title: Dirichlet random walks

abstract:
  This article provides tools for the study of the Dirichlet random walk in
$\mathbb{R}^d$. By this we mean the random variable
$W=X_1\Theta_1+\cdots+X_n\Theta_n$ where $X=(X_1,\ldots,X_n) \sim
\mathcal{D}(q_1,\ldots,q_n)$ is Dirichlet distributed and where
$\Theta_1,\ldots \Theta_n$ are iid, uniformly distributed on the unit sphere of
$\mathbb{R}^d$ and independent of $X.$ In particular we compute explicitely in
a number of cases the distribution of $W.$ Some of our results appear already
in the literature, in particular in the papers by G\'erard Le Ca\"{e}r (2010,
2011). In these cases, our proofs are much simpler from the original ones,
since we use a kind of Stieltjes transform of $W$ instead of the Laplace
transform: as a consequence the hypergeometric functions replace the Bessel
functions. A crucial ingredient is a particular case of the classical and non
trivial identity, true for $0\leq u\leq 1/2$:$$_2F_1(2a,2b;a+b+\frac{1}{2};u)=
\_2F_1(a,b;a+b+\frac{1}{2};4u-4u^2).$$ We extend these results to a study of
the limits of the Dirichlet random walks when the number of added terms goes to
infinity, interpreting the results in terms of an integral by a Dirichlet
process. We introduce the ideas of Dirichlet semigroups and of Dirichlet
infinite divisibility and characterize these infinite divisible distributions
in the sense of Dirichlet when they are concentrated on the unit ball of
$\mathbb{R}^d.$
  {4mm}\noindent \textsc{Keywords:} Dirichlet processes, Stieltjes transforms,
random flight, distributions in a ball, hyperuniformity, infinite divisibility
in the sense of Dirichlet.
  {4mm}\noindent \textsc{AMS classification}: 60D99, 60F99.


title: Fundamental constants and high resolution spectroscopy

abstract:
  Absorption-line systems detected in high resolution quasar spectra can be
used to compare the value of dimensionless fundamental constants such as the
fine-structure constant, alpha, and the proton-to-electron mass ratio, mu =
m_p/m_e, as measured in remote regions of the Universe to their value today on
Earth. In recent years, some evidence has emerged of small temporal and also
spatial variations in alpha on cosmological scales which may reach a fractional
level of 10 ppm . We are conducting a Large Programme of observations with VLT
UVES to explore these variations. We here provide a general overview of the
Large Programme and report on the first results for these two constants,
discussed in detail in Molaro et al. and Rahmani et al. A stringent bound for
Delta(alpha)/Alpha is obtained for the absorber at_abs = 1.6919 towards HE
2217-2818. The absorption profile is complex with several very narrow features,
and is modeled with 32 velocity components. The relative variation in alpha in
this system is +1.3+-2.4_{stat}+-1.0_{sys} ppm if Al II lambda 1670AA and three
Fe II transitions are used, and +1.1+-2.6_{stat} ppm in a lightly different
analysis with only Fe II transitions used. The expectation at this sky position
of the recently-reported dipolar variation of alpha is (3.2--5.4)+-1.7 ppm
depending on dipole model. This constraint of Delta(alpha)/alpha at face value
is not supporting this expectation but is not inconsistent with it at the 3
sigma level. For the proton-to-electron mass ratio the analysis of the H_2
absorption lines of the z_{abs}~2.4018 damped Ly alpha system towards HE 0027-
1836 provides Delta(mu)/mu = (-7.6 +- 8.1_{stat} +- 6.3_{sys}) ppm which is
also consistent with a null variation. (abridged)


title:
Sharp ellipticity conditions for ballistic behavior of random walks in
  random environment

abstract:
  We sharpen ellipticity criteria for random walks in i.i.d. random
environments introduced by Campos and Ram\'{\i}rez which ensure ballistic
behavior. Furthermore, we construct new examples of random environments for
which the walk satisfies the polynomial ballisticity criteria of Berger,
Drewitz and Ram\'{\i}rez. As a corollary, we can exhibit a new range of values
for the parameters of Dirichlet random environments in dimension $d=2$ under
which the corresponding random walk is ballistic.


title: Thermoelectrical detection of Majorana states

abstract:
  We discuss the thermoelectrical properties of nanowires hosting Majorana edge
states. For a Majorana nanowire directly coupled to two normal reservoirs the
thermopower always vanishes regardeless of the value of the Majorana
hybridization. This situation changes drastically if we insert a quantum dot.
Then, the dot Majorana side coupled system exhibits a different behavior for
the thermopower depending on the Majorana hybridization parameter. Thermopower
reverses its sign when the half fermionic state is fully developed. As long as
the hybridization becomes finite the Seebeck coefficient behaves similarly to a
resonant level system. The sign change of the thermopower when Majorana physics
takes place and the fact that both, the electrical and thermal conductances
reach, their half fermionic value could serve as a proof of the existence of
Majorana edge states in nanowires. Finally, we perform some predictions about
the gate dependence of the Seebeck coefficient when Kondo correlations are
present in the dot.


title: The (Nested) Word Problem

abstract:
  In this article we provide a new perspective on the word problem of a group
by using languages of nested words. These were introduced by Alur and
Madhusudan as a way to model programming languages such as HTML. We demonstrate
how a class of nested word languages called visibly pushdown can be used to
study the word problem of virtually free groups in a natural way.


title: On simple modules over conformal Galilei algebras

abstract:
  We study irreducible representations of two classes of conformal Galilei
algebras in 1-spatial dimension. We construct a functor which transforms simple
modules with nonzero central charge over the Heisenberg subalgebra into simple
modules over the conformal Galilei algebras. This can be viewed as an analogue
of oscillator representations. We use oscillator representations to describe
the structure of simple highest weight modules over conformal Galilei algebras.
We classify simple weight modules with finite dimensional weight spaces over
finite dimensional Heisenberg algebras and use this classification and
properties of oscillator representations to classify simple weight modules with
finite dimensional weight spaces over conformal Galilei algebras.


title:
On the need for a nonlinear subscale turbulence term in POD models as
  exemplified for a high Reynolds number flow over an Ahmed body

abstract:
  We investigate a hierarchy of eddy-viscosity terms in POD Galerkin models to
account for a large fraction of unresolved fluctuation energy. These Galerkin
methods are applied to Large Eddy Simulation data for a flow around the
vehicle-like bluff body call Ahmed body. This flow has three challenges for any
reduced-order model: a high Reynolds number, coherent structures with broadband
frequency dynamics, and meta-stable asymmetric base flow states. The Galerkin
models are found to be most accurate with modal eddy viscosities as proposed by
Rempfer & Fasel (1994). Robustness of the model solution with respect to
initial conditions, eddy viscosity values and model order is only achieved for
state-dependent eddy viscosities as proposed by Noack, Morzynski & Tadmor
(2011). Only the POD system with state-dependent modal eddy viscosities can
address all challenges of the flow characteristics. All parameters are
analytically derived from the Navier-Stokes based balance equations with the
available data. We arrive at simple general guidelines for robust and accurate
POD models which can be expected to hold for a large class of turbulent flows.


title: A martingale representation theorem for a class of jump processes

abstract:
  We give a bare-hands approach to the martingale representation theorem for
integer valued random measures, which allows for a wide class of infinite
activity jump processes, as well as all processes with well-ordered jumps.


title: Thermodynamics in dynamical spacetimes

abstract:
  We derive a general formulation of the laws of irreversible thermodynamics in
the presence of electromagnetism and gravity. For the handling of macroscopic
material media, we use as a guide the field equations and the Noether
identities of fundamental matter as deduced in the framework of gauge theories
of the Poincar\'e$\otimes U(1)$ group.


title:
Spatial-Spectral Boosting Analysis for Stroke Patients' Motor Imagery
  EEG in Rehabilitation Training

abstract:
  Current studies about motor imagery based rehabilitation training systems for
stroke subjects lack an appropriate analytic method, which can achieve a
considerable classification accuracy, at the same time detects gradual changes
of imagery patterns during rehabilitation process and disinters potential
mechanisms about motor function recovery. In this study, we propose an adaptive
boosting algorithm based on the cortex plasticity and spectral band shifts.
This approach models the usually predetermined spatial-spectral configurations
in EEG study into variable preconditions, and introduces a new heuristic of
stochastic gradient boost for training base learners under these preconditions.
We compare our proposed algorithm with commonly used methods on datasets
collected from 2 months' clinical experiments. The simulation results
demonstrate the effectiveness of the method in detecting the variations of
stroke patients' EEG patterns. By chronologically reorganizing the weight
parameters of the learned additive model, we verify the spatial compensatory
mechanism on impaired cortex and detect the changes of accentuation bands in
spectral domain, which may contribute important prior knowledge for
rehabilitation practice.


title: Acylindrical hyperbolicity of groups acting on trees

abstract:
  We provide new examples of acylindrically hyperbolic groups arising from
actions on simplicial trees. In particular, we consider amalgamated products
and HNN-extensions, 1-relator groups, automorphism groups of polynomial
algebras, 3-manifold groups and graph products. Acylindrical hyperbolicity is
then used to obtain some results about the algebraic structure, analytic
properties and measure equivalence rigidity of groups from these classes.


title: Phase behaviour of active Brownian particles: The role of dimensionality

abstract:
  Recently, there has been much interest in activity-induced phase separations
in concentrated suspensions of "active Brownian particles" (ABPs),
self-propelled spherical particles whose direction of motion relaxes through
thermal rotational diffusion. To date, almost all these studies have been
restricted to 2 dimensions. In this work we study activity-induced phase
separation in 3D and compare the results with previous and new 2D simulations.
To this end, we performed state-of-the-art Brownian dynamics simulations of up
to 40 million ABPs -- such very large system sizes are unavoidable to evade
finite size effects in 3D. Our results confirm the picture established for 2D
systems in which an activity-induced phase separation occurs, with strong
analogies to equilibrium gas-liquid spinodal decomposition, in spite of the
purely non-equilibrium nature of the driving force behind the phase separation.
However, we also find important differences between the 2D and 3D cases.
Firstly, the shape and position of the phase boundaries is markedly different
for the two cases. Secondly, for the 3D coarsening kinetics we find that the
domain size grows in time according to the classical diffusive $t^{1/3}$ law,
in contrast to the nonstandard subdiffusive exponent observed in 2D.

categories: cond-mat.soft cond-mat.stat-mech physics.bio-ph physics.comp-ph


title: On spectral types of semialgebraic sets

abstract:
  In this work we prove that a semialgebraic set $M\subset{\mathbb R}^m$ is
determined (up to a semialgebraic homeomorphism) by its ring ${\mathcal S}(M)$
of (continuous) semialgebraic functions while its ring ${\mathcal S}^*(M)$ of
(continuous) bounded semialgebraic functions only determines $M$ besides a
distinguished finite subset $\eta(M)\subset M$. In addition it holds that the
rings ${\mathcal S}(M)$ and ${\mathcal S}^*(M)$ are isomorphic if and only if
$M$ is compact. On the other hand, their respective maximal spectra $\beta_s M$
and $\beta_s^* M$ endowed with the Zariski topology are always homeomorphic and
topologically classify a `large piece' of $M$. The proof of this fact requires
a careful analysis of the points of the remainder $\partial M:=\beta_s^*
M\setminus M$ associated with formal paths.


title:
Effect of Quantum Spin Fluctuation on Scalar Chiral Ordering in the
  Kondo Lattice Model on a Triangular Lattice

abstract:
  Spin scalar chiral ordering gives rise to nontrivial topological characters
and peculiar transport properties. We here examine how quantum spin
fluctuations affect the spin scalar chiral ordering in itinerant electron
systems. We take the Kondo lattice model on a triangular lattice, and perform
the linear spin wave analysis in the Chern insulator phases with spin scalar
chiral ordering obtained in the case that the localized spins are classical. We
find that, although the quantum fluctuation destabilizes the spin scalar chiral
phase at 3/4 filling that originates from the perfect nesting of Fermi surface,
it retains the phase at 1/4 filling that is induced by an effective positive
biquadratic interaction. The reduction of the ordered magnetic moment by the
zero-point quantum fluctuation is considerably small, compared with those in
spin-only systems. The results suggest that the Chern insulator at 1/4 filling
remains robust under quantum fluctuations.


title: A Universal Quaternary Quadratic Form over Gaussian Integers

abstract:
  In this article we show that the form $x^2 + iy^2 + z^2 + iw^2$ represents
all gaussian integers. The main tools used in this proof are Fermat's little
theorem (over finite field extensions), the Mordell-Niven theorem
(representation of some gaussians), and the generalized Euler-identity over
finite field extensions.


title:
Co-trapping different species in ion traps using multiple
  radio-frequencies

abstract:
  We consider the stability of systems subjected to periodic parametric driving
such that their equations of motion are ordinary differential equations with
periodic coefficients and carry out a detailed analysis of important aspects of
such systems in the context of the confinement of ions by oscillating electric
fields. We show how they can be understood in terms of a pseudopotential
approximation and resonances arising from the parametric excitation and
investigate the properties of a novel linear Paul trap configuration operating
with two radio-frequencies to simultaneously confine two species with extremely
different charge-to-mass ratios. The theoretical calculations have been
verified by molecular dynamics simulations and normal modes analysis.


title: Kopnin force and chiral anomaly

abstract:
  Kopnin spectral flow force acting on quantized vortices in superfluid and
superconductors is discussed. Kopnin force represents the first realization of
the chiral anomaly in condensed matter.


title: Inclusive Jets in PHP

abstract:
  Differential inclusive-jet cross sections have been measured in
photoproduction for boson virtualities Q^2 < 1 GeV^2 with the ZEUS detector at
HERA using an integrated luminosity of 300 pb^-1. Jets were identified in the
laboratory frame using the k_T, anti-k_T or SIScone jet algorithms. Cross
sections are presented as functions of the jet pseudorapidity, eta(jet), and
the jet transverse energy, E_T(jet). Next-to-leading-order QCD calculations
give a good description of the measurements, except for jets with low E_T(jet)
and high eta(jet). The cross sections have the potential to improve the
determination of the PDFs in future QCD fits. Values of alpha_s(M_Z) have been
extracted from the measurements based on different jet algorithms. In addition,
the energy-scale dependence of the strong coupling was determined.


title: Abundances and possible diffusion of elements in M67 stars

abstract:
  We present a spectroscopic study at high resolution, R~50,000, of 14 stars
located on the main sequence, at the turn-off point and on the early subgiant
branch in the cluster M67 in order to investigate its detailed chemical
composition, for comparison with the Sun and solar twins in the solar
neighbourhood, and to explore selective atomic diffusion of chemical elements
as predicted by stellar-structure theory. We have obtained VLT/FLAMES-UVES
spectra and analysed these strictly differentially in order to explore
chemical-abundance similarities and differences between the M67 stars and the
Sun, and among the M67 stars themselves. Individual abundances of 19 different
chemical elements are obtained for the stars. They are found to agree very well
with solar abundances, with abundance ratios closer to solar than those of most
solar twins in the solar neighbourhood. An exception is Li which shows a
considerable scatter among the cluster stars. There is a tendency for the
cluster-star abundances to be depleted relative to the abundances in the field
stars in correlation with the condensation temperature of the elements, a
tendency earlier found also for the Sun. The results support the hypothesis
that the gas of the proto-cluster was depleted by formation and cleansing of
dust before the stars formed. They also add support to the proposal that the
Sun was once formed in a dense stellar environment. Moreover, the observed
minor reductions of heavy elements in the atmospheres of the dwarfs and
turn-off point stars relative to our standard star M67-1194 and the subgiants
seem to suggest that diffusion processes are at work in these stars, although
the evidence is not compelling. Based on theoretical models the
diffusion-corrected initial metallicity of M67 is estimated to be [Fe/H]=+0.06.


title: The Quest-V Separation Kernel for Mixed Criticality Systems

abstract:
  Multi- and many-core processors are becoming increasingly popular in embedded
systems. Many of these processors now feature hardware virtualization
capabilities, such as the ARM Cortex A15, and x86 processors with Intel VT-x or
AMD-V support. Hardware virtualization offers opportunities to partition
physical resources, including processor cores, memory and I/O devices amongst
guest virtual machines. Mixed criticality systems and services can then
co-exist on the same platform in separate virtual machines. However,
traditional virtual machine systems are too expensive because of the costs of
trapping into hypervisors to multiplex and manage machine physical resources on
behalf of separate guests. For example, hypervisors are needed to schedule
separate VMs on physical processor cores. In this paper, we discuss the design
of the Quest-V separation kernel, that partitions services of different
criticalities in separate virtual machines, or sandboxes. Each sandbox
encapsulates a subset of machine physical resources that it manages without
requiring intervention of a hypervisor. Moreover, a hypervisor is not needed
for normal operation, except to bootstrap the system and establish
communication channels between sandboxes.


title: A Core Calculus for Provenance

abstract:
  Provenance is an increasing concern due to the ongoing revolution in sharing
and processing scientific data on the Web and in other computer systems. It is
proposed that many computer systems will need to become provenance-aware in
order to provide satisfactory accountability, reproducibility, and trust for
scientific or other high-value data. To date, there is not a consensus
concerning appropriate formal models or security properties for provenance. In
previous work, we introduced a formal framework for provenance security and
proposed formal definitions of properties called disclosure and obfuscation.
  In this article, we study refined notions of positive and negative disclosure
and obfuscation in a concrete setting, that of a general-purpose programing
language. Previous models of provenance have focused on special-purpose
languages such as workflows and database queries. We consider a higher-order,
functional language with sums, products, and recursive types and functions, and
equip it with a tracing semantics in which traces themselves can be replayed as
computations. We present an annotation-propagation framework that supports many
provenance views over traces, including standard forms of provenance studied
previously. We investigate some relationships among provenance views and
develop some partial solutions to the disclosure and obfuscation problems,
including correct algorithms for disclosure and positive obfuscation based on
trace slicing.


title: Bell-type inequality and quantum nonlocality in four-qubit systems

abstract:
  We present a Bell-type inequality for four-qubit systems. Using the
inequality we investigate quantum nonlocality of a generic family of states
$\left|G_{abcd}\right >$ [Phys. Rev. A 65, 052112 (2002)] and several canonical
four-qubit entangled states. It has been demonstrated that the inequality is
maximally violated by so called "four-qubit maximal entangled state
$\left|G_{m}\right >$" and it is also violated by the four-qubit W state and a
special family of states $\left|G_{ab00}\right >$. Moreover, a useful
entanglement-nonlocality relationship for the family of states
$\left|G_{ab00}\right >$ is obtained.


title: Predictable Migration and Communication in the Quest-V Multikernel

abstract:
  Quest-V is a system we have been developing from the ground up, with
objectives focusing on safety, predictability and efficiency. It is designed to
work on emerging multicore processors with hardware virtualization support.
Quest-V is implemented as a "distributed system on a chip" and comprises
multiple sandbox kernels. Sandbox kernels are isolated from one another in
separate regions of physical memory, having access to a subset of processing
cores and I/O devices. This partitioning prevents system failures in one
sandbox affecting the operation of other sandboxes. Shared memory channels
managed by system monitors enable inter-sandbox communication.
  The distributed nature of Quest-V means each sandbox has a separate physical
clock, with all event timings being managed by per-core local timers. Each
sandbox is responsible for its own scheduling and I/O management, without
requiring intervention of a hypervisor.
  In this paper, we formulate bounds on inter-sandbox communication in the
absence of a global scheduler or global system clock. We also describe how
address space migration between sandboxes can be guaranteed without violating
service constraints. Experimental results on a working system show the
conditions under which Quest-V performs real-time communication and migration.


title:
Dispersive estimates for four dimensional Schr\"{o}dinger and wave
  equations with obstructions at zero energy

abstract:
  We investigate $L^1(\mathbb R^4)\to L^\infty(\mathbb R^4)$ dispersive
estimates for the Schr\"odinger operator $H=-\Delta+V$ when there are
obstructions, a resonance or an eigenvalue, at zero energy. In particular, we
show that if there is a resonance or an eigenvalue at zero energy then there is
a time dependent, finite rank operator $F_t$ satisfying $\|F_t\|_{L^1\to
L^\infty} \lesssim 1/\log t$ for $t>2$ such that
$$\|e^{itH}P_{ac}-F_t\|_{L^1\to L^\infty} \lesssim t^{-1},\,\,\,\,\,\text{for}
t>2.$$ We also show that the operator $F_t=0$ if there is an eigenvalue but no
resonance at zero energy. We then develop analogous dispersive estimates for
the solution operator to the four dimensional wave equation with potential.


title: Simulation Over One-counter Nets is PSPACE-Complete

abstract:
  One-counter nets (OCN) are Petri nets with exactly one unbounded place. They
are equivalent to a subclass of one-counter automata with just a weak test for
zero. Unlike many other semantic equivalences, strong and weak simulation
preorder are decidable for OCN, but the computational complexity was an open
problem. We show that both strong and weak simulation preorder on OCN are
PSPACE-complete.


title: Combining Structured and Unstructured Randomness in Large Scale PCA

abstract:
  Principal Component Analysis (PCA) is a ubiquitous tool with many
applications in machine learning including feature construction, subspace
embedding, and outlier detection. In this paper, we present an algorithm for
computing the top principal components of a dataset with a large number of rows
(examples) and columns (features). Our algorithm leverages both structured and
unstructured random projections to retain good accuracy while being
computationally efficient. We demonstrate the technique on the winning
submission the KDD 2010 Cup.


title: Boundary energy of the open XXX chain with a non-diagonal boundary term

abstract:
  We analyze the ground state of the open spin-1/2 isotropic quantum spin chain
with a non-diagonal boundary term using a recently proposed Bethe ansatz
solution. As the coefficient of the non-diagonal boundary term tends to zero,
the Bethe roots split evenly into two sets: those that remain finite, and those
that become infinite. We argue that the former satisfy conventional Bethe
equations, while the latter satisfy a generalization of the Richardson-Gaudin
equations. We derive an expression for the leading correction to the boundary
energy in terms of the boundary parameters.


title: Amplitude Variations in Pulsating Red Supergiants

abstract:
  We have used long-term AAVSO visual observations and Fourier and wavelet
analysis to identify periods and study long-term amplitude variations in 44 red
supergiants. Of these, 12 stars had data which were too sparse and/or had low
amplitude and/or were without conspicuous peaks in the Fourier spectrum; 6
stars had only long (2500-4000 days) periods without significant amplitude
variation. The other 26 stars had one or two periods, either "short" (hundreds
of days) or "long" (thousands of days), whose amplitudes varied by up to a
factor of 8, but more typically 2-4. The median timescale of the amplitude
variation was 18 periods. We interpret the shorter periods as due to pulsation,
and the longer periods as analogous to the "long secondary periods" found in
pulsating red giants.


title: Hawking radiation as irreversible tunneling through self-interaction

abstract:
  In this letter, we study the self-force in the Parikh-Wilczek tunneling model
of Hawking radiation for Reissner-Nordstroem black holes. We conclude that the
repulsive self-force speeds up the emission and the radiation becomes an
irreversible process. We also find an upper bound of charge-mass ratio for
emitted particles.


title:
Singular Schroedinger operators as self-adjoint extensions of n-entire
  operators

abstract:
  We investigate the connections between Weyl-Titchmarsh-Kodaira theory for
one-dimensional Schr\"odinger operators and the theory of $n$-entire operators.
As our main result we find a necessary and sufficient condition for a
one-dimensional Schr\"odinger operator to be $n$-entire in terms of square
integrability of derivatives (w.r.t. the spectral parameter) of the Weyl
solution. We also show that this is equivalent to the Weyl function being in a
generalized Herglotz-Nevanlinna class. As an application we show that perturbed
Bessel operators are $n$-entire, improving the previously known conditions on
the perturbation.


title:
NoSOCS in SDSS. IV. The Role of Environment Beyond the Extent of Galaxy
  Clusters

abstract:
  We are able to extend the investigation of the
color-morphology-density-radius relations, for bright and faint galaxies, to $R
\gtrsim 3 \times R_{200}$ and to very low density regions, probing the
transition region between cluster and field galaxies, and finding a smooth
variation between these two populations. We investigate the environmental
variation of galaxy properties (and their relations), such as color, spectral
type and concentration. Our sample comprises 6,415 galaxies that were
previously selected as cluster members from 152 systems with $z \le 0.100$. Our
main findings are: (i) The fraction of discs is generally higher than the ones
for blue and star-forming galaxies, indicating a faster transformation of color
and star-formation compared to structural parameters. (ii) Regarding the
distance to the cluster center we find a small variation in the galaxy
populations outside the virial radius. Once within that radius the fractions of
each population change fast, decreasing even faster within $R \sim 0.3 \times
R_{200}$. (iii) We also find a small increase in the fraction of blue faint
galaxies within $R \sim 0.4 \times R_{200}$, before decreasing again to the
most central bin. (iv) Our results do not indicate a significant dependence on
cluster mass, except for the disc fraction in the core of clusters. (v) The
relations between galaxy properties also point to no dependence on cluster
mass, except for the scatter of the color stellar mass relation. Our results
corroborate a scenario on which pre-processing in groups leads to a strong
evolution in galaxy properties, before they are accreted by large clusters
(abridged).


title: Inverse scattering of Canonical systems and their evolution

abstract:
  In this work we present an analogue of the inverse scattering for Canonical
systems using theory of vessels and associated to them completely integrable
systems. Analytic coefficients fits into this setting, significantly expanding
the class of functions for which the inverse scattering exist. We also derive
an evolutionary equation, arising from canonical systems, which describes the
evolution of the logarithmic derivative of the tau function, associated to
these systems


title: Onomastics and Big Data Mining

abstract:
  As of today, the main business application of onomastics is naming, or
branding: finding the proper name for your company or your product to stand out
in the world. Meaningfully, Onoma, the Greek root for name, is also a
registered trademark of Nomen, the naming agency founded by Marcel Botton in
1981. Nomen initially licensed one of Roland Moreno's inventions, the Radoteur
name generator, and created many distinctive and global brand names such as:
Vinci, Clio or Amundi. But once your business has a name, should you forget
about onomastics? Not anymore. Globalization, digitalization and the Big Data
open new fields to experiment disruptive applications in Sales and Marketing,
Communication, HR and Risk Management. Though discriminating names carries a
high risk of abuse, it can also drive new, unexpected ways for developing poor
areas.


title: A sensitive study of the peculiar jet structure HST-1 in M87

abstract:
  To obtain a better understanding of the location and mechanisms for the
production of the gamma-ray emission in jets of AGN we present a detailed study
of the HST-1 structure, 0.8 arcsec downstream the jet of M87, previously
identified as a possible candidate for TeV emission. HST-1 shows a very
peculiar structure with superluminal as well as possible stationary
sub-components, and appears to be located in the transition from a parabolic to
a conical jet shape, presumably leading to the formation of a recollimation
shock. This scenario is supported by our new RHD simulations in which the
interaction of a moving component with a recollimation shock leads to the
appearance of a new superluminal component. To discern whether HST-1 is
produced by a recollimation shock or some other MHD instability, we present new
polarimetric 2.2 and 5 GHz VLBA, as well as 15, 22 and 43 GHz JVLA observations
obtained between November 2012 and March 2013.


title: Asymptotic Resemblance

abstract:
  Uniformity and proximity are two different ways for defining small scale
structures on a set. Coarse structures are large scale counterparts of uniform
structures. In this paper, motivated by the definition of proximity, we develop
the concept of asymptotic resemblance as a relation between subsets of a set to
define a large scale structure on it. We use our notion of asymptotic
resemblance to generalize some basic concepts of coarse geometry. We introduce
a large scale compactification which in special cases agrees with Higson
compactification. At the end we show that how the asymptotic dimension of a
metric space can be generalized to a set equipped with an asymptotic
resemblance relation.


title:
Model composition through model reduction: a combined model of CD95 and
  NF-{\kappa}B signaling pathways

abstract:
  We propose a new approach to model composition, based on reducing several
models to the same level of complexity and subsequent combining them together.
Firstly, we suggest a set of model reduction tools that can be systematically
applied to a given model. Secondly, we suggest a notion of a minimal complexity
model. This model is the simplest one that can be obtained from the original
model using these tools and still able to approximate experimental data.
Thirdly, we propose a strategy for composing the reduced models together.
Connection with the detailed model is preserved, which can be advantageous in
some applications. A toolbox for model reduction and composition has been
implemented as part of the BioUML software and tested on the example of
integrating two previously published models of the CD95 (APO-1/Fas) signaling
pathways. We show that the reduced models lead to the same dynamical behavior
of observable species and the same predictions as in the precursor models. The
composite model is able to recapitulate several experimental datasets which
were used by the authors of the original models to calibrate them separately,
but also has new dynamical properties.


title: Diffraction dissociation at the LHC

abstract:
  Predictions for the squared momentum transfer and missing mass dependence of
the differential and integrated single- and double low missing-mass diffraction
dissociation in the kinematical range of present and future LHC measurements
are summarized.


title: Modelling excitonic-energy transfer in light-harvesting complexes

abstract:
  The theoretical and experimental study of energy transfer in photosynthesis
has revealed an interesting transport regime, which lies at the borderline
between classical transport dynamics and quantum-mechanical interference
effects. Dissipation is caused by the coupling of electronic degrees of freedom
to vibrational modes and leads to a directional energy transfer from the
antenna complex to the target reaction-center. The dissipative driving is
robust and does not rely on fine-tuning of specific vibrational modes. For the
parameter regime encountered in the biological systems new theoretical tools
are required to directly compare theoretical results with experimental
spectroscopy data. The calculations require to utilize massively parallel
graphics processor units (GPUs) for efficient and exact computations.


title:
The Effect of Toroidal Magnetic Field on Thickness of a
  Viscose-Resistive Hot Accreting Flow

abstract:
  By taking into account the effect of toroidal magnetic field and its
correspond heating, we determine the thickness of advection-dominated accretion
flows. We consider an axisymetric, rotating, steady viscous-resistive,
magnetized accretion flow under an advection dominated stage. The dominant
mechanism of energy dissipation is assumed to be turbulence viscosity and
magnetic diffusivity. We adopt a self-similar assumption in the radial
direction to obtain the dynamical quantities, that is, radial, azimuthal, sound
and Alfv\' en velocities. Our results show the vertical component of magnetic
force acts in the opposite direction of gravity and compresses the disc, thus
compared with the non-magnetic case, in general the disc half-thikness,
$\Delta\theta$, significantly is reduced. On the other hand, two parameters,
appearing due to action of magnetic field and reaction of the flow, affect the
disc thickness. The first one, $\beta_0$, showing the magnetic field strength
at the equatorial plane, decreases $\Delta\theta$. The other one, $\eta_0$ is
the magnetic resistivity parameter and when it increases, $\Delta\theta$
increases, too.


title:
Structure of Advection-Dominated Accretion Disks with Outflows: Role of
  Toroidal Magnetic Field

abstract:
  The main aim of this paper is studying the effect of toroidal magnetic field
on the structure of Advection-Dominated Accretion Flows (ADAF) in the presence
of the turbulence viscosity and diffusivity due to viscosity and magnetic field
respectively. We use self-similar assumption in radial direction to solve the
magnetohydrodynamic (MHD) equations for hot accretion disk. We use spherical
coordinate $ (r, \theta, \varphi) $ to solve our equation. The toroidal
component of magnetic field is considered and all three components of the
velocity field $ \mathbf{v}\equiv (v_{r}, v_{\theta}, v_{\varphi}) $ are
present in our work. We reduce the equations to a set of differential equations
about $ \theta $ and apply the symmetric boundary condition at the equatorial
plane of the disk. Our results indicate that the outflow region, where the
redial velocity becomes positive in a certain inclination angle $ \theta_{0} $,
always exist. The results represent that the stronger the magnetic field, the
smaller the inclination angle, $ \theta_{0} $ becomes. It means that a
magnetized disk is thinner compared to a non-magnetized disk. According to the
work by \citealt{jw}, we can define three regions. The first one is called
inflow region, which starts from the disk midplane to a certain inclination $
\theta_0 $ where $ v_{r}(\theta_{0}) = 0 $. In this region, the velocity has a
negative value and the accretion material moves toward the central object. The
outflow region, where $ v_{r}(\theta) > 0 $, is placed between $ \theta_{0} $
and surface of the disk, $ \theta_{0} < \theta < \theta_{s} $. In this area,
the accretion flow moves away from the central object. The third region, which
is located between the surface of the disk and the polar axis, is called wind
region.


title: Efficient State-Space Inference of Periodic Latent Force Models

abstract:
  Latent force models (LFM) are principled approaches to incorporating
solutions to differential equations within non-parametric inference methods.
Unfortunately, the development and application of LFMs can be inhibited by
their computational cost, especially when closed-form solutions for the LFM are
unavailable, as is the case in many real world problems where these latent
forces exhibit periodic behaviour. Given this, we develop a new sparse
representation of LFMs which considerably improves their computational
efficiency, as well as broadening their applicability, in a principled way, to
domains with periodic or near periodic latent forces. Our approach uses a
linear basis model to approximate one generative model for each periodic force.
We assume that the latent forces are generated from Gaussian process priors and
develop a linear basis model which fully expresses these priors. We apply our
approach to model the thermal dynamics of domestic buildings and show that it
is effective at predicting day-ahead temperatures within the homes. We also
apply our approach within queueing theory in which quasi-periodic arrival rates
are modelled as latent forces. In both cases, we demonstrate that our approach
can be implemented efficiently using state-space methods which encode the
linear dynamic systems via LFMs. Further, we show that state estimates obtained
using periodic latent force models can reduce the root mean squared error to
17% of that from non-periodic models and 27% of the nearest rival approach
which is the resonator model.


title: Epidemics in markets with trade friction and imperfect transactions

abstract:
  Market trade-routes can support infectious-disease transmission, impacting
biological populations and even disrupting causal trade. Epidemiological models
increasingly account for reductions in infectious contact, such as
risk-aversion behaviour in response to pathogen outbreaks. However, market
dynamics clearly differ from simple risk-aversion, as are driven by different
motivation and conditioned by trade constraints, known in economics as
friction, that arise because exchanges are costly. Here we develop a novel
economic-market model where transient and long-term market dynamics are
determined by trade friction and agent adaptation, and can influence disease
transmission. We specify the participants, frequency, volume, and price in
trade transactions, and investigate, using analytical insights and simulation,
how trade friction affects joint market and epidemiological dynamics. The
friction values explored encompass estimates from French cattle and pig
markets. We show that, when trade is the dominant route of transmission, market
friction can be a significantly stronger determinant of epidemics than
risk-aversion behaviour. In particular, there is a critical friction level
above which epidemics do not occur. For a given level of friction, open
unregulated markets can boost epidemics compared with closed or tightly
regulated markets. Our results are robust to model specificities and can hold
in the presence of non-trade disease-transmission routes. In particular, we try
to explain why outbreaks in French livestock markets appear more frequently in
cattle than swine despite swine trade-flow being larger. To minimize contagion
in markets, safety policies could generate incentives for larger-volume,
less-frequent transactions, increasing trade friction without necessarily
affecting overall trade flow.


title: The Becker-Gottlieb Transfer Is Functorial

abstract:
  The Becker-Gottlieb transfer gives a wrong-way map on suspension spectra for
maps of spaces whose homotopy fibres are retracts of finite complexes. We prove
that this construction is contravariantly functorial on the homotopy category
level.


title:
A multi-functional analyzer uses parameter constraints to improve the
  efficiency of model-based gene-set analysis

abstract:
  We develop a model-based methodology for integrating gene-set information
with an experimentally-derived gene list. The methodology uses a previously
reported sampling model, but takes advantage of natural constraints in the
high-dimensional discrete parameter space in order to work from a more
structured prior distribution than is currently available. We show how the
natural constraints are expressed in terms of linear inequality constraints
within a set of binary latent variables. Further, the currently available prior
gives low probability to these constraints in complex systems, such as Gene
Ontology (GO), thus reducing the efficiency of statistical inference. We
develop two computational advances to enable posterior inference within the
constrained parameter space: one using integer linear programming for
optimization and one using a penalized Markov chain sampler. Numerical
experiments demonstrate the utility of the new methodology for a multivariate
integration of genomic data with GO or related information systems. Compared to
available methods, the proposed multi-functional analyzer covers more reported
genes without mis-covering nonreported genes, as demonstrated on genome-wide
data from association studies of type 2 diabetes and from RNA interference
studies of influenza.


title: Logic in the Lab

abstract:
  This file summarizes the plenary talk on laboratory experiments on logic at
the TARK 2013 - 14th Conference on Theoretical Aspects of Rationality and
Knowledge.


title: On Jacobian group arithmetic for typical divisors on curves

abstract:
  In a previous joint article with F. Abu Salem, we gave efficient algorithms
for Jacobian group arithmetic of "typical" divisor classes on C_{3,4} curves,
improving on similar results by other authors. At that time, we could only
state that a generic divisor was typical, and hence unlikely to be encountered
if one implemented these algorithms over a very large finite field. This
article pins down an explicit characterization of these typical divisors, for
an arbitrary smooth projective curve of genus g >= 1 having at least one
rational point. We give general algorithms for Jacobian group arithmetic with
these typical divisors, and prove not only that the algorithms are correct if
various divisors are typical, but also that the success of our algorithms
provides a guarantee that the resulting output is correct and that the
resulting input and/or output divisors are also typical. These results apply in
particular to our earlier algorithms for C_{3,4} curves. As a byproduct, we
obtain a further speedup of approximately 15% on our previous algorithms for
C_{3,4} curves.


title:
Adaptive FE-BE coupling for strongly nonlinear transmission problems
  with friction II

abstract:
  This article discusses the well-posedness and error analysis of the coupling
of finite and boundary elements for transmission or contact problems in
nonlinear elasticity. It concerns W^{1,p}-monotone Hencky materials with an
unbounded stress-strain relation, as they arise in the modelling of ice sheets,
non-Newtonian fluids or porous media. For 1<p<2 the bilinear form of the
boundary element method fails to be continuous in natural function spaces
associated to the nonlinear operator. We propose a functional analytic
framework for the numerical analysis and obtain a priori and a posteriori error
estimates for Galerkin approximations to the resulting boundary/domain
variational inequality. The a posteriori estimate complements recent estimates
obtained for mixed finite element formulations of friction problems in linear
elasticity.


title: Hermitian metrics, (n-1, n-1) forms and Monge-Amp\`ere equations

abstract:
  We show existence of unique smooth solutions to the Monge-Ampere equation for
(n-1)-plurisubharmonic functions on Hermitian manifolds, generalizing previous
work of the authors. As a consequence we obtain Calabi-Yau theorems for
Gauduchon and strongly Gauduchon metrics on a class of non-Kahler manifolds:
those satisfying the Jost-Yau condition known as Astheno-Kahler.
  Gauduchon conjectured in 1984 that a Calabi-Yau theorem for Gauduchon metrics
holds on all compact complex manifolds. We discuss another Monge-Ampere
equation, recently introduced by Popovici, and show that the full Gauduchon
conjecture can be reduced to a second order estimate of Hou-Ma-Wu type.


title:
Dynamic scaling at classical phase transitions approached through
  non-equilibrium quenching

abstract:
  We use Monte Carlo simulations to demonstrate generic scaling aspects of
classical phase transitions approached through a quench (or annealing) protocol
where the temperature changes as a function of time with velocity $v$. Using a
generalized Kibble-Zurek ansatz, we demonstrate dynamic scaling for different
types of stochastic dynamics (Metropolis, Swendsen-Wang, and Wolff) on Ising
models in two and higher dimensions. We show that there are dual scaling
functions governing the dynamic scaling, which together describe the scaling
behavior in the entire velocity range $v \in [0, \infty)$. These functions have
asymptotics corresponding to the adiabatic and diabatic limit, and close to
these limits they are perturbative in $v$ and $1/v$, respectively. Away from
their perturbative domains, both functions cross over into the same universal
power-law scaling form governed by the static and dynamic critical exponents
(as well as an exponent characterizing the quench protocol). As a by-product of
the scaling studies, we obtain high-precision estimates of the dynamic exponent
$z$ for the two-dimensional Ising model subject to the three variants of Monte
Carlo dynamics; for single-spin Metropolis updates $z_M=2.1767(5)$, for
Swendsen-Wang multi-cluster updates $z_{\rm SW}=0.297(3)$, and for Wolff
single-cluster updates $z_{W}=0.30(2)$. For Wolff dynamics, we find an
interesting behavior with a non-analytic break-down of the quasi-adiabatic and
diabatic scaling, instead of the generic smooth cross-over described by a power
law. We interpret this disconnect between the two scaling regimes as a dynamic
phase transition of the Wolff algorithm, caused by an effective sudden loss of
ergodicity at high velocity.


title:
On doubly warped product submanifolds of Generalized
  $(\kappa,\mu)$-Space Forms

abstract:
  In this paper we establish a general inequality involving the Laplacian of
the warping functions and the squared mean curvature of any doubly warped
product isometrically immersed in a Riemannian manifold. Moreover, we obtain
some geometric inequalities for C-totally real doubly warped product
submanifolds of generalized $(\kappa,\mu)$-space forms.


title: A Thousand Problems in Cosmology: Horizons

abstract:
  This is one chapter of the collection of problems in cosmology, in which we
assemble the problems, with solutions, that concern one of the most distinctive
features of general relativity and cosmology---the horizons.
  The first part gives an elementary introduction into the concept in the
cosmological context, then we move to more formal exposition of the subject and
consider first simple, and then composite models, such as $\Lambda$CDM. The
fourth section elevates the rigor one more step and explores the causal
structure of different simple cosmological models in terms of conformal
diagrams. The section on black holes relates the general scheme of constructing
conformal diagrams for stationary black hole spacetimes. The consequent parts
focus on more specific topics, such as the various problems regarding the
Hubble sphere, inflation and holography.
  The full collection is available in the form of a wiki-based resource at
universeinproblems.com. The cosmological community is welcome to contribute to
its development.

categories: physics.ed-ph astro-ph.CO gr-qc physics.pop-ph


title:
Integrable multi-phase thermodynamic systems and Tsallis' composition
  rule

abstract:
  We derive a class of equations of state for a multi-phase thermodynamic
system associated with a finite set of order parameters that satisfy an
integrable system of hydrodynamic type. As particular examples, we discuss
one-phase systems such as the van der Waals gas and the effective molecular
field model. The case of N-phase systems is also discussed in detail in
connection with entropies depending on the order parameter according to
Tsallis' composition rule.


title: Revisionist Integral Deferred Correction with Adaptive Stepsize Control

abstract:
  Adaptive stepsize control is a critical feature for the robust and efficient
numerical solution of initial-value problems in ordinary differential
equations. In this paper, we show that adaptive stepsize control can be
incorporated within a family of parallel time integrators known as Revisionist
Integral Deferred Correction (RIDC) methods. The RIDC framework allows for
various strategies to implement stepsize control, and we report results from
exploring a few of them.


title: The Berry phase and the phase of the determinant

abstract:
  In 1984 Michael Berry discovered that an isolated eigenstate of an
adiabatically changing periodic Hamiltonian $H(t)$ acquires a phase, called the
Berry phase. We show that under very general assumptions the adiabatic
approximation of the phase of the zeta-regularized determinant of the
imaginary-time Schrodinger operator with periodic Hamiltonian is equal to the
Berry phase.


title: Threshold Quantum Cryptography

abstract:
  Most current research on quantum cryptography requires transmission and
reception of single photons that creates severe implementation challenges and
limits range. This paper argues for the development of threshold quantum
cryptography protocols in which the system is secure so long as the number of
photons being exchanged between Alice and Bob is below a specified threshold.
We speak of a (p-k-n) threshold system where if the number of photons exchanged
is less than p, the system is completely secure, when it is between p and k,
the system is partially secure, and when it exceeds k, the system is insecure.
The BB84 protocol is (1-1-1) whereas the three-stage protocol appears to be
(p-4p-n), where p is the least number of photons necessary to determine the
polarization state of identically prepared photons. New quantum cryptography
systems should be sought that provide greater flexibility in the choice of p
and k.


title: The Black Hole Interior in AdS/CFT and the Information Paradox

abstract:
  We show that, within the AdS/CFT correspondence, recent formulations of the
information paradox can be reduced to a question about the existence of certain
kinds of operators in the CFT. We describe a remarkably simple construction of
these operators on a given state of the CFT. Our construction leads to a smooth
horizon, addresses the strong subadditivity paradox, while preserving locality
within effective field theory, and reconciles the existence of the interior
with the growth of states with energy in the CFT. We also extend our
construction to non-equilibrium states.


title: State-Dependent Bulk-Boundary Maps and Black Hole Complementarity

abstract:
  We provide a simple and explicit construction of local bulk operators that
describe the interior of a black hole in the AdS/CFT correspondence. The
existence of these operators is predicated on the assumption that the mapping
of CFT operators to local bulk operators depends on the state of the CFT. We
show that our construction leads to an exactly local effective field theory in
the bulk. Barring the fact that their charge and energy can be measured at
infinity, we show that the commutator of local operators inside and outside the
black hole vanishes exactly, when evaluated within correlation functions of the
CFT. Our construction leads to a natural resolution of the strong subadditivity
paradox of Mathur and Almheiri et al. Furthermore, we show how, using these
operators, it is possible to reconcile small corrections to effective field
theory correlators with the unitarity of black hole evaporation. We address and
resolve all other arguments, advanced in arxiv:1304.6483 and arxiv:1307.4706,
in favour of structure at the black hole horizon. We extend our construction to
states that are near equilibrium, and thereby also address the "frozen vacuum"
objections of arxiv:1308.3697. Finally, we explore an intriguing link between
our construction of interior operators and Tomita-Takesaki theory.


title: Models for exclusive vector meson production in heavy-ion collisions

abstract:
  We discuss coherent and incoherent photoproduction of $J/\Psi$ vector mesons
in high energy heavy ion collisions. In a dipole picture for the photon both
can be naturally related to the dipole cross section that is also probed in
inclusive DIS. We compare results of a particular calculation to ALICE data.


title:
A m\'enage \`a trois of eV-scale sterile neutrinos, cosmology, and
  structure formation

abstract:
  We show that sterile neutrinos with masses ~1 eV or larger, as motivated by
several short-baseline oscillation anomalies, can be consistent with
cosmological constraints if they are charged under a hidden sector force
mediated by a light boson. In this case, sterile neutrinos experience a large
thermal potential that suppresses mixing between active and sterile neutrinos
in the early Universe, even if vacuum mixing angles are large. Thus, the
abundance of sterile neutrinos in the Universe remains very small, and their
impact on Big Bang Nucleosynthesis, Cosmic Microwave Background, and
large-scale structure formation is negligible. It is conceivable that the new
gauge force also couples to dark matter, possibly ameliorating some of the
small-scale structure problems associated with cold dark matter.


title: Risk aversion as an evolutionary adaptation

abstract:
  Risk aversion is a common behavior universal to humans and animals alike.
Economists have traditionally defined risk preferences by the curvature of the
utility function. Psychologists and behavioral economists also make use of
concepts such as loss aversion and probability weighting to model risk
aversion. Neurophysiological evidence suggests that loss aversion has its
origins in relatively ancient neural circuitries (e.g., ventral striatum).
Could there thus be an evolutionary origin to risk avoidance? We study this
question by evolving strategies that adapt to play the equivalent mean payoff
gamble. We hypothesize that risk aversion in the equivalent mean payoff gamble
is beneficial as an adaptation to living in small groups, and find that a
preference for risk averse strategies only evolves in small populations of less
than 1,000 individuals, while agents exhibit no such strategy preference in
larger populations. Further, we discover that risk aversion can also evolve in
larger populations, but only when the population is segmented into small groups
of around 150 individuals. Finally, we observe that risk aversion only evolves
when the gamble is a rare event that has a large impact on the individual's
fitness. These findings align with earlier reports that humans lived in small
groups for a large portion of their evolutionary history. As such, we suggest
that rare, high-risk, high-payoff events such as mating and mate competition
could have driven the evolution of risk averse behavior in humans living in
small groups.


title:
Disconnected quark loop contributions to nucleon observables in lattice
  QCD

abstract:
  We perform a high statistics calculation of disconnected fermion loops on
Graphics Processing Units for a range of nucleon matrix elements extracted
using lattice QCD. The isoscalar electromagnetic and axial vector form factors,
the sigma-terms and the momentum fraction and helicity are among the quantities
we evaluate. We compare the disconnected contributions to the connected ones
and give the physical implications on nucleon observables that probe its
structure.


title: A Novel Spin-Light Polarimeter for the Electron Ion Collider

abstract:
  A novel precision polarimeter will go a long way in satisfying the
requirements of the precision experiments being planned for a future facility
such as the Electron Ion Collider. A polarimeter based on the asymmetry in the
spacial distribution of the spin light component of synchrotron radiation will
make for a fine addition to the existing-conventional M{\o}ller and Compton
polarimeters. The spin light polarimeter consists of a set of wriggler magnet
along the beam that generate synchrotron radiation. The spacial distribution of
synchrotron radiation will be measured by an ionization chamber after being
collimated. The up-down spacial asymmetry in the transverse plane is used to
quantify the polarization of the beam. As a part of the design process,
firstly, a rough calculation was drawn out to establish the validity of such an
idea. Secondly, the fringe fields of the wriggler magnet was simulated using a
2-D magnetic field simulation toolkit called Poisson Superfish, which is
maintained by Los Alamos National Laboratory. This was used to account for beam
motion effects and the corresponding correlations were show to be negligible.
Lastly, a full fledged GEANT-4 simulation was built to study the response time
of the ionization chamber. This GEANT-4 simulation was analyzed for variety of
effects that may hinder precision polarimetry. It was found that a Spin-Light
Polarimeter would be a fine relative polarimeter.


title:
A classification of Lagrangian planes in holomorphic symplectic
  varieties

abstract:
  Classically, an indecomposable class $R$ in the cone of effective curves on a
K3 surface $X$ is representable by a smooth rational curve if and only if
$R^2=-2$. We prove a higher-dimensional generalization conjectured by Hassett
and Tschinkel: for a holomorphic symplectic variety $M$ deformation equivalent
to a Hilbert scheme of $n$ points on a K3 surface, an extremal curve class
$R\in H_2(M,\mathbb{Z})$ in the Mori cone is the line in a Lagrangian $n$-plane
$\mathbb{P}^n\subset M$ if and only if certain intersection-theoretic criteria
are met. In particular, any such class satisfies $(R,R)=-\frac{n+3}{2}$ and the
primitive such classes are all contained in a single monodromy orbit.


title: Cultural Evolution as Distributed Computation

abstract:
  The speed and transformative power of human cultural evolution is evident
from the change it has wrought on our planet. This chapter proposes a human
computation program aimed at (1) distinguishing algorithmic from
non-algorithmic components of cultural evolution, (2) computationally modeling
the algorithmic components, and amassing human solutions to the non-algorithmic
(generally, creative) components, and (3) combining them to develop
human-machine hybrids with previously unforeseen computational power that can
be used to solve real problems. Drawing on recent insights into the origins of
evolutionary processes from biology and complexity theory, human minds are
modeled as self-organizing, interacting, autopoietic networks that evolve
through a Lamarckian (non-Darwinian) process of communal exchange. Existing
computational models as well as directions for future research are discussed.


title: Provable Bounds for Learning Some Deep Representations

abstract:
  We give algorithms with provable guarantees that learn a class of deep nets
in the generative model view popularized by Hinton and others. Our generative
model is an $n$ node multilayer neural net that has degree at most $n^{\gamma}$
for some $\gamma <1$ and each edge has a random edge weight in $[-1,1]$. Our
algorithm learns {\em almost all} networks in this class with polynomial
running time. The sample complexity is quadratic or cubic depending upon the
details of the model.
  The algorithm uses layerwise learning. It is based upon a novel idea of
observing correlations among features and using these to infer the underlying
edge structure via a global graph recovery procedure. The analysis of the
algorithm reveals interesting structure of neural networks with random edge
weights.


title: Fractal Tiling

abstract:
  A simple, yet unifying method is provided for the construction of tilings by
tiles obtained from the attractor of an iterated function system (IFS). Many
examples appearing in the literature in ad hoc ways, as well as new examples,
can be constructed by this method. These tilings can be used to extend a
fractal transformation defined on the attractor of a contractive IFS to a
fractal transformation on the entire space upon which the IFS acts.


title:
Triple point induced by targeted autonomization on interdependent scale
  free networks

abstract:
  Many man-made networks support each other to provide efficient services and
resources to the customers, despite that this support produces a strong
interdependency between the individual networks. Thus an initial failure of a
fraction $1-p$ of nodes in one network, exposes the system to cascade of
failures and, as a consequence, to a full collapse of the overall system.
Therefore it is important to develop efficient strategies to avoid the collapse
by increasing the robustness of the individual networks against failures. Here,
we provide an exact theoretical approach to study the evolution of the cascade
of failures on interdependent networks when a fraction $\alpha$ of the nodes
with higher connectivity in each individual network are autonomous. With this
pattern of interdependency we found, for pair of heterogeneous networks, two
critical percolation thresholds that depend on $\alpha$, separating three
regimes with very different network's final sizes that converge into a triple
point in the plane $p-\alpha$. Our findings suggest that the heterogeneity of
the networks represented by high degree nodes is the responsible of the rich
phase diagrams found in this and other investigations.


title:
The non-magnetic collapsed tetragonal phase of CaFe2As2 and
  superconductivity in the iron pnictides

abstract:
  The relationship between antiferromagnetic spin fluctuations and
superconductivity has become a central topic of research in studies of
superconductivity in the iron pnictides. We present unambiguous evidence of the
absence of magnetic fluctuations in the non-superconducting collapsed
tetragonal phase of CaFe2As2 via inelastic neutron scattering time-of-flight
data, which is consistent with the view that spin fluctuations are a necessary
ingredient for unconventional superconductivity in the iron pnictides. We
demonstrate that the collapsed tetragonal phase of CaFe2As2 is non-magnetic,
and discuss this result in light of recent reports of high-temperature
superconductivity in the collapsed tetragonal phase of closely related
compounds.


title: Evidence for gravitons from decoherence by bremsstrahlung

abstract:
  It is thought that gravitons are impossible to detect, even with the
technological ability to construct experiments larger than Jupiter. However, in
principle it is possible to detect the emission of single gravitons through the
decoherence of relativistic Planck-mass superpositions by gravitational
bremsstrahlung. Although enormous experimental challenges ensure that such an
experiment will not be achievable in the foreseeable future, this possibility
suggests that gravitons are not forever outside our empirical grasp. It is also
evidence that decoherence as a detection method has untapped potential.


title: New addition formula for the little $q$-Bessel functions

abstract:
  Starting from the addition formula for little $q$-Jacobi polynomials, we
derive a new addition formula for the little $q$-Bessel functions. The result
is obtained by the use of a limit transition. We also establish a product
formula for little $q$-Bessel functions with a positive and symmetric kernel.


title: Quest-V: A Virtualized Multikernel for Safety-Critical Real-Time Systems

abstract:
  Modern processors are increasingly featuring multiple cores, as well as
support for hardware virtualization. While these processors are common in
desktop and server-class computing, they are less prevalent in embedded and
real-time systems. However, smartphones and tablet PCs are starting to feature
multicore processors with hardware virtualization. If the trend continues, it
is possible that future real-time systems will feature more sophisticated
processor architectures. Future automotive or avionics systems, for example,
could replace complex networks of uniprocessors with consolidated services on a
smaller number of multicore processors. Likewise, virtualization could be used
to isolate services and increase the availability of a system even when
failures occur.
  This paper investigates whether advances in modern processor technologies
offer new opportunities to rethink the design of real-time operating systems.
We describe some of the design principles behind Quest-V, which is being used
as an exploratory vehicle for real-time system design on multicore processors
with hardware virtualization capabilities. While not all embedded systems
should assume such features, a case can be made that more robust,
safety-critical systems can be built to use hardware virtualization without
incurring significant overheads.


title:
Using an artificial electric field to create the analog of the red spot
  of Jupiter in light-heavy Fermi-Fermi mixtures of ultracold atoms

abstract:
  Time-of-flight images are a common tool in ultracold atomic experiments,
employed to determine the quasimomentum distribution of the interacting
particles. If one introduces a constant artificial electric field, then the
quasimomentum distribution evolves in time as Bloch oscillations are generated
in the system and then damped showing a complex series of patterns.
Surprisingly, in different mass Fermi-Fermi mixtures, these patterns can
survive for long times, and resemble the stability of the red spot of Jupiter
in classical nonlinear hydrodynamics. In this work, we illustrate the rich
phenomena that can be seen in these driven quantum systems.


title:
Embedded Lensing Time Delays, the Fermat Potential, and the Integrated
  Sachs-Wolfe Effect

abstract:
  We derive the Fermat potential for a spherically symmetric lens embedded in
an FLRW cosmology and use it to investigate the late-time integrated
Sachs-Wolfe (ISW) effect, i.e., secondary temperature fluctuations in the
cosmic microwave background (CMB) caused by individual large scale clusters and
voids. We present a simple analytical expression for the temperature
fluctuation in the CMB across such a lens as a derivative of the lens' Fermat
potential. This formalism is applicable to both linear and nonlinear density
evolution scenarios, to arbitrarily large density contrasts, and to all open
and closed background cosmologies. It is much simpler to use and makes the same
predictions as conventional approaches. In this approach the total temperature
fluctuation can be split into a time-delay part and an evolutionary part. Both
parts must be included for cosmic structures that evolve and both can be
equally important. We present very simple ISW models for cosmic voids and
galaxy clusters to illustrate the ease of use of our formalism. We use the
Fermat potentials of simple cosmic void models to compare predicted ISW effects
with those recently extracted from WMAP and \emph{Planck} data by stacking
large cosmic voids using the aperture photometry method. If voids in the local
universe with large density contrasts are no longer evolving we find that the
time delay contribution alone predicts values consistent with the measurements.
However, we find that for voids still evolving linearly, the evolutionary
contribution cancels a significant part of the time delay contribution and
results in predicted signals that are much smaller than recently observed.


title: Gravitino LSP and leptogenesis after the first LHC results

abstract:
  Supersymmetric scenarios where the lightest superparticle (LSP) is the
gravitino are an attractive alternative to the widely studied case of a
neutralino LSP. A strong motivation for a gravitino LSP arises from the
possibility of achieving higher reheating temperatures and thus potentially
allow for thermal leptogenesis. The predictions for the primordial abundances
of light elements in the presence of a late decaying next-to-LSP (NSLP) as well
as the currently measured dark matter abundance allow us to probe the
cosmological viability of such a scenario. Here we consider a gravitino-stau
scenario. Utilizing a pMSSM scan we work out the implications of the 7 and 8
TeV LHC results as well as other experimental and theoretical constraints on
the highest reheating temperatures that are cosmologically allowed. Our
analysis shows that points with T_R>10^9 GeV survive only in a very particular
corner of the SUSY parameter space. Those spectra feature a distinct signature
at colliders that could be looked at in the upcoming LHC run.


title: Kaluza-Klein Towers on General Manifolds

abstract:
  A higher-dimensional universe with compactified extra dimensions admits a
four-dimensional description consisting of an infinite Kaluza-Klein tower of
fields. We revisit the problem of describing the free part of the complete
Kaluza-Klein tower of gauge fields, p-forms, gravity, and flux
compactifications. In contrast to previous studies, we work with a generic
internal manifold of any dimension, completely at the level of the action, in a
gauge invariant formulation, and without resorting to the equations of motion
or analysis of propagators. We demonstrate that the physical fields and
Stuckelberg fields are naturally described by ingredients of the Hodge
decomposition and its analog for symmetric tensors. The spectrum of states and
stability conditions, in terms of the eigenvalues of various Laplacians on the
internal manifold, is easily read from the action.


title:
Haldane Statistics for Fractional Chern Insulators with an Arbitrary
  Chern number

abstract:
  In this paper we provide analytical counting rules for the ground states and
the quasiholes of fractional Chern insulators with an arbitrary Chern number.
We first construct pseudopotential Hamiltonians for fractional Chern
insulators. We achieve this by mapping the lattice problem to the lowest Landau
level of a multicomponent continuum quantum Hall system with specially
engineered boundary conditions. We then analyze the thin-torus limit of the
pseudopotential Hamiltonians, and extract counting rules (generalized Pauli
principles, or Haldane statistics) for the degeneracy of its zero modes in each
Bloch momentum sector.


title:
Equation of state, universal profiles, scaling and macroscopic quantum
  effects in Warm Dark Matter galaxies

abstract:
  The Thomas-Fermi approach to galaxy structure determines selfconsistently and
nonlinearly the gravitational potential of the fermionic WDM particles given
their quantum distribution function f(E). Galaxy magnitudes as the halo radius
r_h, mass M_h, velocity dispersion and phase space density are obtained. We
derive the general equation of state for galaxies (relation between the
pressure and the density), and provide an analytic expression. This clearly
exhibits two regimes: (i) Large diluted galaxies for M_h > 2.3 10^6 Msun
corresponding to temperatures T_0 > 0.017 K, described by the classical self
gravitating WDM Boltzman regime and (ii) Compact dwarf galaxies for 1.6 10^6
Msun > M_h>M_{h,min}=30000 (2keV/m)^{16/5} Msun, T_0<0.011 K described by the
quantum fermionic WDM regime. The T_0=0 degenerate quantum limit predicts the
most compact and smallest galaxy (minimal radius and mass M_{h,min}). All
magnitudes in the diluted regime exhibit square root of M_h scaling laws and
are universal functions of r/r_h when normalized to their values at the origin
or at r_h. We find that universality in galaxies (for M_h > 10^6 Msun) reflects
the WDM perfect gas behaviour. These theoretical results contrasted to robust
and independent sets of galaxy data remarkably reproduce the observations. For
the small galaxies, 10^6>M_h>M_{h,min} corresponding to effective temperatures
T_0 < 0.017 K, the equation of state is galaxy dependent and the profiles are
no more universal. These non-universal properties in small galaxies account to
the quantum physics of the WDM fermions in the compact regime. Our results are
independent of any WDM particle physics model, they only follow from the
gravitational interaction of the WDM particles and their fermionic quantum
nature.


title: Ultra-stripped Type Ic supernovae from close binary evolution

abstract:
  Recent discoveries of weak and fast optical transients raise the question of
their origin. We investigate the minimum ejecta mass associated with
core-collapse supernovae (SNe) of Type Ic. We show that mass transfer from a
helium star to a compact companion can produce an ultra-stripped core which
undergoes iron core collapse and leads to an extremely fast and faint SN Ic. In
this Letter, a detailed example is presented in which the pre-SN stellar mass
is barely above the Chandrasekhar limit, resulting in the ejection of only
~0.05-0.20 M_sun of material and the formation of a low-mass neutron star. We
compute synthetic light curves of this case and demonstrate that SN 2005ek
could be explained by our model. We estimate that the fraction of such
ultra-stripped to all SNe could be as high as 0.001-0.01. Finally, we argue
that the second explosion in some double neutron star systems (for example, the
double pulsar PSR J0737-3039B) was likely associated with an ultra-stripped SN
Ic.


title: Generalized geometry of two-dimensional vacua

abstract:
  We derive the conditions for unbroken supersymmetry for a Mink_2, (2,0)
vacuum, arising from Type II supergravity on a compact eight-dimensional
manifold M_8. When specialized to internal manifolds enjoying SU(4)xSU(4)
structure the resulting system is elegantly rewritten in terms of generalized
complex geometry. This particular class of vacua violates the correspondence
between supersymmetry conditions and calibrations conditions of D branes
(supersymmetry-calibrations correspondence). Our analysis includes and extends
previous results about the failure of the supersymmetry-calibrations
correspondence, and confirms the existence of a precise relation between such a
failure and a subset of the supersymmetry conditions.


title:
Confirmation of Small Dynamical and Stellar Masses for Extreme Emission
  Line Galaxies at z~2

abstract:
  Spectroscopic observations from the Large Binocular Telescope and the Very
Large Telescope reveal kinematically narrow lines (~50 km/s) for a sample of 14
Extreme Emission Line Galaxies (EELGs) at redshifts 1.4 < z < 2.3. These
measurements imply that the total dynamical masses of these systems are low (<
3x10^9 M_sun). Their large [O III] 5007 equivalent widths (500-1100 Angstroms)
and faint blue continuum emission imply young ages of 10-100 Myr and stellar
masses of 10^8-10^9 M_sun, confirming the presence of a violent starburst. The
dynamical masses represent the first such determinations for low-mass galaxies
at z > 1. The stellar mass formed in this vigorous starburst phase represents a
large fraction of the total (dynamical) mass, without a significantly massive
underlying population of older stars. The occurrence of such intense events in
shallow potentials strongly suggests that supernova-driven winds must be of
critical importance in the subsequent evolution of these systems.


title: Found: The Progenitors of AM CVn and Supernovae .Ia

abstract:
  We present optical and X-ray observations of two tidally distorted, extremely
low-mass white dwarfs (WDs) with massive companions. There is no evidence of
neutron stars in our Chandra and XMM observations of these objects. SDSS
J075141.18$-$014120.9 (J0751) is an eclipsing double WD binary containing a
0.19 Msol WD with a 0.97 Msol companion in a 1.9 h orbit. J0751 becomes the
fifth eclipsing double WD system currently known. SDSS J174140.49+652638.7
(J1741) is another binary containing a 0.17 Msol WD with an unseen M > 1.11
Msol WD companion in a 1.5 h orbit. With a mass ratio of ~0.1, J1741 will have
stable mass transfer through an accretion disk and turn into an interacting AM
Canum Venaticorum (AM CVn) system in the next ~160 Myr. With a mass ratio of
0.2, J0751 is likely to follow a similar evolutionary path. These are the first
known AM CVn progenitor binary systems and they provide important constraints
on the initial conditions for AM CVn. Theoretical studies suggest that both
J0751 and J1741 may create thermonuclear supernovae in ~10^8 yr, either .Ia or
Ia. Such explosions can account for ~1% of the Type Ia supernova rate.


title: Stability and Spectrum of Compactifications on Product Manifolds

abstract:
  We study the spectrum and perturbative stability of Freund-Rubin
compactifications on $M_p \times M_{Nq}$, where $M_{Nq}$ is itself a product of
$N$ $q$-dimensional Einstein manifolds. The higher-dimensional action has a
cosmological term $\Lambda$ and a $q$-form flux, which individually wraps each
element of the product; the extended dimensions $M_p$ can be anti-de Sitter,
Minkowski, or de Sitter. We find the masses of every excitation around this
background, as well as the conditions under which these solutions are stable.
This generalizes previous work on Freund-Rubin vacua, which focused on the
$N=1$ case, in which a $q$-form flux wraps a single $q$-dimensional Einstein
manifold. The $N=1$ case can have a classical instability when the
$q$-dimensional internal manifold is a product---one of the members of the
product wants to shrink while the rest of the manifold expands. Here, we will
see that individually wrapping each element of the product with a lower-form
flux cures this cycle-collapse instability. The $N=1$ case can also have an
instability when $\Lambda>0$ and $q\ge4$ to shape-mode perturbations; we find
the same instability in compactifications with general $N$, and show that it
even extends to cases where $\Lambda\le0$. On the other hand, when $q=2$ or 3,
the shape modes are always stable and there is a broad class of AdS and de
Sitter vacua that are perturbatively stable to all fluctuations.


title:
The Gas-Rich Circumbinary Disk of HR 4049 I: A Detailed Study of the
  Mid-Infrared Spectrum

abstract:
  We present a detailed analysis of the mid-infrared spectrum of the peculiar
evolved object HR 4049. The full Spitzer-IRS high-resolution spectrum shows a
wealth of emission with prominent features from CO$_2$ and H$_2$O and possible
contributions from HCN and OH. We model the molecular emission and find that it
originates from a massive ($M \gtrsim 8 \times 10^{-3}$ M$_{\odot}$), warm
($T_{\rm ex} \approx 500$ K) and radially extended gas disk that is optically
thick at infrared wavelengths. We also report less enrichment in $^{17}$O and
$^{18}$O than previously found and a comparison of the Spitzer observations to
earlier data obtained by ISO-SWS reveals that the CO$_2$ flux has more than
doubled in 10 years time, indicating active and ongoing chemical evolution in
the circumbinary disk. If the gas originates from interaction between the
stellar wind and the dust, this suggests that the dust could be oxygen-rich in
nature. The molecular gas plays a crucial role in the thermal properties of the
circumbinary disk by allowing visible light to heat the dust and then trapping
the infrared photons emitted by the dust. This results in higher temperatures
and a more homogeneous temperature structure in the disk.


title:
An ALMA Survey of Submillimetre Galaxies in the Extended Chandra Deep
  Field South: The Far-Infrared Properties of SMGs

abstract:
  We exploit ALMA 870um (345GHz) observations of submillimetre sources in the
Extended Chandra Deep Field South to investigate the far-infrared properties of
high-redshift submillimetre galaxies (SMGs). Using the precisely located 870um
ALMA positions of 99 SMGs, together with 24um and radio imaging of this field,
we deblend the Herschel/SPIRE imaging of this region to extract their
far-infrared fluxes and colours. The median photometric redshifts for ALMA LESS
(ALESS) SMGs which are detected in at least two SPIRE bands increases with
wavelength of the peak in their SEDs, with z=2.3+/-0.2, 2.5+/-0.3 and 3.5+/-0.5
for the 250, 350 and 500-um peakers respectively. We find that 34 ALESS SMGs do
not have a >3-sigma counterpart at 250, 350 or 500-um. These galaxies have a
median photometric redshift of z=3.3+/-0.5, which is higher than the full ALESS
SMG sample; z=2.5+/-0.2. Using the photometric redshifts together with the
250-870um photometry, we estimate the far-infrared luminosities and
characteristic dust temperature of each SMG. The median infrared luminosity of
the S_870um>2mJy SMGs is L_IR=(3.0+/-0.3)x10^{12}Lo(SFR=300+/-30Mo/yr). At a
fixed luminosity, the characteristic dust temperature of these high-redshift
SMGs is 2-3K lower than comparably luminous galaxies at z=0, reflecting the
more extended star formation occurring in these systems. By extrapolating the
870um number counts to S_ 870um=1mJy, we show that the contribution of
S_870um>1mJy SMGs to the cosmic star formation budget is 20% of the total over
the redshift range z~1-4. We derive a median dust mass for these SMGs of
M_d=(3.6+/-0.3)x10^8Mo and by adopting an appropriate gas-to-dust ratio, we
estimate an average molecular mass of M_H2=(4.2+/-0.4)x10^{10}Mo. Finally, we
use our estimates of the H2 masses to show that SMGs with S_870um>1mJy contain
~10% of the z~2 volume-averaged H2 mass density at this epoch.


title:
An ALMA Survey of Submillimeter Galaxies in the Extended Chandra Deep
  Field South: The Redshift Distribution and Evolution of Submillimeter
  Galaxies

abstract:
  We present the first photometric redshift distribution for a large unbiased
sample of 870um selected submillimeter galaxies (SMGs) with robust
identifications based on observations with the Atacama Large Millimeter Array
(ALMA). In our analysis we consider 96 SMGs in the Extended Chandra Deep Field
South, 77 of which have 4-19 band, optical-near-infrared, photometry. We model
the Spectral Energy Distributions (SEDs) for these 77 SMGs, deriving a median
photometric redshift of z=2.3+/-0.1. The remaining 19 SMGs have insufficient
optical or near-infrared photometry to derive photometric redshifts, but a
stacking analysis of IRAC and Herschel observations confirms they are not
spurious. Assuming these sources have an absolute H-band magnitude distribution
comparable to that of a complete sample of z~1-2 SMGs, we demonstrate that the
undetected SMGs lie at higher redshifts, raising the median redshift for SMGs
to z=2.5+/-0.2. More critically we show that the proportion of galaxies
undergoing an SMG phase at z>3 is 35+/-5% of the total population. We derive a
median stellar mass for SMGs of Mstar=(8+/-1)x10^10Mo, but caution that there
are significant systematic uncertainties in our stellar mass estimate, up to x5
for individual sources. We compare our sample of SMGs to a volume-limited,
morphologically classified sample of ellipticals in the local Universe.
Assuming the star formation activity in SMGs has a timescale of ~100Myr we show
that their descendants at z~0 would have a space density and M_H distribution
which are in good agreement with those of local ellipticals. In addition the
inferred mass-weighted ages of the local ellipticals broadly agree with the
look-back times of the SMG events. Taken together, these results are consistent
with a simple model that identifies SMGs as events that form most of the stars
seen in the majority of luminous elliptical galaxies at the present day.


title:
An ALMA Survey of Submillimeter Galaxies in the Extended Chandra Deep
  Field South: The AGN Fraction and X-ray Properties of Submillimeter Galaxies

abstract:
  The large gas and dust reservoirs of submm galaxies (SMGs) could potentially
provide ample fuel to trigger an Active Galactic Nucleus (AGN), but previous
studies of the AGN fraction in SMGs have been controversial largely due to the
inhomogeneity and limited angular resolution of the available submillimeter
surveys. Here we set improved constraints on the AGN fraction and X-ray
properties of the SMGs with ALMA and Chandra observations in the Extended
Chandra Deep Field-South (E-CDF-S). This study is the first among similar works
to have unambiguously identified the X-ray counterparts of SMGs; this is
accomplished using the fully submm-identified, statistically reliable SMG
catalog with 99 SMGs from the ALMA LABOCA E-CDF-S Submillimeter Survey (ALESS).
We found 10 X-ray sources associated with SMGs (median redshift z = 2.3), of
which 8 were identified as AGNs using several techniques that enable
cross-checking. The other 2 X-ray detected SMGs have levels of X-ray emission
that can be plausibly explained by their star-formation activity. 6 of the 8
SMG-AGNs are moderately/highly absorbed, with N_H > 10e23 cm-2. An analysis of
the AGN fraction, taking into account the spatial variation of X-ray
sensitivity, yields an AGN fraction of 17+16-6% for AGNs with rest-frame 0.5-8
keV absorption-corrected luminosity >7.8x10e42 erg s-1; we provide estimated
AGN fractions as a function of X-ray flux and luminosity. ALMA's high angular
resolution also enables direct X-ray stacking at the precise positions of SMGs
for the first time, and we found 4 potential SMG-AGNs in our stacking sample.


title:
Dwarfs walking in a row. The filamentary nature of the NGC3109
  association

abstract:
  We re-consider the association of dwarf galaxies around NGC3109, whose known
members were NGC3109, Antlia, Sextans A and Sextans B, based on a new updated
list of nearby galaxies and the most recent data. We find that the original
members of the NGC3109 association, together with the recently discovered and
adjacent dwarf irregular Leo P, form a very tight and elongated configuration
in space. All these galaxies lie within ~100 kpc of a line that is ~1070 kpc
long, from one extreme (NGC3109) to the other (Leo P), and they show a gradient
in the Local Group standard of rest velocity with a total amplitude of 43 km/s
Mpc and a r.m.s. scatter of just 16.8 km/s. It is shown that the reported
configuration is exceptional given the known dwarf galaxies in the Local Group
and its surroundings. We conclude that (a) Leo P is likely an additional member
of the NGC3109 association, and (b) the association is highly ordered in space
and velocity, and it is very elongated, suggesting that it has been originated
by a tidal interaction or it was accreted as a filamentary sub-structure.


title: Pan-STARRS1: Galaxy Clustering in the Small Area Survey 2

abstract:
  The Pan-STARRS1 survey is currently obtaining imaging in 5 bands (grizy) for
the $3\pi$ steradian survey, one of the largest optical surveys ever conducted.
The finished survey will have spatially varying depth, due to the survey
strategy. This paper presents a method to correct galaxy number counts and
galaxy clustering for this potential systematic based on a simplified signal to
noise measurement. A star and galaxy separation method calibrated using
realistic synthetic images is also presented, along with an approach to mask
bright stars. By using our techniques on a ~69 sq. degree region of science
verification data this paper shows PS1 measurements of the two point angular
correlation function as a function of apparent magnitude agree with
measurements from deeper, smaller surveys. Clustering measurements appear
reliable down to a magnitude limit of rps<22.5. Additionally, stellar
contamination and false detection issues are discussed and quantified. This
work is the second of two papers which pave the way for the exploitation of the
full $3\pi$ survey for studies of large scale structure.


title: NGC1277: a massive compact relic galaxy in the nearby Universe

abstract:
  As early as 10 Gyr ago, galaxies with more than 10^11 Msun in stars already
existed. While most of these massive galaxies must have subsequently
transformed through on-going star formation and mergers with other galaxies, a
small fraction (<0.1%) may have survived untouched till today. Searches for
such relic galaxies, useful windows to explore the early Universe, have been
inconclusive to date: galaxies with masses and sizes like those observed at
high redshift (M*>10^11 Msun; Re<1.5 kpc) have been found in the local
Universe, but their stars are far too young for the galaxy to be a relic
galaxy. This paper explores the first case of a nearby galaxy, NGC1277 (in the
Perseus cluster at a distance of 73 Mpc), which fulfills all the criteria to be
considered a relic galaxy. Using deep optical spectroscopy, we derive the star
formation history along the structure of the galaxy: the stellar populations
are uniformly old (>10 Gyr) with no evidence for more recent star formation
episodes. The metallicity of their stars is super-solar ([Fe/H]=0.20+-0.04) and
alpha enriched ([alpha/Fe]=0.4+-0.1). This suggests a very short formation time
scale for the bulk of stars of this galaxy. This object also rotates very fast
(Vrot~300 km/s) and has a large velocity dispersion (sigma>300 km/s). NGC1277
will allow future explorations in full detail of properties such as the
structure, internal dynamics, metallicity, dust content and initial mass
function at around 10-12 Gyr back in time when the first massive galaxies were
built.


title: The Pan-STARRS1 Small Area Survey 2

abstract:
  The Pan-STARRS1 survey is acquiring multi-epoch imaging in 5 bands (grizy)
over the entire sky north of declination -30deg (the $3\pi$ survey). In July
2011 a test area of about 70 sq.deg. was observed to the expected final depth
of the main survey. In this, the first of a series of papers targetting the
galaxy count and clustering properties of the combined multi-epoch test area
data, we present a detailed investigation into the depth of the survey and the
reliability of the Pan-STARRS1 analysis software. We show that the Pan-STARRS1
reduction software can recover the properties of fake sources, and show good
agreement between the magnitudes measured by Pan-STARRS1 and those from Sloan
Digital Sky Survey. We also examine the number of false detections apparent in
the Pan-STARRS1 data. Our comparisons show that the test area survey is
somewhat deeper than the Sloan Digital Sky Survey in all bands, and, in
particular, the z band approaches the depth of the stacked Sloan Stripe 82
data.


title:
Vector-like Fields, Messenger Mixing and the Higgs mass in Gauge
  Mediation

abstract:
  In order to generate, in the context of gauge mediation, a Higgs mass around
126 GeV that avoids the little hierarchy problem, we explore a set of models
where the messengers are directly coupled to new vector-like fields at the TeV
scale in addition to the usual low energy degrees of freedom. We find that in
this context, stop masses lighter than 2 TeV and large $A$-terms are generated,
thereby improving issues of fine tuning.


title: Fermionic variations on AdS/CFT themes

abstract:
  This thesis aims to explore the effects caused by the presence of Grassmann
numbers in two different frameworks derived from AdS/CFT correspondence: purely
fermionic sigma-models and fluid/gravity correspondence. The first analysis we
present deals with fermionic sigma-models constructed by means of purely
fermionic coset spaces, namely we consider models with anticommuting
target-space fields only. We notice that the Grassmanian behaviour of the
fields implies several simplifications when we derive the action and the
radiative corrections, however it provides obstructions to some
supercoordinates transformations. In the second part of the work we extend the
fluid/gravity correspondence by considering supergravity theories in the bulk
and computing the black hole superpartner. The resulting metric is a black hole
solution of the supergravity equations of motion and its associated charges and
entropy depend upon Grassmann numbers. Moreover by fluid/gravity techniques we
find that also the fluid dynamics parameters, such as the temperature and the
velocity, are in general affected by Grassmann numbers.


title:
Fractional Chern insulators with strong interactions far exceeding
  bandgaps

abstract:
  We study two models for spinless fermions featuring topologically non-trivial
bands characterized by Chern numbers $C=\pm1$ at fractional filling. Using
exact diagonalization, we show that, even for infinitely strong
nearest-neighbor repulsion, the ground states of these models belong to the
recently discovered class of quantum liquids called fractional Chern insulators
(FCI). We thus establish that FCI states can arise even if interaction
strengths are arbitrarily larger than the noninteracting band gap, going beyond
the limits in which FCI states have been previously studied. The
strong-coupling FCI states therefore depart from the usual isolated-band
picture that parallels the fractional quantum Hall effect in Landau levels and
demonstrate how a topologically ordered state can arise in a truly multiband
system.


title: A multiobjective optimization approach to statistical mechanics

abstract:
  Optimization problems have been the subject of statistical physics
approximations. A specially relevant and general scenario is provided by
optimization methods considering tradeoffs between cost and efficiency, where
optimal solutions involve a compromise between both. The theory of Pareto (or
multi objective) optimization provides a general framework to explore these
problems and find the space of possible solutions compatible with the
underlying tradeoffs, known as the {\em Pareto front}. Conflicts between
constraints can lead to complex landscapes of Pareto optimal solutions with
interesting implications in economy, engineering, or evolutionary biology.
Despite their disparate nature, here we show how the structure of the Pareto
front uncovers profound universal features that can be understood in the
context of thermodynamics. In particular, our study reveals that different
fronts are connected to different classes of phase transitions, which we can
define robustly, along with critical points and thermodynamic potentials. These
equivalences are illustrated with classic thermodynamic examples.


title:
Narrow Band X-ray Photometry as a Tool for Studying Galaxy and Cluster
  Mass Distributions

abstract:
  We explore the utility of narrow band X-ray surface photometry as a tool for
making fully Bayesian, hydrostatic mass measurements of clusters of galaxies,
groups and early-type galaxies. We demonstrate that it is sufficient to measure
the surface photometry with the Chandra X-ray observatory in only three (rest
frame) bands (0.5--0.9 keV, 0.9--2.0 keV and 2.0--7.0 keV) in order to
constrain the temperature, density and abundance of the hot interstellar medium
(ISM). Adopting parametrized models for the mass distribution and radial
entropy profile and assuming spherical symmetry, we show that the constraints
on the mass and thermodynamic properties of the ISM that are obtained by
fitting data from all three bands simultaneously are comparable to those
obtained by fitting similar models to the temperature and density profiles
derived from spatially resolved spectroscopy, as is typically done. We
demonstrate that the constraints can be significantly tightened when exploiting
a recently derived, empirical relationship between the gas fraction and the
entropy profile at large scales, eliminating arbitrary extrapolations at large
radii. This "Scaled Adiabatic Model" (ScAM) is well suited to modest
signal-to-noise data, and we show that accurate, precise measurements of the
global system properties are inferred when employing it to fit data from even
very shallow, snapshot X-ray observations. The well-defined asymptotic
behaviour of the model also makes it ideally suited for use in
Sunyaev-Zeldovich studies of galaxy clusters.


title: New bounds for $\psi(x)$

abstract:
  In this article we provide new explicit Chebyshev's bounds for the prime
counting function $\psi(x)$. The proof relies on two new arguments: smoothing
the prime counting function which allows to generalize the previous approaches,
and a new explicit zero density estimate for the zeros of the Riemann zeta
function.


title:
Picosecond Dynamic Heterogeneity, Hopping and Johari-Goldstein
  Relaxation in Glassforming Liquids

abstract:
  We show that incoherent quasi-elastic neutron scattering (QENS) from
molecular liquids reveals a two-state dynamic heterogeneity on a 1 ps
timescale, where molecules are either highly confined or are free to undergo
relatively large excursions. Data ranging from deep in the glassy state to well
above the melting point allows us to observe temperature-dependent population
levels and exchange between these two states. A simple physical picture emerges
from this data, combined with published work, that provides a mechanism for
"hopping" and for the Johari-Goldstein ($\beta_{JG}$) relaxation, and allows us
to accurately calculate the diffusion coefficient, $D_T$, and characteristic
times for $\alpha$, and $\beta_{JG}$ relaxations from ps timescale neutron
data.