related to symmetries of the quenched Hamiltonian. A
qualitatively similar behavior is found for the string order of the Mott
insulating phase in the Bose-Hubbard chain. This paves the way towards an
experimental testing of our results in present cold-atom setups.


title:
Description of Induced Nuclear Fission with Skyrme Energy Functionals:
  I. Static Potential Energy Surfaces and Fission Fragment Properties

abstract:
  Eighty years after its experimental discovery, a microscopic description of
induced nuclear fission based solely on the interactions between neutrons and
protons and quantum many-body methods still poses formidable challenges. The
goal of this paper is to contribute to the development of a predictive
microscopic framework for the accurate calculation of static properties of
fission fragments for hot fission and thermal or slow neutrons. To this end, we
focus on the 239Pu(n,f) reaction and employ nuclear density functional theory
with Skyrme energy densities. Potential energy surfaces are computed at the
Hartree-Fock-Bogoliubov approximation with up to five collective variables. We
find that the triaxial degree of freedom plays an important role, both near the
fission barrier and at scission. The impact of the parameterization of the
Skyrme energy density on deformation properties from the ground-state up to
scission is also quantified. We introduce a general template for the detailed
description of fission fragment properties. It is based on the careful analysis
of the scission point, using both advanced topological methods and recently
proposed quantum many-body techniques. We conclude that an accurate prediction
of fission fragment properties at low incident neutron energies, although
technologically demanding, should be within the reach of current nuclear
density functional theory.


title:
Uncovering the physics behind the blazar sequence using a realistic
  model for jet emission

abstract:
  Blazar spectra are one of the most important windows into the physical
processes occurring along jets. The spectrum, composed from the different
emitting regions along the jet, allows us to constrain the physical conditions
in the jet. I present my work modelling blazar spectra using an extended
inhomogeneous jet model with an accelerating, magnetically dominated, parabolic
base transitioning to a slowly decelerating, conical section motivated by
observations, simulations and theory. We set the inner geometry of our
multi-zone model using observations of the jet in M87 which transitions from
parabolic to conical at 10^5 Schwarzschild radii. This model is able to
reproduce quiescent blazar spectra very well across all wavelengths (including
radio observations) for a sample of 42 BL Lacs and FSRQs.
  Using this inhomogeneous model we are able to constrain the location at which
the synchrotron emission is brightest in these jets by fitting to the optically
thick to thin synchrotron break. We find that the radius of the jet at which
the synchrotron emission is brightest (where the jet first approaches
equipartition) scales approximately linearly with the jet power. We also find a
correlation between the length of the accelerating, parabolic section of the
jet and the maximum bulk Lorentz factor. In agreement with previous work we
find that BL Lacs are low power blazars whereas FSRQs are high power blazars.
Together with our simple jet power-radius relation this leads us to a deeper
understanding of the physics underlying the blazar sequence.


title: Excluded vertex-minors for graphs of linear rank-width at most k

abstract:
  Linear rank-width is a graph width parameter, which is a variation of
rank-width by restricting its tree to a caterpillar. As a corollary of known
theorems, for each $k$, there is a finite obstruction set $\mathcal{O}_k$ of
graphs such that a graph $G$ has linear rank-width at most $k$ if and only if
no vertex-minor of $G$ is isomorphic to a graph in $\mathcal{O}_k$. However, no
attempts have been made to bound the number of graphs in $\mathcal{O}_k$ for
$k\ge 2$. We show that for each $k$, there are at least $2^{\Omega(3^k)}$
pairwise locally non-equivalent graphs in $\mathcal{O}_k$, and therefore the
number of graphs in $\mathcal{O}_k$ is at least double exponential.
  To prove this theorem, it is necessary to characterize when two graphs in
$\mathcal O_k$ are locally equivalent. A graph is a block graph if all of its
blocks are complete graphs. We prove that if two block graphs without
simplicial vertices of degree at least $2$ are locally equivalent, then they
are isomorphic. This not only is useful for our theorem but also implies a
theorem of Bouchet [Transforming trees by successive local complementations, J.
Graph Theory 12 (1988), no. 2, 195-207] stating that if two trees are locally
equivalent, then they are isomorphic.


title: The New Quantum Logic

abstract:
  It is shown how all the major conceptual difficulties of standard (textbook)
quantum mechanics, including the two measurement problems and the (supposed)
nonlocality that conflicts with special relativity, are resolved in the
consistent or decoherent histories interpretation of quantum mechanics by using
a modified form of quantum logic to discuss quantum properties (subspaces of
the quantum Hilbert space), and treating quantum time development as a
stochastic process. The histories approach in turn gives rise to some
conceptual difficulties, in particular the correct choice of a framework
(probabilistic sample space) or family of histories, and these are discussed.
The central issue is that the principle of unicity, the idea that there is a
unique single true description of the world, is incompatible with our current
understanding of quantum mechanics.


title:
Description of Induced Nuclear Fission with Skyrme Energy Functionals:
  II. Finite Temperature Effects

abstract:
  Understanding the mechanisms of induced nuclear fission for a broad range of
neutron energies could help resolve fundamental science issues, such as the
formation of elements in the universe, but could have also a large impact on
societal applications in energy production or nuclear waste management. The
goal of this paper is to set up the foundations of a microscopic theory to
study the static aspects of induced fission as a function of the excitation
energy of the incident neutron, from thermal to fast neutrons. To account for
the high excitation energy of the compound nucleus, we employ a statistical
approach based on finite-temperature nuclear density functional theory with
Skyrme energy densities, which we benchmark on the 239 Pu(n,f) reaction. We
compute the evolution of the least-energy fission pathway across
multidimensional potential energy surfaces with up to five collective variables
as a function of the nuclear temperature, and predict the evolution of both the
inner and outer fission barriers as a function of the excitation energy of the
compound nucleus. We show that the coupling to the continuum induced by the
finite temperature is negligible in the range of neutron energies relevant for
many applications of neutron-induced fission. We prove that the concept of
quantum localization introduced recently can be extended to T > 0, and we apply
the method to study the interaction energy and total kinetic energy of fission
fragments as a function of the temperature for the most probable fission. While
large uncertainties in theoretical modeling remain, we conclude that
finite-temperature nuclear density functional may provide a useful framework to
obtain accurate predictions of fission fragment properties.


title:
Determining Leishmania Infection Levels by Automatic Analysis of
  Microscopy Images

abstract:
  Analysis of microscopy images is one important tool in many fields of
biomedical research, as it allows the quantification of a multitude of
parameters at the cellular level. However, manual counting of these images is
both tiring and unreliable and ultimately very time-consuming for biomedical
researchers. Not only does this slow down the overall research process, it also
introduces counting errors due to a lack of objectivity and consistency
inherent to the researchers own human nature.
  This thesis addresses this issue by automatically determining infection
indexes of macrophages parasite by Leishmania in microscopy images using
computer vision and pattern recognition methodologies. Initially images are
submitted to a pre-processing stage that consists in a normalization of
illumination conditions. Three algorithms are then applied in parallel to each
image. Algorithm A intends to detect macrophage nuclei and consists of
segmentation via adaptive multi-threshold, and classification of resulting
regions using a set of collected features. Algorithm B intends to detect
parasites and is similar to Algorithm A but the adaptive multi-threshold is
parameterized with a different constraints vector. Algorithm C intends to
detect the macrophages and parasites cytoplasm and consists of a cut-off
version of the previous two algorithms, where the classification step is
skipped. Regions with multiple nuclei or parasites are processed by a voting
system that employs both a Support Vector Machine and a set of region features
for determining the number of objects present in each region. The previous vote
is then taken into account as the number of mixtures to be used in a Gaussian
Mixture Model to decluster the said region. Finally each parasite is assigned
to, at most, a single macrophage using minimum Euclidean distance to a cell
nucleus, thus quantifying Leishmania infection levels.


title:
Universal curvature identities and Euler Lagrange Formulas for Kaehler
  manifolds

abstract:
  We relate certain universal curvature identities for Kaehler manifolds to the
Euler-Lagrange equations of the scalar invariants which are defined by pairing
characteristic forms with powers of the Kaehler form.


title:
Generating infinite-dimensional algebras from loop algebras by expanding
  Maurer Cartan forms

abstract:
  It is shown that the expansion methods developed in refs.
arXiv:hep-th/0212347 and arXiv:hep-th/0401033v2 can be generalized so that they
permit to study the expansion of algebras of loops, both when the compact
finite-dimensional algebra and the algebra of loops have a decomposition into
two subspaces.


title: The mass-metallicity relation at z~1.4 revealed with Subaru/FMOS

abstract:
  We present a stellar mass-metallicity relation at z~1.4 with an
unprecedentedly large sample of ~340 star-forming galaxies obtained with FMOS
on the Subaru Telescope. We observed K-band selected galaxies at 1.2 < z_{ph} <
1.6 in the SXDS/UDS fields with M_{*} > 10^{9.5} M_{\sun}, and expected
F(H\alpha) > 5 \times 10^{-17} erg s^{-1} cm^{-2}. Among the observed ~1200
targets, 343 objects show significant H\alpha emission lines. The gas-phase
metallicity is obtained from [NII]\lambda 6584/H\alpha line ratio, after
excluding possible active galactic nuclei (AGNs). Due to the faintness of the
[NII]\lambda 6584 lines, we apply the stacking analysis and derive the
mass-metallicity relation at z~1.4. Our results are compared to past results at
different redshifts in the literature. The mass-metallicity relation at z~1.4
is located between those at z~0.8 and z~2.2; it is found that the metallicity
increases with decreasing redshift from z~3 to z~0 at fixed stellar mass.
Thanks to the large size of the sample, we can study the dependence of the
mass-metallicity relation on various galaxy physical properties. The average
metallicity from the stacked spectra is close to the local FMR in the higher
metallicity part but >0.1 dex higher in metallicity than the FMR in the lower
metallicity part. We find that galaxies with larger E(B-V), B-R, and R-H
colours tend to show higher metallicity by ~0.05 dex at fixed stellar mass. We
also find relatively clearer size dependence that objects with smaller half
light radius tend to show higher metallicity by ~0.1 dex at fixed stellar mass,
especially in the low mass part.


title: Asymptotically Truthful Equilibrium Selection in Large Congestion Games

abstract:
  Studying games in the complete information model makes them analytically
tractable. However, large $n$ player interactions are more realistically
modeled as games of incomplete information, where players may know little to
nothing about the types of other players. Unfortunately, games in incomplete
information settings lose many of the nice properties of complete information
games: the quality of equilibria can become worse, the equilibria lose their
ex-post properties, and coordinating on an equilibrium becomes even more
difficult. Because of these problems, we would like to study games of
incomplete information, but still implement equilibria of the complete
information game induced by the (unknown) realized player types.
  This problem was recently studied by Kearns et al. and solved in large games
by means of introducing a weak mediator: their mediator took as input reported
types of players, and output suggested actions which formed a correlated
equilibrium of the underlying game. Players had the option to play
independently of the mediator, or ignore its suggestions, but crucially, if
they decided to opt-in to the mediator, they did not have the power to lie
about their type. In this paper, we rectify this deficiency in the setting of
large congestion games. We give, in a sense, the weakest possible mediator: it
cannot enforce participation, verify types, or enforce its suggestions.
Moreover, our mediator implements a Nash equilibrium of the complete
information game. We show that it is an (asymptotic) ex-post equilibrium of the
incomplete information game for all players to use the mediator honestly, and
that when they do so, they end up playing an approximate Nash equilibrium of
the induced complete information game. In particular, truthful use of the
mediator is a Bayes-Nash equilibrium in any Bayesian game for any prior.


title: Second-order Shape Optimization for Geometric Inverse Problems in Vision

abstract:
  We develop a method for optimization in shape spaces, i.e., sets of surfaces
modulo re-parametrization. Unlike previously proposed gradient flows, we
achieve superlinear convergence rates through a subtle approximation of the
shape Hessian, which is generally hard to compute and suffers from a series of
degeneracies. Our analysis highlights the role of mean curvature motion in
comparison with first-order schemes: instead of surface area, our approach
penalizes deformation, either by its Dirichlet energy or total variation.
Latter regularizer sparks the development of an alternating direction method of
multipliers on triangular meshes. Therein, a conjugate-gradients solver enables
us to bypass formation of the Gaussian normal equations appearing in the course
of the overall optimization. We combine all of the aforementioned ideas in a
versatile geometric variation-regularized Levenberg-Marquardt-type method
applicable to a variety of shape functionals, depending on intrinsic properties
of the surface such as normal field and curvature as well as its embedding into
space. Promising experimental results are reported.


title: Is gravitational mass of a quantum body equivalent to its energy?

abstract:
  We define passive gravitational mass operator of a hydrogen atom in the
post-Newtonian approximation of general relativity and show that it does not
commute with energy operator, taken in the absence of gravitational field.
Nevertheless, the equivalence between the expectation values of passive
gravitational mass and energy is shown to survive for stationary quantum
states. Inequivalence between passive gravitational mass and energy at a
macroscopic level results in time dependent oscillations of the expectation
values of passive gravitational mass for superpositions of stationary quantum
states, where the equivalence restores after averaging over time. Inequivalence
between gravitational mass and energy at a microscopic level reveals itself as
unusual electromagnetic radiation, emitted by the atoms, supported and moved in
the Earth gravitational field with constant velocity using spacecraft or
satellite, which can be experimentally measured.


title:
Joint asymptotics for semi-nonparametric regression models with
  partially linear structure

abstract:
  We consider a joint asymptotic framework for studying semi-nonparametric
regression models where (finite-dimensional) Euclidean parameters and
(infinite-dimensional) functional parameters are both of interest. The class of
models in consideration share a partially linear structure and are estimated in
two general contexts: (i) quasi-likelihood and (ii) true likelihood. We first
show that the Euclidean estimator and (pointwise) functional estimator, which
are re-scaled at different rates, jointly converge to a zero-mean Gaussian
vector. This weak convergence result reveals a surprising joint asymptotics
phenomenon: these two estimators are asymptotically independent. A major goal
of this paper is to gain first-hand insights into the above phenomenon.
Moreover, a likelihood ratio testing is proposed for a set of joint local
hypotheses, where a new version of the Wilks phenomenon [Ann. Math. Stat. 9
(1938) 60-62; Ann. Statist. 1 (2001) 153-193] is unveiled. A novel technical
tool, called a joint Bahadur representation, is developed for studying these
joint asymptotics results.


title: Derived intersections and the Hodge theorem

abstract:
  The algebraic Hodge theorem was proved in a beautiful 1987 paper by Deligne
and Illusie, using positive characteristic methods. We argue that the central
algebraic object of their proof can be understood geometrically as a line
bundle on a derived scheme. In this interpretation, the Deligne-Illusie result
can be seen as a proof that this line bundle is trivial under certain
assumptions.
  We give a criterion for the triviality of this line bundle in a more general
context. The proof uses techniques from derived algebraic geometry,
specifically arguments which show the formality of certain derived
intersections. Applying our criterion we recover Deligne and Illusie's original
result. We also apply these techniques to the result of Barannikov-Kontsevich,
Sabbah, and Ogus-Vologodsky concerning the formality of the twisted de Rham
complex.


title:
Deployment of Stream Control Transmission Protocol (SCTP) to Maintain
  the Applications of Data Centers

abstract:
  With developments of real-time applications into data centers, the need for
alternatives of the standard TCP protocol has been prime demand in several
applications of data centers. The several alternatives of TCP protocol has been
proposed but SCTP has edge due to its several well-built characteristics that
make it capable to work efficiently. In this paper, we examine the features of
SCTP into data centers like Multi-streaming and Multi-homing over the features
of TCP protocol. In this paper, our objective is to introduce internal problems
of data centers. Robust transport protocol reduces the problems with some
extend. Focusing the problems of data centers, we also examine weakness of
highly deployed standard TCP, and evaluate the performance of SCTP in context
of faster communication for data centers. We also discover some weaknesses and
shortcomings of SCTP into data centers and try to propose some ways to avoid
them by maintaining SCTP native features. To validate strength and weakness of
TCP and SCTP, we use ns2 for simulation in context of data center. On basis of
findings, we highlight major strength of SCTP. At the end, we Implemen


title:
Radio continuum observations of local star-forming galaxies using the
  Caltech Continuum Backend on the Green Bank Telescope

abstract:
  We observed radio continuum emission in 27 local (D < 70 Mpc) star-forming
galaxies with the Robert C. Byrd Green Bank Telescope between 26 GHz and 40 GHz
using the Caltech Continuum Backend. We obtained detections for 22 of these
galaxies at all four sub-bands and four more marginal detections by taking the
average flux across the entire bandwidth. This is the first detection (full or
marginal) at these frequencies for 22 of these galaxies. We fit spectral energy
distributions (SEDs) for all of the four-sub-band detections. For 14 of the
galaxies, SEDs were best fit by a combination of thermal free-free and
nonthermal synchrotron components. Eight galaxies with four-sub-band detections
had steep spectra that were only fit by a single nonthermal component. Using
these fits, we calculated supernova rates, total number of equivalent O stars,
and star formation rates within each ~23 arcsecond beam. For unresolved
galaxies, these physical properties characterize the galaxies' recent star
formation on a global scale. We confirm that the radio-far-infrared correlation
holds for the unresolved galaxies' total 33 GHz flux regardless of their
thermal fractions, though the scatter on this correlation is larger than that
at 1.4 GHz. In addition, we found that for the unresolved galaxies, there is an
inverse relationship between the ratio of 33 GHz flux to total far-infrared
flux and the steepness of the galaxy's spectral index between 1.4 GHz and 33
GHz. This relationship could be an indicator of the timescale of the observed
episode of star formation.


title:
Isotropic Band Gaps and Freeform Waveguides Observed in Hyperuniform
  Disordered Photonic Solids

abstract:
  Recently, disordered photonic media and random textured surfaces have
attracted increasing attention as strong light diffusers with broadband and
wide-angle properties. We report the first experimental realization of an
isotropic complete photonic band gap (PBG) in a two-dimensional (2D) disordered
dielectric structure. This structure is designed by a constrained-optimization
method, which combines advantages of both isotropy due to disorder and
controlled scattering properties due to low density fluctuations
(hyperuniformity) and uniform local topology. Our experiments use a modular
design composed of Al2O3 walls and cylinders arranged in a hyperuniform
disordered network. We observe a complete PBG in the microwave region, in good
agreement with theoretical simulations, and show that the intrinsic isotropy of
this novel class of PBG materials enables remarkable design freedom, including
the realization of waveguides with arbitrary bending angles impossible in
photonic crystals. This first experimental verification of a complete PBG and
realization of functional defects in this new class of materials demonstrates
their potential as building blocks for precise manipulation of photons in
planar optical micro-circuits and has implications for disordered acoustic and
electronic bandgap materials.


title: Stratified and unstratified bordism of pseudomanifolds

abstract:
  We study bordism groups and bordism homology theories based on
pseudomanifolds and stratified pseudomanifolds. The main seam of the paper
demonstrates that when we uses classes of spaces determined by local link
properties, the stratified and unstratified bordism theories are identical;
this includes the known examples of pseudomanifold bordism theories, such as
bordism of Witt spaces and IP spaces. Along the way, we relate the stratified
and unstratified points of view for describing various (stratified)
pseudomanifold classes.


title:
A New Look at Dual-Hop Relaying: Performance Limits with Hardware
  Impairments

abstract:
  Physical transceivers have hardware impairments that create distortions which
degrade the performance of communication systems. The vast majority of
technical contributions in the area of relaying neglect hardware impairments
and, thus, assumes ideal hardware. Such approximations make sense in low-rate
systems, but can lead to very misleading results when analyzing future
high-rate systems. This paper quantifies the impact of hardware impairments on
dual-hop relaying, for both amplify-and-forward and decode-and-forward
protocols. The outage probability (OP) in these practical scenarios is a
function of the effective end-to-end signal-to-noise-and-distortion ratio
(SNDR). This paper derives new closed-form expressions for the exact and
asymptotic OPs, accounting for hardware impairments at the source, relay, and
destination. A similar analysis for the ergodic capacity is also pursued,
resulting in new upper bounds. We assume that both hops are subject to
independent but non-identically distributed Nakagami-m fading. This paper
validates that the performance loss is small at low rates, but otherwise can be
very substantial. In particular, it is proved that for high signal-to-noise
ratio (SNR), the end-to-end SNDR converges to a deterministic constant, coined
the SNDR ceiling, which is inversely proportional to the level of impairments.
This stands in contrast to the ideal hardware case in which the end-to-end SNDR
grows without bound in the high-SNR regime. Finally, we provide fundamental
design guidelines for selecting hardware that satisfies the requirements of a
practical relaying system.


title: Stochastic approach to diffusion inside the chaotic layer of a resonance

abstract:
  We model chaotic diffusion, in a symplectic 4D map by using the result of a
theorem that was developed for stochastically perturbed integrable Hamiltonian
systems. We explicitly consider a map defined by a free rotator (FR) coupled to
a standard map (SM). We focus in the diffusion process in the action, $I$, of
the FR, obtaining a semi--numerical method to compute the diffusion
coefficient. We study two cases corresponding to a thick and a thin chaotic
layer in the SM phase space and we discuss a related conjecture stated in the
past. In the first case the numerically computed probability density function
for the action $I$ is well interpolated by the solution of a Fokker-Planck
(F-P) equation, whereas it presents a non--constant time delay respect to the
concomitant F-P solution in the second case suggesting the presence of an
anomalous diffusion time scale. The explicit calculation of a diffusion
coefficient for a 4D symplectic map can be useful to understand the slow
diffusion observed in Celestial Mechanics and Accelerator Physics.


title: The Geometry and Arithmetic of Kleinian Groups

abstract:
  In this article we survey and describe various aspects of the geometry and
arithmetic of Kleinian groups - discrete nonelementary groups of isometries of
hyperbolic $3$-space. In particular we make a detailed study of two-generator
groups and discuss the classification of the arithmetic generalised triangle
groups (and their near relatives). This work is mainly based around my
collaborations over the last two decades with Fred Gehring and Colin
Maclachlan, both of whom passed away in 2012. There are many others involved as
well.
  Over the last few decades the theory of Kleinian groups has flourished
because of its intimate connections with low dimensional topology and geometry.
We give little of the general theory and its connections with $3$-manifold
theory here, but focus on two main problems: Siegel's problem of identifying
the minimal covolume hyperbolic lattice and the Margulis constant problem.
These are both "universal constraints" on Kleinian groups -- a feature of
discrete isometry groups in negative curvature and include results such as
J{\o}rgensen's inequality, the higher dimensional version of Hurwitz's $84g-84$
theorem and a number of other things. We will see that big part of the work
necessary to obtain these results is in getting concrete descriptions of
various analytic spaces of two-generator Kleinian groups, somewhat akin to the
Riley slice.


title: Self-Dual codes from $(-1,1)$-matrices of skew symmetric type

abstract:
  Previously, self-dual codes have been constructed from weighing matrices, and
in particular from conference matrices (skew and symmetric). In this paper,
codes constructed from matrices of skew symmetric type whose determinants reach
the Ehlich-Wojtas' bound are presented. A necessary and sufficient condition
for these codes to be self-dual is given, and examples are provided for lengths
up to 52.


title:
Recurrent construction of optimal entanglement witnesses for 2N qubit
  systems

abstract:
  We provide a recurrent construction of entanglement witnesses for a bipartite
systems living in a Hilbert space corresponding to $2N$ qubits ($N$ qubits in
each subsystem). Our construction provides a new method of generalization of
the Robertson map that naturally meshes with $2N$ qubit systems, i.e., its
structure respects the $2^{2N}$ growth of the state space. We prove that for
$N>1$ these witnesses are indecomposable and optimal. As a byproduct we provide
a new family of PPT (Positive Partial Transpose) entangled states.


title: Texture and Cofactor Zeros of the Neutrino Mass Matrix

abstract:
  We study Majorana neutrino mass matrices that have two texture zeros, or two
cofactor zeros, or one texture zero and one cofactor zero. The two
texture/cofactor zero conditions give four constraints, which in conjunction
with the five measured oscillation parameters completely determine the nine
independent real parameters of the neutrino mass matrix. We also study the
implications that future measurements of neutrinoless double beta decay and the
Dirac CP phase will have on these cases.


title: A Landau-Squire Nanojet

abstract:
  Fluid jets are found in nature at all length scales, from microscopic to
cosmological. Here we report on an electroosmotically driven jet from a single
glass nanopore about 75 nm in radius with a maximum flow rate ~15 pL/s. A novel
anemometry technique allows us to map out the vorticity and velocity fields
that show excellent agreement with the classical Landau-Squire solution of the
Navier Stokes equations for a point jet. We observe a phenomenon that we call
flow rectification: an asymmetry in the flow rate with respect to voltage
reversal. Such a nanojet could potentially find applications in
micromanipulation, nanopatterning, and as a diode in microfluidic circuits.


title:
Necessary condition for local quantum operations and classical
  communication with extensive violation by separable operations

abstract:
  We give a conceptually simple necessary condition such that a separable
quantum operation can be implemented by local operations on subsystems and
classical communication between parties (LOCC), a condition which follows from
a novel approach to understanding LOCC. This necessary condition holds for any
number of parties and any finite number of rounds of communication and as such,
also provides a completely general sufficient condition that a given separable
operation cannot be exactly implemented by LOCC. Furthermore, it demonstrates
an extremely strong difference between separable operations and LOCC, in that
there exist examples of the former for which the condition is extensively
violated. More precisely, the violation by separable operations of our
necessary condition for LOCC grows without limit as the number of parties
increases.


title:
Volumetric Reconstruction Applied to Perceptual Studies of Size and
  Weight

abstract:
  We explore the application of volumetric reconstruction from structured-light
sensors in cognitive neuroscience, specifically in the quantification of the
size-weight illusion, whereby humans tend to systematically perceive smaller
objects as heavier. We investigate the performance of two commercial
structured-light scanning systems in comparison to one we developed
specifically for this application. Our method has two main distinct features:
First, it only samples a sparse series of viewpoints, unlike other systems such
as the Kinect Fusion. Second, instead of building a distance field for the
purpose of points-to-surface conversion directly, we pursue a first-order
approach: the distance function is recovered from its gradient by a screened
Poisson reconstruction, which is very resilient to noise and yet preserves
high-frequency signal components. Our experiments show that the quality of
metric reconstruction from structured light sensors is subject to systematic
biases, and highlights the factors that influence it. Our main performance
index rates estimates of volume (a proxy of size), for which we review a
well-known formula applicable to incomplete meshes. Our code and data will be
made publicly available upon completion of the anonymous review process.


title:
Channel noise induced stochastic facilitation in an auditory brainstem
  neuron model

abstract:
  Neuronal membrane potentials fluctuate stochastically due to conductance
changes caused by random transitions between the open and close states of ion
channels. Although it has previously been shown that channel noise can
nontrivially affect neuronal dynamics, it is unknown whether ion-channel noise
is strong enough to act as a noise source for hypothesised noise-enhanced
information processing in real neuronal systems, i.e. 'stochastic
facilitation.' Here, we demonstrate that biophysical models of channel noise
can give rise to two kinds of recently discovered stochastic facilitation
effects in a Hodgkin-Huxley-like model of auditory brainstem neurons. The
first, known as slope-based stochastic resonance (SBSR), enables phasic neurons
to emit action potentials that can encode the slope of inputs that vary slowly
relative to key time-constants in the model. The second, known as inverse
stochastic resonance (ISR), occurs in tonically firing neurons when small
levels of noise inhibit tonic firing and replace it with burst-like dynamics.
Consistent with previous work, we conclude that channel noise can provide
significant variability in firing dynamics, even for large numbers of channels.
Moreover, our results show that possible associated computational benefits may
occur due to channel noise in neurons of the auditory brainstem. This holds
whether the firing dynamics in the model are phasic (SBSR can occur due to
channel noise) or tonic (ISR can occur due to channel noise).


title:
Yield and Solidification of Yield-Stress Materials in Rigid Networks and
  Porous Structures

abstract:
  In this paper, we address the issue of threshold yield pressure of
yield-stress materials in rigid networks of interconnected conduits and porous
structures subject to a pressure gradient. We compare the results as obtained
dynamically from solving the pressure field to those obtained statically from
tracing the path of the minimum sum of threshold yield pressures of the
individual conduits by using the threshold path algorithms. We refute
criticisms directed recently to our previous findings that the pressure field
solution generally produces a higher threshold yield pressure than the one
obtained by the threshold path algorithms. Issues related to the solidification
of yield stress materials in their transition from fluid phase to solid state
have also been investigated and assessed as part of the investigation of the
yield point.


title: Program Evaluation and Causal Inference with High-Dimensional Data

abstract:
  In this paper, we provide efficient estimators and honest confidence bands
for a variety of treatment effects including local average (LATE) and local
quantile treatment effects (LQTE) in data-rich environments. We can handle very
many control variables, endogenous receipt of treatment, heterogeneous
treatment effects, and function-valued outcomes. Our framework covers the
special case of exogenous receipt of treatment, either conditional on controls
or unconditionally as in randomized control trials. In the latter case, our
approach produces efficient estimators and honest bands for (functional)
average treatment effects (ATE) and quantile treatment effects (QTE). To make
informative inference possible, we assume that key reduced form predictive
relationships are approximately sparse. This assumption allows the use of
regularization and selection methods to estimate those relations, and we
provide methods for post-regularization and post-selection inference that are
uniformly valid (honest) across a wide-range of models. We show that a key
ingredient enabling honest inference is the use of orthogonal or doubly robust
moment conditions in estimating certain reduced form functional parameters. We
illustrate the use of the proposed methods with an application to estimating
the effect of 401(k) eligibility and participation on accumulated assets.


title:
Spatial population expansion promotes the evolution of cooperation in an
  experimental Prisoner's Dilemma

abstract:
  Cooperation is ubiquitous in nature, but explaining its existence remains a
central interdisciplinary challenge. Cooperation is most difficult to explain
in the Prisoner's Dilemma game, where cooperators always lose in direct
competition with defectors despite increasing mean fitness. Here we demonstrate
how spatial population expansion, a widespread natural phenomenon, promotes the
evolution of cooperation. We engineer an experimental Prisoner's Dilemma game
in the budding yeast Saccharomyces cerevisiae to show that, despite losing to
defectors in nonexpanding conditions, cooperators increase in frequency in
spatially expanding populations. Fluorescently labeled colonies show genetic
demixing of cooperators and defectors, followed by increase in cooperator
frequency as cooperator sectors overtake neighboring defector sectors. Together
with lattice-based spatial simulations, our results suggest that spatial
population expansion drives the evolution of cooperation by (1) increasing
positive genetic assortment at population frontiers and (2) selecting for
phenotypes maximizing local deme productivity. Spatial expansion thus creates a
selective force whereby cooperator-enriched demes overtake neighboring
defector-enriched demes in a "survival of the fastest". We conclude that colony
growth alone can promote cooperation and prevent defection in microbes. Our
results extend to other species with spatially restricted dispersal undergoing
range expansion, including pathogens, invasive species, and humans.


title: The Higgs Bridge

abstract:
  The particle recently discovered at the Large Hadron Collider near Geneva is
almost certainly a Higgs boson, the long-sought completion of the Standard
Model of particle physics. But this discovery, an achievement by more than six
thousand scientists (including students), is actually much more than a mere
capstone of the Standard Model. It instead represents a bridge from the
Standard Model to exciting discoveries of the future, at higher energies or in
other experiments, and to the properties of matter at very low temperatures.
The mere existence of a particle with zero spin implies a need for new physics,
with the most likely candidate being supersymmetry, which requires that every
known particle has a superpartner yet to be discovered. And phenomena similar
to the Higgs are seen in superconducting metals and superfluid gases at low
temperatures, which extend down to a millionth or even a billionth of a degree
Kelvin. So the discovery of a Higgs boson has a central place in our attempts
both to achieve a true understanding of Nature and to harness Nature in
practical applications.