title: Multivariate regression and fit function uncertainty

abstract:
  This article describes a multivariate polynomial regression method where the
uncertainty of the input parameters are approximated with Gaussian
distributions, derived from the central limit theorem for large weighted sums,
directly from the training sample. The estimated uncertainties can be
propagated into the optimal fit function, as an alternative to the statistical
bootstrap method. This uncertainty can be propagated further into a loss
function like quantity, with which it is possible to calculate the expected
loss function, and allows to select the optimal polynomial degree with
statistical significance. Combined with simple phase space splitting methods,
it is possible to model most features of the training data even with low degree
polynomials or constants.


title:
Criticality in a disordered quantum antiferromagnet by neutron
  diffraction

abstract:
  Field-induced magnetic ordering in the structurally disordered quantum
magnets Ni(Cl$_{1-x}$Br$_x$)$_2$$\cdot$4SC(NH$_2$)$_2$, $x=8$% and 13%, is
studied by means of neutron diffraction. The order parameter critical exponent
is found to be very close to its value $\beta=0.5$ expected for magnetic
Bose-Einstein condensation in the absence of disorder. This result applies to
temperatures down to 40 mK, and a 1 T range in magnetic field. The crossover
exponent is found to be $\phi \sim 0.4$, for temperature ranges as small as 300
mK. Possible reasons for a discrepancy with recent numerical simulations and
bulk measurements are discussed.


title: A Simple Method for Generating Electromagnetic Oscillations

abstract:
  We propose a novel approach to the generation of electromagnetic oscillations
by means of a low-frequency pumping of two coupled linear oscillators. A theory
of such generation mechanism is proposed, and its feasibility is demonstrated
by using coupled RLC oscillators. A comparison of the theoretical results and
the experimental data is presented.


title: Distributed Control with Low-Rank Coordination

abstract:
  A common approach to distributed control design is to impose sparsity
constraints on the controller structure. Such constraints, however, may greatly
complicate the control design procedure. This paper puts forward an alternative
structure, which is not sparse yet might nevertheless be well suited for
distributed control purposes. The structure appears as the optimal solution to
a class of coordination problems arising in multi-agent applications. The
controller comprises a diagonal (decentralized) part, complemented by a
rank-one coordination term. Although this term relies on information about all
subsystems, its implementation only requires a simple averaging operation.


title:
Higher Dimensional Vortex Standing Waves for Nonlinear Schr{\"o}dinger
  Equations

abstract:
  We study standing wave solutions to nonlinear Schr{\"o}dinger equations, on a
manifold with a rotational symmetry, which transform in a natural fashion under
the group of rotations. We call these vortex solutions. They are higher
dimensional versions of vortex standing waves that have been studied on the
Euclidean plane. We focus on two types of vortex solutions, which we call
spherical vortices and axial vortices.


title:
Integrated density of states for Poisson-Schr\"odinger perturbations of
  subordinate Brownian motions on the Sierpi\'nski gasket

abstract:
  We prove the existence of the integrated density of states for subordinate
Brownian motions in presence of the Poissonian random potentials on the
Sierpi\'nski gasket.


title: Inhomogeneity implies Accelerated Expansion

abstract:
  The Einstein equations for an inhomogeneous irrotational dust universe are
analysed. A set of mild assumptions, all of which are shared by the standard
FLRW type scenarios, results in a model that depends only on the distribution
of scalar spatial curvature. If the shape of this distribution is made to fit
the structure of the present universe, with most of the matter in galaxy
clusters and very little in the voids that will eventually dominate the volume,
then there is a period of accelerated expansion after cluster formation, even
in the absence of a cosmological constant.


title: Universal features of dynamic heterogeneity in supercooled liquids

abstract:
  A few years ago it was showed that some systems that have very similar local
structure, as quantified by the pair correlation function, exhibit vastly
different slowing down upon supercooling [L. Berthier and G. Tarjus, Phys. Rev.
Lett. 103, 170601 (2009); U.R. Pedersen, T.B. Schroder and J.C. Dyre, Phys.
Rev. Lett. 105, 157801 (2010)]. Recently, a more subtle structural quantity,
the so-called "point-to-set" length, was found to reliably correlate with the
average dynamics [G.M. Hocky, T.E. Markland and D.R. Reichman, Phys. Rev. Lett.
108, 225506 (2012)]. Here we use computer simulations to examine the behavior
of fluctuations around the average dynamics, i.e., dynamic heterogeneity. We
study five model glass-forming liquids: three model liquids used in previous
works and two additional model liquids with finite range interactions. Some of
these systems have very similar local structure but vastly different dynamics.
We show that for all these systems the spatial extent and the anisotropy of
dynamic heterogeneity correlate very well with the average dynamics.


title: Persistent Homology Transform for Modeling Shapes and Surfaces

abstract:
  In this paper we introduce a statistic, the persistent homology transform
(PHT), to model surfaces in $\mathbb{R}^3$ and shapes in $\mathbb{R}^2$. This
statistic is a collection of persistence diagrams - multiscale topological
summaries used extensively in topological data analysis. We use the PHT to
represent shapes and execute operations such as computing distances between
shapes or classifying shapes. We prove the map from the space of simplicial
complexes in $\mathbb{R}^3$ into the space spanned by this statistic is
injective. This implies that the statistic is a sufficient statistic for
probability densities on the space of piecewise linear shapes. We also show
that a variant of this statistic, the Euler Characteristic Transform (ECT),
admits a simple exponential family formulation which is of use in providing
likelihood based inference for shapes and surfaces. We illustrate the utility
of this statistic on simulated and real data.


title:
Rational Cayley inner Herglotz-Agler functions: positive-kernel
  decompositions and transfer-function realizations

abstract:
  The Bessmertny\u{\i} class consists of rational matrix-valued functions of
$d$ complex variables representable as the Schur complement of a block of a
linear pencil $A(z)=z_1A_1+\cdots+z_dA_d$ whose coefficients $A_k$ are positive
semidefinite matrices. We show that it coincides with the subclass of rational
functions in the Herglotz-Agler class over the right poly-halfplane which are
homogeneous of degree one and which are Cayley inner. The latter means that
such a function is holomorphic on the right poly-halfplane and takes
skew-Hermitian matrix values on $(i\mathbb{R})^d$, or equivalently, is the
double Cayley transform (over the variables and over the matrix values) of an
inner function on the unit polydisk.
  Using Agler-Knese's characterization of rational inner Schur-Agler functions
on the polydisk, extended now to the matrix-valued case, and applying
appropriate Cayley transformations, we obtain characterizations of
matrix-valued rational Cayley inner Herglotz-Agler functions both in the
setting of the polydisk and of the right poly-halfplane, in terms of
transfer-function realizations and in terms of positive-kernel decompositions.
In particular, we extend Bessmertny\u{\i}'s representation to rational Cayley
inner Herglotz-Agler functions on the right poly-halfplane, where a linear
pencil $A(z)$ is now in the form $A(z)=A_0+z_1A_1+\cdots +z_dA_d$ with $A_0$
skew-Hermitian and the other coefficients $A_k$ positive semidefinite matrices.


title:
Janus II: a new generation application-driven computer for spin-system
  simulations

abstract:
  This paper describes the architecture, the development and the implementation
of Janus II, a new generation application-driven number cruncher optimized for
Monte Carlo simulations of spin systems (mainly spin glasses). This domain of
computational physics is a recognized grand challenge of high-performance
computing: the resources necessary to study in detail theoretical models that
can make contact with experimental data are by far beyond those available using
commodity computer systems. On the other hand, several specific features of the
associated algorithms suggest that unconventional computer architectures, which
can be implemented with available electronics technologies, may lead to order
of magnitude increases in performance, reducing to acceptable values on human
scales the time needed to carry out simulation campaigns that would take
centuries on commercially available machines. Janus II is one such machine,
recently developed and commissioned, that builds upon and improves on the
successful JANUS machine, which has been used for physics since 2008 and is
still in operation today. This paper describes in detail the motivations behind
the project, the computational requirements, the architecture and the
implementation of this new machine and compares its expected performances with
those of currently available commercial systems.

categories: cs.AR cond-mat.dis-nn cond-mat.stat-mech physics.comp-ph


title:
George Gamow and Albert Einstein: Did Einstein say the cosmological
  constant was the "biggest blunder" he ever made in his life?

abstract:
  In 1956/1970 Gamow wrote that much later, when he was discussing cosmological
problems with Einstein, he remarked that the introduction of the cosmological
term was the "biggest blunder" he ever made in his life. But the cosmological
constant rears its ugly head again and again and again. Apparently, Einstein
himself has never used the apercu "biggest blunder"; nevertheless a vast
literature grew up around this notion and associated it with Einstein. The
present work is prompted by questions put by Mario Livio in his latest book
"Brilliant Blunders" as to the phrase "biggest blunder": Did Einstein actually
say, "biggest blunder"? I show that in 1947 Einstein wrote Lemaitre that he
found it "very ugly" that the field law of gravitation should be composed of
two logically independent terms. Earlier, in 1922 Einstein wrote Max Born that
he committed "a monumental blunder some time ago". In 1965 Born commented:
"Here Einstein admits that the considerations which led him to the positive-ray
experiments were wrong: 'a monumental [capital] blunder'". It is likely that
when Einstein met Gamow he formulated his views in his native German, and
perhaps he told Gamow that suggesting his cosmological constant was a
"blunder". I suggest that, Einstein perhaps told Gamow that the cosmological
constant was a "capital blunder" or a "monumental blunder", and Gamow could
have embellished Einstein's words to become the famous apercu "biggest
blunder".


title: Computing Exact Clustering Posteriors with Subset Convolution

abstract:
  An exponential-time exact algorithm is provided for the task of clustering n
items of data into k clusters. Instead of seeking one partition, posterior
probabilities are computed for summary statistics: the number of clusters, and
pairwise co-occurrence. The method is based on subset convolution, and yields
the posterior distribution for the number of clusters in O(n * 3^n) operations,
or O(n^3 * 2^n) using fast subset convolution. Pairwise co-occurrence
probabilities are then obtained in O(n^3 * 2^n) operations. This is
considerably faster than exhaustive enumeration of all partitions.


title:
Realizations of slice hyperholomorphic generalized contractive and
  positive functions

abstract:
  We introduce generalized Schur functions and generalized positive functions
in setting of slice hyperholomorphic functions and study their realizations in
terms of associated reproducing kernel Pontryagin spaces


title: An optimal dissipative encoder for the toric code

abstract:
  We consider the problem of preparing specific encoded resource states for the
toric code by local, time-independent interactions with a memoryless
environment. We propose a construction of such a dissipative encoder which
converts product states to topologically ordered ones while preserving logical
information. The corresponding Liouvillian is made up of four-local Lindblad
operators. For a qubit lattice of size $L\times L$, we show that this process
prepares encoded states in time $O(L)$, which is optimal. This scaling compares
favorably with known local unitary encoders for the toric code which take time
of order $\Omega(L^2)$ and require active time-dependent control.


title: Generating topological order: no speedup by dissipation

abstract:
  We consider the problem of preparing topologically ordered states using
unitary and non-unitary circuits, as well as local time-dependent Hamiltonian
and Liouvillian evolutions. We prove that for any topological code in $D$
dimensions, the time required to encode logical information into the ground
space is at least $\Omega(d^{1/(D-1)})$, where $d$ is the code distance. This
result is tight for the toric code, giving a scaling with the linear system
size. More generally, we show that the linear scaling is necessary even when
dropping the requirement of encoding: preparing any state close to the ground
space using dissipation takes an amount of time proportional to the diameter of
the system in typical 2D topologically ordered systems, as well as for example
the 3D and 4D toric codes.


title:
Intermittent Giant Goos-Hanchen shifts from Airy beams at nonlinear
  interfaces

abstract:
  We study the giant Goos-Hanchen shift obtained from an Airy beam impinging on
a nonlinear interface. To avoid any angular restriction associated with the
paraxial approximation, the analysis is based on the numerical solution of the
nonlinear Helmholtz equation. We report the existence of non-standard
intermittent and oscillatory regimes for the nonlinear Goos-Hanchen shifts
which can be explained in terms of the competition between the critical
coupling to a surface mode of the reflected component of the Airy beam and the
soliton emission from the refracted beam component.


title:
Critical properties of 3D Z(N) lattice gauge theories at finite
  temperature

abstract:
  The phase structure of three-dimensional Z(N>4) lattice gauge theories at
finite temperature is investigated. Using the dual formulation of the models
and a cluster algorithm we locate the critical points of the two transitions,
determine various critical indices and compute average action and specific
heat. Results are consistent with two transitions of infinite order, belonging
to the universality class of two-dimensional Z(N) vector spin models.


title:
Gap generation in ABC-stacked multilayer graphene: screening vs band
  flattening

abstract:
  We calculate the dynamical polarization function and solve a self-consistent
gap equation in the random phase approximation in undoped ABC-stacked n-layer
graphene. We find that the gap is maximal in trilayer graphene and decreases
monotonously for $n \ge 4$ because the effects of screening in the gap equation
win over those connected with the flattening of electron bands as n increases.


title:
High-dimensional asymptotics for percolation of Gaussian free field
  level sets

abstract:
  We consider the Gaussian free field on $\mathbb{Z}^d$, $d$ greater or equal
to $3$, and prove that the critical density for percolation of its level sets
behaves like $1/d^{1 + o(1)}$ as $d$ tends to infinity. Our proof gives the
principal asymptotic behavior of the corresponding critical level $h_*(d)$.
Moreover, it shows that a related parameter $h_{**}(d) \geq h_*(d)$ introduced
by Rodriguez and Sznitman in arXiv:1202.5172 is in fact asymptotically
equivalent to $h_*(d)$.


title: Cubic graphs with large circumference deficit

abstract:
  The circumference $c(G)$ of a graph $G$ is the length of a longest cycle. By
exploiting our recent results on resistance of snarks, we construct infinite
classes of cyclically $4$-, $5$- and $6$-edge-connected cubic graphs with
circumference ratio $c(G)/|V(G)|$ bounded from above by $0.876$, $0.960$ and
$0.990$, respectively. In contrast, the dominating cycle conjecture implies
that the circumference ratio of a cyclically $4$-edge-connected cubic graph is
at least $0.75$.
  In addition, we construct snarks with large girth and large circumference
deficit, solving Problem 1 proposed in [J. H\"agglund and K. Markstr\"om, On
stable cycles and cycle double covers of graphs with large circumference, Disc.
Math. 312 (2012), 2540--2544].


title: The relativity of space-time-property

abstract:
  We describe a geometrical way to unify gravity with the other natural forces
by adding fermionic Lorentz scalar variables, characterising attribute, or
property, to space-time location. [With five such properties one can
accommodate all known leptons and quarks.] Using just one property, viz.
electricity, the general relativity of such a scheme and its superscalar
curvature automatically produces the Einstein-Maxwell Lagrangian and a
cosmological term. By adding more properties we envisage the geometrical
unification of the standard model with gravitation.


title:
Spin-filtered Edge States with an Electrically Tunable Gap in a
  Two-Dimensional Topological Crystalline Insulator

abstract:
  Three-dimensional topological crystalline insulators were recently predicted
and observed in the SnTe class of IV-VI semiconductors, which host metallic
surface states protected by crystal symmetries. In this work, we study thin
films of these materials and expose their potential for device applications. We
demonstrate that thin films of SnTe and Pb(1-x)Sn(x)Se(Te) grown along the
(001) direction are topologically nontrivial in a wide range of film thickness
and carry conducting spin-filtered edge states that are protected by the (001)
mirror symmetry via a topological invariant. Application of an electric field
perpendicular to the film will break the mirror symmetry and generate a band
gap in these edge states. This functionality motivates us to propose a novel
topological transistor device, in which charge and spin transport are maximally
entangled and simultaneously controlled by an electric field. The high on/off
operation speed and coupling of spin and charge in such a device may lead to
electronic and spintronic applications for topological crystalline insulators.


title: The divergence of the barycentric Pade approximants

abstract:
  We explain that, like the usual Pad\'e approximants, the barycentric Pad\'e
approximants proposed recently by Brezinski and Redivo-Zaglia can diverge. More
precisely, we show that for every polynomial P there exists a power series S,
with arbitrarily small coefficients, such that the sequence of barycentric
Pad\'e approximants of P + S do not converge uniformly in any subset of the
complex plane with a non-empty interior.


title:
Design and performance of an ultra-high vacuum scanning tunneling
  microscope operating at dilution refrigerator temperatures and high magnetic
  fields

abstract:
  We describe the construction and performance of a scanning tunneling
microscope (STM) capable of taking maps of the tunneling density of states with
sub-atomic spatial resolution at dilution refrigerator temperatures and high
(14 T) magnetic fields. The fully ultra-high vacuum system features visual
access to a two-sample microscope stage at the end of a bottom-loading dilution
refrigerator, which facilitates the transfer of in situ prepared tips and
samples. The two-sample stage enables location of the best area of the sample
under study and extends the experiment lifetime. The successful thermal
anchoring of the microscope, described in detail, is confirmed through a base
temperature reading of 20 mK, along with a measured electron temperature of 250
mK. Atomically-resolved images, along with complementary vibration
measurements, are presented to confirm the effectiveness of the vibration
isolation scheme in this instrument. Finally, we demonstrate that the
microscope is capable of the same level of performance as typical machines with
more modest refrigeration by measuring spectroscopic maps at base temperature
both at zero field and in an applied magnetic field.


title: Quantum Monte Carlo applied to solids

abstract:
  We apply diffusion quantum Monte Carlo (DMC) to a broad set of solids,
benchmarking the method by comparing bulk structural properties (equilibrium
volume and bulk modulus) to experiment and DFT based theories. The test set
includes materials with many different types of binding including ionic,
metallic, covalent and van der Waals. We show that, on average, the accuracy is
comparable to or better than that of density functional theory (DFT) when using
the new generation of functionals, including one hybrid functional and two
dispersion corrected functionals. The excellent performance of quantum Monte
Carlo (QMC) on solids is promising for its application to heterogeneous systems
and high-pressure/high density conditions. Important to the results here is the
application of a consistent procedure with regards to the several
approximations that are made, such as finite-size corrections and
pseudo-potential approximations. This test set allows for any improvements in
these methods to be judged in a systematic way.


title: Revisiting the Problem of Searching on a Line

abstract:
  We revisit the problem of searching for a target at an unknown location on a
line when given upper and lower bounds on the distance D that separates the
initial position of the searcher from the target. Prior to this work, only
asymptotic bounds were known for the optimal competitive ratio achievable by
any search strategy in the worst case. We present the first tight bounds on the
exact optimal competitive ratio achievable, parameterized in terms of the given
bounds on D, along with an optimal search strategy that achieves this
competitive ratio. We prove that this optimal strategy is unique. We
characterize the conditions under which an optimal strategy can be computed
exactly and, when it cannot, we explain how numerical methods can be used
efficiently. In addition, we answer several related open questions, including
the maximal reach problem, and we discuss how to generalize these results to m
rays, for any m >= 2.


title:
Theory of melting at high pressures: Amending Density Functional Theory
  with Quantum Monte Carlo

abstract:
  We present an improved first-principles description of melting under pressure
based on thermodynamic integration comparing Density Functional Theory (DFT)
and quantum Monte Carlo (QMC) treatments of the system. The method is applied
to address the longstanding discrepancy between density functional theory (DFT)
calculations and diamond anvil cell (DAC) experiments on the melting curve of
xenon, a noble gas solid where van der Waals binding is challenging for
traditional DFT methods. The calculations show excellent agreement with data
below 20 GPa and that the high-pressure melt curve is well described by a
Lindemann behavior up to at least 80 GPa, a finding in stark contrast to DAC
data.


title:
The failure tolerance of mechatronic software systems to random and
  targeted attacks

abstract:
  This paper describes a complex networks approach to study the failure
tolerance of mechatronic software systems under various types of hardware
and/or software failures. We produce synthetic system architectures based on
evidence of modular and hierarchical modular product architectures and known
motifs for the interconnection of physical components to software. The system
architectures are then subject to various forms of attack. The attacks simulate
failure of critical hardware or software. Four types of attack are
investigated: degree centrality, betweenness centrality, closeness centrality
and random attack. Failure tolerance of the system is measured by a 'robustness
coefficient', a topological 'size' metric of the connectedness of the attacked
network. We find that the betweenness centrality attack results in the most
significant reduction in the robustness coefficient, confirming betweenness
centrality, rather than the number of connections (i.e. degree), as the most
conservative metric of component importance. A counter-intuitive finding is
that "designed" system architectures, including a bus, ring, and star
architecture, are not significantly more failure-tolerant than interconnections
with no prescribed architecture, that is, a random architecture. Our research
provides a data-driven approach to engineer the architecture of mechatronic
software systems for failure tolerance.


title: A Two-Loop Five-Gluon Helicity Amplitude in QCD

abstract:
  We compute the planar part of the two-loop five gluon amplitude with all
helicities positive. To perform the calculation we develop a D-dimensional
generalized unitarity procedure allowing us to reconstruct the amplitude by
cutting into products of six-dimensional trees. We find a compact form for the
integrand which only requires topologies with six or more propagators. We
perform cross checks of the universal infra-red structure using numerical
integration techniques.


title: Diagonal changes for surfaces in hyperelliptic components

abstract:
  We describe geometric algorithms that generalize the classical continued
fraction algorithm for the torus to all translation surfaces in hyperelliptic
components of translation surfaces. We show that these algorithms produce all
saddle connections which are best approximations in a geometric sense, which
generalizes the notion of best approximation for the classical continued
fraction. In addition, they allow to list all systoles along a Teichmueller
geodesic and all bispecial words which appear in the symbolic coding of linear
flows. The elementary moves of the described algorithms provide a geometric
invertible extension of the renormalization moves introduced by S. Ferenczi and
L. Zamboni for the corresponding interval exchange transformations.


title:
Resonance Chiral Lagrangian Currents and Experimental Data for
  $\tau^-\to\pi^{-}\pi^{-}\pi^{+}\nu_{\tau}$

abstract:
  In this paper we document the modifications introduced to the previous
version of the Resonance Chiral Lagrangian current ({\it Phys.Rev.} {\bf D86}
(2012) 113008) of the $\tau^\pm \to \pi^\pm \pi^\pm \pi^\mp \nu_\tau$ decay
which enable the one dimensional distributions measured by the BaBar
collaboration to be well modeled. The main change required to model the data is
the addition of the $\sigma$ resonance. Systematic errors, theoretical and
experimental ones, limitations due to fits of one dimensional distributions
only, and resulting difficulties and statistical/systematic errors for fitted
parameters are addressed. The current and fitting environment is ready for
comparisons with the fully exclusive experimental data. The present result for
$\tau^\pm \to \pi^\pm \pi^\pm \pi^\mp \nu_\tau$ is encouraging for work on
other $\tau$ decay modes and Resonance Chiral Lagrangian based currents.


title:
Border collision bifurcations of stroboscopic maps in periodically
  driven spiking models

abstract:
  In this work we consider a general non-autonomous hybrid system based on the
integrate-and-fire model, widely used as simplified version of neuronal models
and other types of excitable systems. Our unique assumption is that the system
is monotonic, possesses an attracting subthreshold equilibrium point and is
forced by means of periodic pulsatile (square wave) function.\\ In contrast to
classical methods, in our approach we use the stroboscopic map (time-$T$ return
map) instead of the so-called firing-map. It becomes a discontinuous map
potentially defined in an infinite number of partitions. By applying theory for
piecewise-smooth systems, we avoid relying on particular computations and we
develop a novel approach that can be easily extended to systems with other
topologies (expansive dynamics) and higher dimensions.\\ More precisely, we
rigorously study the bifurcation structure in the two-dimensional parameter
space formed by the amplitude and the duty cycle of the pulse. We show that it
is covered by regions of existence of periodic orbits given by period adding
structures. They do not only completely describe all the possible spiking
asymptotic dynamics but also the behavior of the firing rate, which is a
devil's staircase as a function of the parameters.


title:
An epistemology and expectations survey about experimental physics:
  Development and initial results

abstract:
  In response to national calls to better align physics laboratory courses with
the way physicists engage in research, we have developed an epistemology and
expectations survey to assess how students perceive the nature of physics
experiments in the contexts of laboratory courses and the professional research
laboratory. The Colorado Learning Attitudes about Science Survey for
Experimental Physics (E-CLASS) evaluates students' epistemology at the
beginning and end of a semester. Students respond to paired questions about how
they personally perceive doing experiments in laboratory courses and how they
perceive an experimental physicist might respond regarding their research.
Also, at the end of the semester, the E-CLASS assesses a third dimension of
laboratory instruction, students' reflections on their course's expectations
for earning a good grade. By basing survey statements on widely embraced
learning goals and common critiques of teaching labs, the E-CLASS serves as an
assessment tool for lab courses across the undergraduate curriculum and as a
tool for physics education research. We present the development, evidence of
validation, and initial formative assessment results from a sample that
includes 45 classes at 20 institutions. We also discuss feedback from
instructors and reflect on the challenges of large-scale online administration
and distribution of results.


title:
Applications of Ultrafilters in Ergodic Theory and Combinatorial Number
  Theory

abstract:
  Ultrafilters are very useful and versatile objects with applications
throughout mathematics: in topology, analysis, combinarotics, model theory, and
even theory of social choice. Proofs based on ultrafilters tend to be shorter
and more elegant than their classical counterparts. In this thesis, we survey
some of the most striking ways in which ultrafilters can be exploited in
combinatorics and ergodic theory, with a brief mention of model theory.
  In the initial sections, we establish the basics of the theory of
ultrafilters in the hope of keeping our exposition possibly self-contained, and
then proceed to specific applications. Important combinatorial results we
discuss are the theorems of Hindman, van der Waerden and Hales-Jewett. Each of
them asserts essentially that in a finite partition of, respectively, the
natural numbers or words over a finite alphabet, one cell much of the
combinatorial structure. We next turn to results in ergodic theory, which rely
strongly on combinatorial preliminaries. They assert essentially that certain
sets of return times are combinatorially rich. We finish by presenting the
ultrafilter proof of the famous Arrow's Impossibility Theorem and the
construction of the ultraproduct in model theory.


title: Unboundedness of the Lagrangian Hofer distance in the Euclidean ball

abstract:
  Let L denote the space of Lagrangians Hamiltonian isotopic to the standard
Lagrangian in the unit ball in Euclidean space. We prove that the Lagrangian
Hofer distance on L is unbounded.


title: Aging renewal theory and application to random walks

abstract:
  The versatility of renewal theory is owed to its abstract formulation.
Renewals can be interpreted as steps of a random walk, switching events in
two-state models, domain crossings of a random motion, etc. We here discuss a
renewal process in which successive events are separated by scale-free waiting
time periods. Among other ubiquitous long time properties, this process
exhibits aging: events counted initially in a time interval [0,t] statistically
strongly differ from those observed at later times [t_a,t_a+t]. In complex,
disordered media, processes with scale-free waiting times play a particularly
prominent role. We set up a unified analytical foundation for such anomalous
dynamics by discussing in detail the distribution of the aging renewal process.
We analyze its half-discrete, half-continuous nature and study its aging time
evolution. These results are readily used to discuss a scale-free anomalous
diffusion process, the continuous time random walk. By this we not only shed
light on the profound origins of its characteristic features, such as weak
ergodicity breaking. Along the way, we also add an extended discussion on aging
effects. In particular, we find that the aging behavior of time and ensemble
averages is conceptually very distinct, but their time scaling is identical at
high ages. Finally, we show how more complex motion models are readily
constructed on the basis of aging renewal dynamics.


title:
Analysis of some projection method based preconditioners for models of
  incompressible flow

abstract:
  In this paper, several projection method based preconditioners for various
incompressible flow models are studied. In particular, we are interested in the
theoretical analysis of a pressure-correction projection method based
preconditioner \cite{griffith2009accurate}. For both the steady and unsteady
Stokes problems, we will show that the preconditioned systems are well
conditioned. Moreover, when the flow model degenerates to the mixed form of an
elliptic operator, the preconditioned system is an identity no matter what type
of boundary conditions are imposed; when the flow model degenerates to the
steady Stokes problem, the multiplicities of the non-unitary eigenvalues of the
preconditioned system are derived. These results demonstrate the effects of
boundary treatments and are related to the stability of the staggered grid
discretization. To further investigate the effectiveness of these projection
method based preconditioners, numerical experiments are given to compare their
performances. Generalizations of these preconditioners to other saddle point
problems will also be discussed.


title: Framed M-branes, corners, and topological invariants

abstract:
  We uncover and highlight relations between the M-branes in M-theory and
various topological invariants: the Hopf invariant over $\mathbb{Q}$,
$\mathbb{Z}$ and $\mathbb{Z}_2$, the Kervaire invariant, the $f$-invariant, and
the $\nu$-invariant. This requires either a framing or a corner structure. The
canonical framing provides a minimum for the classical action and the change of
framing encodes the structure of the action and possible anomalies. We
characterize the flux quantization condition on the C-field and the topological
action of the M5-brane via the Hopf invariant, and the dual of the C-field as
(a refinement of) an element of Hopf invariant two. In the signature
formulation, the contribution to the M-brane effective action is given by the
Maslov index of the corner. The Kervaire invariant implies that the effective
action of the M5-brane is quadratic. Our study leads to viewing the self-dual
string, which is the boundary of the M2-brane on the M5-brane worldvolume, as a
string theory in the sense of cobordism of manifolds with corners. We show that
the dynamics of the C-field and its dual are encoded in unified way in the
4-sphere, which suggests the corresponding spectrum as the generalized
cohomology theory describing the fields. The effective action of the corner is
captured by the $f$-invariant, which is an invariant at chromatic level two.
Finally, considering M-theory on manifolds with G_2 holonomy we show that the
canonical ${\rm G}_2$ structure minimizes the topological part of the M5-brane
action. This is done via the $\nu$-invariant and a variant that we introduce
related to the one-loop polynomial.


title: Dynamical symmetry breaking in non-Abelian geometrodynamics

abstract:
  We are going to analyze through a first order perturbative formulation the
local loss of symmetry when a source of non-Abelian Yang-Mills and
gravitational fields interacts with an external agent that perturbes the
original geometry associated to the source. Then, as the symmetry in Abelian
and non-Abelian field structures in four-dimensional Lorentzian spacetimes is
displayed through the existence of local orthogonal planes of symmetry that we
previously called blades one and two, the loss of symmetry will be manifested
by the tilting of these planes under the influence of the external agent. It
was found already that there is an algorithm to block diagonalize the
Yang-Mills field strength isospace projections in a local gauge invariant way.
Independently, it was also found an algorithm to diagonalize the Yang-Mills
stress-energy tensor in a gauge invariant way. Using these results and
perturbative analysis from a previous manuscript dealing with the Abelian case,
we are going to demonstrate how to develop an algorithm for constructing local
energy-momentum conserved currents inside both local orthogonal planes. As the
interaction proceeds, the planes are going to tilt perturbatively, and in this
strict sense the original local symmetries will be lost. But we will prove that
the new blades at the same point will correspond after the tilting generated by
perturbation, to new symmetries, with associated new local currents, both on
each new local planes of symmetry. Old symmetries will be broken, new will
arise. There will be a local symmetry evolution in the non-Abelian case as
well.


title: The new radiation-hard optical links for the ATLAS pixel detector

abstract:
  The ATLAS detector is currently being upgraded with a new layer of pixel
based charged particle tracking and a new arrangement of the services for the
pixel detector. These upgrades require the replacement of the opto-boards
previously used by the pixel detector. In this report we give details on the
design and production of the new opto-boards.


title:
Realization of tangent perturbations in discrete and continuous time
  conservative systems

abstract:
  We prove that any perturbation of the symplectic part of the derivative of a
Poisson diffeomorphism can be realized as the derivative of a $C^1$-close
Poisson diffeomorphism. We also show that a similar property holds for the
Poincar\'e map of a Hamiltonian on a Poisson manifold. These results are the
conservative counterparts of the Franks lemma, a perturbation tool used in
several contexts most notably in the theory of smooth dynamical systems.


title: Neutrinoless double beta decay and QCD corrections

abstract:
  We consider one loop QCD corrections and renormalization group running of the
neutrinoless double beta decay amplitude focusing on the short-range part of
the amplitude (without the light neutrino exchange) and find that these
corrections can be sizeable. Depending on the operator under consideration,
there can be moderate to large cancellations or significant enhancements. We
discuss several specific examples in this context. Such large corrections will
lead to significant shifts in the half-life estimates which currently are known
to be plagued with the uncertainties due to nuclear physics inputs to the
physical matrix elements.


title:
Phase-matching condition for enhanced entanglement of colliding
  indistinguishable quantum bright solitons in a harmonic trap

abstract:
  We investigate finite number effects in collisions between two states of an
initially well defined number of identical bosons with attractive contact
interactions, oscillating in the presence of harmonic confinement in one
dimension. We investigate two $N/2$ atom bound states, which are initially
displaced (symmetrically) from the trap center, and then left to freely evolve.
For sufficiently attractive interactions, these bound states are like those
found through use of the Bethe Ansatz (quantum solitons). However, unlike the
free case, the integrability is lost due to confinement, and collisions can
cause mixing into different bound state configurations. We study the system
numerically for the simplest case of $N=4$, via an exact diagonalization of the
Hamiltonian within a finite basis, investigating left/right number uncertainty
as our primary measure of entanglement. We find that for certain interaction
strengths, a phase matching condition leads to resonant transfer to different
bound state configurations with highly non-Poissonian relative number
statistics.


title:
Computation of the correlated metal-insulator transition in vanadium
  dioxide from first principles

abstract:
  Vanadium dioxide(VO$_2$) is a paradigmatic example of a strongly correlated
system that undergoes a metal-insulator transition at a structural phase
transition. To date, this transition has necessitated significant post-hoc
adjustments to theory in order to be described properly. Here we report
standard state-of-the-art first principles quantum Monte Carlo (QMC)
calculations of the structural dependence of the properties of VO$_2$. Using
this technique, we simulate the interactions between electrons explicitly,
which allows for the metal-insulator transition to naturally emerge,
importantly without ad-hoc adjustments. The QMC calculations show that the
structural transition directly causes the metal-insulator transition and a
change in the coupling of vanadium spins. This change in the spin coupling
results in a prediction of a momentum-independent magnetic excitation in the
insulating state. While two-body correlations are important to set the stage
for this transition, they do not change significantly when VO$_2$ becomes an
insulator. These results show that it is now possible to account for electron
correlations in a quantitatively accurate way that is also specific to
materials.


title: Cosmology of Holographic and New Agegraphic $f(R,T)$ Models

abstract:
  We consider the $f(R,T)$ theory, where $R$ is the scalar curvature and $T$ is
the trace of energy-momentum tensor, as an effective description for the
holographic and new agegraphic dark energy and reconstruct the corresponding
$f(R,T)$ functions. In this study, we concentrate on two particular models of
$f(R,T)$ gravity namely, $R+2A(T)$ and $B(R)+\lambda{T}$. We conclude that the
derived $f(R,T)$ models can represent phantom or quintessence regimes of the
universe which are compatible with the current observational data. In addition,
the conditions to preserve the generalized second law of thermodynamics are
established.


title:
A novel spectral method for inferring general diploid selection from
  time series genetic data

abstract:
  The increased availability of time series genetic variation data from
experimental evolution studies and ancient DNA samples has created new
opportunities to identify genomic regions under selective pressure and to
estimate their associated fitness parameters. However, it is a challenging
problem to compute the likelihood of nonneutral models for the population
allele frequency dynamics, given the observed temporal DNA data. Here, we
develop a novel spectral algorithm to analytically and efficiently integrate
over all possible frequency trajectories between consecutive time points. This
advance circumvents the limitations of existing methods which require
fine-tuning the discretization of the population allele frequency space when
numerically approximating requisite integrals. Furthermore, our method is
flexible enough to handle general diploid models of selection where the
heterozygote and homozygote fitness parameters can take any values, while
previous methods focused on only a few restricted models of selection. We
demonstrate the utility of our method on simulated data and also apply it to
analyze ancient DNA data from genetic loci associated with coat coloration in
horses. In contrast to previous studies, our exploration of the full fitness
parameter space reveals that a heterozygote advantage form of balancing
selection may have been acting on these loci.


title: Strange Baryon to Meson Ratio

abstract:
  We present a model to compute baryon and meson transverse momentum
distributions, and their ratios, in relativistic heavy-ion collisions. The
model allows to compute the probability to form colorless bound states of
either two or three quarks as functions of the evolving density during the
collision. The qualitative differences of the baryon to meson ratio for
different collision energies and for different particle species can be
associated to the different density dependent probabilities and to the
combinatorial factors which in turn depend on whether the quarks forming the
bound states are heavy or light. We compare to experimental data and show that
we obtain a good description up to intermediate values of $pt$.


title:
Constraining RS Models by Future Flavor and Collider Measurements: A
  Snowmass Whitepaper

abstract:
  Randall-Sundrum models are models of quark flavor, because they explain the
hierarchies in the quark masses and mixings in terms of order one localization
parameters of extra dimensional wavefunctions. The same small numbers which
generate the light quark masses suppress contributions to flavor violating tree
level amplitudes. In this note we update universal constraints from electroweak
precision parameters and demonstrate how future measurements of flavor
violation in ultra rare decay channels of Kaons and B mesons will constrain the
parameter space of this type of models. We show how collider signatures are
correlated with these flavor measurements and compute projected limits for
direct searches at the 14 TeV LHC run, a 14 TeV LHC luminosity upgrade, a 33
TeV LHC energy upgrade, and a potential 100 TeV machine. We further discuss the
effects of a warped model of leptons in future measurements of lepton flavor
violation.


title: Unified formalism for the generalized kth-order Hamilton-Jacobi problem

abstract:
  The geometric formulation of the Hamilton-Jacobi theory enables us to
generalize it to systems of higher-order ordinary differential equations. In
this work we introduce the unified Lagrangian-Hamiltonian formalism for the
geometric Hamilton-Jacobi theory on higher-order autonomous dynamical systems
described by regular Lagrangian functions.


title: Shedding Light on Dark Matter at Colliders

abstract:
  Dark matter remains one of the most puzzling mysteries in Fundamental Physics
of our times. Experiments at high-energy physics colliders are expected to shed
light to its nature and determine its properties. This review focuses on recent
searches for dark-matter signatures at the Large Hadron Collider, also
discussing related prospects in future e+e- colliders.


title:
Dynamical Conductivity Across The Disorder-Tuned
  Superconductor-Insulator Transition

abstract:
  A quantum phase transition is a dramatic event marked by large spatial and
temporal fluctuations, where one phase of matter with its ground state and
tower of excitations reorganizes into a completely different phase. We provide
new insight into the disorder-driven superconductor-insulator transition (SIT)
in two dimensions, a problem of great theoretical and experimental interest,
with the dynamical conductivity \sigma(\omega) and the bosonic (pair) spectral
function P(\omega) calculated from quantum Monte Carlo simulations. We identify
characteristic energy scales in the superconducting and insulating phases that
vanish at the transition due to enhanced quantum fluctuations, despite the
persistence of a robust fermionic gap across the SIT. Disorder leads to
enhanced absorption in \sigma(\omega) at low frequencies compared to the SIT in
a clean system. Disorder also expands the quantum critical region, due to a
change in the universality class, with an underlying T=0 critical point with a
finite low-frequency conductivity.


title:
Wet Disc Contraction to Galactic Blue Nuggets and Quenching to Red
  Nuggets

abstract:
  We study the origin of high-redshift, compact, quenched spheroids (red
nuggets) through the dissipative shrinkage of gaseous discs into compact
star-forming systems (blue nuggets). The discs, fed by cold streams, undergo
violent disc instability (VDI) that drives gas into the centre (along with
mergers). The inflow is dissipative when its timescale is shorter than the star
formation timescale. This implies a threshold of 0.28 in the cold-to-total mass
ratio within the disc radius. For the typical gas fraction 0.5 at z=2, this
threshold is traced back to a maximum spin parameter of 0.05, implying that
half the star-forming galaxies contract to blue nuggets, while the rest form
extended stellar discs. Thus, the surface density of blue galaxies is expected
to be bimodal about 10^9 Msun/kpc^2, slightly increasing with mass. Blue
nuggets are expected to be rare at low z when the gas fraction is low. The blue
nuggets quench to red nuggets by complementary internal and external
mechanisms. Internal quenching by a compact bulge, operating as a fast mode and
especially at high z, may involve starbursts, stellar and AGN feedback, or
Q-quenching. Quenching due to hot-medium haloes above 10^{12} Msun provides
maintenance and a slower mode at low redshift. These predictions are confirmed
in simulations and are consistent with observations at z=0-3.


title:
Solution of the Bethe-Goldstone Equation without Partial Wave
  Decomposition

abstract:
  We present a method for solving the nucleon-nucleon scattering equation
without the use of a partial wave expansion of the scattering amplitude. After
verifying the accuracy of the numerical solutions, we proceed to apply the
method to the in-medium scattering equation (the Bethe-Goldstone equation) in
three dimensions. A focal point is a study of Pauli blocking effects calculated
in the (angle-dependent) three-dimensional formalism as compared to the usual
spherical approximation. We discuss our results and their implications.


title: Compressed Counting Meets Compressed Sensing

abstract:
  Compressed sensing (sparse signal recovery) has been a popular and important
research topic in recent years. By observing that natural signals are often
nonnegative, we propose a new framework for nonnegative signal recovery using
Compressed Counting (CC). CC is a technique built on maximally-skewed p-stable
random projections originally developed for data stream computations. Our
recovery procedure is computationally very efficient in that it requires only
one linear scan of the coordinates. Our analysis demonstrates that, when
0<p<=0.5, it suffices to use M= O(C/eps^p log N) measurements so that all
coordinates will be recovered within eps additive precision, in one scan of the
coordinates. The constant C=1 when p->0 and C=pi/2 when p=0.5. In particular,
when p->0 the required number of measurements is essentially M=K\log N, where K
is the number of nonzero coordinates of the signal.


title: The largest strong left quotient ring of a ring

abstract:
  For an arbitrary ring $R$, the largest strong left quotient ring $Q_l^s(R)$
of $R$ and the strong left localization radical $\glsR$ are introduced and
their properties are studied in detail. In particular, it is proved that
$Q_l^s(Q_l^s(R))\simeq Q_l^s(R)$, $\gll^s_{R/\glsR}=0$ and a criterion is given
for the ring $ Q_l^s(R)$ to be a semisimple ring. There is a canonical
homomorphism from the classical left quotient ring $Q_{l, cl}(R)$ to $Q_l^s(R)$
which is not an isomorphism, in general. The objects $Q_l^s(R)$ and $\gll^s_R$
are explicitly described for several large classes of rings (semiprime left
Goldie ring, left Artinian rings, rings with left Artinian left quotient ring,
etc).


title:
Nonequilibrium Statistical Mechanics of Systems with Long-Range
  Interactions: Ubiquity of Core-Halo Distributions

abstract:
  Systems with long-range (LR) forces, for which the interaction potential
decays with the interparticle distance with an exponent smaller than the
dimensionality of the embedding space, remain an outstanding challenge to
statistical physics. The internal energy of such systems lacks extensivity and
additivity. Although the extensivity can be restored by scaling the interaction
potential with the number of particles, the non-additivity still remains. Lack
of additivity leads to inequivalence of statistical ensembles. Before relaxing
to thermodynamic equilibrium, isolated systems with LR forces become trapped in
out-of-equilibrium quasi-stationary state (qSS), the lifetime of which diverges
with the number of particles. Therefore, in thermodynamic limit LR systems will
not relax to equilibrium. The qSSs are attained through the process of
collisionless relaxation. Density oscillations lead to particle-wave
interactions and excitation of parametric resonances. The resonant particles
escape from the main cluster to form a tenuous halo. Simultaneously, this cools
down the core of the distribution and dampens out the oscillations. When all
the oscillations die out the ergodicity is broken and a qSS is born. In this
report, we will review a theory which allows us to quantitatively predict the
particle distribution in the qSS. The theory is applied to various LR
interacting systems, ranging from plasmas to self-gravitating clusters and
kinetic spin models.


title:
The Dwarfs Beyond: The Stellar-to-Halo Mass Relation for a New Sample of
  Intermediate Redshift Low Mass Galaxies

abstract:
  A number of recent challenges to the standard Lambda-CDM paradigm relate to
discrepancies that arise in comparing the abundance and kinematics of local
dwarf galaxies with the predictions of numerical simulations. Such arguments
rely heavily on the assumption that the local dwarf and satellite galaxies form
a representative distribution in terms of their stellar-to-halo mass ratios. To
address this question, we present new, deep spectroscopy using DEIMOS on Keck
for 82 low mass (10^7-10^9 solar masses) star-forming galaxies at intermediate
redshift (z=0.2-1). For 50 percent of these we are able to determine resolved
rotation curves using nebular emission lines and thereby construct the stellar
mass Tully-Fisher relation to masses as low as 10^7 solar masses. Using scaling
relations determined from weak lensing data, we convert this to a
stellar-to-halo mass (SHM) relation for comparison with abundance matching
predictions. We find a discrepancy between the propagated predictions from
simulations compared to our observations, and suggest possible reasons for this
as well as future tests that will be more effective.


title: Olivine-dominated asteroids: Mineralogy and origin

abstract:
  Olivine-dominated asteroids are a rare type of objects formed either in
nebular processes or through magmatic differentiation. The analysis of
meteorite samples suggest that at least 100 parent bodies in the main belt
experienced partial or complete melting and differentiation before being
disrupted. However, only a few olivine-dominated asteroids, representative of
the mantle of disrupted differentiated bodies, are known to exist. Due to the
paucity of these objects in the main belt their origin and evolution have been
a matter of great debate over the years. In this work we present a detailed
mineralogical analysis of twelve olivine-dominated asteroids. Within our sample
we distinguish two classes, one that we call monomineralic-olivine asteroids
and another referred to as olivine-rich asteroids. For the
monomineralic-olivine asteroids the olivine chemistry was found to range from ~
Fo49 to Fo70, consistent with the values measured for brachinites and R
chondrites. In the case of the olivine-rich asteroids we determined their
olivine and low-Ca pyroxene abundance using a new set of spectral calibrations
derived from the analysis of R chondrites spectra. We found that the olivine
abundance for these asteroids varies from 0.68 to 0.93, while the fraction of
low-Ca pyroxene to total pyroxene ranges from 0.6 to 0.9. A search for
dynamical connections between the olivine-dominated asteroids and asteroid
families found no genetic link (of the type core-mantel-crust) between these
objects.


title: W-propagator corrections to muon and tau leptonic decays

abstract:
  We derive the corrections induced by the W-boson propagator to the
differential rates of the leptonic decay of a polarized muon and tau lepton.
Results are presented both for decays inclusive of inner bremsstrahlung as well
as for radiative ones, when a photon emitted in the decay process is measured.
The numerical effect of these corrections is discussed. The definition of the
Fermi constant is briefly reviewed.


title: An explicit Z'-boson explanation of the B->K*mu+mu- anomaly

abstract:
  A global fit to the recent B->K*mu+mu- data shows indications for a large
new-physics contribution to the Wilson coefficient of the semi-leptonic vector
operator. In this article we consider a simple Z'-boson model of 3-3-1 type
that can accommodate such an effect without violating any other constraint from
quark-flavour physics. Implications for yet unobserved decay modes such as
B->Xsnunubar and longstanding puzzles like B->piK are also discussed. The
Z'-boson masses required to address the observed anomaly lie in the range of 7
TeV. Such heavy Z' bosons evade the existing bounds from precision data and
direct searches, and will remain difficult to discover even at a
high-luminosity LHC. The potential of an ILC as well as the next generation of
low-energy parity-violation experiments in constraining the Z'-boson parameter
space is also examined.


title: Unitarity Constraints on Higgs Portals

abstract:
  Dark matter that was once in thermal equilibrium with the Standard Model is
generally prohibited from obtaining all of its mass from the electroweak phase
transition. This implies a new scale of physics and mediator particles to
facilitate dark matter annihilation. In this work, we focus on dark matter that
annihilates through a generic Higgs portal. We show how partial wave unitarity
places an upper bound on the mass of the mediator (or dark) Higgs when its mass
is increased to be the largest scale in the effective theory. For models where
the dark matter annihilates via fermion exchange, an upper bound is generated
when unitarity breaks down around 8.5 TeV. Models where the dark matter
annihilates via fermion and higgs boson exchange push the bound to 45.5 TeV. We
also show that if dark matter obtains all of its mass from a new symmetry
breaking scale that scale is also constrained. We improve these constraints by
requiring perturbativity in the Higgs sector up to each unitarity bound. In
this limit, the bounds on the dark symmetry breaking vev and the dark Higgs
mass are now 2.4 and 3 TeV, respectively, when the dark matter annihilates via
fermion exchange. When dark matter annihilates via fermion and higgs boson
exchange, the bounds are now 12 and 14.2 TeV, respectively. The available
parameter space for Higgs portal dark matter annihilation is outlined. We also
show how the bounds are improved if Higgs portal dark matter is only a fraction
of the observed relic abundance. Finally, we discuss how to apply these
arguments to other dark matter scenarios and discuss prospects for direct
detection and future collider searches. If the Higgs portal is responsible for
dark matter annihilation, planned direct detection experiments will cover
almost all the parameter space. The ILC and/or VLHC, however, is needed to
establish the Higgs portal mechanism.


title: Further on up the road: $hhjj$ production at the LHC

abstract:
  A measurement of the $hh+2j$ channel at the LHC would be particularly
thrilling for electroweak physics. It is not only the leading process which is
sensitive to the $W^+W^- hh$ and $ZZhh$ interactions, but also provides a
potentially clear window to study the electroweak symmetry-breaking sector by
probing Higgs-Goldstone interactions through the weak boson fusion component of
the scattering process. Until now, a phenomenologically complete analysis of
this channel has been missing. This is mostly due to the high complexity of the
involved one-loop gluon fusion contribution and the fact that a reliable
estimate thereof cannot be obtained through simplified calculations in the
$m_t\to \infty$ limit. In particular, the extraction of the Higgs trilinear
coupling from this final state rests on a delicate $m_t$-dependent interference
pattern which is not captured in an effective field theory approach. In this
paper, we report on the LHC's potential to access di-Higgs production in
association with two jets in a fully-showered hadron-level analysis. Our study
includes the finite top and bottom mass dependencies for the gluon fusion
contribution. On the basis of these results, we also comment on the potential
sensitivity to the trilinear Higgs and $VV^\dagger hh$ ($V=W^\pm,Z$) couplings
that can be expected from measurements of this final state.


title:
Consequences of Dynamical Disruption and Mass Segregation for the Binary
  Frequencies of Star Clusters

abstract:
  The massive (13,000-26,000 Msolar), young (15-30 Myr) Large Magellanic Cloud
star cluster NGC 1818 reveals an unexpected increasing binary frequency with
radius for F-type stars (1.3-2.2 Msolar). This is in contrast to many older
star clusters that show a decreasing binary frequency with radius. We study
this phenomenon with sophisticated N-body modeling, exploring a range of
initial conditions, from smooth virialized density distributions to highly
substructured and collapsing configurations. We find that many of these models
can reproduce the cluster's observed properties, although with a modest
preference for substructured initial conditions. Our models produce the
observed radial trend in binary frequency through disruption of soft binaries
(with semi-major axes, a > 3000 AU), on approximately a crossing time (~ 5.4
Myr), preferentially in the cluster core. Mass segregation subsequently causes
the binaries to sink towards the core. After roughly one initial half-mass
relaxation time (t_rh(0) ~ 340 Myr) the radial binary frequency distribution
becomes bimodal, the innermost binaries having already segregated towards the
core, leaving a minimum in the radial binary frequency distribution that
marches outwards with time. After 4-6 t_rh(0), the rising distribution in the
halo disappears, leaving a radial distribution that rises only towards the
core. Thus, both a radial binary frequency distribution that falls towards the
core (as observed for NGC 1818) and one that rises towards the core (as for
older star clusters) can arise naturally from the same evolutionary sequence
owing to binary disruption and mass segregation in rich star clusters.


title: A Fast Route to Modified Gravitational Growth

abstract:
  The growth rate of the large-scale structure of the universe has been
advocated as the observable par excellence for testing gravity on cosmological
scales. By considering linear-order deviations from General Relativity, we show
that corrections to the growth rate, f, can be expressed as an integral over a
`source' term, weighted by a theory-independent `response kernel'. This leads
to an efficient and accurate `plug-and-play' expression for generating growth
rates in alternative gravity theories, bypassing lengthy theory-specific
computations. We use this approach to explicitly show that f is sensitive to a
degenerate combination of modified expansion and modified clustering effects.
Hence the growth rate, when used in isolation, is not a straightforward
diagnostic of modified gravity.


title:
Near-infrared Metallicities, Radial Velocities and Spectral Types for
  447 Nearby M Dwarfs

abstract:
  We present metallicities, radial velocities and near-infrared spectral types
for 447 M dwarfs determined from moderate resolution (R~2000) near-infrared
(NIR) spectra obtained with IRTF/SpeX. These M dwarfs are targets of the MEarth
Survey, a transiting planet survey searching for super Earths around
mid-to-late M dwarfs within 33pc. We present NIR spectral types and new IRTF
spectral templates in the Z, J, H and K-bands, created using M dwarfs with
near-solar metallicities. We developed two spectroscopic distance calibrations
that use NIR spectral type or an index based on the curvature of the K-band
continuum. Our distance calibration has a scatter of 14%. We searched 27 NIR
spectral lines and 10 spectral indices for metallicity sensitive features,
taking into account correlated noise in our estimates of the errors on these
parameters. We calibrated our relation using 36 M dwarfs in common proper pairs
with an F, G or K-type star of known metallicity. We validated the physical
association of these pairs using proper motions, radial velocities and
spectroscopic distance estimates. Our resulting metallicity calibration uses
the sodium doublet at 2.2um as the sole indicator for metallicity. It has an
accuracy of 0.12dex inferred from the scatter between the metallicities of the
primaries and the estimated metallicities of the secondaries. Our relation is
valid for NIR spectral types from M1V to M5V and for -1.0<[Fe/H]<+0.35dex. We
present a new metallicity relation using J-H and J-K colors that directly
relates two observables: the distance from the M dwarf main sequence and
equivalent width of the sodium line at 2.2um. We measured radial velocities by
modeling telluric features to determine the absolute wavelength calibration of
our spectra, and used M dwarf binaries, observations at different epochs, and
comparison to precisely measured radial velocities to demonstrate 4.4km/s
accuracy.


title: Geometrodynamics and Lorentz symmetry

abstract:
  We study the dynamics of gauge theory and general relativity using fields of
local observers, thus maintaining local Lorentz symmetry despite a space/time
splitting of fields. We start with Yang--Mills theory, where observer fields
are defined as normalized future-timelike vector fields. We then define
observers without a fixed geometry, and find these play two related roles in
general relativity: splitting fields into spatial and temporal parts, and
"breaking" gauge symmetry, effectively reducing the spacetime SO(n,1)
connection to an observer-dependent spatial SO(n) connection. In both gauge
theory and gravity, the observer field reduces the action to canonical form,
without using gauge fixing. In the 4d gravity case, the result is a manifestly
Lorentz covariant counterpart of the Ashtekar-Barbero formulation. We also
explain how this leads geometrically to a picture of general relativity in
terms of "observer space" rather than spacetime---a setting where both
spacetime symmetry and the dynamical description are simultaneously available.


title: Bayesian Reweighting for Global Fits

abstract:
  Two different techniques for adding additional data sets to existing global
fits using Bayesian reweighting have been proposed in the literature. The
derivation of each reweighting formalism is critically reviewed. A simple
example is constructed that conclusively favors one of the two formalisms. The
effects of this choice for global fits is discussed.


title:
Exponentially spread dynamical Yukawa couplings from non-perturbative
  chiral symmetry breaking in the dark sector

abstract:
  We propose a new paradigm for generating exponentially spread standard model
Yukawa couplings from a new $U(1)_F$ gauge symmetry in the dark sector. Chiral
symmetry is spontaneously broken among dark fermions that obtain non-vanishing
masses from a non-perturbative solution to the mass gap equation. The necessary
ingredient for this mechanism to work is the existence of higher derivative
terms in the dark $U(1)_F$ theory, or equivalently the existence of Lee-Wick
ghosts, that (i) allow for a non-perturbative solution to the mass gap equation
in the weak coupling regime of the Abelian theory; (ii) induce exponential
dependence of the generated masses on dark fermion $U(1)_F$ quantum numbers.
The generated flavor and chiral symmetry breaking in the dark sector is
transferred to the standard model Yukawa couplings at one loop level via Higgs
portal type scalar messenger fields. The latter carry quantum numbers of
squarks and sleptons. A new intriguing phenomenology is predicted that could be
potentially tested at the LHC, provided the characteristic mass scale of the
messenger sector is accessible at the LHC as is suggested by naturalness
arguments.


title: Anomaly Nucleation Constrains SU(2) Gauge Theories

abstract:
  We argue for the existence of additional constraints on SU(2) gauge theories
in four dimensions when realized in ultraviolet completions admitting an analog
of D-brane nucleation. In type II string compactifications these constraints
are necessary and sufficient for the absence of cubic non-abelian anomalies in
certain nucleated SU(N>2) theories. It is argued that they appear quite broadly
in the string landscape. Implications for particle physics are discussed; most
realizations of the standard model in this context are inconsistent, unless
extra electroweak fermions are added.


title:
Collapse of a molecular cloud core to stellar densities: stellar core
  and outflow formation in radiation magnetohydrodynamics simulations

abstract:
  We have performed smoothed particle radiation magnetohydrodynamics (SPRMHD)
simulations of the collapse of rotating, magnetised molecular cloud cores to
form protostars. The calculations follow the formation and evolution of the
first hydrostatic core, the collapse to form a stellar core, the launching of
outflows from both the first hydrostatic core and stellar cores, and the
breakout of the stellar outflow from the remnant of the first core. We
investigate the roles of magnetic fields and thermal feedback on the outflow
launching process, finding that both magnetic and thermal forces contribute to
the launching of the stellar outflow. We also follow the stellar cores until
they grow to masses of up to 20 Jupiter-masses, and determine their properties.
We find that at this early stage, before fusion begins, the stellar cores have
radii of $\approx 3$ R$_\odot$ with radial entropy profiles that increase
outward (i.e. are convectively stable) and minimum entropies per baryon of
$s/k_{\rm B} \approx 14$ in their interiors. The structure of the stellar cores
is found to be insensitive to variations in the initial magnetic field
strength. With reasonably strong initial magnetic fields, accretion on to the
stellar cores occurs through inspiralling magnetised pseudo-discs with
negligible radiative losses, as opposed to first cores which effectively
radiate away the energy liberated in the accretion shocks at their surfaces. We
find that magnetic field strengths of >10 kG can be implanted in stellar cores
at birth.


title:
PRIMUS: Galaxy Clustering as a Function of Luminosity and Color at
  0.2<z<1

abstract:
  We present measurements of the luminosity and color-dependence of galaxy
clustering at 0.2<z<1.0 in the PRIsm MUlti-object Survey (PRIMUS). We quantify
the clustering with the redshift-space and projected two-point correlation
functions, xi(rp,pi) and wp(rp), using volume-limited samples constructed from
a parent sample of over 130,000 galaxies with robust redshifts in seven
independent fields covering 9 sq. deg. of sky. We quantify how the
scale-dependent clustering amplitude increases with increasing luminosity and
redder color, with relatively small errors over large volumes. We find that red
galaxies have stronger small-scale (0.1<rp<1 Mpc/h) clustering and steeper
correlation functions compared to blue galaxies, as well as a strong color
dependent clustering within the red sequence alone. We interpret our measured
clustering trends in terms of galaxy bias and obtain values between
b_gal=0.9-2.5, quantifying how galaxies are biased tracers of dark matter
depending on their luminosity and color. We also interpret the color dependence
with mock catalogs, and find that the clustering of blue galaxies is nearly
constant with color, while redder galaxies have stronger clustering in the
one-halo term due to a higher satellite galaxy fraction. In addition, we
measure the evolution of the clustering strength and bias, and we do not detect
statistically significant departures from passive evolution. We argue that the
luminosity- and color-environment (or halo mass) relations of galaxies have not
significantly evolved since z=1. Finally, using jackknife subsampling methods,
we find that sampling fluctuations are important and that the COSMOS field is
generally an outlier, due to having more overdense structures than other
fields; we find that 'cosmic variance' can be a significant source of
uncertainty for high-redshift clustering measurements.


title:
Exploration of the helimagnetic and skyrmion lattice phase diagram in
  Cu2OSeO3 using magnetoelectric susceptibility

abstract:
  Using SQUID magnetometry techniques, we have studied the change in
magnetization versus applied ac electric field, i.e. the magnetoelectric (ME)
susceptibility dM/dE, in the chiral-lattice ME insulator Cu2OSeO3. Measurements
of the dM/dE response provide a sensitive and efficient probe of the magnetic
phase diagram, and we observe clearly distinct responses for the different
magnetic phases, including the skyrmion lattice phase. By combining our results
with theoretical calculation, we estimate quantitatively the ME coupling
strength as {\lambda} = 0.0146 meV/(V/nm) in the conical phase. Our study
demonstrates the ME susceptibility to be a powerful, sensitive and efficient
technique for both characterizing and discovering new multiferroic materials
and phases.


title:
On the Relation between the Psychological and Thermodynamic Arrows of
  Time

abstract:
  In this paper we lay out an argument that generically the psychological arrow
of time should align with the thermodynamic arrow of time where that arrow is
well-defined. This argument applies to any physical system that can act as a
memory, in the sense of preserving a record of the state of some other system.
This result follows from two principles: the robustness of the thermodynamic
arrow of time to small perturbations in the state, and the principle that a
memory should not have to be fine-tuned to match the state of the system being
recorded. This argument applies even if the memory system itself is completely
reversible and non-dissipative. We make the argument with a paradigmatic
system, then formulate it more broadly for any system that can be considered a
memory. We illustrate these principles for a few other example systems, and
compare our criteria to earlier treatments of this problem.


title: Many-body Localization and Symmetry Protected Topological Order

abstract:
  Recent work shows that highly excited many-body localized eigenstates can
exhibit broken symmetries and topological order, including in dimensions where
such order would be forbidden in equilibrium. In this paper we extend this
analysis to discrete symmetry protected order via the explicit examples of the
Haldane phase of one dimensional spin chains and the topological Ising
paramagnet in two dimensions. We comment on the challenge of extending these
results to cases where the protecting symmetry is continuous.


title:
Comment on "Nonexistence of the final first integral in the
  Zipoy-Voorhees space-time"

abstract:
  The accuracy of the numerical findings of Lukes-Gerakopoulos PRD 86, 044013
(2012), regarding the existence of additional first integrals in the
Zipoy-Voorhees space-time, was recently questioned by Maciejewski et al. PRD
88, 064003 (2013). In this comment, it is shown that the discrepancy between
the results of Lukes-Gerakopoulos (2012) and Maciejewski et al. (2013) is not
due to issues related to numerical accuracy, as claimed in Maciejewski et al
(2013), but due to different choice of coordinates used in Maciejewski et
al.(2013).


title:
A Prototype of Wireless Power and Data Acquisition System for Large
  Detectors

abstract:
  A new prototype wireless data acquisition system has been developed with the
intended application to read-out instrumentation systems having a large number
of channels. In addition such system could be deployed in smaller detectors
requiring increased mobility. The data acquisition and control system is based
on 802.11n compliant hardware and protocols. In this paper we describe our case
study with a single readout channel performed for a potential large detector
containing photomultiplier tubes. The front-end circuitry, including a
high-voltage power supply is powered wirelessly thus creating an all-wireless
detector readout. The benchmarked performance of the prototype system and how a
large scale implementation of the system might be realized are discussed.


title: Hot Galactic Winds Constrained by the X-Ray Luminosities of Galaxies

abstract:
  Galactic superwinds may be driven by very hot outflows generated by
overlapping supernovae within the host galaxy. We use the Chevalier & Clegg
(CC85) wind model and the observed correlation between X-ray luminosities of
galaxies and their SFRs to constrain the mass loss rates (\dot{M}_hot) across a
wide range of star formation rates (SFRs), from dwarf starbursts to
ultra-luminous infrared galaxies. We show that for fixed thermalization
efficiency and mass loading rate, the X-ray luminosity of the hot wind scales
as L_X ~ SFR^2, significantly steeper than is observed for star-forming
galaxies: L_X ~ SFR. Using this difference we constrain the mass-loading and
thermalization efficiency of hot galactic winds. For reasonable values of the
thermalization efficiency (<~ 1) and for SFR >~ 10 M_sun/yr we find that
\dot{M}_hot/SFR <~ 1, significantly lower than required by integrated
constraints on the efficiency of stellar feedback in galaxies, and potentially
too low to explain observations of winds from rapidly star-forming galaxies. In
addition, we highlight the fact that heavily mass-loaded winds cannot be
described by the adiabatic CC85 model because they become strongly radiative.


title: Connection between maximum-work and maximum-power thermal cycles

abstract:
  We propose a new connection between maximum-power Curzon-Ahlborn thermal
cycles and maximum-work reversible cycles. This linkage is built through a
mapping between the exponents of a class of heat transfer laws and the
exponents of a family of heat capacities depending on temperature. This
connection leads to the recovery of known results and to a wide and interesting
set of new results for a class of thermal cycles. Among other results we find
that it is possible to use analytically closed expressions for maximum-work
efficiencies to calculate good approaches to maximum-power efficiencies.


title: Studies of N^* structure from the CLAS meson electroproduction data

abstract:
  The transition \gamma_{v}pN^* amplitudes (electrocouplings) for prominent
excited nucleon states obtained in a wide area of photon virtualities offer
valuable information for the exploration of the N^* structure at different
distances and allow us to access the complex dynamics of non-perturbative
strong interaction. The current status in the studies of \gamma_{v}pN^*
electrocouplings from the data on exclusive meson electroproduction off protons
measured with the CLAS detector at Jefferson Lab is presented. The impact of
these results on exploration of the N^* structure is discussed.


title: Arbitrage-Free Pricing Before and Beyond Probabilities

abstract:
  "Fundamental theorem of asset pricing" roughly states that absence of
arbitrage opportunity in a market is equivalent to the existence of a
risk-neutral probability. We give a simple counterexample to this
oversimplified statement. Prices are given by linear forms which do not always
correspond to probabilities. We give examples of such cases. We also show that
arbitrage freedom is equivalent to the continuity of the pricing linear form in
the relevant topology. Finally we analyze the possible loss of martingality of
asset prices with lognormal stochastic volatility. For positive correlation
martingality is lost when the financial process is modelled through standard
probability theory. We show how to recover martingality using the appropriate
mathematical tools.


title:
Continuous-time Modeling of Bid-Ask Spread and Price Dynamics in Limit
  Order Books

abstract:
  We derive a continuous time model for the joint evolution of the mid price
and the bid-ask spread from a multiscale analysis of the whole limit order book
(LOB) dynamics. We model the LOB as a multiclass queueing system and perform
our asymptotic analysis using stylized features observed empirically. We argue
that in the asymptotic regime supported by empirical observations the mid price
and bid-ask-spread can be described using only certain parameters of the book
(not the whole book itself). Our limit process is characterized by reflecting
behavior and state-dependent jumps. Our analysis allows to explain certain
characteristics observed in practice such as: the connection between power-law
decaying tails in the volumes of the order book and the returns, as well as
statistical properties of the long-run spread distribution.


title:
The production of strong broad He II emission after the tidal disruption
  of a main-sequence star by a supermassive black hole

abstract:
  The tidal disruption event (TDE) PS1-10jh lacked strong Balmer lines but
showed strong, broad, He II emission both before maximum light and for at least
8 months thereafter. Gezari et al. interpreted this as evidence for the
disruption of a rare hydrogen-deficient star. However, Guillochon et al. have
argued instead that the disrupted star was a normal main-sequence star and that
the strength of the He II emission compared with the Balmer lines is a result
the emission being similar to the broad-line region (BLR) of an AGN, but
lacking the outer, lower-ionization BLR gas. We show that the profile of He II
4686 in PS1-10jh is similar to the blueshifted profiles of high-ionization
lines in AGNs. We find an He II 4686/Halpha ratio for PS1-10jh of ~ 3.7. We
show that both the high-velocity gas of the inner BLR of normal AGNs and the
spectra of type II-P supernovae right after shock break out also produce very
high He II 4686/Halpha ratios. A high He II 4686/Halpha ratio can thus be
produced with a solar H/He abundance ratio. We demonstrate from photoionization
modelling that the estimated He II 4686/Halpha ratio can be produced with a BLR
truncated before the He++ Stroemgren length if the density is ~ 10^{11}
cm^{-3}. The similarity of the He II 4686 emission in PS1-10jh to the emission
from the inner BLRs of AGNs supports the idea that the emission after a TDE
event is similar to that of normal AGNs.


title: Cognitive Radio with Random Number of Secondary Number of Users

abstract:
  A single primary user cognitive radio system with multi-user diversity at the
secondary users is considered where there is an interference constraint between
secondary and primary users. The secondary user with the highest instantaneous
SNR is selected for communication from a set of active users which also
satisfies the interference constraint. The active number of secondary users is
shown to be binomial, negative binomial, or Poisson-binomial distributed
depending on various modes of operation. Outage probability in the slow fading
scenario is also studied. This is then followed by a derivation of the scaling
law of the ergodic capacity and BER averaged across the fading, and user
distribution for a large mean number of users. The ergodic capacity and average
BER under the binomial user distribution is shown to outperform the negative
binomial case with the same mean number of users. Moreover, the Poisson
distribution is used to approximate the user distribution under the non-i.i.d
interference scenario, and compared with binomial and negative binomial
distributions in a stochastic ordering sense. Monte-Carlo simulations are used
to supplement our analytical results and compare the performances under
different user distributions.


title:
The Clustering of Galaxies in the SDSS-III DR10 Baryon Oscillation
  Spectroscopic Survey: No Detectable Colour Dependence of Distance Scale or
  Growth Rate Measurements

abstract:
  We study the clustering of galaxies, as a function of their colour, from Data
Release Ten (DR10) of the SDSS-III Baryon Oscillation Spectroscopic Survey. We
select 122,967 galaxies with 0.43 < z < 0.7 into a "Blue" sample and 131,969
into a "Red" sample based on k+e corrected (to z=0.55) r-i colours and i band
magnitudes. The samples are chosen to each contain more than 100,000 galaxies,
have similar redshift distributions, and maximize the difference in clustering
amplitude. The Red sample has a 40% larger bias than the Blue (b_Red/b_Blue =
1.39+-0.04), implying the Red galaxies occupy dark matter halos with an average
mass that is 0.5 log Mo greater. Spherically averaged measurements of the
correlation function, \xi 0, and the power spectrum are used to locate the
position of the baryon acoustic oscillation (BAO) feature of both samples.
Using \xi 0, we obtain distance scales, relative to our reference LCDM
cosmology, of 1.010+-0.027 for the Red sample and 1.005+-0.031 for the Blue.
After applying reconstruction, these measurements improve to 1.013+/-0.020 for
the Red sample and 1.008+-0.026 for the Blue. For each sample, measurements of
\xi 0 and the second multipole moment, \xi 2, of the anisotropic correlation
function are used to determine the rate of structure growth, parameterized by
f\sigma 8. We find f\sigma 8,Red = 0.511+-0.083, f\sigma 8,Blue =
0.509+/-0.085, and f\sigma 8,Cross = 0.423+-0.061 (from the cross-correlation
between the Red and Blue samples). We use the covariance between the bias and
growth measurements obtained from each sample and their cross-correlation to
produce an optimally-combined measurement of f\sigma 8,comb = 0.443+-0.055. In
no instance do we detect significant differences in distance scale or structure
growth measurements obtained from the Blue and Red samples.


title: Recent Progress in Cosmology and Particle Astrophysics

abstract:
  Recent years have seen dramatic progress in cosmology and particle
astrophysics. So much so that anyone who dares to offer an overview would
certainly risk him- or herself for being incomplete and biased at best, and
even incorrect due to the author's limited expertise. It is with this
understanding and excuse that I risk myself in offering this review. After a
brief summary of Planck mission's first results, I highlight some selected
theoretical and experimental advancement in dark energy, dark matter, and
cosmic neutrinos research. It is hoped that with a glance through these
exciting development, one would be convinced that we are now a step closer to
the ultimate understanding of our universe, while major breakthroughs are still
required.


title:
Early evolution of clumps formed via gravitational instability in
  protoplanetary disks; precursors of Hot Jupiters?

abstract:
  Although it is fairly established that Gravitational Instability (GI) should
occur in the early phases of the evolution of a protoplanetary disk, the fate
of the clumps resulting from disk fragmentation and their role in planet
formation is still unclear. In the present study we investigate
semi-analytically their evolution following the contraction of a synthetic
population of clumps with varied initial structure and orbits coupled with the
surrounding disk and the central star. Our model is based on recently published
state-of-the-art 3D collapse simulations of clumps with varied thermodynamics.
Various evolutionary mechanisms are taken into account, and their effect is
explored both individually and in combination with others: migration and tidal
disruption, mass accretion, gap opening and disk viscosity. It is found that,
in general, at least 50% of the initial clumps survive tides, leaving behind
potential gas giant progenitors after ~10^5 yr of evolution in the disk. The
rest might be either disrupted or produce super-Earths and other low mass
planets provided that a solid core can be assembled on a sufficiently short
timescale, a possibility that we do not address in this paper. Extrapolating to
million year timescales, all our surviving protoplanets would lead to close-in
gas giants. This outcome might in part reflect the limitations of the migration
model adopted, and is reminiscent of the analogous result found in
core-accretion models in absence of fine-tuning of the migration rate. Yet it
suggests that a significant fraction of the clumps formed by gravitational
instability could be the precursors of Hot Jupiters.


title: Minimal forbidden sets for degree sequence characterizations

abstract:
  Given a set $\mathcal{F}$ of graphs, a graph $G$ is $\mathcal{F}$-free if $G$
does not contain any member of $\mathcal{F}$ as an induced subgraph. Barrus,
Kumbhat, and Hartke [M. D. Barrus, M. Kumbhat, and S. G. Hartke, Graph classes
characterized both by forbidden subgraphs and degree sequences, J. Graph Theory
(2008), no. 2, 131--148] called $\mathcal{F}$ a degree-sequence-forcing (DSF)
set if, for each graph $G$ in the class $\mathcal{C}$ of $\mathcal{F}$-free
graphs, every realization of the degree sequence of $G$ is also in
$\mathcal{C}$. A DSF set is minimal if no proper subset is also DSF. In this
paper, we present new properties of minimal DSF sets, including that every
graph is in a minimal DSF set and that there are only finitely many DSF sets of
cardinality $k$. Using these properties and a computer search, we characterize
the minimal DSF triples.


title: Role of correlations in the two-body-marginal problem

abstract:
  Quantum properties of correlations have a key role in disparate fields of
physics, from quantum information processing, to quantum foundations, to
strongly correlated systems. We tackle a specific aspect of the fundamental
quantum marginal problem: we address the issue of deducing the global
properties of correlations of tripartite quantum states based on the knowledge
of their bipartite reductions, focusing on relating specific properties of
bipartite correlations to global correlation properties. We prove that strictly
classical bipartite correlations may still require global entanglement and that
unentangled---albeit not strictly classical---reductions may require global
genuine multipartite entanglement, rather than simple entanglement. On the
other hand, for three qubits, the strict classicality of the bipartite
reductions rules out the need for genuine multipartite entanglement. Our work
sheds new light on the relation between local and global properties of quantum
states, and on the interplay between classical and quantum properties of
correlations.


title: Observation of Coherence in the Photosystem II Reaction Center

abstract:
  Photosynthesis powers life on our planet. The basic photosynthetic
architecture comprises antenna complexes to harvest solar energy and reaction
centers to convert the energy into a stable charge separated state. In oxygenic
photosynthesis, the initial charge separation event occurs in the photosystem
II reaction center; the only known natural enzyme that uses solar energy to
split water. Energy transfer and charge separation in photosynthesis are rapid
and have high quantum efficiencies. Recently, nonlinear spectroscopic
experiments have suggested that electronic coherence may play a role in energy
transfer efficiency in antenna complexes. Here we report the observation of
coherence in the photosystem II reaction center by two dimensional electronic
spectroscopy. The frequencies of the observed coherences match exciton
difference frequencies and/or known vibrational modes of the photosystem II
reaction center. These observations raise questions about the possible role of
electronic and/or vibrational coherence in the fundamental charge separation
process in oxygenic photosynthesis.


title: On fractional realizations of graph degree sequences

abstract:
  We introduce fractional realizations of a graph degree sequence and a closely
associated convex polytope. Simple graph realizations correspond to a subset of
the vertices of this polytope. We describe properties of the polytope vertices
and characterize degree sequences for which each polytope vertex corresponds to
a simple graph realization. These include the degree sequences of pseudo-split
graphs, and we characterize their realizations both in terms of forbidden
subgraphs and graph structure.


title:
Coulomb effects in cold fission from reactions 233U(nth,f) and
  235U(nth,f)

abstract:
  The Coulomb effect hypothesis in cold fission, formerly used to interpret
fluctuations in the curve of maximal total kinetic energy as a function of
fragments mass, in reactions 233U(nth,f), 235U(nth,f) and 239Pu(nth,f), is
confirmed by the preference for more asymmetrical charge splits observed in
cold fragmentations. Several experimental results on reactions 233U(nth,f) and
235U(nth,f) show that, for two isobaric fragmentations with similar Q-values,
the greater is the value of the kinetic energy of the fragments, the greater
will be the probability of more asymmetric charge split.


title:
General relativistic polytropes for anisotropic matter: The general
  formalism and applications

abstract:
  We set up in detail the general formalism to model polytropic general
relativistic stars with anisotropic pressure. We shall consider two different
possible polytropic equations, all of which yield the same Lane-Emden equation
in the Newtonian limit. A heuristic model based on an ansatz to obtain
anisotropic matter solutions from known solutions for isotropic matter is
adopted to illustrate the effects of the pressure anisotropy on the structure
of the star. In this context, the Tolman mass, which is a measure of the active
gravitational mass, is invoked to explain some features of the models.
Prospective extensions of the proposed approach are pointed out.


title:
Minimizers and Gradient Flows of Attraction-Repulsion Functionals with
  Power Kernels and Their Total Variation Regularization

abstract:
  We study properties of an attractive-repulsive energy functional based on
power-kernels, which can be used for halftoning of images. In the first part of
this work, using a variational framework for probability measures, we examine
existence and behavior of minimizers to the functional and to a regularization
of it by a total variation term. Moreover, we introduce particle approximations
to the functional and to its regularized version and prove their consistency in
terms of Gamma-convergence, which we additionally illustrate by numerical
examples. In the second part, we consider the gradient flow of the functional
in the 2-Wasserstein space and prove statements about its asymptotic behavior
for large times, for which we employ the pseudo-inverse technique for
probability measures in 1D. Depending on the parameter range, this includes
existence of a subsequence converging to a steady state or even convergence of
the whole trajectory to a limit which we can specify explicitly. For both parts
of the work, a key ingredient is the generalized Fourier transform, which
allows us to verify the conditional positive definiteness of the interaction
kernel for coinciding attractive and repulsive exponents.


title: Uniqueness and minimal obstructions for tree-depth

abstract:
  A k-ranking of a graph G is a labeling of the vertices of G with values from
{1,...,k} such that any path joining two vertices with the same label contains
a vertex having a higher label. The tree-depth of G is the smallest value of k
for which a k-ranking of G exists. The graph G is k-critical if it has
tree-depth k and every proper minor of G has smaller tree-depth.
  We establish partial results in support of two conjectures about the order
and maximum degree of k-critical graphs. As part of these results, we define a
graph G to be 1-unique if for every vertex v in G, there exists an optimal
ranking of G in which v is the unique vertex with label 1. We show that several
classes of k-critical graphs are 1-unique, and we conjecture that the property
holds for all k-critical graphs. Generalizing a previously known construction
for trees, we exhibit an inductive construction that uses 1-unique k-critical
graphs to generate large classes of critical graphs having a given tree-depth.


title: Modeling Pulse Characteristics in Xenon with NEST

abstract:
  A comprehensive model for describing the characteristics of pulsed signals,
generated by particle interactions in xenon detectors, is presented. An
emphasis is laid on two-phase time projection chambers, but the models
presented are also applicable to single phase detectors. In order to simulate
the pulse shape due to primary scintillation light, the effects of the ratio of
singlet and triplet dimer state populations, as well as their corresponding
decay times, and the recombination time are incorporated into the model. In a
two phase time projection chamber, when simulating the pulse caused by
electroluminescence light, the ionization electron mean free path in gas, the
drift velocity, singlet and triplet decay times, diffusion constants, and the
electron trapping time, have been implemented. This modeling has been
incorporated into a complete software package, which realistically simulates
the expected pulse shapes for these types of detectors.


title:
Evolution of choices over time: The U.S. Presidential election 2012 and
  the NY City Mayoral Election, 2013

abstract:
  We conducted surveys before and after the 2012 U.S. Presidential election and
prior to the NY City Mayoral election in 2013. The surveys were done using
Amazon Turk. This poster describes the results of our analysis of the surveys
and predicts the winner of the NY City Mayoral Election.