title: Braid equivalence in 3-manifolds with rational surgery description

abstract:
  In this paper we describe braid equivalence for knots and links in a
3-manifold $M$ obtained by rational surgery along a framed link in $S^3$. We
first prove a sharpened version of the Reidemeister theorem for links in $M$.
We then give geometric formulations of the braid equivalence via mixed braids
in $S^3$ using the $L$-moves and the braid band moves.
  We finally give algebraic formulations in terms of the mixed braid groups
$B_{m,n}$ using cabling and the techniques of parting and combing for mixed
braids. We also provide concrete formuli of the braid equivalence in the case
where $M$ is a lens space, a Seifert manifold or a homology sphere obtained
from the trefoil. The algebraic classification of knots and links in a
$3$-manifold via mixed braids is a useful tool for studying skein modules of
$3$-manifolds.


title: Parameterized Approximation Schemes using Graph Widths

abstract:
  Combining the techniques of approximation algorithms and parameterized
complexity has long been considered a promising research area, but relatively
few results are currently known. In this paper we study the parameterized
approximability of a number of problems which are known to be hard to solve
exactly when parameterized by treewidth or clique-width. Our main contribution
is to present a natural randomized rounding technique that extends well-known
ideas and can be used for both of these widths. Applying this very generic
technique we obtain approximation schemes for a number of problems, evading
both polynomial-time inapproximability and parameterized intractability bounds.


title: Funding the Search for Extraterrestrial Intelligence with a Lottery Bond

abstract:
  I propose the establishment of a SETI Lottery Bond to provide a continued
source of funding for the search for extraterrestrial intelligence (SETI). The
SETI Lottery Bond is a fixed rate perpetual bond with a lottery at maturity,
where maturity occurs only upon discovery and confirmation of extraterrestrial
intelligent life. Investors in the SETI Lottery Bond purchase shares that yield
a fixed rate of interest that continues indefinitely until SETI succeeds---at
which point a random subset of shares will be awarded a prize from a lottery
pool. SETI Lottery Bond shares also are transferable, so that investors can
benefact their shares to kin or trade them in secondary markets. The total
capital raised this way will provide a fund to be managed by a financial
institution, with annual payments from this fund to support SETI research, pay
investor interest, and contribute to the lottery fund. Such a plan could
generate several to tens of millions of dollars for SETI research each year,
which would help to revitalize and expand facilities such as the Allen
Telescope Array. The SETI Lottery Bond is a savings product that only can be
offered by a financial institution with authorization to engage in banking and
gaming activities. I therefore suggest that one or more banks offer a
lottery-linked savings product in support of SETI research, with the added
benefit of promoting personal savings and intergenerational wealth building
among individuals.


title: Fundamental Particle Structure in the Cosmological Dark Matter

abstract:
  The nonbaryonic dark matter of the Universe is assumed to consist of new
stable forms of matter. Their stability reflects symmetry of micro world and
mechanisms of its symmetry breaking. Particle candidates for cosmological dark
matter are lightest particles that bear new conserved quantum numbers. Dark
matter particles may represent ideal gas of non-interacting particles.
Self-interacting dark matter weakly or superweakly coupled to ordinary matter
is also possible, reflecting nontrivial pattern of particle symmetry in the
hidden sector of particle theory. In the early Universe the structure of
particle symmetry breaking gives rise to cosmological phase transitions, from
which macroscopic cosmological defects or primordial nonlinear structures can
be originated. Primordial black holes (PBHs) can be not only a candidate for
dark matter, but also represent a universal probe for super-high energy physics
in the early Universe. Evaporating PBHs turn to be a source of even superweakly
interacting particles, while clouds of massive PBHs can serve as a nonlinear
seeds for galaxy formation. The observed broken symmetry of the three known
families may provide a simultaneous solution for the problems of the mass of
neutrino and strong CP violation in the unique framework of models of
horizontal unification. The existence of new stable charged leptons and quarks
is possible, hidden in elusive "dark atoms". Such possibility, strongly
restricted by the constraints on anomalous isotopes of light elements, is not
excluded in scenarios that predict stable double charged particles. The
excessive -2 charged particles are bound in these scenarios with primordial
helium in O-helium "atoms", maintaining specific nuclear-interacting form of
the dark matter, which may provide an interesting solution for the puzzles of
the direct dark matter searches. (abridged)


title:
NGC 1817, NGC 2141, and Berkeley 81: three BOCCE clusters of
  intermediate age

abstract:
  In this paper we analyse the evolutionary status of three open clusters: NGC
1817, NGC 2141, and Berkeley 81. They are all of intermediate age, two are
located in the Galactic anti-centre direction while the third one is located in
the Galactic centre direction. All of them were observed with LBC@LBT using the
Bessel B, V, and I filters. The cluster parameters have been obtained using the
synthetic colour-magnitude diagram (CMD) method, i.e. the direct comparison of
the observational CMDs with a library of synthetic CMDs generated with
different evolutionary sets (Padova, FRANEC, and FST). This analysis shows that
NGC 1817 has subsolar metallicity, age between 0.8 and 1.2 Gyr, reddening
E(B-V) in the range 0.21 and 0.34, and distance modulus (m-M)_0 of about 10.9;
NGC 2141 is older, with age in the range 1.25 and 1.9 Gyr, E(B-V) between 0.36
and 0.45, (m-M)_0 between 11.95 and 12.21, and subsolar metallicity;
Berkeley~81 has metallicity about solar, with age between 0.75 and 1.0 Gyr, has
reddening E(B-V)~0.90 and distance modulus (m-M)_0~12.4. Exploiting the large
field of view of the instrument we derive the structure parameters for NGC 2141
and Be 81 by fitting a King profile to the estimated density profile. Combining
this information with the synthetic CMD technique we estimate a lower limit for
the cluster total mass for these two systems.


title:
Differential algebra on lattice Green functions and Calabi-Yau operators
  (unabridged version)

abstract:
  We revisit miscellaneous linear differential operators mostly associated with
lattice Green functions in arbitrary dimensions, but also Calabi-Yau operators
and order-seven operators corresponding to exceptional differential Galois
groups. We show that these irreducible operators are not only globally
nilpotent, but are such that they are homomorphic to their (formal) adjoints.
Considering these operators, or, sometimes, equivalent operators, we show that
they are also such that, either their symmetric square or their exterior
square, have a rational solution. This is a general result: an irreducible
linear differential operator homomorphic to its (formal) adjoint is necessarily
such that either its symmetric square, or its exterior square has a rational
solution, and this situation corresponds to the occurrence of a special
differential Galois group. We thus define the notion of being "Special
Geometry" for a linear differential operator if it is irreducible, globally
nilpotent, and such that it is homomorphic to its (formal) adjoint. Since many
Derived From Geometry n-fold integrals ("Periods") occurring in physics, are
seen to be diagonals of rational functions, we address several examples of
(minimal order) operators annihilating diagonals of rational functions, and
remark that they also seem to be, systematically, associated with irreducible
factors homomorphic to their adjoint.


title: Anomalous magnetic moment with heavy virtual leptons

abstract:
  We compute the contributions to the electron and muon anomalous magnetic
moment induced by heavy leptons up to four-loop order. Asymptotic expansion is
applied to obtain three analytic expansion terms which show rapid convergence.


title: The Hubble flow: an observer's perspective

abstract:
  In this methodological note we discuss some details and peculiarities of the
cosmic expansion as viewed by a realistic observer. We show that the velocity
$v_\Theta$ related to a change (measured by observer's clock) of the angular
distance, plays an important role in formation of a meaningful observed picture
of the expansion of the universe. Usage of this velocity and the angular
distance (in addition to the standard approach --- proper distance and
corresponding velocity) allows to present the cosmic expansion in a more
illustrative manner. These parameters play a key role in visualization of the
expansion.


title: Charm production in double parton scattering at the LHC

abstract:
  We calculate $c\bar{c}c\bar{c}$ and $b\bar{b}b\bar{b}$ production cross
section in Double Parton Scattering (DPS) processes at the energies of LHC. In
our calculation we include saturation effects in the gluon distribution. For
charm production, our results confirm the prediction of a previous work in
which saturation effects were neglected, namely that at the energies of LHC
charm production in DPS processes becomes comparable with charm production in
SPS. We also estimate the production of $c\bar{c}b\bar{b}$ in DPS. Our results
indicate that at $\sqrt{s}=14$ TeV half of the total amount of bottom produced
in proton-proton collisions comes from this process.


title: Low dimensional neutron moderators for enhanced source brightness

abstract:
  In a recent numerical optimization study we have found that liquid
para-hydrogen coupled cold neutron moderators deliver 3 - 5 times higher cold
neutron brightness at a spallation neutron source if they take the form of a
flat, quasi 2-dimensional disc, in contrast to the conventional more voluminous
shapes used by now. In the present paper we describe a simple theoretical
explanation of this unexpected behavior, which is based on the large difference
in para-hydrogen between the values of the scattering mean free path for
thermal neutrons (in the range of 1 cm) and its much larger equivalent for cold
neutrons. This model leads to the conclusions that the optimal shape for high
brightness para-hydrogen neutron moderators is the quasi 1-dimensional tube and
these low dimensional moderators can also deliver much enhanced cold neutron
brightness in fission reactor neutron sources, compared to much more voluminous
liquid D2 or H2 moderators currently used. Neutronic simulation calculations
confirm both of these theoretical conclusions.


title: On almost complex Lie algebroids

abstract:
  The almost complex Lie algebroids over smooth manifolds are introduced in the
paper. In the first part we give some examples and we obtain a
Newlander-Nirenberg type theorem on almost complex Lie algebroids. Next the
almost Hermitian Lie algebroids and some related structures on the associated
complex Lie algebroid are studied. For instance, we obtain that the $E$-Chern
form of $E^{1,0}$ associated to an almost complex connection $\nabla$ on $E$
can be expressed in terms of the matrix $J_ER$, where $J_E$ is the almost
complex structure of $E$ and $R$ is the curvature of $\nabla$. Also, we
consider a metric product connection associated to an almost Hermitian Lie
algebroid and we prove that the mean curvature section of $E^{0,1}$ vanishes
and the second fundamental $2$--form section of $E^{0,1}$ vanishes iff the Lie
algebroid is Hermitian.


title: Existentially closed structures and some embedding theorems

abstract:
  Using the notion of existentially closed structures, we obtain embedding
theorems for groups and Lie algebras. We also prove the existence of some
groups and Lie algebras with prescribed properties.


title:
Characterisation of the Energy of Gaussian Beams on Lorentzian Manifolds
  - with Applications to Black Hole Spacetimes

abstract:
  It is known that using the Gaussian beam approximation one can show that
there exist solutions of the wave equation on a general globally hyperbolic
Lorentzian manifold whose energy is localised along a given null geodesic for a
finite, but arbitrarily long time. In this paper, we show that the energy of
such a localised solution is determined by the energy of the underlying null
geodesic. This result opens the door to various applications of Gaussian beams
on Lorentzian manifolds that do not admit a globally timelike Killing vector
field. In particular we show that trapping in the exterior of Kerr or at the
horizon of an extremal Reissner-Nordstr\"om black hole necessarily leads to a
`loss of derivative' in a local energy decay statement. We also demonstrate the
obstruction formed by the red-shift effect at the event horizon of a
Schwarzschild black hole to scattering constructions from the future (where the
red-shift turns into a blue-shift): we construct solutions to the backwards
problem whose energies grow exponentially for a finite, but arbitrarily long
time. Finally, we give a simple mathematical realisation of the heuristics for
the blue-shift effect near the Cauchy horizon of sub-extremal and extremal
black holes: we construct a sequence of solutions to the wave equation whose
initial energies are uniformly bounded, whereas the energy near the Cauchy
horizon goes to infinity.


title: Snowmass 2013 Computing Frontier: Networking

abstract:
  Computing has become a major component of all particle physics experiments
and in many areas of theoretical particle physics. Progress in HEP experiment
and theory will require significantly more computing, software development,
storage, and networking, with different projects stretching future capabilities
in different ways. However, there are many common needs among different areas
in HEP, so more community planning is advised to increase efficiency. Careful
and continuing review of the topics we studied, i.e., user needs and
capabilities of current and future technology, is needed.


title:
Degenerate Parametric Amplification of Squeezed Photons: Explicit
  Solutions, Statistics, Means and Variances

abstract:
  In the Schroedinger picture, we find explicit solutions for two models of
degenerate parametric oscillators in the case of multiparameter squeezed input
photons. The corresponding photon statistics and Wigner's function are also
derived in coordinate representation. Their time evolution is investigated in
detail. The unitary transformation is briefly discussed too.


title:
A first principles study of As doping at a disordered Si--SiO$_2$
  interface

abstract:
  Understanding the interaction between dopants and semiconductor-oxide
interfaces is an increasingly important concern in the drive to further
miniaturize modern transistors. To this end, using a combination of
first-principles density-functional theory and a continuous random network
Monte Carlo method, we investigate electrically active arsenic donors at the
interface between silicon and its oxide. Using a realistic model of the
disordered interface, we find that a small percentage (on the order of ~10%) of
the atomic sites in the first few monolayers on the silicon side of the
interface are energetically favourable for segregation, and that this is
controlled by the local bonding and local strain of the defect centre. We also
find that there is a long-range quantum confinement effect due to the
interface, which results in an energy barrier for dopant segregation, but that
this barrier is small in comparison to the effect of the local environment.
Finally, we consider the extent to which the energetics of segregation can be
controlled by the application of strain to the interface.


title:
A Hybrid MPI-OpenMP Parallel Implementation for pseudospectral
  simulations with application to Taylor-Couette Flow

abstract:
  A hybrid-parallel direct-numerical-simulation method with application to
turbulent Taylor-Couette flow is presented. The Navier-Stokes equations are
discretized in cylindrical coordinates with the spectral Fourier-Galerkin
method in the axial and azimuthal directions, and high-order finite differences
in the radial direction. Time is advanced by a second-order, semi-implicit
projection scheme, which requires the solution of five Helmholtz/Poisson
equations, avoids staggered grids and renders very small slip velocities.
Nonlinear terms are computed with the pseudospectral method. The code is
parallelized using a hybrid MPI-OpenMP strategy, which is simpler to implement,
reduces inter-node communications and is more efficient compared to a flat MPI
parallelization. A strong scaling study shows that the hybrid code maintains
very good scalability up to more than 20000 processor cores and thus allows to
perform simulations at higher resolutions than previously feasible, and opens
up the possibility to simulate turbulent Taylor-Couette flows at Reynolds
numbers up to $\mathcal{O}(10^5)$. This enables to probe hydrodynamic
turbulence in Keplerian flows in experimentally relevant regimes.


title: Roadmap on the theoretical work of BinaMIcS

abstract:
  We review the different theoretical challenges concerning magnetism in
interacting binary or multiple stars that will be studied in the BinaMIcS
(Binarity and Magnetic Interactions in various classes of Stars) project during
the corresponding spectropolarimetric Large Programs at CFHT and TBL. We
describe how completely new and innovative topics will be studied with BinaMIcS
such as the complex interactions between tidal flows and stellar magnetic
fields, the MHD star-star interactions, and the role of stellar magnetism in
stellar formation and vice versa. This will strongly modify our vision of the
evolution of interacting binary and multiple stars.


title: Global Sensitivity Analysis with Dependence Measures

abstract:
  Global sensitivity analysis with variance-based measures suffers from several
theoretical and practical limitations, since they focus only on the variance of
the output and handle multivariate variables in a limited way. In this paper,
we introduce a new class of sensitivity indices based on dependence measures
which overcomes these insufficiencies. Our approach originates from the idea to
compare the output distribution with its conditional counterpart when one of
the input variables is fixed. We establish that this comparison yields
previously proposed indices when it is performed with Csiszar f-divergences, as
well as sensitivity indices which are well-known dependence measures between
random variables. This leads us to investigate completely new sensitivity
indices based on recent state-of-the-art dependence measures, such as distance
correlation and the Hilbert-Schmidt independence criterion. We also emphasize
the potential of feature selection techniques relying on such dependence
measures as alternatives to screening in high dimension.


title: Scaling Navier-Stokes Equation in Nanotubes

abstract:
  On one hand, classical Monte Carlo and molecular dynamics (MD) simulations
have been very useful in the study of liquids in nanotubes, enabling a wide
variety of properties to be calculated in intuitive agreement with experiments.
On the other hand, recent studies indicate that the theory of continuum breaks
down only at the nanometer level; consequently flows through nanotubes still
can be investigated with Navier-Stokes equations if we take suitable boundary
conditions into account. The aim of this paper is to study the statics and
dynamics of liquids in nanotubes by using methods of non-linear continuum
mechanics. We assume that the nanotube is filled with only a liquid phase; by
using a second gradient theory the static profile of the liquid density in the
tube is analytically obtained and compared with the profile issued from
molecular dynamics simulation. Inside the tube there are two domains: a thin
layer near the solid wall where the liquid density is non-uniform and a central
core where the liquid density is uniform. In the dynamic case a closed form
analytic solution seems to be no more possible, but by a scaling argument it is
shown that, in the tube, two distinct domains connected at their frontiers
still exist. The thin inhomogeneous layer near the solid wall can be
interpreted in relation with the Navier length when the liquid slips on the
boundary as it is expected by experiments and molecular dynamics calculations.

categories: physics.flu-dyn math-ph math.MP physics.chem-ph


abstract:
  Continuous-time quantum error correction (CTQEC) is an approach to protecting
quantum information from noise in which both the noise and the error correcting
operations are treated as processes that are continuous in time. This chapter
investigates CTQEC based on continuous weak measurements and feedback from the
point of view of the subsystem principle, which states that protected quantum
information is contained in a subsystem of the Hilbert space. We study how to
approach the problem of constructing CTQEC protocols by looking at the
evolution of the state of the system in an encoded basis in which the subsystem
containing the protected information is explicit. This point of view allows us
to reduce the problem to that of protecting a known state, and to design CTQEC
procedures from protocols for the protection of a single qubit. We show how
previously studied CTQEC schemes with both direct and indirect feedback can be
obtained from strategies for the protection of a single qubit via weak
measurements and weak unitary operations. We also review results on the
performance of CTQEC with direct feedback in cases of Markovian and
non-Markovian decoherence, where we have shown that due to the existence of a
Zeno regime in non-Markovian dynamics, the performance of CTQEC can exhibit a
quadratic improvement if the time resolution of the weak error-correcting
operations is high enough to reveal the non-Markovian character of the noise
process.


title: How Vertex reinforced jump process arises naturally

abstract:
  We prove that the only nearest neighbor jump process with local dependence on
the occupation times satisfying the partial exchangeability property is the
vertex reinforced jump process, under some technical conditions. This result
gives a counterpart to the characterization of edge reinforced random walk
given by Rolles.


title: Rashba spin splitting in symmetric structures

abstract:
  It is widely believed that Rasba spin splitting occurs only in systems
lacking space inversion invariance. In this letter we present analytical
analysis which suggests that non-zero Rashba spin splitting occurs in systems
possessing space inversion invariance. We present numerical simulations which
confirm that non-zero Rashba spin splitting occurs in symmetric structures but
this splitting is several orders of magnitude smaller than the Rashba spin
splitting due to broken space inversion invariance.


title:
A numerical strategy to discretize and solve the Poisson equation on
  dynamically adapted multiresolution grids for time-dependent streamer
  discharge simulations

abstract:
  We develop a numerical strategy to solve multi-dimensional Poisson equations
on dynamically adapted grids for evolutionary problems disclosing propagating
fronts. The method is an extension of the multiresolution finite volume scheme
used to solve hyperbolic and parabolic time-dependent PDEs. Such an approach
guarantees a numerical solution of the Poisson equation within a user-defined
accuracy tolerance. Most adaptive meshing approaches in the literature solve
elliptic PDEs level-wise and hence at uniform resolution throughout the set of
adapted grids. Here we introduce a numerical procedure to represent the
elliptic operators on the adapted grid, strongly coupling inter grid relations
that guarantee the conservation and accuracy properties of multiresolution
finite volume schemes. The discrete Poisson equation is solved at once over the
entire computational domain as a completely separate process. The accuracy and
numerical performance of the method is assessed in the context of streamer
discharge simulations.


title: Quantum gravity via supersymmetry and holography

abstract:
  We review the approach to quantum gravity based on supersymmetry, strings,
and holography. This includes a survey of black holes in higher-dimensions,
supersymmetry and supergravity, as well as string theory, black hole
microstates, and the gauge/gravity duality. This presentation will appear as a
chapter in "General Relativity and Gravitation: A Centennial Perspective", to
be published by Cambridge University Press.


title: Semiclassical quantization of classical field theories

abstract:
  These lectures are an introduction to formal semiclassical quantization of
classical field theory. First we develop the Hamiltonian formalism for
classical field theories on space time with boundary. It does not have to be a
cylinder as in the usual Hamiltonian framework. Then we outline formal
semiclassical quantization in the finite dimensional case. Towards the end we
give an example of such a quantization in the case of Abelian Chern-Simons
theory.


title:
The Prime Number Theorem via Karamata's proof of the Landau-Ingham
  Tauberian theorem

abstract:
  This is an exposition, in 12 pages including all prerequisites and a
generalization, of Karamata's little known elementary proof of the
Landau-Ingham Tauberian theorem, a result in real analysis from which the Prime
Number Theorem follows in a few lines. We believe this to be the most
transparent of the elementary proofs of the PNT.


title:
Notes on Elementary Spectral Graph Theory. Applications to Graph
  Clustering Using Normalized Cuts

abstract:
  These are notes on the method of normalized graph cuts and its applications
to graph clustering. I provide a fairly thorough treatment of this deeply
original method due to Shi and Malik, including complete proofs. I include the
necessary background on graphs and graph Laplacians. I then explain in detail
how the eigenvectors of the graph Laplacian can be used to draw a graph. This
is an attractive application of graph Laplacians. The main thrust of this paper
is the method of normalized cuts. I give a detailed account for K = 2 clusters,
and also for K > 2 clusters, based on the work of Yu and Shi. Three points that
do not appear to have been clearly articulated before are elaborated:
  1. The solutions of the main optimization problem should be viewed as tuples
in the K-fold cartesian product of projective space RP^{N-1}.
  2. When K > 2, the solutions of the relaxed problem should be viewed as
elements of the Grassmannian G(K,N).
  3. Two possible Riemannian distances are available to compare the closeness
of solutions: (a) The distance on (RP^{N-1})^K. (b) The distance on the
Grassmannian.
  I also clarify what should be the necessary and sufficient conditions for a
matrix to represent a partition of the vertices of a graph to be clustered.


title: Nanoantennas for ultrabright single photon sources

abstract:
  We propose to use nanoantennas coupled to incoherently pumped quantum dots
for ultra-bright single photon emission. Besides fully quantum calculations, we
analyze an analytical expression for the emitted photon rate. From these
analytical considerations it turns out that the Purcell factor and the pumping
rate are the main quantities of interest. We also disclose a trade-off between
the emitted photon rate and the nonclassical nature of the emitted light. This
trade-off has to be considered while designing suitable nanoantennas, which we
also discuss in depth.


title:
Improved annotation of 3-prime untranslated regions and complex loci by
  combination of strand-specific Direct RNA Sequencing, RNA-seq and ESTs

abstract:
  The reference annotations made for a genome sequence provide the framework
for all subsequent analyses of the genome. Correct annotation is particularly
important when interpreting the results of RNA-seq experiments where short
sequence reads are mapped against the genome and assigned to genes according to
the annotation. Inconsistencies in annotations between the reference and the
experimental system can lead to incorrect interpretation of the effect on RNA
expression of an experimental treatment or mutation in the system under study.
Until recently, the genome-wide annotation of 3-prime untranslated regions
received less attention than coding regions and the delineation of intron/exon
boundaries. In this paper, data produced for samples in Human, Chicken and A.
thaliana by the novel single-molecule, strand-specific, Direct RNA Sequencing
technology from Helicos Biosciences which locates 3-prime polyadenylation sites
to within +/- 2 nt, were combined with archival EST and RNA-Seq data. Nine
examples are illustrated where this combination of data allowed: (1) gene and
3-prime UTR re-annotation (including extension of one 3-prime UTR by 5.9 kb);
(2) disentangling of gene expression in complex regions; (3) clearer
interpretation of small RNA expression and (4) identification of novel genes.
While the specific examples displayed here may become obsolete as genome
sequences and their annotations are refined, the principles laid out in this
paper will be of general use both to those annotating genomes and those seeking
to interpret existing publically available annotations in the context of their
own experimental data


title: The Noisy Power Method: A Meta Algorithm with Applications

abstract:
  We provide a new robust convergence analysis of the well-known power method
for computing the dominant singular vectors of a matrix that we call the noisy
power method. Our result characterizes the convergence behavior of the
algorithm when a significant amount noise is introduced after each
matrix-vector multiplication. The noisy power method can be seen as a
meta-algorithm that has recently found a number of important applications in a
broad range of machine learning problems including alternating minimization for
matrix completion, streaming principal component analysis (PCA), and
privacy-preserving spectral analysis. Our general analysis subsumes several
existing ad-hoc convergence bounds and resolves a number of open problems in
multiple applications including streaming PCA and privacy-preserving singular
vector computation.


title: Spectroscopy in the Era of LSST

abstract:
  This report summarizes the results of the 'Spectroscopy in the Era of LSST'
workshop held April 11-12, 2013 in Tucson, Arizona. At the workshop, there were
breakout sessions covering four broad science topics. These were: time domain
science, Galactic structure and stellar populations, galaxies and AGN, and dark
energy and cosmology. We present the science cases discussed in these breakout
sessions and provide a synthesis of highly desired capabilities that meet needs
across all four broad topics. We also present a table that will be useful to
characterize the needs of specific science cases in a format that provides a
general framework for discussion of future spectroscopic capabilities.


title: Stable cohomology of spaces of non-singular hypersurfaces

abstract:
  We prove that the rational cohomology of the space of non-singular complex
homogeneous polynomials of degree d in a fixed number of variables stabilizes
to the cohomology of the general linear group for d sufficiently large.


title:
Magneto-electric and thermo-magneto-electric effects in ferromagnetic
  transition-metal alloys from first-principles

abstract:
  The electric and thermo-magneto-electric transport of the prototypical
ferromagnetic transition-metal alloy system fcc-Co$_x$Pd$_{1-x}$ has been
investigated on the basis of Kubo's linear response formalism. The results for
the full electric conductivity tensor allow to discuss the spin-orbit induced
anisotropic magneto-resistance (AMR) and the anomalous Hall effect (AHE). These
are complemented by results for the corresponding thermo-magneto-electric
transport properties anisotropy of the Seebeck effect (ASE) and anomalous
Nernst effect (ANE). The relation between the respective response coefficients
is discussed with the underlying electronic structure calculated
relativistically within the Korringa-Kohn-Rostoker coherent potential
approximation (KKR-CPA) band structure method for disordered alloys.


title:
Thermally-Activated Post-Glitch Response of the Neutron Star Inner Crust
  and Core. I: Theory

abstract:
  Pinning of superfluid vortices is predicted to prevail throughout much of a
neutron star. Based on the idea of Alpar et al., I develop a description of the
coupling between the solid and liquid components of a neutron star through {\em
thermally-activated vortex slippage}, and calculate the the response to a spin
glitch. The treatment begins with a derivation of the vortex velocity from the
vorticity equations of motion. The activation energy for vortex slippage is
obtained from a detailed study of the mechanics and energetics of vortex
motion. I show that the "linear creep" regime introduced by Alpar et al. and
invoked in fits to post-glitch response is not realized for physically
reasonable parameters, a conclusion that strongly constrains the physics of
post-glitch response through thermal activation. Moreover, a regime of
"superweak pinning", crucial to the theory of Alpar et al. and its extensions,
is probably precluded by thermal fluctuations. The theory given here has a
robust conclusion that can be tested by observations: {\em for a glitch in spin
rate of magnitude $\Delta\nu$, pinning introduces a delay in the post-glitch
response time}. The delay time is $t_d=7
(t_{sd}/10^4\mbox{yr})((\Delta\nu/\nu)/10^{-6})$ d where $t_{sd}$ is the
spin-down age; $t_d$ is typically weeks for the Vela pulsar and months in older
pulsars, and is independent of the details of vortex pinning. Post-glitch
response through thermal activation cannot occur more quickly than this
timescale. Quicker components of post-glitch response as have been observed in
some pulsars, notably, the Vela pulsar, cannot be due to thermally-activated
vortex motion but must represent a different process, such as drag on vortices
in regions where there is no pinning. I also derive the mutual friction force
for a pinned superfluid at finite temperature for use in other studies of
neutron star hydrodynamics.


title: Compact embedded minimal surfaces in $\mathbb{S}^2\times \mathbb{S}^1$

abstract:
  We prove that closed surfaces of all topological types, except for the
non-orientable odd-genus ones, can be minimally embedded in the Riemannian
product of a sphere and a circle of arbitrary radius. We illustrate it by
obtaining some periodic minimal surfaces in $\mathbb{S}^2\times\mathbb{R}$ via
conjugate constructions. The resulting surfaces can be seen as the analogy to
the Schwarz P-surface in these homogeneous 3-manifolds.


title:
A reduction of proof complexity to computational complexity for
  $AC^0[p]$ Frege systems

abstract:
  We give a general reduction of lengths-of-proofs lower bounds for constant
depth Frege systems in DeMorgan language augmented by a connective counting
modulo a prime $p$ (the so called $AC^0[p]$ Frege systems) to computational
complexity lower bounds for search tasks involving search trees branching upon
values of maps on the vector space of low degree polynomials over the finite
filed with $p$ elements.


title: Higher order temporal finite element methods through mixed formulations

abstract:
  The EHP and the MCAP provide new rigorous weak variational formalism for a
broad range of initial boundary value problems in mathematical physics and
mechanics. Both approaches utilize the mixed formulation and lead to the
development of various space-time finite element methods. In this paper, their
potential when adopting temporally higher order approximations is investigated.
The classical single-degree-of-freedom dynamical systems are primarily
considered to validate and to investigate the performance of the numerical
algorithms developed from both formulations. For the undamped system, all the
algorithms are found to be symplectic and unconditionally stable with respect
to the time step. On the other hand, for the damped system, the approach is
shown to be robust and to be accurate with good convergence characteristics.


title: Predictable Feature Analysis

abstract:
  Every organism in an environment, whether biological, robotic or virtual,
must be able to predict certain aspects of its environment in order to survive
or perform whatever task is intended. It needs a model that is capable of
estimating the consequences of possible actions, so that planning, control, and
decision-making become feasible. For scientific purposes, such models are
usually created in a problem specific manner using differential equations and
other techniques from control- and system-theory. In contrast to that, we aim
for an unsupervised approach that builds up the desired model in a
self-organized fashion. Inspired by Slow Feature Analysis (SFA), our approach
is to extract sub-signals from the input, that behave as predictable as
possible. These "predictable features" are highly relevant for modeling,
because predictability is a desired property of the needed
consequence-estimating model by definition. In our approach, we measure
predictability with respect to a certain prediction model. We focus here on the
solution of the arising optimization problem and present a tractable algorithm
based on algebraic methods which we call Predictable Feature Analysis (PFA). We
prove that the algorithm finds the globally optimal signal, if this signal can
be predicted with low error. To deal with cases where the optimal signal has a
significant prediction error, we provide a robust, heuristically motivated
variant of the algorithm and verify it empirically. Additionally, we give
formal criteria a prediction-model must meet to be suitable for measuring
predictability in the PFA setting and also provide a suitable default-model
along with a formal proof that it meets these criteria.


title: A Semi-automated Peer-review System

abstract:
  A semi-supervised model of peer review is introduced that is intended to
overcome the bias and incompleteness of traditional peer review. Traditional
approaches are reliant on human biases, while consensus decision-making is
constrained by sparse information. Here, the architecture for one potential
improvement (a semi-supervised, human-assisted classifier) to the traditional
approach will be introduced and evaluated. To evaluate the potential advantages
of such a system, hypothetical receiver operating characteristic (ROC) curves
for both approaches will be assessed. This will provide more specific
indications of how automation would be beneficial in the manuscript evaluation
process. In conclusion, the implications for such a system on measurements of
scientific impact and improving the quality of open submission repositories
will be discussed.


title: On optimal constacyclic codes

abstract:
  In this paper we investigate the class of constacyclic codes, which is a
natural generalization of the class of cyclic and negacyclic codes. This class
of codes is interesting in the sense that it contains codes with good or even
optimal parameters. In this light, we propose constructions of families of
classical block and convolutional maximum-distance-separable (MDS) constacyclic
codes, as well as families of asymmetric quantum MDS codes derived from
(classical-block) constacyclic codes. These results are mainly derived from the
investigation of suitable properties on cyclotomic cosets of these
corresponding codes.


title:
A Comment on "Cycles and Instability in a Rock-Paper-Scissors Population
  Game: A Continuous Time Experiment"

abstract:
  The authors (Cason, Friedman and Hopkins, Reviews of Economics Studies, 2014)
claimed a result that the treatments (using simultaneous matching in discrete
time) replicate previous results that exhibit weak or no cycles. After correct
two mathematical mistakes in their cycles tripwire algorithm, we research the
cycles by scanning the tripwire in the full strategy space of the games and we
find significant cycles missed by the authors. So we suggest that, all of the
treatments (using simultaneous matching in discrete time) exhibit significant
cycles.


title:
Robust Beamforming for Secure Communication in Systems with Wireless
  Information and Power Transfer

abstract:
  This paper considers a multiuser multiple-input single-output (MISO) downlink
system with simultaneous wireless information and power transfer. In
particular, we focus on secure communication in the presence of passive
eavesdroppers and potential eavesdroppers (idle legitimate receivers). We study
the design of a resource allocation algorithm minimizing the total transmit
power for the case when the legitimate receivers are able to harvest energy
from radio frequency signals. Our design advocates the dual use of both
artificial noise and energy signals in providing secure communication and
facilitating efficient wireless energy transfer. The algorithm design is
formulated as a non-convex optimization problem. The problem formulation takes
into account artificial noise and energy signal generation for protecting the
transmitted information against both considered types of eavesdroppers when
imperfect channel state information (CSI) of the potential eavesdroppers and no
CSI of the passive eavesdroppers are available at the transmitter. In light of
the intractability of the problem, we reformulate the considered problem by
replacing a non-convex probabilistic constraint with a convex deterministic
constraint. Then, a semi-definite programming (SDP) relaxation approach is
adopted to obtain the optimal solution for the reformulated problem.
Furthermore, we propose a suboptimal resource allocation scheme with low
computational complexity for providing communication secrecy and facilitating
efficient energy transfer. Simulation results demonstrate a close-to-optimal
performance achieved by the proposed schemes and significant transmit power
savings by optimization of the artificial noise and energy signal generation.


title: Funk and Hilbert geometries from the Finslerian Viewpoint

abstract:
  In 1929, Paul Funk and Ludwig Berwald gave a characterization of Hilbert
geometries from the Finslerian viewpoint. They showed that a smooth Finsler
metric in a convex bounded domain of $\mathbb{R}^n$ is the Hilbert geometry in
that domain if and only if it is complete, if its geodesics are straight lines
and if its flag curvature is equal to -1. The goal of this chapter is to
explain these notions in details, to illustrate the relation between Hilbert
geometry, Finsler geometry and the calculus of variations, and to prove the
Funk-Berwald characterization Theorem.


title: Cartan-type criterions for constancy of almost Hermitian manifolds

abstract:
  We studied the axiom of anti-invariant 2-spheres and the axiom of
co-holomorphic $(2n+1)$-spheres. We proved that a nearly K\"{a}hlerian manifold
satisfying the axiom of anti-invariant 2-spheres is a space of constant
holomorphic sectional curvature. We also showed that an almost Hermitian
manifold $M$ of dimension $2m\geq6$ satisfying the axiom of co-holomorphic
$(2n+1)$-spheres for some $n,$ where $(1\leq n\leq m-1)$, the manifold $M$ has
pointwise constant type $\alpha$ if and only if $M$ has pointwise constant
anti-holomorphic sectional curvature $\alpha$.


title:
Ab-initio characterization of the quantum linear-zigzag transition using
  DMRG

abstract:
  Ions of the same charge inside confining potentials can form crystalline
structures which can be controlled by means of the ions density and of the
external trap parameters. In particular, a linear chain of trapped ions
exhibits a transition to a zigzag equilibrium configuration, which is
controlled by the strength of the transverse confinement. Studying this phase
transition in the quantum regime is a challenging problem, even when employing
numerical methods to simulate microscopically quantum many-body systems. Here
we present a compact analytical treatment to map the original long-range
problem into a short-range quantum field theory on a lattice. We provide a
complete numerical architecture, based on Density Matrix Renormalization Group,
to address the effective quantum phi-four model. This technique is instrumental
in giving a complete characterization of the phase diagram, as well as pinpoint
the universality class of the criticality.


title: Spin Glasses and Nonlinear Constraints in Portfolio Optimization

abstract:
  We discuss the portfolio optimization problem with the obligatory deposits
constraint. Recently it has been shown that as a consequence of this nonlinear
constraint, the solution consists of an exponentially large number of optimal
portfolios, completely different from each other, and extremely sensitive to
any changes in the input parameters of the problem, making the concept of
rational decision making questionable. Here we reformulate the problem using a
quadratic obligatory deposits constraint, and we show that from the physics
point of view, finding an optimal portfolio amounts to calculating the
mean-field magnetizations of a random Ising model with the constraint of a
constant magnetization norm. We show that the model reduces to an eigenproblem,
with 2N solutions, where N is the number of assets defining the portfolio.
Also, in order to illustrate our results, we present a detailed numerical
example of a portfolio of several risky common stocks traded on the Nasdaq
Market.


title:
Exact high temperature expansion of the one-loop thermodynamic potential
  with complex chemical potential

abstract:
  We present a derivation of an exact high temperature expansion for a one-loop
thermodynamic potential $\Omega(\tilde{\mu})$ with complex chemical potential
$\tilde{\mu}$. The result is given in terms of a single sum the coefficients of
which are analytical functions of $\tilde{\mu}$ consisting of polynomials and
polygamma functions, decoupled from the physical expansion parameter $\beta m$.
The analytic structure of the coefficients permits us to explicitly calculate
the thermodynamic potential for the imaginary chemical potential and
analytically continue the domain to the complex $\tilde{\mu}$ plane.
Furthermore, our representation of $\Omega(\tilde{\mu})$ is particularly well
suited for the Landau--Ginzburg-type of phase transition analysis. This fact,
along with the possibility of interpreting the imaginary chemical potential as
an effective generalized-statistics phase, allows us to investigate the
singular origin of the $m^3$ term appearing only in the bosonic thermodynamic
potential.


title: Breaking the PPSZ Barrier for Unique 3-SAT

abstract:
  The PPSZ algorithm by Paturi, Pudl\'ak, Saks, and Zane (FOCS 1998) is the
fastest known algorithm for (Promise) Unique k-SAT. We give an improved
algorithm with exponentially faster bounds for Unique 3-SAT.
  For uniquely satisfiable 3-CNF formulas, we do the following case
distinction: We call a clause critical if exactly one literal is satisfied by
the unique satisfying assignment. If a formula has many critical clauses, we
observe that PPSZ by itself is already faster. If there are only few clauses
allover, we use an algorithm by Wahlstr\"om (ESA 2005) that is faster than PPSZ
in this case. Otherwise we have a formula with few critical and many
non-critical clauses. Non-critical clauses have at least two literals
satisfied; we show how to exploit this to improve PPSZ.


title:
Tight-Binding Model for Adatoms on Graphene: Analytical Density of
  States, Spectral Function, and Induced Magnetic Moment

abstract:
  In the limit of low adatom concentration, we obtain exact analytic
expressions for the local and total density of states (LDOS, TDOS) for a
tight-binding model of adatoms on graphene. The model is not limited to
nearest-neighbor hopping but can include hopping between carbon atoms at any
separation. We also find an analytical expression for the spectral function
$A({\bf k}, E)$ of an electron of Bloch vector ${\bf k}$ and energy E on the
graphene lattice, to first order in the adatom concentration. We treat the
electron-electron interaction by including a Hubbard term on the adatom, which
we solve within a mean-field approximation. For finite Hubbard $U$, we find the
spin-polarized LDOS, TDOS, and spectral function self-consistently. For any
choice of parameters of the tight-binding model within mean field theory, we
find a critical value of $U$ above which a moment develops on the adatom. For
most choices of parameters, we find a substantial charge transfer from the
adatom to the graphene host.


title: Some haracterizations of almost Hermitian manifolds

abstract:
  We give a condition for an almost constant-type manifold to be a
constant-type manifold, and holomorphic and $R$-invariant submanifolds of
almost Hermitian manifolds are studied. Generalizations of some results in [5]
are given.


title:
Localized orientational order chaperons the nucleation of Rotator phases
  in hard polyhedral particles

abstract:
  The nucleation kinetics of the rotator phase in hard cuboctahedra, truncated
octahedra, and rhombic dodecahedra is simulated via a combination of Forward
Flux Sampling and Umbrella Sampling. For comparable degree of supersaturation,
the polyhedra are found to have significantly lower free-energy barriers and
faster nucleation rates than hard spheres. This difference primarily stems from
localized orientational ordering, which steers polyhedral particles to pack
more efficiently. Orientational order hence fosters here the growth of
orientationally disordered nuclei.


title: Covert Ephemeral Communication in Named Data Networking

abstract:
  In the last decade, there has been a growing realization that the current
Internet Protocol is reaching the limits of its senescence. This has prompted
several research efforts that aim to design potential next-generation Internet
architectures. Named Data Networking (NDN), an instantiation of the
content-centric approach to networking, is one such effort. In contrast with
IP, NDN routers maintain a significant amount of user-driven state. In this
paper we investigate how to use this state for covert ephemeral communication
(CEC). CEC allows two or more parties to covertly exchange ephemeral messages,
i.e., messages that become unavailable after a certain amount of time. Our
techniques rely only on network-layer, rather than application-layer, services.
This makes our protocols robust, and communication difficult to uncover. We
show that users can build high-bandwidth CECs exploiting features unique to
NDN: in-network caches, routers' forwarding state and name matching rules. We
assess feasibility and performance of proposed cover channels using a local
setup and the official NDN testbed.


title:
Restrictions of harmonic functions and Dirichlet eigenfunctions of the
  Hata set to the interval

abstract:
  In this paper we study the harmonic functions and the Dirichlet
eigenfunctions of the Hata set, and their restrictions to the interval $[0,1]$,
its main edge. We prove that these restrictions of the harmonic functions are
singular, \ie monotone and with zero derivatives almost everywhere, and provide
numerical evidence that this is also the case for the eigenfunctions.


title: QED plasma in a background of static gravitational fields

abstract:
  We obtain the effective Lagrangian of static gravitational fields interacting
with a QED plasma at high temperature. Using the equivalence between the static
hard thermal loops and those with zero external energy-momentum, we compute the
effective Lagrangian up to two-loop order. We also obtain a non-perturbative
contribution which arises from the sum of all infrared divergent ring-diagrams.
From the gauge and Weyl symmetries of the theory, we deduce to all orders that
this effective Lagrangian is equivalent to the pressure of a QED plasma in
Minkowski space-time, with the global temperature replaced by the Tolman local
temperature.


title: The Infinite Degree Corrected Stochastic Block Model

abstract:
  In Stochastic blockmodels, which are among the most prominent statistical
models for cluster analysis of complex networks, clusters are defined as groups
of nodes with statistically similar link probabilities within and between
groups. A recent extension by Karrer and Newman incorporates a node degree
correction to model degree heterogeneity within each group. Although this
demonstrably leads to better performance on several networks it is not obvious
whether modelling node degree is always appropriate or necessary. We formulate
the degree corrected stochastic blockmodel as a non-parametric Bayesian model,
incorporating a parameter to control the amount of degree correction which can
then be inferred from data. Additionally, our formulation yields principled
ways of inferring the number of groups as well as predicting missing links in
the network which can be used to quantify the model's predictive performance.
On synthetic data we demonstrate that including the degree correction yields
better performance both on recovering the true group structure and predicting
missing links when degree heterogeneity is present, whereas performance is on
par for data with no degree heterogeneity within clusters. On seven real
networks (with no ground truth group structure available) we show that
predictive performance is about equal whether or not degree correction is
included; however, for some networks significantly fewer clusters are
discovered when correcting for degree indicating that the data can be more
compactly explained by clusters of heterogenous degree nodes.


title: Resource Letter Exo-1: Exoplanets

abstract:
  This Resource Letter gives an introduction to the main topics in exoplanet
research. It is intended to serve as a guide to the field for upper-division
undergraduate and graduate students, both theoretical and experimental, and for
workers in other fields of physics and astronomy who wish learn about this new
discipline. Topics include historical background, detection methods, host star
properties, theories of planet formation and evolution, their interiors and
atmospheres, their relationship to the formation and evolution of our own solar
system, and issues of life and habitability.


title:
The resurgence properties of the large order asymptotics of the
  Anger--Weber function I

abstract:
  The aim of this paper is to derive new representations for the Anger--Weber
function, exploiting the reformulation of the method of steepest descents by C.
J. Howls (Howls, Proc. R. Soc. Lond. A 439 (1992) 373--396). Using these
representations, we obtain a number of properties of the large order asymptotic
expansions of the Anger--Weber function, including explicit and realistic error
bounds, asymptotics for the late coefficients, exponentially improved
asymptotic expansions, and the smooth transition of the Stokes discontinuities.


title: Predicting Stellar Angular Sizes

abstract:
  Our survey of long-baseline infrared and optical interferometry measurements
is producing considerable numbers of directly determined stellar angular sizes.
We use our sample of 124 high-precision (5\%) angular stellar diameter values
and correlate them with stellar magnitude values from the literature to produce
empirical relations for main-sequence stars between observed apparent
magnitudes, stellar colors, and angular sizes (surface brightness relations).
We find a significant dependence on stellar metallicity for ($B-V$) colors. The
scatter in the calculated relations is small ($\sim$5\%), which makes them a
robust tool for the prediction of main-sequence stellar angular sizes based on
photometry. We apply these relations via the calculation of the radius of the
multiplanet host star GJ 667C.


title:
Rich feature hierarchies for accurate object detection and semantic
  segmentation

abstract:
  Object detection performance, as measured on the canonical PASCAL VOC
dataset, has plateaued in the last few years. The best-performing methods are
complex ensemble systems that typically combine multiple low-level image
features with high-level context. In this paper, we propose a simple and
scalable detection algorithm that improves mean average precision (mAP) by more
than 30% relative to the previous best result on VOC 2012---achieving a mAP of
53.3%. Our approach combines two key insights: (1) one can apply high-capacity
convolutional neural networks (CNNs) to bottom-up region proposals in order to
localize and segment objects and (2) when labeled training data is scarce,
supervised pre-training for an auxiliary task, followed by domain-specific
fine-tuning, yields a significant performance boost. Since we combine region
proposals with CNNs, we call our method R-CNN: Regions with CNN features. We
also compare R-CNN to OverFeat, a recently proposed sliding-window detector
based on a similar CNN architecture. We find that R-CNN outperforms OverFeat by
a large margin on the 200-class ILSVRC2013 detection dataset. Source code for
the complete system is available at http://www.cs.berkeley.edu/~rbg/rcnn.


title: SN 2009N: Linking normal and subluminous type II-P SNe

abstract:
  We present ultraviolet, optical, near-infrared photometry and spectroscopy of
SN 2009N in NGC 4487. This object is a type II-P supernova with spectra
resembling those of subluminous II-P supernovae, while its bolometric
luminosity is similar to that of the intermediate luminosity SN 2008in. We
created SYNOW models of the plateau phase spectra for line identification and
to measure the expansion velocity. In the near-infrared spectra we find signs
indicating possible weak interaction between the supernova ejecta and the
pre-existing circumstellar material. These signs are also present in the
previously unpublished near-infrared spectra of SN 2008in. The distance to SN
2009N is determined via the expanding photosphere method and the standard
candle method as $D= 21.6 \pm 1.1\,{\mathrm {Mpc}}$. The produced nickel-mass
is estimated to be $\sim 0.020 \pm 0.004\,{\mathrm M_\odot}$. We infer the
physical properties of the progenitor at the explosion through hydrodynamical
modelling of the observables. We find the values of the total energy as $\sim
0.48 \times 10^{51}\, {\mathrm {erg}}$, the ejected mass as $\sim
11.5\,{\mathrm M_\odot}$, and the initial radius as $\sim 287\,{\mathrm
R_\odot}$.


title:
User recommendation in reciprocal and bipartite social networks -- a
  case study of online dating

abstract:
  Many social networks in our daily life are bipartite networks built on
reciprocity. How can we recommend users/friends to a user, so that the user is
interested in and attractive to recommended users? In this research, we propose
a new collaborative filtering model to improve user recommendations in
reciprocal and bipartite social networks. The model considers a user's "taste"
in picking others and "attractiveness" in being picked by others. A case study
of an online dating network shows that the new model has good performance in
recommending both initial and reciprocal contacts.


title: On shifted primes with large prime factors and their products

abstract:
  We estimate from below the lower density of the set of prime numbers p such
that p-1 has a prime factor of size at least p^c, where c lies in between 1/4
and 1/2. We also establish upper and lower bounds on the counting function of
the set of positive integers n up to x with exactly k prime factors, counted
with or without multiplicity, such that the largest prime factor of gcd(p-1 : p
| n) exceeds n^{1/2k}.


title:
Gauge Fluctuations and Interlayer Coherence in Bilayer Composite Fermion
  Metals

abstract:
  We study the effect of the Chern-Simons gauge fields on the possible
transition from two decoupled composite fermion metals to the interlayer
coherent composite fermion state proposed by Alicea et al. [Phys. Rev. Lett.
103, 256403 (2009)] in a symmetrically doped quantum Hall bilayer with total
Landau level filling fraction $\nu_{tot} = 1$. In this transition, interlayer
Coulomb repulsion leads to excitonic condensation of composite fermions which
are then free to tunnel coherently between layers. We find that this coherent
tunneling is strongly suppressed by the layer-dependent Aharonov-Bohm phases
experienced by composite fermions as they propagate through the fluctuating
gauge fields in the system. This suppression is analyzed by treating these
gauge fluctuations within the random-phase approximation and calculating their
contribution to the energy cost for forming an exciton condensate of composite
fermions. This energy cost leads to (1) an increase in the critical interlayer
repulsion needed to drive the transition; and (2) a discontinuous jump in the
energy gaps to out-of-phase excitations (i.e., excitations involving currents
with opposite signs in the two layers) at the transition.


title: On computing Belyi maps

abstract:
  We survey methods to compute three-point branched covers of the projective
line, also known as Belyi maps. These methods include a direct approach,
involving the solution of a system of polynomial equations, as well as complex
analytic methods, modular forms methods, and p-adic methods. Along the way, we
pose several questions and provide numerous examples.


title: Spectral dimension in causal set quantum gravity

abstract:
  We evaluate the spectral dimension in causal set quantum gravity by
simulating random walks on causal sets. In contrast to other approaches to
quantum gravity, we find an increasing spectral dimension at small scales. This
observation can be connected to the non-locality of causal set theory that is
deeply rooted in its fundamentally Lorentzian nature. Based on its large-scale
behaviour, we conjecture that the spectral dimension can serve as a tool to
distinguish causal sets that approximate manifolds from those that do not. As a
new tool to probe quantum spacetime in different quantum gravity approaches, we
introduce a novel dimensional estimator, the causal spectral dimension, based
on the meeting probability of two random walkers, which respect the causal
structure of the quantum spacetime. We discuss a causal-set example, where the
spectral dimension and the causal spectral dimension differ, due to the
existence of a preferred foliation.


title: Motility at the origin of life: Its characterization and a model

abstract:
  Due to recent advances in synthetic biology and artificial life, the origin
of life is currently a hot topic of research. We review the literature and
argue that the two traditionally competing "replicator-first" and
"metabolism-first" approaches are merging into one integrated theory of
individuation and evolution. We contribute to the maturation of this more
inclusive approach by highlighting some problematic assumptions that still lead
to an impoverished conception of the phenomenon of life. In particular, we
argue that the new consensus has so far failed to consider the relevance of
intermediate timescales. We propose that an adequate theory of life must
account for the fact that all living beings are situated in at least four
distinct timescales, which are typically associated with metabolism, motility,
development, and evolution. On this view, self-movement, adaptive behavior and
morphological changes could have already been present at the origin of life. In
order to illustrate this possibility we analyze a minimal model of life-like
phenomena, namely of precarious, individuated, dissipative structures that can
be found in simple reaction-diffusion systems. Based on our analysis we suggest
that processes in intermediate timescales could have already been operative in
prebiotic systems. They may have facilitated and constrained changes occurring
in the faster- and slower-paced timescales of chemical self-individuation and
evolution by natural selection, respectively.


title: Topological gravity and Wess-Zumino-Witten term

abstract:
  It is shown that the action for topological gravity in even dimensions is,
except by a multiplicative constant, a gauged Wess-Zumino-Witten Term.


title: Reconfigurable nonreciprocity with nonlinear Fano diode

abstract:
  We propose a dynamically tunable nonreciprocal response for wave propagations
by employing nonlinear Fano resonances. We demonstrate that transmission
contrast of waves propagation in opposite directions can be controlled by
excitation signal. In particular, the unidirectional transmission can be
flipped at different times of a pulse, resembling a diode operation with {\em
dynamical reconfigurable nonreciprocity}. The key mechanism is the interaction
between the linear and nonlinear Fano resonances that allows for the tunable
unidirectional wave propagation and ultrahigh transmission contrast ratio. We
further present a realistic photonic example which demonstrates the properties
of nonreciprocity can be dynamically manipulated using a pump pulse, based on
the general theoretical model.


title:
Tracking Photon Jumps with Repeated Quantum Non-Demolition Parity
  Measurements

abstract:
  Quantum error correction (QEC) is required for a practical quantum computer
because of the fragile nature of quantum information. In QEC, information is
redundantly stored in a large Hilbert space and one or more observables must be
monitored to reveal the occurrence of an error, without disturbing the
information encoded in an unknown quantum state. Such observables, typically
multi-qubit parities such as <XXXX>, must correspond to a special symmetry
property inherent to the encoding scheme. Measurements of these observables, or
error syndromes, must also be performed in a quantum non-demolition (QND) way
and faster than the rate at which errors occur. Previously, QND measurements of
quantum jumps between energy eigenstates have been performed in systems such as
trapped ions, electrons, cavity quantum electrodynamics (QED), nitrogen-vacancy
(NV) centers, and superconducting qubits. So far, however, no fast and repeated
monitoring of an error syndrome has been realized. Here, we track the quantum
jumps of a possible error syndrome, the photon number parity of a microwave
cavity, by mapping this property onto an ancilla qubit. This quantity is just
the error syndrome required in a recently proposed scheme for a
hardware-efficient protected quantum memory using Schr\"{o}dinger cat states in
a harmonic oscillator. We demonstrate the projective nature of this measurement
onto a parity eigenspace by observing the collapse of a coherent state onto
even or odd cat states. The measurement is fast compared to the cavity
lifetime, has a high single-shot fidelity, and has a 99.8% probability per
single measurement of leaving the parity unchanged. In combination with the
deterministic encoding of quantum information in cat states realized earlier,
our demonstrated QND parity tracking represents a significant step towards
implementing an active system that extends the lifetime of a quantum bit.


title:
Issues about the Adoption of Formal Methods for Dependable Composition
  of Web Services

abstract:
  Web Services provide interoperable mechanisms for describing, locating and
invoking services over the Internet; composition further enables to build
complex services out of simpler ones for complex B2B applications. While
current studies on these topics are mostly focused - from the technical
viewpoint - on standards and protocols, this paper investigates the adoption of
formal methods, especially for composition. We logically classify and analyze
three different (but interconnected) kinds of important issues towards this
goal, namely foundations, verification and extensions. The aim of this work is
to individuate the proper questions on the adoption of formal methods for
dependable composition of Web Services, not necessarily to find the optimal
answers. Nevertheless, we still try to propose some tentative answers based on
our proposal for a composition calculus, which we hope can animate a proper
discussion.


title: Confining Boundary conditions from dynamical Coupling Constants

abstract:
  It is shown that it is possible to consistently and gauge invariantly
formulate models where the coupling constant is a non trivial function of a
scalar field . In the $U(1)$ case the coupling to the gauge field contains a
term of the form $g(\phi)j_\mu (A^{\mu} +\partial^{\mu}B)$ where $B$ is an
auxiliary field and $j_\mu$ is the Dirac current. The scalar field $\phi$
determines the local value of the coupling of the gauge field to the Dirac
particle. The consistency of the equations determine the condition
$\partial^{\mu}\phi j_\mu = 0$ which implies that the Dirac current cannot have
a component in the direction of the gradient of the scalar field. As a
consequence, if $\phi$ has a soliton behaviour, like defining a bubble that
connects two vacuua, we obtain that the Dirac current cannot have a flux
through the wall of the bubble, defining a confinement mechanism where the
fermions are kept inside those bags. Consistent models with time dependent fine
structure constant can be also constructed


title: Visualization of Rabi oscillations in a magnetic resonance

abstract:
  A visualization scheme for dynamics of a qudit polarization vector in a
time-dependent magnetic field is presented by solving equations for a density
matrix in Hermitian basis. This is realized by means of mapping solution for
the polarization vector on the three-dimensional spherical curve (vector
hodograph).
  The obtained results obviously display the interference of precessional and
nutational effects on the polarization vector in a magnetic resonance. The
study can find the practical applications in a magnetic resonance and 3D
visualization of computational data.


title:
The Evolving Magnetic Scales of the Outer Solar Atmosphere and Their
  Potential Impact on Heliospheric Turbulence

abstract:
  The presence of turbulent phenomena in the outer solar atmosphere is a given.
However, because we are reduced to remotely sensing the atmosphere of a star
with instruments of limited spatial and/or spectral resolution, we can only
infer the physical progression from macroscopic to microscopic phenomena. Even
so, we know that many, if not all, of the turbulent phenomena that pervade
interplanetary space have physical origins at the Sun and so in this brief
article we consider some recent measurements which point to sustained potential
source(s) of heliospheric turbulence in the magnetic and thermal domains. In
particular, we look at the scales of magnetism that are imprinted on the outer
solar atmosphere by the relentless magneto-convection of the solar interior and
combine state-of-the-art observations from the Solar Dynamics Observatory (SDO)
and the Coronal Multi-channel Polarimeter (CoMP) which are beginning to hint at
the origins of the wave/plasma interplay prevalent closer to the Earth. While
linking these disparate scales of observation and understanding of their
connection is near to impossible, it is clear that the constant evolution of
subsurface magnetism on a host of scales guides and governs the flow of mass
and energy at the smallest scales. In the near future significant progress in
this area will be made by linking observations from high resolution platforms
like the Interface Region Imaging Spectrograph (IRIS) and Advanced Technology
Solar Telescope (ATST) with full-disk synoptic observations such as those
presented herein.


title: Field independent cosmic evolution

abstract:
  It has been shown earlier that Noether symmetry does not admit a form of F(R)
corresponding to an action in which F(R) is coupled to scalar-tensor action for
gravity or even for pure F(R) gravity taking anisotropic model into account.
Here, we prove that F(R) theory of gravity does not admit Noether symmetry even
if it is coupled to Tachyonic field and considering a gauge in addition. To
handle such a theory, a general conserved current has been constructed under a
condition which decouples higher order curvature part from the field part. This
condition in principle, solves for the scale factor, independently. Thus
cosmological evolution remains independent of the form of the chosen field,
whether it be a scalar or a tachyon.


title:
Asymmetric numeral systems: entropy coding combining speed of Huffman
  coding with compression rate of arithmetic coding

abstract:
  The modern data compression is mainly based on two approaches to entropy
coding: Huffman (HC) and arithmetic/range coding (AC). The former is much
faster, but approximates probabilities with powers of 2, usually leading to
relatively low compression rates. The latter uses nearly exact probabilities -
easily approaching theoretical compression rate limit (Shannon entropy), but at
cost of much larger computational cost.
  Asymmetric numeral systems (ANS) is a new approach to accurate entropy
coding, which allows to end this trade-off between speed and rate: the recent
implementation [1] provides about $50\%$ faster decoding than HC for 256 size
alphabet, with compression rate similar to provided by AC. This advantage is
due to being simpler than AC: using single natural number as the state, instead
of two to represent a range. Beside simplifying renormalization, it allows to
put the entire behavior for given probability distribution into a relatively
small table: defining entropy coding automaton. The memory cost of such table
for 256 size alphabet is a few kilobytes. There is a large freedom while
choosing a specific table - using pseudorandom number generator initialized
with cryptographic key for this purpose allows to simultaneously encrypt the
data.
  This article also introduces and discusses many other variants of this new
entropy coding approach, which can provide direct alternatives for standard AC,
for large alphabet range coding, or for approximated quasi arithmetic coding.


title: The soft function for color octet production at threshold

abstract:
  We evaluate the next-to-next-to-leading order soft function for the
production of a massive color octet state at rest in the collision of two
massless colored partons in either the fundamental or the adjoint
representation. The main application of our result is the determination of the
threshold expansion of the heavy-quark pair-production cross sections in the
quark annihilation and gluon fusion channels. We discuss the factorization
necessary for this purpose and explain the relationship between hard functions
and virtual amplitudes.


title:
Toward a unified theory of sparse dimensionality reduction in Euclidean
  space

abstract:
  Let $\Phi\in\mathbb{R}^{m\times n}$ be a sparse Johnson-Lindenstrauss
transform [KN14] with $s$ non-zeroes per column. For a subset $T$ of the unit
sphere, $\varepsilon\in(0,1/2)$ given, we study settings for $m,s$ required to
ensure $$ \mathop{\mathbb{E}}_\Phi \sup_{x\in T} \left|\|\Phi x\|_2^2 - 1
\right| < \varepsilon , $$ i.e. so that $\Phi$ preserves the norm of every
$x\in T$ simultaneously and multiplicatively up to $1+\varepsilon$. We
introduce a new complexity parameter, which depends on the geometry of $T$, and
show that it suffices to choose $s$ and $m$ such that this parameter is small.
Our result is a sparse analog of Gordon's theorem, which was concerned with a
dense $\Phi$ having i.i.d. Gaussian entries. We qualitatively unify several
results related to the Johnson-Lindenstrauss lemma, subspace embeddings, and
Fourier-based restricted isometries. Our work also implies new results in using
the sparse Johnson-Lindenstrauss transform in numerical linear algebra,
classical and model-based compressed sensing, manifold learning, and
constrained least squares problems such as the Lasso.

categories: cs.DS cs.CG cs.IT math.IT math.PR stat.ML


title: Parallel Universe, Dark Matter and Invisible Higgs Decays

abstract:
  The existence of the dark matter with amount about five times the ordinary
matter is now well established experimentally. There are now many candidates
for this dark matter. However, dark matter could be just like the ordinary
matter in a parallel universe. If both universes are described by a non-abelian
gauge symmetries, then there will be no kinetic mixing between the ordinary
photon and the dark photon, and the dark proton, dark electron and the
corresponding dark nuclei, belonging to the parallel universe, will be stable.
If the strong coupling constant, $(\alpha_s)_{dark}$ in the parallel universe
is five times that of $\alpha_s$, then the dark proton will be about five time
heavier, explaining why the dark matter is five times the ordinary matter.
However, the two sectors will still interact via the Higgs boson of the two
sectors. This will lead to the existence of a second light Higss boson, just
like the Standard Model Higgs boson. This gives rise to the invisible decay
modes of the Higgs boson which can be tested at the LHC, and the proposed ILC.


title:
Effective-one-body model for black-hole binaries with generic mass
  ratios and spins

abstract:
  Gravitational waves emitted by black-hole binary systems have the highest
signal-to-noise ratio in LIGO and Virgo detectors when black-hole spins are
aligned with the orbital angular momentum and extremal. For such systems, we
extend the effective-one-body inspiral-merger-ringdown waveforms to generic
mass ratios and spins calibrating them to 38 numerical-relativity nonprecessing
waveforms produced by the SXS Collaboration. The numerical-relativity
simulations span mass ratios from 1 to 8, spin magnitudes up to 98% of
extremality, and last for 40 to 60 gravitational-wave cycles. When the total
mass of the binary is between 20Msun and 200Msun, the effective-one-body
nonprecessing (dominant mode) waveforms have overlaps above 99% (using the
advanced-LIGO design noise spectral density) with all of the 38 nonprecessing
numerical waveforms, when maximizing only on initial phase and time. This
implies a negligible loss in event rate due to modeling. Moreover, without
further calibration, we show that the precessing effective-one-body (dominant
mode) waveforms have overlaps above 97% with two very long, strongly precessing
numerical-relativity waveforms, when maximizing only on the initial phase and
time.


title: A physicist's view of DNA

abstract:
  Nucleic acids, like DNA and RNA, are molecules that are present in any life
form. Their most notable function is to encode biological information. Why then
would a physicist be interested in these molecules? As we will see, DNA is an
interesting molecular tool for physicists to test and explore physical laws and
theories, like the ergodic theorem, the theory of elasticity and information
theory. DNA also has unique material properties, which attract material
scientists, nanotechnologists and engineers. Among interesting developments in
this field are DNA-based hybrid materials and DNA origami.


title:
Petviashvili type methods for traveling wave computations: I. Analysis
  of convergence

abstract:
  In this paper a family of fixed point algorithms for the numerical resolution
of some systems of nonlinear equations is designed and analyzed. The family
introduced here generalizes the Petviashvili method and can be applied to the
numerical generation of traveling waves in some nonlinear dispersive systems.
Conditions for the local convergence are derived and numerical comparisons
between different elements of the family are carried out.


title: Learning Mixtures of Linear Classifiers

abstract:
  We consider a discriminative learning (regression) problem, whereby the
regression function is a convex combination of k linear classifiers. Existing
approaches are based on the EM algorithm, or similar techniques, without
provable guarantees. We develop a simple method based on spectral techniques
and a `mirroring' trick, that discovers the subspace spanned by the
classifiers' parameter vectors. Under a probabilistic assumption on the feature
vector distribution, we prove that this approach has nearly optimal statistical
efficiency.


title:
Effect of collective molecular reorientations on Brownian motion of
  colloids in nematic liquid crystal

abstract:
  In the simplest realization of Brownian motion, a colloidal sphere moves
randomly in an isotropic fluid; its mean squared displacement (MSD) grows
linearly with time $\textit{\tau}$. Brownian motion in an orientationally
ordered fluid, a nematic, is anisotropic, with the MSD being larger along the
axis of molecular orientation, called the director. We show that at short time
scales, the anisotropic diffusion in a nematic becomes also anomalous, with the
MSD growing slower (subdiffusion) and faster (superdiffusion) than
$\textit{\tau}$. The anomalous diffusion occurs at time scales that correspond
to the relaxation times of director deformations around the sphere. Once the
nematic melts, the diffusion becomes normal and isotropic. The experiment shows
that the deformations and fluctuations of long-range orientational order
profoundly influence diffusive regimes.


title: A doubling construction for self-orthogonal codes

abstract:
  A simple construction of quaternary hermitian self-orthogonal codes with
parameters $[2n+1,k+1]$ and $[2n+2,k+2]$ from a given pair of self-orthogonal
$[n,k]$ codes, and its link to quantum codes is considered. As an application,
an optimal quaternary linear $[28,20,6]$ dual containing code is found that
yields a new optimal $[[28,12,6]]$ quantum code.


title: The Kelly growth optimal strategy with a stop-loss rule

abstract:
  From the Hamilton-Jacobi-Bellman equation for the value function we derive a
non-linear partial differential equation for the optimal portfolio strategy
(the dynamic control). The equation is general in the sense that it does not
depend on the terminal utility and provides additional analytical insight for
some optimal investment problems with known solutions. Furthermore, when
boundary conditions for the optimal strategy can be established independently,
it is considerably simpler than the HJB to solve numerically. Using this method
we calculate the Kelly growth optimal strategy subject to a periodically reset
stop-loss rule.


title: Social Networks and Collective Intelligence: A Return to the Agora

abstract:
  Nowadays, acquisition of trustable information is increasingly important in
both professional and private contexts. However, establishing what information
is trustable and what is not, is a very challenging task. For example, how can
information quality be reliably assessed? How can sources? credibility be
fairly assessed? How can gatekeeping processes be found trustworthy when
filtering out news and deciding ranking and priorities of traditional media? An
Internet-based solution to a human-based ancient issue is being studied, and it
is called Polidoxa, from Greek "poly", meaning "many" or "several" and "doxa",
meaning "common belief" or "popular opinion". This old problem will be solved
by means of ancient philosophies and processes with truly modern tools and
technologies. This is why this work required a collaborative and
interdisciplinary joint effort from researchers with very different backgrounds
and institutes with significantly different agendas. Polidoxa aims at offering:
1) a trust-based search engine algorithm, which exploits stigmergic behaviours
of users? network, 2) a trust-based social network, where the notion of trust
derives from network activity and 3) a holonic system for bottom-up
self-protection and social privacy. By presenting the Polidoxa solution, this
work also describes the current state of traditional media as well as newer
ones, providing an accurate analysis of major search engines such as Google and
social network (e.g., Facebook). The advantages that Polidoxa offers, compared
to these, are also clearly detailed and motivated. Finally, a Twitter
application (Polidoxa@twitter) which enables experimentation of basic Polidoxa
principles is presented.


title:
Localized correlated features in the CMB power spectrum and primordial
  bispectrum from a transient reduction in the speed of sound

abstract:
  The first year of observations by the Planck satellite mission shows that the
cosmic microwave background (CMB) fluctuations are consistent with gaussian
statistics in the primordial perturbations, a key prediction of the simplest
models of inflation. However, there are hints of anomalies in the CMB power
spectrum and bispectrum. We check for the possibility that some of these
anomalous features have a common physical origin in a transient reduction of
the inflaton speed of sound. We do this by exploiting predicted correlations
between the power spectrum and bispectrum. Our results suggest that current
data might already be sensitive enough to detect transient reductions in the
speed of sound as mild as a few percent. Since this is a signature of
interactions, it opens a new window for the detection of extra degrees of
freedom during inflation.


title:
Atomic data for S II - Toward Better Diagnostics of Chemical Evolution
  in High-redshift Galaxies

abstract:
  Absorption-line spectroscopy is a powerful tool used to estimate element
abundances in the nearby as well as distant universe. The accuracy of the
abundances thus derived is, naturally, limited by the accuracy of the atomic
data assumed for the spectral lines. We have recently started a project to
perform the new extensive atomic data calculations used for optical/UV spectral
lines in the plasma modeling code Cloudy using state-of-the-art quantal
calculations. Here we demonstrate our approach by focussing on S II, an ion
used to estimate metallicities for Milky Way interstellar clouds as well as
distant damped Lyman-alpha (DLA) and sub-DLA absorber galaxies detected in the
spectra of quasars and gamma-ray bursts (GRBs). We report new extensive
calculations of a large number of energy levels of S II, and the line strengths
of the resulting radiative transitions. Our calculations are based on the
configuration interaction approach within a numerical Hartree-Fock framework,
and utilize both non-ralativistic and quasirelativistic one-electron radial
orbitals. The results of these new atomic calculations are then incorporated
into Cloudy and applied to a lab plasma, and a typical DLA, for illustrative
purposes. The new results imply relatively modest changes (~0.04 dex) to the
metallicities estimated from S II in past studies. These results will be
readily applicable to other studies of S II in the Milky Way and other
galaxies.


title:
A genome wide dosage suppressor network reveals genetic robustness and a
  novel mechanism for Huntington's disease

abstract:
  Mutational robustness is the extent to which an organism has evolved to
withstand the effects of deleterious mutations. We explored the extent of
mutational robustness in the budding yeast by genome wide dosage suppressor
analysis of 53 conditional lethal mutations in cell division cycle and RNA
synthesis related genes, revealing 660 suppressor interactions of which 642 are
novel. This collection has several distinctive features, including high
co-occurrence of mutant-suppressor pairs within protein modules, highly
correlated functions between the pairs, and higher diversity of functions among
the co-suppressors than previously observed. Dosage suppression of essential
genes encoding RNA polymerase subunits and chromosome cohesion complex suggest
a surprising degree of functional plasticity of macromolecular complexes and
the existence od degenerate pathways for circumventing potentially lethal
mutations. The utility of dosage-suppressor networks is illustrated by the
discovery of a novel connection between chromosome cohesion-condensation
pathways involving homologous recombination, and Huntington's disease.


title: Hamiltonian gadgets with reduced resource requirements

abstract:
  Application of the adiabatic model of quantum computation requires efficient
encoding of the solution to computational problems into the lowest eigenstate
of a Hamiltonian that supports universal adiabatic quantum computation.
Experimental systems are typically limited to restricted forms of 2-body
interactions. Therefore, universal adiabatic quantum computation requires a
method for approximating quantum many-body Hamiltonians up to arbitrary
spectral error using at most 2-body interactions. Hamiltonian gadgets,
introduced around a decade ago, offer the only current means to address this
requirement. Although the applications of Hamiltonian gadgets have steadily
grown since their introduction, little progress has been made in overcoming the
limitations of the gadgets themselves. In this experimentally motivated
theoretical study, we introduce several gadgets which require significantly
more realistic control parameters than similar gadgets in the literature. We
employ analytical techniques which result in a reduction of the resource
scaling as a function of spectral error for the commonly used subdivision, 3-
to 2-body and $k$-body gadgets. Accordingly, our improvements reduce the
resource requirements of all proofs and experimental proposals making use of
these common gadgets. Next, we numerically optimize these new gadgets to
illustrate the tightness of our analytical bounds. Finally, we introduce a new
gadget that simulates a $YY$ interaction term using Hamiltonians containing
only $\{X,Z,XX,ZZ\}$ terms. Apart from possible implications in a theoretical
context, this work could also be useful for a first experimental implementation
of these key building blocks by requiring less control precision without
introducing extra ancillary qubits.


title:
Examining the Geometric Mean Method for the Extraction of Spatial
  Resolution

abstract:
  The spatial resolution of a detector, using a reference detector telecscope,
can be measured applying the geometric mean method, with tracks reconstructed
from hits of all the detectors, including ($\sigma_\mathrm{in}$) and excluding
($\sigma_\mathrm{ex}$) the hit from the detector under study. The geometric
mean of the two measured resolution values
($\sigma=\sqrt{\sigma_\mathrm{ex}\sigma_\mathrm{in}}$), is proposed to provide
a more accurate estimate of the intrinsic detector resolution. This method has
been tested using a Monte Carlo algorithm and is proven to give accurate
results, independently of the distance between the detectors used for the track
fitting. The method does not give meaningful results if all the detectors do
not carry the same characteristics.


title: Efficiently Computing Edit Distance to Dyck Language

abstract:
  Given a string $\sigma$ over alphabet $\Sigma$ and a grammar $G$ defined over
the same alphabet, how many minimum number of repairs: insertions, deletions
and substitutions are required to map $\sigma$ into a valid member of $G$ ? We
investigate this basic question in this paper for $Dyck(s)$. $Dyck(s)$ is a
fundamental context free grammar representing the language of well-balanced
parentheses with s different types of parentheses and has played a pivotal role
in the development of theory of context free languages. Computing edit distance
to $Dyck(s)$ significantly generalizes string edit distance problem and has
numerous applications ranging from repairing semi-structured documents such as
XML to memory checking, automated compiler optimization, natural language
processing etc.
  In this paper we give the first near-linear time algorithm for edit distance
computation to $Dyck(s)$ that achieves a nontrivial approximation factor of
$O(\frac{1}{\epsilon}\log{OPT}(\log{n})^{\frac{1}{\epsilon}})$ in
$O(n^{1+\epsilon}\log{n})$ time. In fact, given there exists an algorithm for
computing string edit distance on input of size $n$ in $\alpha(n)$ time with
$\beta(n)$-approximation factor, we can devise an algorithm for edit distance
problem to $Dyck(s)$ running in $\tilde{O}(n^{1+\epsilon}+\alpha(n))$ and
achieving an approximation factor of $O(\frac{1}{\epsilon}\beta(n)\log{OPT})$.
  We show that the framework for efficiently approximating edit distance to
$Dyck(s)$ can be applied to many other languages. We illustrate this by
considering various memory checking languages which comprise of valid
transcripts of stacks, queues, priority queues, double-ended queues etc.
Therefore, any language that can be recognized by these data structures, can
also be repaired efficiently by our algorithm.


title: Seeding Life on the Moons of the Outer Planets via Lithopanspermia

abstract:
  Material from the surface of a planet can be ejected into space by a large
impact, and could carry primitive life forms with it. We performed n-body
simulations of such ejecta to determine where in the Solar System rock from
Earth and Mars may end up. We find that, in addition to frequent transfer of
material among the terrestrial planets, transfer of material from Earth and
Mars to the moons of Jupiter and Saturn is also possible, but rare. We expect
that such transfer is most likely during the Late Heavy Bombardment or during
the next one or two billion years. At this time, the icy moons were warmer and
likely had little or no icy shell to prevent meteorites from reaching their
liquid interiors. We also note significant rates of re-impact in the first
million years after ejection. This could re-seed life on a planet after partial
or complete sterilization by a large impact, which would aid the survival of
early life during the Late Heavy Bombardment.


title: Paramagnetic squeezing of QCD matter

abstract:
  We determine the magnetization of Quantum Chromodynamics (QCD) for several
temperatures around and above the transition between the hadronic and the
quark-gluon phases of strongly interacting matter. We obtain a paramagnetic
response that increases in strength with the temperature. We argue that due to
this paramagnetism, chunks of quark-gluon plasma produced in non-central heavy
ion collisions should become elongated along the direction of the magnetic
field. This anisotropy will then contribute to the elliptic flow v_2 observed
in such collisions, in addition to the pressure gradient that is usually taken
into account. We present a simple estimate for the magnitude of this new effect
and a rough comparison to the effect due to the initial collision geometry. We
conclude that the paramagnetic effect might have a significant impact on the
value of v_2.


title: Landau Level Splitting in Rotationally Faulted Multilayer Graphene

abstract:
  We show that valley degeneracy in rotationally faulted multilayer graphene
may be broken in the presence of a magnetic field and interlayer
commensurations. This happens due to a simultaneous breaking of both
time-reversal and inversion symmetries leading to a splitting of Landau levels
linear in the field. Our theoretical work is motivated by an experiment [Y. J.
Song et al., Nature 467, 185 (2010)] on epitaxially grown multilayer graphene
where such linear splitting of Landau levels was observed at moderate fields.
We consider both bilayer and trilayer configurations and, although a linear
splitting occurs in both cases, we show that the latter produces a splitting
that is in quantitative agreement with the experiment.


title:
Performing edge detection by difference of Gaussians using q-Gaussian
  kernels

abstract:
  In image processing, edge detection is a valuable tool to perform the
extraction of features from an image. This detection reduces the amount of
information to be processed, since the redundant information (considered less
relevant) can be unconsidered. The technique of edge detection consists of
determining the points of a digital image whose intensity changes sharply. This
changes are due to the discontinuities of the orientation on a surface for
example. A well known method of edge detection is the Difference of Gaussians
(DoG). The method consists of subtracting two Gaussians, where a kernel has a
standard deviation smaller than the previous one. The convolution between the
subtraction of kernels and the input image results in the edge detection of
this image. This paper introduces a method of extracting edges using DoG with
kernels based on the q-Gaussian probability distribution, derived from the
q-statistic proposed by Constantino Tsallis. To demonstrate the method's
potential, we compare the introduced method with the traditional DoG using
Gaussians kernels. The results showed that the proposed method can extract
edges with more accurate details.


title: Two dimensional quantum quenches and holography

abstract:
  We propose a holographic realization of quantum quenches in two dimensional
conformal field theories. In particular, we discuss time evolutions of
holographic entanglement entropy in these backgrounds and compare them with CFT
results. The key ingredient of the construction is an introduction of a
spacetime boundary into bulk geometries, which is the gravity counterpart of a
boundary state in the dual CFT. We consider several examples, including local
quenches and an inhomogeneous quench which is dual to fusion of two black
string into the third one.


title: Minimum Bisection is fixed parameter tractable

abstract:
  In the classic Minimum Bisection problem we are given as input a graph $G$
and an integer $k$. The task is to determine whether there is a partition of
$V(G)$ into two parts $A$ and $B$ such that $||A|-|B|| \leq 1$ and there are at
most $k$ edges with one endpoint in $A$ and the other in $B$. In this paper we
give an algorithm for Minimum Bisection with running time $O(2^{O(k^{3})}n^3
\log^3 n)$. This is the first fixed parameter tractable algorithm for Minimum
Bisection. At the core of our algorithm lies a new decomposition theorem that
states that every graph $G$ can be decomposed by small separators into parts
where each part is "highly connected" in the following sense: any cut of
bounded size can separate only a limited number of vertices from each part of
the decomposition. Our techniques generalize to the weighted setting, where we
seek for a bisection of minimum weight among solutions that contain at most $k$
edges.