title:
Functionalized AFM probes for force spectroscopy: eigenmodes shape and
  stiffness calibration through thermal noise measurements

abstract:
  The functionalization of an Atomic Force Microscope (AFM) cantilever with a
colloidal bead is a widely used technique when the geometry between the probe
and the sample must be controlled, particularly in force spectroscopy. But some
questions remain: how does a bead glued at the end of a cantilever influence
its mechanical response ? And more important for quantitative measurements, can
we still determine the stiffness of the AFM probe with traditional techniques?
In this article, the influence of a colloidal mass loading on the eigenmodes
shape and resonant frequency is investigated by measuring the thermal noise on
rectangular AFM microcantilevers with and without a bead attached at their
extremities. The experiments are performed with a home-made ultra-sensitive
AFM, based on differential interferometry. The focused beam from the
interferometer probes the cantilever at different positions and the spatial
shapes of the modes are determined up to the fifth resonance, without external
excitation. The results clearly demonstrate that the first eigenmode almost
doesn't change by mass loading. However the oscillation behavior of higher
resonances present a marked difference: with a particle glued at its extremity,
the nodes of the mode are displaced towards the free end of the cantilever.
These results are compared to an analytical model taking into account the mass
and the inertial moment of the load in an Euler-Bernoulli framework, where the
normalization of the eigenmodes is explicitly worked out in order to allow a
quantitative prediction of the thermal noise amplitude of each mode. A good
agreement between the experimental results and the analytical model is
demonstrated, allowing a clean calibration of the probe stiffness.


title: Reasoning About Higher-Order Relational Specifications

abstract:
  The logic of hereditary Harrop formulas (HH) has proven useful for specifying
a wide range of formal systems. This logic includes a form of hypothetical
judgment that leads to dynamically changing sets of assumptions and that is key
to encoding side conditions and contexts that occur frequently in structural
operational semantics (SOS) style presentations. Specifications are often
useful in reasoning about the systems they describe. The Abella theorem prover
supports such reasoning by explicitly embedding the specification logic within
a rich reasoning logic; specifications are then reasoned about through this
embedding. However, realizing an induction principle in the face of dynamically
changing assumption sets is nontrivial and the original Abella system uses only
a subset of the HH specification logic for this reason. We develop a method
here for supporting inductive reasoning over all of HH. Our approach takes
advantage of a focusing property of HH to isolate the use of an assumption and
the ability to finitely characterize the structure of any such assumption in
the reasoning logic. We demonstrate the effectiveness of these ideas via
several specification and meta-theoretic reasoning examples that have been
implemented in an extended version of Abella.


title:
On a Lagrangian method for the convergence from a non-local to a local
  Korteweg capillary fluid model

abstract:
  In the present article we are interested in further investigations for the
barotropic compressible Navier-Stokes system endowed with a non-local
capillarity we studied in [7]. Thanks to an accurate study of the associated
linear system using a Lagrangian change of coordinates, we provide more precise
energy estimates in terms of hybrid Besov spaces naturally depending on a
threshold frequency (which is determined in function of the physical parameter)
distinguishing the low and the high regimes. It allows us in particular to
prove the convergence of the solutions from the non-local to the local Korteweg
system. Another mathematical interest of this article is the study of the
effect of the Lagrangian change on the non-local capillary term.


title: From Sommerfeld and Brillouin forerunners to optical precursors

abstract:
  The Sommerfeld and Brillouin forerunners generated in a single-resonance
absorbing medium by an incident step-modulated pulse are theoretically
considered in the double limit where the susceptibility of the medium is weak
and the resonance is narrow. Combining direct Laplace-Fourier integration and
calculations by the saddle-point method, we establish an explicit analytical
expression of the transmitted field valid at any time, even when the two
forerunners significantly overlap. We examine how their complete overlapping,
occurring for shorter propagation distances, originates the formation of the
unique transient currently named resonant precursor or dynamical beat. We
obtain an expression of this transient identical to that usually derived within
the slowly varying envelope in spite of the initial discontinuity of the
incident field envelope. The dynamical beats and 0Pi pulses generated by
ultra-short incident pulses are also briefly examined


title: The Legacy of the Tevatron in the Area of Accelerator Science

abstract:
  For more than 25 years the Tevatron was the highest energy accelerator in the
world, providing the first access to particle collisions beyond 1 TeV and
achieving an ultimate performance a factor of four hundred beyond the original
design goals. This article reviews the many formidable challenges that were
overcome, and the knowledge gained, in building, operating, and improving the
Tevatron over its lifetime. These challenges included: the first operations of
an accelerator based on superconducting magnets, production of antiprotons in
sufficient numbers to support a useable luminosity, management of beam-beam,
intrabeam, and other collective effects, novel manipulations of the beam
longitudinal phase space, and development and application of a wide variety of
innovative technologies. These achievements established the legacy of the
Tevatron as the progenitor of all subsequently constructed high energy hadron
colliders.


title:
A global approach to the Schr\"odinger-Poisson system: An Existence
  result in the case of infinitely many states

abstract:
  In this paper we prove the existence of a solution to a nonlinear
Schr{\"o}dinger--Poisson eigenvalue problem in dimension less than $3$. Our
proof is based on a global approach to the determination of eigenvalues and
eigenfunctions which allows us to characterize the complete sequence of
eigenvalues and eigenfunctions at once, via a variational approach, and thus
differs from the usual and less general proofs developed for similar problems
in the literature. Our approach seems to be new for the determination of the
spectrum and eigenfunctions for compact and self-adjoint operators, even in a
finite dimensional setting.


title:
The number of topological generators for full groups of ergodic
  equivalence relations

abstract:
  We completely elucidate the relationship between two invariants associated
with an ergodic probability measure-preserving (pmp) equivalence relation,
namely its cost and the minimal number of topological generators of its full
group. It follows that for any free pmp ergodic action of the free group on $n$
generators, the minimal number of topological generators for the full group of
the action is $n+1$, answering a question of Kechris.


title:
High frequency waves and the maximal smoothing effect for nonlinear
  scalar conservation laws

abstract:
  The article first studies the propagation of well prepared high frequency
waves with small amplitude $\eps$ near constant solutions for entropy solutions
of multidimensional nonlinear scalar conservation laws. Second, such
oscillating solutions are used to highlight a conjecture of Lions, Perthame,
Tadmor, (1994), about the maximal regularizing effect for nonlinear
conservation laws. For this purpose, a new definition of nonlinear flux is
stated and compared to classical definitions. Then it is proved that the
smoothness expected in Sobolev spaces cannot be exceeded.


title:
ESO VLT Optical Spectroscopy of BL Lac Objects IV. New spectra and
  properties of the full sample

abstract:
  We present the last chapter of a spectroscopy program aimed at deriving the
redshift or a lower limit to the redshift of BL Lac objects using medium
resolution spectroscopy. Here we report new spectra for 33 BL Lac object
candidates obtained in 2008-2009 confirming the BL Lac nature of 25 sources and
for 5 objects we obtained new redshifts. These new observations are combined
with our previous data in order to construct a homogeneous sample of \sim 70 BL
Lacs with high quality spectroscopy. All these spectra can be accessed at the
website http://www.oapd.inaf.it/zbllac/. The average spectrum, beaming
properties of the full sample, discussion on intervening systems and future
perspectives are addressed.


title:
Computing phase diagrams for a quasicrystal-forming patchy-particle
  system

abstract:
  We introduce an approach to computing the free energy of quasicrystals, which
we use to calculate phase diagrams for systems of two-dimensional patchy
particles with five regularly arranged patches that have previously been shown
to form dodecagonal quasicrystals. We find that the quasicrystal is a
thermodynamically stable phase for a wide range of conditions and remains a
robust feature of the system as the potential's parameters are varied. We also
demonstrate that the quasicrystal is entropically stabilised over its
crystalline approximants.


title: Constraints on Modified Gravity from ACT and SPT

abstract:
  The Atacama Cosmology Telescope (ACT) and the South Pole Telescope (SPT) have
recently provided new and precise measurements of the Cosmic Microwave
Background anisotropy damping tail. This region of the CMB angular spectra,
thanks to the angular distortions produced by gravitational lensing, can probe
the growth of matter perturbations and provide a test for general relativity.
Here we make use of the ACT and SPT power spectrum measurements (combined with
the recent WMAP9 data) to constrain f(R) gravity theories. Adopting a
parametrized approach, we obtain an upper limit on the lengthscale of the
theory of B_0 < 0.86 at 95% c.l. from ACT, while we get a significantly
stronger bound from SPT with B_0 < 0.14 at 95% c.l..


title:
Regular and chaotic vortex core reversal by a resonant perpendicular
  magnetic field

abstract:
  Under the action of an alternating perpendicular magnetic field the polarity
of the vortex state nanodisk can be efficiently switched. We predict the
regular and chaotic dynamics of the vortex polarity and propose simple
analytical description in terms of a reduced vortex core model. Conditions for
the controllable polarity switching are analyzed.


title:
Formation of magnetic nanocolumns during vapor phase deposition of a
  metal-polymer nanocomposite: experiments and kinetic Monte Carlo simulations

abstract:
  Metal-polymer nanocomposites have been investigated extensively during the
last years due to their interesting functional applications. They are often
produced by vapor phase deposition which generally leads to the self-organized
formation of spherical metallic nanoparticles in the organic matrix, while
nanocolumns are only obtained under very specific conditions.
Experiments\cite{Grev+06} have shown that co-evaporation of the metallic and
organic components in a simple single-step process can give rise to the
formation of ultrahigh-density Fe-Ni-Co nanocolumnar structures embedded in a
fluoropolymer matrix. Here we present a kinetic Monte Carlo approach which is
based on an new model involving the depression of the melting point on the
nanoscale and a critical nanoparticle size required for solidification. In
addition we present new experimental results down to a deposition temperature
of \cel{-70} and also report the magnetic properties. The simulations provide a
detailed understanding of the transition from spherical cluster growth to
formation of elongated structures and are in quantitative agreement with the
experiments.


title:
Kepler-68: Three Planets, One With a Density Between That of Earth and
  Ice Giants

abstract:
  NASA's Kepler Mission has revealed two transiting planets orbiting Kepler-68.
Follow-up Doppler measurements have established the mass of the innermost
planet and revealed a third jovian-mass planet orbiting beyond the two
transiting planets. Kepler-68b, in a 5.4 day orbit has mass 8.3 +/- 2.3 Earth,
radius 2.31 +/- 0.07 Earth radii, and a density of 3.32 +/- 0.92 (cgs), giving
Kepler-68b a density intermediate between that of the ice giants and Earth.
Kepler-68c is Earth-sized with a radius of 0.953 Earth and transits on a 9.6
day orbit; validation of Kepler-68c posed unique challenges. Kepler-68d has an
orbital period of 580 +/- 15 days and minimum mass of Msin(i) = 0.947 Jupiter.
Power spectra of the Kepler photometry at 1-minute cadence exhibit a rich and
strong set of asteroseismic pulsation modes enabling detailed analysis of the
stellar interior. Spectroscopy of the star coupled with asteroseismic modeling
of the multiple pulsation modes yield precise measurements of stellar
properties, notably Teff = 5793 +/- 74 K, M = 1.079 +/- 0.051 Msun, R = 1.243
+/- 0.019 Rsun, and density 0.7903 +/- 0.0054 (cgs), all measured with
fractional uncertainties of only a few percent. Models of Kepler-68b suggest it
is likely composed of rock and water, or has a H and He envelope to yield its
density of about 3 (cgs).


title:
Observable effects of Interplanetary Coronal Mass Ejections on ground
  level neutron monitor counting rates

abstract:
  In this work, non-recurrent Forbush decreases (FDs) triggered by the passage
of shock-driven interplanetary coronal mass ejections (ICMEs) have been
analyzed. Fifty-nine ICMEs have been studied but only the 25% of them were
associated to a FD. We find that shock-driving magnetic clouds (MCs) produce
deeper FDs than shock-driving ejecta. This fact can be explained regarding to
the observed growing trends between decreases in neutron monitor (NM) count
rate and MC/ejecta speed and its associated rigidity. MCs are faster and have
higher associated rigidities than ejecta. Also the deceleration of ICMEs seems
to be a cause in producing FDs as can be inferred from the decreasing trend
between NM count rate and deceleration. This probably implies that the
interaction between the ICME traveling from the corona to the Earth and the
solar wind can play an important role to produce deeper FDs. Finally, we
conclude that ejecta without flux rope topology are the less effective in
unchaining FDs.


title: Neutrino Beam Constraints on Flavor-Diagonal Lorentz Violation

abstract:
  Breaking of isotropy and Lorentz boost invariance in the dynamics of
second-generation leptons would lead to direction-dependent changes in the
lifetimes of charged pions. This would make the intensity of a neutrino beam
produced via pion decay a function of the beam orientation. The experimental
signature of this phenomenon--sidereal variations in the event rate at a
downstream neutrino detector--has already been studied, in searches for
Lorentz-violating neutrino oscillations. Existing analyses of MINOS near
detector data can be used to constrain the flavor-diagonal Lorentz violation
coefficients affecting muon neutrino speeds at roughly the 10^(-5) level.


title: $(3,1)^*$-choosability of planar graphs without adjacent short cycles

abstract:
  A list assignment of a graph $G$ is a function $L$ that assigns a list $L(v)$
of colors to each vertex $v\in V(G)$. An $(L,d)^*$-coloring is a mapping $\pi$
that assigns a color $\pi(v)\in L(v)$ to each vertex $v\in V(G)$ so that at
most $d$ neighbors of $v$ receive color $\pi(v)$. A graph $G$ is said to be
$(k,d)^*$-choosable if it admits an $(L,d)^*$-coloring for every list
assignment $L$ with $|L(v)|\ge k$ for all $v\in V(G)$. In 2001, Lih et al.
\cite{LSWZ-01} proved that planar graphs without 4- and $l$-cycles are
$(3,1)^*$-choosable, where $l\in \{5,6,7\}$. Later, Dong and Xu \cite{DX-09}
proved that planar graphs without 4- and l-cycles are $(3,1)^*$-choosable,
where $l\in \{8,9\}$.
  There exist planar graphs containing 4-cycles that are not
$(3,1)^*$-choosable (Crown, Crown and Woodall, 1986 \cite{CCW-86}). This partly
explains the fact that in all above known sufficient conditions for the
$(3,1)^*$-choosability of planar graphs the 4-cycles are completely forbidden.
In this paper we allow 4-cycles nonadjacent to relatively short cycles. More
precisely, we prove that every planar graph without 4-cycles adjacent to 3- and
4-cycles is $(3,1)^*$-choosable. This is a common strengthening of all above
mentioned results. Moreover as a consequence we give a partial answer to a
question of Xu and Zhang \cite{XZ-07} and show that every planar graph without
4-cycles is $(3,1)^*$-choosable.


title: Omega_bbb excited-state spectroscopy from lattice QCD

abstract:
  Triply heavy baryons are very interesting systems analogous to heavy
quarkonia, but are difficult to access experimentally. Lattice QCD can provide
precise predictions for these systems, which can be compared to other
theoretical approaches. In this work, the spectrum of excited states of the
Omega_bbb baryon is calculated using lattice NRQCD for the b quarks, and using
a domain-wall action for the u, d and s sea quarks. The calculations are done
for multiple values of the sea-quark masses, and for two different lattice
spacings. The energies of states with angular momentum up to J=7/2 are
calculated, and the effects of rotational symmetry breaking by the lattice are
analyzed. Precise results are obtained even for the small spin-dependent energy
splittings, and the contributions of individual NRQCD interactions to these
energy splittings are studied. The results are compared to potential-model
calculations.


title: Partial mixing of semi-random transposition shuffles

abstract:
  We show that for any semi-random transposition shuffle on $n$ cards, the
mixing time of any given $k$ cards is at most $n\log k$, provided $k=o((n/\log
n)^{1/2})$. In the case of the top-to-random transposition shuffle we show that
there is cutoff at this time with a window of size O(n), provided further that
$k\to\infty$ as $n\to\infty$ (and no cutoff otherwise). For the
random-to-random transposition shuffle we show cutoff at time $(1/2)n\log k$
for the same conditions on $k$. Finally, we analyse the cyclic-to-random
transposition shuffle and show partial mixing occurs at time $\le\alpha n\log
k$ for some $\alpha$ just larger than 1/2. We prove these results by relating
the mixing time of $k$ cards to the mixing of one card. Our results rely
heavily on coupling arguments to bound the total variation distance.


title: Wei-Norman equations for a unitary evolution

abstract:
  The Wei-Norman technique allows to express the solution of a system of linear
non-autonomous differential equations in terms of product of exponentials. In
particular it enables to find a time-ordered product of exponentials by solving
a set of nonlinear differential equations. The method has numerous theoretical
and computational advantages, in particular in optimal control theory. We show
that in the unitary case, i.e.\ when the solution of the linear system is given
by a unitary evolution operator, the nonlinear system can be by an appropriate
choice of ordering reduced to a hierarchy of matrix Riccati equations. Our
findings have a particular significance in quantum control theory since pure
quantum evolution is unitary.


title: The relativity of simultaneity and presentism

abstract:
  According to conventional wisdom, presentism is at odds with the theory of
relativity. This is supposed to be shown quite simply just by considering the
relativity of simultaneity. In this paper I will show that conventional wisdom
is wrong. In fact by clarifying the physical meaning of the relativity of
simultaneity one can inform the philosophical debate and endorse a presentist
view.


title: Conformal nets I: coordinate-free nets

abstract:
  We describe a coordinate-free perspective on conformal nets, as functors from
intervals to von Neumann algebras. We discuss an operation of fusion of
intervals and observe that a conformal net takes a fused interval to the fiber
product of von Neumann algebras. Though coordinate-free nets do not a priori
have vacuum sectors, we show that there is a vacuum sector canonically
associated to any circle equipped with a conformal structure. This is the first
in a series of papers constructing a 3-category of conformal nets, defects,
sectors, and intertwiners.


title:
Remarks on a population-level model of chemotaxis: advection-diffusion
  approximation and simulations

abstract:
  This note works out an advection-diffusion approximation to the density of a
population of E. coli bacteria undergoing chemotaxis in a one-dimensional
space. Simulations show the high quality of predictions under a
shallow-gradient regime.


title: A new bio-inspired method for remote sensing imagery classification

abstract:
  The problem of supervised classification of the satellite image is considered
to be the task of grouping pixels into a number of homogeneous regions in space
intensity. This paper proposes a novel approach that combines a radial basic
function clustering network with a growing neural gas include utility factor
classifier to yield improved solutions, obtained with previous networks. The
double objective technique is first used to the development of a method to
perform the satellite images classification, and finally, the implementation to
address the issue of the number of nodes in the hidden layer of the classic
Radial Basis functions network. Results demonstrating the effectiveness of the
proposed technique are provided for numeric remote sensing imagery. Moreover,
the remotely sensed image of Oran city in Algeria has been classified using the
proposed technique to establish its utility.


title: Weak gravitational lensing of intrinsically aligned galaxies

abstract:
  Subject of this paper is the weak lensing effect on galaxies that show
intrinsically correlated ellipticities. In our model, we investigate the
distortion of the ellipticity field if the galaxies experience an apparent
shift in their position by weak lensing deflection and compare this effect to
the shearing effect induced by tidal fields. Starting with a derivation of
intrinsic ellipticity spectra by employing a tidal torquing model generating
galactic angular momenta, we model the galaxy ellipticity by assuming that the
galactic disk forms perpendicularly to the host halo angular momentum direction
and derive intrinsic ellipticity E-mode and B-mode spectra from the angular
momentum statistics. The lensing effect on the ellipticity field is modeled by
employing the methodology developed in the framework of lensing of the cosmic
microwave background polarisation. For EUCLID, ellipticity correlations are
altered by lensing deflection on multipoles l>1000 by ~5% for the ellipticity
E-modes and by ~30% for the B-modes, while a shallower survey would exhibit
larger changes on larger angular scales. In addition to the convolving effect
of lensing on the ellipticity spectra we investigate the E/B-mode conversion,
and discuss the possibility of measuring correlations between different
multipoles which is evoked by the homogeneity breaking effect of the lensing
displacement. Our conclusion is that although shape correlations generated by
weak gravitational shear is dominant, the shifting effect due to lensing is
shaping the ellipticity spectra on small angular scales and causes a number of
interesting phenomena, which might be observable by future surveys.


title: A Stochastic Method for Computing Hadronic Matrix Elements

abstract:
  We present a stochastic method for the calculation of baryon three-point
functions that is more versatile compared to the typically used sequential
method. We analyze the scaling of the error of the stochastically evaluated
three-point function with the lattice volume and find a favorable
signal-to-noise ratio suggesting that our stochastic method can be used
efficiently at large volumes to compute hadronic matrix elements.


title:
Non-adiabatic Coulomb effects in strong field ionisation in circularly
  polarised laser fields

abstract:
  We develop the recently proposed analytical R-matrix (ARM) method to
encompass strong field ionisation by circularly polarised fields, for atoms
with arbitrary binding potentials. Through ARM, the effect of the potential can
now be included consistently both during and after ionisation, providing a
complete picture for the effects of the long-range potential. We find that the
Coulomb effects modify the ionisation dynamics in several ways, including
modification of (i) the ionisation (exit) times, (ii) the initial conditions
for the electron continuum dynamics, (iii) the "tunnelling angle", at which the
electron "enters" the barrier, and (iv) the electron drift momentum. We derive
analytical expressions for the Coulomb-corrected ionisation times, initial
velocities, momentum shifts and ionisation rates in circularly polarised
fields, for arbitrary angular momentum of the initial state. We also analyse
how the non-adiabatic Coulomb effects modify (i) the calibration of the
attoclock in the angular streaking method, and (ii) the ratio of ionisation
rates from $p^{-}$ and $p^{+}$ orbitals.


title:
De Donder-Weyl Hamiltonian formulation and precanonical quantization of
  vielbein gravity

abstract:
  The De Donder-Weyl (DW) covariant Hamiltonian formulation of Palatini
first-order Lagrangian of vielbein (tetrad) gravity and its precanonical
quantization are presented. No splitting into the space and time is required in
this formulation. Our recent generalization of Dirac brackets is used to treat
the second class primary constraints appearing in the DW Hamiltonian
formulation and to find the fundamental brackets. Quantization of the latter
yields the representation of vielbeins as differential operators with respect
to the spin connection coefficients, and the Dirac-like precanonical
Schr\"odinger equation on the space of spin connection coefficients and
space-time variables. The transition amplitudes on this space describe the
quantum geometry of space-time. We also discuss the Hilbert space of the
theory, the invariant measure on the spin connection coefficients, and point to
the possible quantum singularity avoidance built in in the natural choice of
the boundary conditions of the wave functions on the space of spin connection
coefficients.


title:
Spin-resolved Andreev levels and parity crossings in hybrid
  superconductor-semiconductor nanostructures

abstract:
  The hybrid combination of superconductors and low-dimensional semiconductors
offers a versatile ground for novel device concepts, such as sources of
spin-entangled electrons, nanoscale superconducting magnetometers, or recently
proposed qubits based on topologically protected Majorana fermions. The
underlying physics behind such hybrid devices ultimately rely on the magnetic
properties of sub-gap excitations, known as Andreev levels. Here we report the
Zeeman effect on the Andreev levels of a semiconductor nanowire quantum dot
(QD) strongly coupled to a conventional superconductor. The combination of the
large QD g-factor with the large superconductor critical magnetic field allows
spin degeneracy to be lifted without suppressing superconductivity. We show
that a Zeeman-split Andreev level crossing the Fermi energy signals a quantum
phase transition in the ground state of the superconductivity-induced QD,
denoting a change in the fermionic parity of the system. This transition
manifests itself as a zero-bias conductance anomaly appearing at a finite
magnetic field, with properties that resemble those expected for Majorana
fermions in a topological superconductor. Although the herein reported
zero-bias anomalies do not hold any relation with topological
superconductivity, the observed parity transitions can be regarded as
precursors of Majorana modes in the long-wire limit.


title:
Effects of electron scattering on the topological properties of
  nanowires: Majorana fermions from disorder and superlattices

abstract:
  We focus on inducing topological state from regular, or irregular scattering
in (i) p-wave superconducting wires and (ii) Rashba wires proximity coupled to
an s-wave superconductor. We find that contrary to common expectations the
topological properties of both systems are fundamentally different: In p-wave
wires, disorder generally has a detrimental effect on the topological order and
the topological state is destroyed beyond a critical disorder strength. In
contrast, in Rashba wires, which are relevant for recent experiments, disorder
can {\it induce} topological order, reducing the need for quasiballistic
samples to obtain Majorana fermions. Moreover, we find that the total phase
space area of the topological state is conserved for long disordered Rashba
wires, and can even be increased in an appropriately engineered superlattice
potential.


title:
Nonviolent information transfer from black holes: a field theory
  parameterization

abstract:
  A candidate parameterization is introduced, in an effective field theory
framework, for the quantum information transfer from a black hole that is
necessary to restore unitarity. This in particular allows description of the
effects of this information transfer in the black hole atmosphere, for example
seen by infalling observers. In the presence of such information transfer, it
is shown that infalling observers need not experience untoward violence.
Moreover, the presence of general moderate-frequency couplings to field modes
with high angular momenta offers a mechanism to enhance information transfer
rates, commensurate with the increased energy flux, when a string is introduced
to "mine" a black hole. Generic such models for nonviolent information transfer
predict extra energy flux from a black hole, beyond that of Hawking.


title:
Improved Electroweak Phase Transition with Subdominant Inert Doublet
  Dark Matter

abstract:
  The inert doublet dark matter model has recently gained attention as a
possible means of facilitating a strongly first order electroweak phase
transition (EWPT), as needed for baryogenesis. We extend previous results by
considering the regime where the DM is heavier than half the Higgs mass, and
its relic density is determined by annihilation into W, Z and Higgs bosons. We
find a large natural region of parameter space where the EWPT is strongly first
order, while the lightest inert doublet state typically contributes only 0.1-3%
of the total dark matter. Despite this small density, its interactions with
nucleons are strong enough to be directly detectable given a factor of 5
improvement over the current sensitivity of XENON100. A 10% decrease in the
branching ratio for Higgs decays to two photons is predicted.


title: Assessing Semantic Quality of Web Directory Structure

abstract:
  The administration of a Web directory content and associated structure is a
labor intensive task performed by human domain experts. Because of that there
always exists a realistic risk of the structure becoming unbalanced, uneven and
difficult to use to all except for a few users proficient in a particular Web
directory. These problems emphasize the importance of generic and objective
measures of Web directories structure quality. In this paper we demonstrate how
to formally merge Web directories into the Semantic Web vision. We introduce a
set of objective criterions for evaluation of a Web directory's structure
quality. Some criteria functions are based on heuristics while others require
the application of ontologies.


title:
Functional methods underlying classical mechanics, relativity and
  quantum theory

abstract:
  The paper investigates the physical content of a recently proposed
mathematical framework that unifies the standard formalisms of classical
mechanics, relativity and quantum theory. In the framework states of a
classical particle are identified with Dirac delta functions. The classical
space is "made" of these functions and becomes a submanifold in a Hilbert space
of states of the particle. The resulting embedding of the classical space into
the space of states is highly non-trivial and accounts for numerous deep
relations between classical and quantum physics and relativity. One of the most
striking results is the proof that the normal probability distribution of
position of a macroscopic particle (equivalently, position of the corresponding
delta state within the classical space submanifold) yields the Born rule for
transitions between arbitrary quantum states.


title:
Convergence of a low order non-local Navier-Stokes-Korteweg system: the
  order-parameter model

abstract:
  In the present article we consider a capillary compressible system introduced
by C. Rohde after works of Bandon, Lin and Rogers, called the order-parameter
model, and whose aim is to reduce the numerical difficulties that one
encounters in the case of the classical local Korteweg system (involving
derivatives of order three) or the non-local system (also introduced by Rohde
after works of Van der Waals, and which involves a convolution operator). We
prove that this system has a unique global solution for initial data close to
an equilibrium and we precisely study the convergence of this solution towards
the local Korteweg model.


title:
The MaGICC volume: reproducing statistical properties of high redshift
  galaxies

abstract:
  We present a cosmological hydrodynamical simulation of a representative
volume of the Universe, as part of the Making Galaxies in a Cosmological
Context (MaGICC) project. MaGICC uses a thermal implementation for supernova
and early stellar feedback. This work tests the feedback model at lower
resolution across a range of galaxy masses, morphologies and merger histories.
The simulated sample compares well with observations of high redshift galaxies
($z \ge 2$) including the stellar mass - halo mass ($M_\star - M_h$ ) relation,
the Galaxy Stellar Mass Function (GSMF) at low masses ($M_\star \lt 5 \times
10^{10} M_\odot$ ) and the number density evolution of low mass galaxies. The
poor match of $M_\star - M_h$ and the GSMF at high masses ($M_\star \ge 5
\times 10^{10} M_\odot$ ) indicates supernova feedback is insufficient to limit
star formation in these haloes. At $z = 0$, our model produces too many stars
in massive galaxies and slightly underpredicts the stellar mass around
$L_\star$ mass galaxy. Altogether our results suggest that early stellar
feedback, in conjunction with supernovae feedback, plays a major role in
regulating the properties of low mass galaxies at high redshift.


title:
Characterisation of SCUBA-2 450um and 850um-selected Galaxies in the
  COSMOS Field

abstract:
  We present deep 450um and 850um observations of a large, uniformly covered
394arcmin^2 area in the COSMOS field obtained with the SCUBA-2 instrument on
the James Clerk Maxwell Telescope (JCMT). We achieve root-mean-square noise
values of 4.13mJy at 450um and 0.80mJy at 850um. The differential and
cumulative number counts are presented and compared to similar previous works.
Individual point sources are identified at >3.6sigma significance, a threshold
corresponding to a 3-5% sample contamination rate. We identify 78 sources at
450um and 99 at 850um, with flux densities S450=13-37mJy and S850=2-16mJy. Only
62-76% of 450um sources are 850um detected and 61-81% of 850um sources are
450um detected. The positional uncertainties at 450um are small (1-2.5") and
therefore allow a precise identification of multiwavelength counterparts
without reliance on detection at 24um or radio wavelengths; we find that only
44% of 450um-selected galaxies and 60% of 850um-sources have 24um or radio
counterparts. 450um-selected galaxies peak at <z>=1.95+-0.19 and 850um=selected
galaxies peak at <z>=2.16+-0.11. The two samples occupy similar parameter space
in redshift and luminosity, while their median SED peak wavelengths differ by
~10-50um (translating to deltaTdust =8-12K, where 450um-selected galaxies are
warmer). The similarities of the 450um and 850um populations, yet lack of
direct overlap between them, suggests that submillimeter surveys conducted at
any single far-infrared wavelength will be significantly incomplete (~>30%) at
censusing infrared-luminous star formation at high-z.


title: A Cosmological Upper Bound on Superpartner Masses

abstract:
  If some superpartners were in thermal equilibrium in the early universe, and
if the lightest superpartner is a cosmologically stable gravitino, then there
is a powerful upper bound on the scale of the superpartner masses. Typically
the bound is below tens of TeV, often much lower, and has similar parametrics
to the WIMP miracle.


title:
The Stagger-grid: A Grid of 3D Stellar Atmosphere Models - I. Methods
  and General Properties

abstract:
  We present the Stagger-grid, a comprehensive grid of time-dependent, 3D
hydrodynamic model atmospheres for late-type stars with realistic treatment of
radiative transfer, covering a wide range in stellar parameters. This grid of
3D models is intended for various applications like stellar spectroscopy,
asteroseismology and the study of stellar convection. In this introductory
paper, we describe the methods used for the computation of the grid and discuss
the general properties of the 3D models as well as their temporal and spatial
averages (<3D>). All our models were generated with the Stagger-code, using
realistic input physics for the equation of state (EOS) and for continuous and
line opacities. Our ~220 grid models range in Teff from 4000 to 7000K in steps
of 500K, in log g from 1.5 to 5.0 in steps of 0.5 dex, and [Fe/H] from -4.0 to
+0.5 in steps of 0.5 and 1.0 dex. We find a tight scaling relation between the
vertical velocity and the surface entropy jump, which itself correlates with
the constant entropy value of the adiabatic convection zone. The range in
intensity contrast is enhanced at lower metallicity. The granule size
correlates closely with the pressure scale height sampled at the depth of
maximum velocity. We compare the <3D> models with widely applied 1D models, as
well as with theoretical 1D hydrostatic models generated with the same EOS and
opacity tables as the 3D models, in order to isolate the effects of using
self-consistent and hydrodynamic modeling of convection, rather than the
classical mixing length theory approach. For the first time, we are able to
quantify systematically over a broad range of stellar parameters the
uncertainties of 1D models arising from the simplified treatment of physics, in
particular convective energy transport. In agreement with previous findings, we
find that the differences can be significant, especially for metal-poor stars.


title: Sculpting the disk around T Cha: an interferometric view

abstract:
  (Abridged) Circumstellar disks are believed to be the birthplace of planets
and are expected to dissipate on a timescale of a few Myr. The processes
responsible for the removal of the dust and gas will strongly modify the radial
distribution of the dust and consequently the SED. In particular, a young
planet will open a gap, resulting in an inner disk dominating the near-IR
emission and an outer disk emitting mostly in the far-IR. We analyze a full set
of data (including VLTI/Pionier, VLTI/Midi, and VLT/NaCo/Sam) to constrain the
structure of the transition disk around TCha. We used the Mcfost radiative
transfer code to simultaneously model the SED and the interferometric
observations. We find that the dust responsible for the emission in excess in
the near-IR must have a narrow temperature distribution with a maximum close to
the silicate sublimation temperature. This translates into a narrow inner dusty
disk (0.07-0.11 AU). We find that the outer disk starts at about 12 AU and is
partially resolved by the Pionier, Sam, and Midi instruments. We show that the
Sam closure phases, interpreted as the signature of a candidate companion, may
actually trace the asymmetry generated by forward scattering by dust grains in
the upper layers of the outer disk. These observations help constrain the
inclination and position angle of the outer disk. The presence of matter inside
the gap is difficult to assess with present-day observations. Our model
suggests the outer disk contaminates the interferometric signature of any
potential companion that could be responsible for the gap opening, and such a
companion still has to be unambiguously detected. We stress the difficulty to
observe point sources in bright massive disks, and the consequent need to
account for disk asymmetries (e.g. anisotropic scattering) in model-dependent
search for companions.


title:
A z=3.045 Lyman alpha emitting halo hosting a QSO and a possible
  candidate for AGN-triggered star-formation

abstract:
  In this third paper in a series on the nature of extended, asymmetric Lyman
alpha emitters at z ~ 3 we report the discovery, in an ultra-deep, blind,
spectroscopic long-slit survey, of a Lyman alpha emitting halo around a QSO at
redshift 3.045. The QSO is a previously known, obscured AGN. The halo appears
extended along the direction of the slit and exhibits two faint patches
separated by 17 proper kpc in projection from the QSO. Comparison of the
2-dimensional spectrum with archival HST ACS images shows that these patches
coincide spatially with emission from a peculiar, dumbbell-shaped, faint
galaxy. The assumptions that the Lyman alpha emission patches are originating
in the galaxy and that the galaxy is physically related to the QSO are at
variance with photometric estimates of the galaxy redshift. We show, however,
that a population of very young stars at the redshift of the QSO may fit the
existing rest frame broad band UV photometry of the galaxy. If this scenario is
correct then the symmetry of the galaxy in continuum and Lyman alpha emission,
the extension of the QSO's Lyman alpha emission in its direction, and the
likely presence of a young stellar population in close proximity to a
(short-lived) AGN suggest that this may be an example of AGN feedback
triggering external star formation in high redshift galaxies.


title:
Fundamental Properties of Kepler Planet-Candidate Host Stars using
  Asteroseismology

abstract:
  We have used asteroseismology to determine fundamental properties for 66
Kepler planet-candidate host stars, with typical uncertainties of 3% and 7% in
radius and mass, respectively. The results include new asteroseismic solutions
for four host stars with confirmed planets (Kepler-4, Kepler-14, Kepler-23 and
Kepler-25) and increase the total number of Kepler host stars with
asteroseismic solutions to 77. A comparison with stellar properties in the
planet-candidate catalog by Batalha et al. shows that radii for subgiants and
giants obtained from spectroscopic follow-up are systematically too low by up
to a factor of 1.5, while the properties for unevolved stars are in good
agreement. We furthermore apply asteroseismology to confirm that a large
majority of cool main-sequence hosts are indeed dwarfs and not misclassified
giants. Using the revised stellar properties, we recalculate the radii for 107
planet candidates in our sample, and comment on candidates for which the radii
change from a previously giant-planet/brown-dwarf/stellar regime to a
sub-Jupiter size, or vice versa. A comparison of stellar densities from
asteroseismology with densities derived from transit models in Batalha et al.
assuming circular orbits shows significant disagreement for more than half of
the sample due to systematics in the modeled impact parameters, or due to
planet candidates which may be in eccentric orbits. Finally, we investigate
tentative correlations between host-star masses and planet candidate radii,
orbital periods, and multiplicity, but caution that these results may be
influenced by the small sample size and detection biases.


title: keV Neutrino Model Building

abstract:
  We review the model building aspects for keV sterile neutrinos as Dark Matter
candidates. After giving a brief discussion of some cosmological and
astrophysical aspects, we first discuss the currently known neutrino data and
observables. We then explain the purpose and goal of neutrino model building,
and review some generic methods used. Afterwards certain aspects specific for
keV neutrino model building are discussed, before reviewing the bulk of models
in the literature. We try to keep the discussion on a pedagogical level, while
nevertheless pointing out some finer details where necessary and useful.
Ideally, this review should enable a grad student or an interested colleague
from cosmology or astrophysics with some prior experience to start working on
the field.


title:
Testing galaxy formation models with the GHOSTS survey: The color
  profile of M81's stellar halo

abstract:
  We study the properties of the stellar populations in M81's outermost part,
which hereafter we will term the stellar halo, using HST ACS/WFC observations
of 19 fields from the GHOSTS survey. The observed fields probe the stellar halo
out to a projected distance of ~ 50 kpc from the galactic center. Each field
was observed in both F606W and F814W filters. The 50% completeness levels of
the color magnitude diagrams (CMDs) are typically at 2 mag below the tip of the
red giant branch (TRGB). Fields at distances closer than 15 kpc show evidence
of disk-dominated populations whereas fields at larger distances are mostly
populated by halo stars. The RGB of the M81's halo CMDs is well matched with
isochrones of ~ 10 Gyr and metallicities [Fe/H] ~ -1.2 dex, suggesting that the
dominant stellar population of M81's halo has a similar age and metallicity.
The halo of M81 is characterized by a color distribution of width ~ 0.4 mag and
an approximately constant median value of (F606W - F814W) ~ 1 mag measured
using stars within the magnitude range 23.7 < F814W < 25.5. When considering
only fields located at galactocentric radius R > 15 kpc, we detect no color
gradient in the stellar halo of M81. We place a limit of 0.03+/-0.11 mag
difference between the median color of RGB M81 halo stars at ~ 15 and at 50
kpc, corresponding to a metallicity difference of 0.08+/-0.35 dex over that
radial range for an assumed constant age of 10 Gyr. We compare these results
with model predictions for the colors of stellar halos formed purely via
accretion of satellite galaxies. When we analyze the cosmologically motivated
models in the same way as the HST data, we find that they predict no color
gradient for the stellar halos, in good agreement with the observations.


title:
Convergence zones for Type I migration: an inward shift for multiple
  planet systems

abstract:
  Earth-mass planets embedded in gaseous protoplanetary disks undergo Type I
orbital migration. In radiative disks an additional component of the corotation
torque scaling with the entropy gradient across the horseshoe region can
counteract the general inward migration, Type I migration can then be directed
either inward or outward depending on the local disk properties. Thus, special
locations exist in the disk toward which planets migrate in a convergent way.
  Here we present N-body simulations of the convergent migration of systems of
low-mass (M=1-10 m_earth) planets. We show that planets do not actually
converge in convergence zones. Rather, they become trapped in chains of mean
motion resonances (MMRs). This causes the planets' eccentricities to increase
to high enough values to affect the structure of the horseshoe region and
weaken the positive corotation torque. The zero-torque equilibrium point of the
resonant chain of planets is determined by the sum of the attenuated corotation
torques and unattenuated differential Lindblad torques acting on each planet.
  The effective convergence zone is shifted inward. Systems with several
planets can experience stochastic migration as a whole due to continuous
perturbations from planets entering and leaving resonances.


title:
SOPHIE velocimetry of Kepler transit candidates. VIII. KOI-205 b: a
  brown-dwarf companion to a K-type dwarf

abstract:
  We report the discovery of a transiting brown dwarf companion to KOI-205, a
K0 main-sequence star, in a 11.720125-day period orbit. The transits were
detected by the Kepler space telescope, and the reflex motion of the star was
measured using radial velocity observations obtained with the SOPHIE
spectrograph. The atmospheric parameters of the host stars were determined from
the analysis of high-resolution, high signal-to-noise ratio ESPaDOns spectra
obtained for this purpose. Together with spectrophotometric measurements
recovered from the literature, these spectra indicate that the star is a mildly
metallic K0 dwarf with Teff 5237 $\pm$ 60 K. The mass of the companion is 39.9
$\pm$ 1.0 MJup and its radius is 0.81 $\pm$ 0.02 RJup, in agreement with
current theoretical predictions. This is the first time a bona fide brown dwarf
companion is detected in orbit around a star of this type. The formation and
orbital evolution of brown dwarf companions is briefly discussed in the light
of this new discovery.


title: Single degenerate supernova type Ia progenitors

abstract:
  There is general agreement that supernovae Ia correspond to the thermonuclear
runaway of a white dwarf that is part of a compact binary, but the details of
the progenitor systems are still unknown and much debated. One of the proposed
progenitor theories is the single-degenerate channel in which a white dwarf
accretes from a companion, grows in mass, reaches a critical mass limit, and is
then consumed after thermonuclear runaway sets in. However, there are major
disagreements about the theoretical delay time distribution and the
corresponding time-integrated supernova Ia rate from this channel. We
investigate whether the differences are due to the uncertainty in the common
envelope phase and the fraction of transferred mass that is retained by the
white dwarf. This so-called retention efficiency may have a strong influence on
the final amount and timing of supernovae Ia. Using the population synthesis
code SeBa, we simulated large numbers of binaries for various assumptions on
common envelopes and retention efficiencies. We compare the resulting supernova
Ia rates and delay time distributions with each other and with those from the
literature, including observational data. For the three assumed retention
efficiencies, the integrated rate varies by a factor 3-4 to even more than a
factor 100, so in extreme cases, the retention efficiency strongly suppresses
the single-degenerate channel. Our different assumptions for the common
envelope phase change the integrated rate by a factor 2-3. Although our results
do recover the trend in the theoretical predictions from different binary
population synthesis codes, they do not fully explain the large disagreement
among them.


title:
Two-loop QCD helicity amplitudes for $g\,g \to Z\,g$ and $g\,g \to
  Z\,\gamma $

abstract:
  We compute the helicity amplitudes for the processes $gg\to Zg$ and $gg\to
Z\gamma$ to two loops in massless QCD. The perturbative expansion of these
processes starts only at the one-loop level, such that our results are a
crucial ingredient to the NLO corrections to $Z\gamma$ and $Z+$jet production
through gluon fusion.


title: On the Star Formation-AGN Connection at $z \lesssim 0.3$

abstract:
  Using the spectra of a sample of $\sim$28,000 nearby obscured active galaxies
from Data Release 7 of the Sloan Digital Sky Survey (SDSS), we probe the
connection between AGN activity and star formation over a range of radial
scales in the host galaxy. We use the extinction-corrected luminosity of the
[OIII] 5007 \AA\ line as a proxy of intrinsic AGN power and supermassive black
hole (SMBH) accretion rate. The star formation rates (SFRs) are taken from the
MPA-JHU value-added catalog and are measured through the 3$^{\prime\prime}$
SDSS aperture. We construct matched samples of galaxies covering a range in
redshifts. With increasing redshift, the projected aperture size encompasses
increasing amounts of the host galaxy. This allows us to trace the radial
distribution of star-formation as a function of AGN luminosity. We find that
the star formation becomes more centrally concentrated with increasing AGN
luminosity and Eddington ratio. This implies that such circumnuclear star
formation is associated with AGN activity, and that it increasingly dominates
over omnipresent disk star formation at higher AGN luminosities, placing
critical constraints on theoretical models that link host galaxy star formation
and SMBH fueling. We parametrize this relationship and find that the star
formation on radial scales $<$1.7 kpc, when including a constant disk
component, has a sub-linear dependence on SMBH accretion rate: $SFR \propto
\dot{M}^{0.36}$, suggesting that angular momentum transfer through the disk
limits accretion efficiency rather than the supply from stellar mass loss.


title: Generalized Probabilistic Theories Without the No-Restriction Hypothesis

abstract:
  The framework of generalized probabilistic theories (GPTs) is a popular
approach for studying the physical foundations of quantum theory. The standard
framework assumes the no-restriction hypothesis, in which the state space of a
physical theory determines the set of measurements. However, this assumption is
not physically motivated. We generalize the framework to account for systems
that do not obey the no-restriction hypothesis. We then show how our framework
can be used to describe new classes of probabilistic theories, for example
those which include intrinsic noise. Relaxing the restriction hypothesis also
allows us to introduce a 'self-dualization' procedure, which yields a new class
of theories that share many features of quantum theory, such as obeying
Tsirelson's bound for the maximally entangled state. We then characterize joint
states, generalizing the maximal tensor product. We show how this new tensor
product can be used to describe the convex closure of the Spekkens toy theory,
and in doing so we obtain an analysis of why it is local in terms of the
geometry of its state space. We show that the unrestricted version of the
Spekkens toy theory is the theory known as 'boxworld' that allows maximal
nonlocal correlations.


title: An outburst from a massive star 40 days before a supernova explosion

abstract:
  Various lines of evidence suggest that very massive stars experience extreme
mass-loss episodes shortly before they explode as a supernova. Interestingly,
several models predict such pre-explosion outbursts. Establishing a causal
connection between these mass-loss episodes and the final supernova explosion
will provide a novel way to study pre-supernova massive-star evolution. Here we
report on observations of a remarkable mass-loss event detected 40 days prior
to the explosion of the Type IIn supernova SN 2010mc (PTF 10tel). Our
photometric and spectroscopic data suggest that this event is a result of an
energetic outburst, radiating at least 6x10^47 erg of energy, and releasing
about 0.01 Solar mass at typical velocities of 2000 km/s. We show that the
temporal proximity of the mass-loss outburst and the supernova explosion
implies a causal connection between them. Moreover, we find that the outburst
luminosity and velocity are consistent with the predictions of the wave-driven
pulsation model and disfavor alternative suggestions.


title:
Classification and Properties of Symmetry Enriched Topological Phases: A
  Chern-Simons approach with applications to Z2 spin liquids

abstract:
  We study 2+1 dimensional phases with topological order, such as fractional
quantum Hall states and gapped spin liquids, in the presence of global
symmetries. Phases that share the same topological order can then differ
depending on the action of symmetry, leading to symmetry enriched topological
(SET) phases. Here we present a K-matrix Chern-Simons approach to identify all
distinct phases with Abelian topological order, in the presence of unitary or
anti-unitary global symmetries . A key step is the identification of an edge
sewing condition that is used to check if two putative phases are indeed
distinct. We illustrate this method for the case of $Z_2$ topological order
($Z_2$ spin liquids), in the presence of an internal Z$_2$ global symmetry. We
find 6 distinct phases. The well known quantum number fractionalization
patterns account for half of these states. Phases also differ due to the
addition of a symmetry protected topological (SPT) phase. Also, we allow for
the unconventional possibility that anyons are exchanged by the symmetry. This
leads to 2 additional phases with symmetry protected Majorana edge modes. Other
routes to realizing protected edge states in SET phases are identified.
Symmetry enriched Laughlin states and double semion theories are also
discussed. Two surprising lessons that emerge are: (i) gauging the global
symmetry of distinct SET phases always lead to different topological orders
with the same total quantum dimension, (ii) gauge theories with distinct
Dijkgraaf-Witten topological terms may have the same topological order.


title:
Reanalysis of F-statistic gravitational-wave searches with the higher
  criticism statistic

abstract:
  We propose a new method of gravitational wave detection using a modified form
of higher criticism, a statistical technique introduced by Donoho & Jin (2004).
Higher criticism is designed to detect a group of sparse, weak sources, none of
which are strong enough to be reliably estimated or detected individually. We
apply higher criticism as a second-pass method to synthetic F-statistic and
C-statistic data for a monochromatic periodic source in a binary system and
quantify the improvement relative to the first-pass methods. We find that
higher criticism on C-statistic data is more sensitive by ~6% than the
C-statistic alone under optimal conditions (i.e. binary orbit known exactly)
and the relative advantage increases as the error in the orbital parameters
increases. Higher criticism is robust even when the source is not monochromatic
(e.g. phase wandering in an accreting system). Applying higher criticism to a
phase-wandering source over multiple time intervals gives a >30% increase in
detectability with few assumptions about the frequency evolution. By contrast,
in all-sky searches for unknown periodic sources, which are dominated by the
brightest source, second-pass higher criticism does not provide any benefits
over a first pass search


title: Finite size effects in the Z_2 spin liquid on the kagome lattice

abstract:
  Motivated by the recent discovery of the Z_2 quantum spin liquid state in the
nearest neighbor Heisenberg model on the kagome lattice, we investigate the
"even-odd" effect occuring when this state is confined to infinitely long
cylinders of finite circumference. We pursue a dual analysis, where we map the
effective Z_2 gauge theory from the kagome lattice to a frustrated Ising model
on the dice lattice. Unexpectedly, we find that the latter theory, if
restricted to nearest neighbor interactions, is insufficient to capture this
effect. We provide an explanation of why further neighbor interactions are
needed via a high-temperature expansion of the effective Hamiltonian. We then
carry out projective symmetry group analysis to understand which second
neighbor interactions can be introduced while respecting the lattice
symmetries. Finally, we qualitatively compare our results to numerics by
computing the dimerization operator within our theory. Systems with odd
circumferences exhibit a non-vanishing dimerization that decays exponentially
with circumference.


title: Cosmological perturbations from a Spectator field during inflation

abstract:
  In this paper we will discuss analytically the perturbations created from a
slowly rolling subdominant spectator field which decays much before the end of
inflation. The quantum fluctuations of such a spectator field can seed
perturbations on very large scales and explain the temperature anisotropy in
the cosmic microwave background radiation with moderate non-Gaussianity,
provided the relevant modes leave the Hubble patch while the spectator is
slowly rolling. Furthermore, the perturbations are purely {\it adiabatic} since
the inflaton decay dominates and creates all the Standard Model degrees of
freedom. We will provide two examples for the spectator field potential, one
with a step function profile, and the other with an inflection point. In both
the cases we will compute higher order curvature perturbations, i.e.\ local
bispectrum and trispectrum, which can be constrained by the forthcoming Planck
data.


title:
Skew orthogonal polynomials for the real and quaternion real Ginibre
  ensembles and generalizations

abstract:
  There are some distinguished ensembles of non-Hermitian random matrices for
which the joint PDF can be written down explicitly, is unchanged by rotations,
and furthermore which have the property that the eigenvalues form a Pfaffian
point process. For these ensembles, in which the elements of the matrices are
either real, or real quaternion, the kernel of the Pfaffian is completely
determined by certain skew orthogonal polynomials, which permit an expression
in terms of averages over the characteristic polynomial, and the characteristic
polynomial multiplied by the trace. We use Schur polynomial theory, knowledge
of the value of a Schur polynomial averaged against real, and real quaternion
Gaussian matrices, and the Selberg integral to evaluate these averages.


title: Matrix Completion and Tensor Rank

abstract:
  In this paper, we show that the low rank matrix completion problem can be
reduced to the problem of finding the rank of a certain tensor.


title: Production and evaporation of Planck scale black holes at the LHC

abstract:
  We review the phenomenology of mini black holes at colliders in light of the
latest data from the LHC. By improving the conventional production
cross-section, we show that the current non-observation of black hole signals
can be explained in terms of quantum gravity effects. In the most optimistic
case, black hole production could take place at a scale slightly above the LHC
design energy. We also analyse possible new signatures of quantum-corrected
Planck-scale black holes: in contrast to the semiclassical scenario the
emission would take place in terms of soft particles mostly on the brane.


title:
Theta dependence of the deconfining phase transition in pure SU(N_c)
  Yang-Mills theories

abstract:
  Recently, it has been conjectured that deconfining phase transition in
SU(N_c) pure Yang-Mills theories is continuously connected to a quantum phase
transition in softly broken N=1 super Yang-Mills on R^{1,2}*S^1. We exploit
this conjecture to study the strength of the transition and deconfining
temperature as a function of the vacuum angle theta in pure Yang-Mills. We find
that the transition temperature is a decreasing function of theta in [0, \pi),
in an excellent agreement with recent lattice simulations. We also predict that
the transition becomes stronger for the same range of theta, and comment on the
theta dependence in the large N_c limit. More lattice studies are required to
test our predictions.


title: General Messenger Higgs Mediation

abstract:
  We present a general formalism for analyzing supersymmetric models where the
Higgs sector directly couples to the messengers of supersymmetry breaking. Such
Higgs-messenger interactions are strongly motivated by the discovery of a Higgs
boson near 125 GeV, but they also raise the specter of the mu/B_mu and A/m_H^2
problems. Using our formalism, we identify new avenues to solving these
problems through strong dynamics in the messenger sector or hidden sector.
Although our formalism is entirely general, we show how it reproduces familiar
results in two simplifying limits: one where the hidden sector consists of a
single spurion, and the other where it is approximately superconformal. In the
latter limit, our formalism generalizes and clarifies the scenario of hidden
sector sequestering, which we show can solve both the mu/B_mu and A/m_H^2
problems uniformly.


title: The Mass of Quasars

abstract:
  I review the current status of quasar black hole (BH) mass estimations.
Spectroscopic methods have been developed to estimate BH mass in broad line
quasars to an accuracy of ~0.5 dex. Despite their popularity, significant
issues and confusion remain regarding these mass estimators. I provide an
in-depth discussion on the merits and caveats of the single-epoch (SE) virial
BH mass estimators, and a detailed derivation of the statistical biases of
these SE mass estimates resulting from their errors. I show that error-induced
sample biases on the order of a factor of several are likely present in the SE
mass estimates for flux-limited, statistical quasar samples, and the
distribution of SE masses in finite luminosity bins can be narrower than the
nominal uncertainty of these mass estimates. I then discuss the latest
applications of SE virial masses in quasar studies, including the early growth
of supermassive black holes, quasar demography in the mass-luminosity plane,
and the evolution of the BH-host scaling relations, with specific emphases on
selection effects and sample biases in the SE masses. I conclude that there is
a pressing need to understand and deal with the errors in these BH mass
estimates, and to improve these BH weighing methods with substantially more and
better reverberation mapping data.


title:
B-meson decay constants from improved lattice NRQCD and physical u, d, s
  and c sea quarks

abstract:
  We present the first lattice QCD calculation of the decay constants f_B and
f_{B_s} with physical light quark masses. We use configurations generated by
the MILC collaboration including the effect of u, d, s and c HISQ sea quarks at
three lattice spacings and with three u/d quark mass values going down to the
physical value. We use improved NRQCD for the valence b quarks. Our results are
f_B = 0.186(4) GeV, f_{B_s} = 0.224(5) GeV, f_{B_s}/f_B = 1.205(7) and
M_{B_s}-M_B=85(2) MeV, superseding earlier results with NRQCD b quarks. We
discuss the implications of our results for the Standard Model rates for B_s ->
mu+ mu- and B -> tau nu.


title: Geometrical complexity of data approximators

abstract:
  There are many methods developed to approximate a cloud of vectors embedded
in high-dimensional space by simpler objects: starting from principal points
and linear manifolds to self-organizing maps, neural gas, elastic maps, various
types of principal curves and principal trees, and so on. For each type of
approximators the measure of the approximator complexity was developed too.
These measures are necessary to find the balance between accuracy and
complexity and to define the optimal approximations of a given type. We propose
a measure of complexity (geometrical complexity) which is applicable to
approximators of several types and which allows comparing data approximations
of different types.


title: Into the lair: gravitational-wave signatures of dark matter

abstract:
  The nature and properties of dark matter (DM) are both outstanding issues in
physics. Besides clustering in halos, the universal character of gravity
implies that self-gravitating compact DM configurations might be spread
throughout the universe. The astrophysical signature of these objects may be
used to probe fundamental particle physics, or even to provide an alternative
description of compact objects in active galactic nuclei. Here we discuss the
most promising dissection tool of these configurations: the inspiral of a
compact stellar-size object and consequent gravitational-wave emission. The
inward motion of this "test probe" encodes unique information about the nature
of the central, supermassive DM configuration. When the probe travels through
some compact DM profile we show that, within a Newtonian approximation, the
quasi-adiabatic evolution of the inspiral is mainly driven by DM accretion into
the small compact object and by dynamical friction, rather than by
gravitational-wave radiation-reaction. These effects circularize the orbits and
leave a peculiar imprint on the gravitational waves emitted at late time. When
accretion dominates, the frequency and the amplitude of the gravitational-wave
signal produced during the latest stages of the inspiral are nearly constant.
In the exterior region we study a relativistic model in which the inspiral is
driven by the emission of gravitational and scalar waves. Resonances in the
energy flux appear whenever the orbital frequency matches the mass of the DM
particle and they correspond to the excitation of the central object's
quasinormal frequencies. Unexpectedly, these resonances can lead to large
dephasing with respect to standard inspiral templates, to such an extent as to
prevent detection with matched filtering techniques. We discuss some
observational consequences of these effects for gravitational-wave detection.


title: Four-Dimensional Quantum Hall Effect in a Two-Dimensional Quasicrystal

abstract:
  One-dimensional (1D) quasicrystals exhibit physical phenomena associated with
the 2D integer quantum Hall effect. Here, we transcend dimensions and show that
a previously inaccessible phase of matter --- the 4D integer quantum Hall
effect --- can be incorporated in a 2D quasicrystal. Correspondingly, our 2D
model has a quantized charge-pump accommodated by an elaborate edge phenomena
with protected level crossings. We propose experiments to observe these 4D
phenomena, and generalize our results to a plethora of topologically equivalent
quasicrystals. Thus, 2D quasicrystals may pave the way to the experimental
study of 4D physics.


title: Electrical control over single hole spins in nanowire quantum dots

abstract:
  Single electron spins in semiconductor quantum dots (QDs) are a versatile
platform for quantum information processing, however controlling decoherence
remains a considerable challenge. Recently, hole spins have emerged as a
promising alternative. Holes in III-V semiconductors have unique properties,
such as strong spin-orbit interaction and weak coupling to nuclear spins, and
therefore have potential for enhanced spin control and longer coherence times.
Weaker hyperfine interaction has already been reported in self-assembled
quantum dots using quantum optics techniques. However, challenging fabrication
has so far kept the promise of hole-spin-based electronic devices out of reach
in conventional III-V heterostructures. Here, we report gate-tuneable hole
quantum dots formed in InSb nanowires. Using these devices we demonstrate Pauli
spin blockade and electrical control of single hole spins. The devices are
fully tuneable between hole and electron QDs, enabling direct comparison
between the hyperfine interaction strengths, g-factors and spin blockade
anisotropies in the two regimes.


title: On the consistency of the spindown behavior of young and old pulsars

abstract:
  We study the spindown of pulsars due to gravitational wave emission and show
that r-modes in neutron stars provide a quantitative explanation for the
observed low rotation frequencies of young pulsars if the r-mode saturation
amplitude is sufficiently large. In contrast for such large saturation
amplitudes old hadronic millisecond pulsars would spin down much faster than
observed. We discuss resolutions of this apparent discrepancy that could make
this mechanism consistent with the observational data.


title:
Robust Distant Entanglement Generation Using Coherent Multiphoton
  Scattering

abstract:
  We describe a protocol to entangle two qubits at a distance by using
resonance fluorescence. The scheme makes use of the postselection of large and
distinguishable fluorescence signals corresponding to entangled and unentangled
qubit states and has the merits of both high success probability and high
entanglement fidelity owing to the multiphoton nature. Our result shows that
the entanglement generation is robust against photon fluctuations in the
fluorescence signals for a wide range of driving fields. We also demonstrate
that this new protocol has an average entanglement duration within the
decoherence time of corresponding qubit systems, based on current experimental
photon efficiency.


title: A method for statistical comparison of histograms

abstract:
  We propose an approach for testing the hypothesis that two realizations of
the random variables in the form of histograms are taken from the same
statistical population (i.e. that two histograms are drawn from the same
distribution). The approach is based on the notion "significance of deviation".
Our approach allows also to estimate the statistical difference between two
histograms.


title: Uniqueness of radial solutions for the fractional Laplacian

abstract:
  We prove general uniqueness results for radial solutions of linear and
nonlinear equations involving the fractional Laplacian $(-\Delta)^s$ with $s
\in (0,1)$ for any space dimensions $N \geq 1$. By extending a monotonicity
formula found by Cabre and Sire \cite{CaSi-10}, we show that the linear
equation $(-\Delta)^s u+ Vu = 0$ in $\mathbb{R}^N$ has at most one radial and
bounded solution vanishing at infinity, provided that the potential $V$ is a
radial and non-decreasing. In particular, this result implies that all radial
eigenvalues of the corresponding fractional Schr\"odinger operator
$H=(-\Delta)^s + V$ are simple. Furthermore, by combining these findings on
linear equations with topological bounds for a related problem on the upper
half-space $\mathbb{R}^{N+1}_+$, we show uniqueness and nondegeneracy of ground
state solutions for the nonlinear equation $(-\Delta)^s Q + Q - |Q|^{\alpha} Q
= 0$ in $\mathbb{R}^N$ for arbitrary space dimensions $N \geq 1$ and all
admissible exponents $\alpha >0$. This generalizes the nondegeneracy and
uniqueness result for dimension N=1 recently obtained by the first two authors
in \cite{FrLe-10} and, in particular, the uniqueness result for solitary waves
of the Benjamin--Ono equation found by Amick and Toland \cite{AmTo-91}.


title:
Effect of microtubule-associated protein tau in dynamics of
  single-headed motor proteins KIF1A

abstract:
  Intracellular transport based on molecular motors and its regulation are
crucial to the functioning of cells. Filamentary tracks of the cells are
abundantly decorated with non-motile microtubule-associated proteins, such as
tau. Motivated by experiments on kinesin-tau interactions [Dixit et al. Science
319, 1086 (2008)] we developed a stochastic model of interacting single-headed
motor proteins KIF1A that also takes into account the interactions between
motor proteins and tau molecules. Our model reproduce experimental observations
and predicts significant effects of tau on bound time and run length which
suggest an important role of tau in regulation of kinesin-based transport.


title:
Enabling Secure Database as a Service using Fully Homomorphic
  Encryption: Challenges and Opportunities

abstract:
  The database community, at least for the last decade, has been grappling with
querying encrypted data, which would enable secure database as a service
solutions. A recent breakthrough in the cryptographic community (in 2009)
related to fully homomorphic encryption (FHE) showed that arbitrary computation
on encrypted data is possible. Successful adoption of FHE for query processing
is, however, still a distant dream, and numerous challenges have to be
addressed. One challenge is how to perform algebraic query processing of
encrypted data, where we produce encrypted intermediate results and operations
on encrypted data can be composed. In this paper, we describe our solution for
algebraic query processing of encrypted data, and also outline several other
challenges that need to be addressed, while also describing the lessons that
can be learnt from a decade of work by the database community in querying
encrypted data.


title: Snarks from a Kaszonyi perspective: a survey

abstract:
  This is a survey or exposition of a particular collection of results and open
problems involving snarks --- simple "cubic" (3-valent) graphs for which, for
nontrivial reasons, the edges cannot be 3-colored. The results and problems
here are rooted in a series of papers by Laszlo Kaszonyi that were published in
the early 1970s. The problems posed in this survey paper can be tackled without
too much specialized mathematical preparation, and in particular seem well
suited for interested undergraduate mathematics students to pursue as
independent research projects. This survey paper is intended to facilitate
research on these problems.


title: How to choose a PIN - assessment of dictionary methods

abstract:
  Personal Identification Numbers (PINs) are commonly used as an authentication
mechanism. An important security requirement is that PINs should be hard to
guess for an attacker. On the other hand, remembering several random PINs can
be difficult task for an individual. We evaluate several dictionary-based
methods of choosing a PIN. We experimentally show that these methods are far
from ideal with respect to expected covering of the PIN space and the entropy
of PINs. We also discuss two methods for constructing easy to memorize PIN
words for randomly chosen PINs.


title: Metrics for Assessing The Design of Software Interfaces

abstract:
  Recent studies have largely investigated the detection of class design
anomalies. They proposed a large set of metrics that help in detecting those
anomalies and in predicting the quality of class design. While those studies
and the proposed metrics are valuable, they do not address the particularities
of software interfaces. Interfaces define the contracts that spell out how
software modules and logic units interact with each other. This paper proposes
a list of design defects related to interfaces: shared similarity between
interfaces, interface clones and redundancy in interface hierarchy. We identify
and describe those design defects through real examples, taken from well-known
Java applications. Then we define three metrics that help in automatically
estimating the interface design quality, regarding the proposed design
anomalies, and identify refactoring candidates. We investigate our metrics and
show their usefulness through an empirical study conducted on three large Java
applications.


title: Low bend loss waveguides enable compact, efficient 3D photonic chips

abstract:
  We present a novel method to fabricate low bend loss femtosecond-laser
written waveguides that exploits the differential thermal stabilities of laser
induced refractive index modifications. The technique consists of a two-step
process; the first involves fabricating large multimode waveguides, while the
second step consists of a thermal post-annealing process, which erases the
outer ring of the refractive index profile, enabling single mode operation in
the C-band. By using this procedure we report waveguides with sharp bends (down
to 16.6 mm radius) and high (80%) normalized throughputs. This procedure was
used to fabricate an efficient 3D, photonic device known as a pupil-remapper
with negligible bend losses for the first time. The process will also allow for
complex chips, based on 10's - 100's of waveguides to be realized in a compact
foot print with short fabrication times.


title: Inverted Ionization Zones in Eta Carinae's "Weigelt Knots"

abstract:
  The Weigelt knots, dense slow-moving ejecta near eta Car, are mysterious in
structure as well as in origin. Using a special set of spectrograms obtained
with the HST/STIS, we have partially resolved the ionization zones of one knot
to an accuracy of about 10 mas. Contrary to simple models, higher ionization
levels occur on the_outer_ side of the knot, i.e., farther from the star. They
cannot represent a bow shock, and no truly satisfying explanation is yet
available -- though we sketch one tentative possibility. We emphasize that STIS
spectrograms provide far more reliable spatial measurements of the Weigelt
Knots than HST images do, and this technique can also be applied to the knots'
proper motion problem.


title:
Fabrication of high quality sub-micron Au gratings over large areas with
  pulsed laser interference lithography for SPR sensors

abstract:
  Metallic gratings were fabricated using high energy laser interference
lithography with a frequency tripled Nd:YAG nanosecond laser. The grating
structures were first recorded in a photosensitive layer and afterwards
transferred to an Au film. High quality Au gratings with a period of 770 nm and
peak-to-valley heights of 20-60 nm exhibiting plasmonic resonance response were
successfully designed, fabricated and characterized.


title:
On an Extension of Korn's First Inequality to Incompatible Tensor Fields
  on Domains of Arbitrary Dimensions

abstract:
  For a bounded N-dimensional domain with Lipschitz boundary we extend Korn's
first inequality to incompatible tensor fields. For compatible tensor fields
our estimate reduces to a non-standard variant of the well known Korn's first
inequality. On the other hand, for skew-symmetric tensor fields our new
estimate turns to Poincare's inequality. Therefore, our result may be viewed as
a natural common generalization of Korn's first and Poincare's inequality.
Decisive tools for this unexpected estimate are the classical Korn's first
inequality, Helmholtz decompositions for mixed boundary conditions and the
Maxwell estimate.


title: The Hilbert series of a linear symplectic circle quotient

abstract:
  We compute the Hilbert series of the graded algebra of regular functions on a
symplectic quotient of a unitary circle representation. Additionally, we
elaborate explicit formulas for the lowest coefficients of the Laurent
expansion of such a Hilbert series in terms of rational symmetric functions of
the weights. Considerable efforts are devoted to including the cases where the
weights are degenerate. We find that these Laurent expansions formally resemble
Laurent expansions of Hilbert series of graded rings of real invariants of
finite subgroups of $\U_n$. Moreover, we prove that certain Laurent
coefficients are strictly positive. Experimental observations are presented
concerning the behavior of these coefficients as well as relations among higher
coefficients, providing empirical evidence that these relations hold in
general.


title:
The CASSOWARY spectroscopy survey: A new sample of gravitationally
  lensed galaxies in SDSS

abstract:
  Bright gravitationally lensed galaxies provide our most detailed view of
galaxies at high redshift. Yet as a result of the small number of ultra-bright
z~2 lensed systems with confirmed redshifts, most detailed spectroscopic
studies have been limited in their scope. With the goal of increasing the
number of bright lensed galaxies available for detailed follow-up, we have
undertaken a spectroscopic campaign targeting wide separation (>3 arcsec)
galaxy-galaxy lens candidates within the Sloan Digital Sky Survey (SDSS).
Building on the earlier efforts of our CASSOWARY survey, we target a large
sample of candidate galaxy-galaxy lens systems in SDSS using a well-established
search algorithm which identifies blue arc-like structures situated around
luminous red galaxies. In this paper, we present a new redshift catalog
containing 25 lensed sources in SDSS confirmed through spectroscopic follow-up
of candidate galaxy-galaxy lens systems. Included in this new sample are two of
the brightest galaxies (r=19.6 and 19.7) galaxies known at z~2, a low
metallicity (12 + log (O/H)~8.0) extreme nebular line emitting galaxy at
z=1.43, and numerous systems for which detailed follow-up will be possible. The
source redshifts span 0.9<z<2.5 (median redshift of 1.9), and their optical
magnitudes are in the range 19.6<r<22.3. We present a brief source-by-source
discussion of the spectroscopic properties extracted from our confirmatory
spectra and discuss some initial science results. With more than 50
gravitationally lensed z>1 galaxies now confirmed within SDSS, it will soon be
possible for the first time to develop generalized conclusions from detailed
spectroscopic studies of the brightest lensed systems at high redshift.


title: The q-Dixon sum Dirichlet series analogue

abstract:
  A few years ago, the concept of a D-analogue was introduced as a Dirichlet
series analogue for the already known and well researched hypergeometric
q-series. The D-analogue of the q-Dixon sum is given here, in the context of
seeing a direct comparison with the old Dixon theorem and the q-analogue.


title: Travelling waves in hybrid chemotaxis models

abstract:
  Hybrid models of chemotaxis combine agent-based models of cells with partial
differential equation models of extracellular chemical signals. In this paper,
travelling wave properties of hybrid models of bacterial chemotaxis are
investigated. Bacteria are modelled using an agent-based (individual-based)
approach with internal dynamics describing signal transduction. In addition to
the chemotactic behaviour of the bacteria, the individual-based model also
includes cell proliferation and death. Cells consume the extracellular nutrient
field (chemoattractant) which is modelled using a partial differential
equation. Mesoscopic and macroscopic equations representing the behaviour of
the hybrid model are derived and the existence of travelling wave solutions for
these models is established. It is shown that cell proliferation is necessary
for the existence of non-transient (stationary) travelling waves in hybrid
models. Additionally, a numerical comparison between the wave speeds of the
continuum models and the hybrid models shows good agreement in the case of weak
chemotaxis and qualitative agreement for the strong chemotaxis case. In the
case of slow cell adaptation, we detect oscillating behaviour of the wave,
which cannot be explained by mean-field approximations.


title:
Monitoring subunit rotation in single FRET-labeled FoF1-ATP synthase in
  an anti-Brownian electrokinetic trap

abstract:
  FoF1-ATP synthase is the membrane protein catalyzing the synthesis of the
'biological energy currency' adenosine triphosphate (ATP). The enzyme uses
internal subunit rotation for the mechanochemical conversion of a proton motive
force to the chemical bond. We apply single-molecule F\"orster resonance energy
transfer (FRET) to monitor subunit rotation in the two coupled motors F1 and
Fo. Therefore, enzymes have to be isolated from the plasma membranes of
Escherichia coli, fluorescently labeled and reconstituted into 120-nm sized
lipid vesicles to yield proteoliposomes. These freely diffusing proteoliposomes
occasionally traverse the confocal detection volume resulting in a burst of
photons. Conformational dynamics of the enzyme are identified by sequential
changes of FRET efficiencies within a single photon burst. The observation
times can be extended by capturing single proteoliposomes in an anti-Brownian
electrokinetic trap (ABELtrap, invented by A. E. Cohen and W. E. Moerner). Here
we describe the preparation procedures of FoF1-ATP synthase and simulate FRET
efficiency trajectories for 'trapped' proteoliposomes. Hidden Markov Models are
applied at signal-to-background ratio limits for identifying the dwells and
substeps of the rotary enzyme when running at low ATP concentrations, excited
by low laser power, and confined by the ABELtrap.


title:
Quantum Bowling: Particle-hole transmutation in one-dimensional strongly
  interacting lattice models

abstract:
  We study the scattering of a soliton-like propagating particle with a wall of
bound particles, in several strongly interacting one-dimensional lattice models
with discrete degrees of freedom. We consider spin-polarized fermions
(anisotropic Heisenberg spin chain), the fermionic Hubbard model, and the Bose
Hubbard model, using precise numerical time dependent Density Matrix
Renormalization Group techniques. We show that in all integrable models
studied, there is no reflection. Instead, an incoming particle experiences
particle-hole transmutation upon entry and exit of the wall, and travels inside
the wall as a hole, analoguous to Klein tunneling, even though the dispersion
is highly nonlinear and there is no external potential. {\em Two} particles are
added to the wall on the incoming side and removed on the opposite side. For
spin-polarized fermions a single transmitted particle thus shifts the wall by
two lattice sites, in complete contrast to classical physics. For both Hubbard
models, the wall shifts by one doubly occupied single site. In the
nonintegrable models studied, the same process occurs in linear superposition
with backscattering events. We demonstrate a corresponding fermionic quantum
Newton's cradle and a metamaterial with "tachyonic" modes travelling faster
than in an empty system. We present a possible atomic scale signal counter for
spintronics. Our scenario should be realizable in future cold atom experiments.


title:
Genetic Exponentially Fitted Method for Solving Multi-dimensional
  Drift-diffusion Equations

abstract:
  A general approach was proposed in this article to develop high-order
exponentially fitted basis functions for finite element approximations of
multi-dimensional drift-diffusion equations for modeling biomolecular
electrodiffusion processes. Such methods are highly desirable for achieving
numerical stability and efficiency. We found that by utilizing the one-one
correspondence between continuous piecewise polynomial space of degree $k+1$
and the divergence-free vector space of degree $k$, one can construct
high-order 2-D exponentially fitted basis functions that are strictly
interpolative at a selected node set but are discontinuous on edges in general,
spanning nonconforming finite element spaces. First order convergence was
proved for the methods constructed from divergence-free Raviart-Thomas space
$RT_0^0$ at two different node sets


title: An efficient Markov chain Monte Carlo algorithm for the surface code

abstract:
  Minimum-weight perfect matching (MWPM) has been been the primary classical
algorithm for error correction in the surface code, since it is of low runtime
complexity and achieves relatively low logical error rates [Phys. Rev. Lett.
108, 180501 (2012)]. A Markov chain Monte Carlo (MCMC) algorithm [Phys. Rev.
Lett. 109, 160503 (2012)] is able to achieve lower logical error rates and
higher thresholds than MWPM, but requires a classical runtime complexity which
is super-polynomial in L, the linear size of the code. In this work we present
an MCMC algorithm that achieves significantly lower logical error rates than
MWPM at the cost of a polynomially increased classical runtime complexity. For
error rates p close to the threshold, our algorithm needs a runtime complexity
which is increased by O(L^2) relative to MWPM in order to achieve a lower
logical error rate. If p is below an L-dependent critical value, no increase in
the runtime complexity is necessary any longer. For p->0, the logical error
rate achieved by our algorithm is exponentially smaller (in L) than that of
MWPM, without requiring an increased runtime complexity. Our algorithm allows
for trade-offs between runtime and achieved logical error rates as well as for
parallelization, and can be also used to correct in the case of imperfect
stabilizer measurements.


title: Equilibration of quantum Hall edge states by an Ohmic contact

abstract:
  Ohmic contacts are crucial elements of electron optics that have not received
a clear theoretical description yet. We propose a model of an Ohmic contact as
a piece of metal of the finite capacitance $C$ attached to a quantum Hall edge.
It is shown that charged quantum Hall edge states may have weak coupling to
neutral excitations in an Ohmic contact. Consequently, despite being a
reservoir of neutral excitations, an Ohmic contact is not able to efficiently
equilibrate edge states if its temperature is smaller than $\hbar\Omega_c$,
where $\Omega_c$ is the inverse RC time of the contact. This energy scale for a
floating contact may become as large as the single-electron charging energy
$e^2/ C$.


title: Latent Self-Exciting Point Process Model for Spatial-Temporal Networks

abstract:
  We propose a latent self-exciting point process model that describes
geographically distributed interactions between pairs of entities. In contrast
to most existing approaches that assume fully observable interactions, here we
consider a scenario where certain interaction events lack information about
participants. Instead, this information needs to be inferred from the available
observations. We develop an efficient approximate algorithm based on
variational expectation-maximization to infer unknown participants in an event
given the location and the time of the event. We validate the model on
synthetic as well as real-world data, and obtain very promising results on the
identity-inference task. We also use our model to predict the timing and
participants of future events, and demonstrate that it compares favorably with
baseline approaches.


title: Competing With Strategies

abstract:
  We study the problem of online learning with a notion of regret defined with
respect to a set of strategies. We develop tools for analyzing the minimax
rates and for deriving regret-minimization algorithms in this scenario. While
the standard methods for minimizing the usual notion of regret fail, through
our analysis we demonstrate existence of regret-minimization methods that
compete with such sets of strategies as: autoregressive algorithms, strategies
based on statistical models, regularized least squares, and follow the
regularized leader strategies. In several cases we also derive efficient
learning algorithms.


title:
Synthetic Topological Qubits in Conventional Bilayer Quantum Hall
  Systems

abstract:
  The idea of topological quantum computation is to build powerful and robust
quantum computers with certain macroscopic quantum states of matter called
topologically ordered states. These systems have degenerate ground states that
can be used as robust "topological qubits" to store and process quantum
information. However, a topological qubit has not been realized since the
proposed systems either require sophisticated topologically ordered states that
are not available yet, or require complicated geometries that are too difficult
to realize. In this paper, we propose a new experimental setup which can
realize topological qubits in a simple bilayer fractional quantum Hall (FQH)
system with proper electric gate configurations. Compared to previous works,
our proposal is accessible with current experimental techniques and only
involves well-established topological states. Our system can realize a large
class of topological qubits, generalizing the Majorana zero modes studied in
the recent literature to more computationally powerful possibilities. We
propose three tunneling and interferometry experiments to detect the existence
and non-local topological properties of the topological qubits.


title: The temperatures of Red Supergiants

abstract:
  We present a re-appraisal of the temperatures of Red Supergiants (RSGs) using
their optical and near-infrared spectral energy distributions (SEDs). We have
obtained data of a sample of RSGs in the Magellanic Clouds using VLT+XSHOOTER,
and we fit MARCS model atmospheres to different regions of the spectra,
deriving effective temperatures for each star from (a) the TiO bands, (b)
line-free continuum regions of the spectral energy distributions (SEDs), and
(c) the integrated fluxes. We show that the temperatures derived from fits to
the TiO bands are systematically {\it lower} than the other two methods by
several hundred Kelvin. The TiO fits also dramatically over-predict the flux in
the near-IR, and imply extinctions which are anomalously low compared to
neighbouring stars. In contrast, the SED temperatures provide good fits to the
fluxes at all wavelengths other than the TiO bands, are in agreement with the
temperatures from the flux integration method, and imply extinctions consistent
with nearby stars. After considering a number of ways to reconcile this
discrepancy, we conclude that 3-D effects (i.e.\ granulation) are the most
likely cause, as they affect the temperature structure in the upper layers
where the TiO lines form. The continuum, however, which forms at much deeper
layers, is apparently more robust to such effects. We therefore conclude that
RSG temperatures are much warmer than previously thought. We discuss the
implications of this result for stellar evolution and supernova progenitors,
and provide relations to determine the bolometric luminosities of RSGs from
single-band photometry.


title: Unifying B\"uchi Complementation Constructions

abstract:
  Complementation of B\"uchi automata, required for checking automata
containment, is of major theoretical and practical interest in formal
verification. We consider two recent approaches to complementation. The first
is the rank-based approach of Kupferman and Vardi, which operates over a DAG
that embodies all runs of the automaton. This approach is based on the
observation that the vertices of this DAG can be ranked in a certain way,
termed an odd ranking, iff all runs are rejecting. The second is the
slice-based approach of K\"ahler and Wilke. This approach tracks levels of
"split trees" - run trees in which only essential information about the history
of each run is maintained. While the slice-based construction is conceptually
simple, the complementing automata it generates are exponentially larger than
those of the recent rank-based construction of Schewe, and it suffers from the
difficulty of symbolically encoding levels of split trees. In this work we
reformulate the slice-based approach in terms of run DAGs and preorders over
states. In doing so, we begin to draw parallels between the rank-based and
slice-based approaches. Through deeper analysis of the slice-based approach, we
strongly restrict the nondeterminism it generates. We are then able to employ
the slice-based approach to provide a new odd ranking, called a retrospective
ranking, that is different from the one provided by Kupferman and Vardi. This
new ranking allows us to construct a deterministic-in-the-limit rank-based
automaton with a highly restricted transition function. Further, by phrasing
the slice-based approach in terms of ranks, our approach affords a simple
symbolic encoding and achieves the tight bound of Schewe's construction