title:
Possible superfluidity of molecular hydrogen in a two-dimensional
  crystal phase of sodium

abstract:
  We theoretically investigate the ground-state properties of a molecular
para-hydrogen (p-H2) film in which crystallization is energetically frustrated
by embedding sodium (Na) atoms periodically distributed in a triangular
lattice. In order to fully deal with the quantum nature of p-H2 molecules, we
employ the diffusion Monte Carlo method and realistic semi-empirical pairwise
potentials describing the interactions between H2-H2 and Na-H2 species. In
particular, we calculate the energetic, structural and superfluid properties of
two-dimensional Na-H2 systems within a narrow density interval around
equilibrium at zero temperature. In contrast to previous computational studies
considering other alkali metal species such as rubidium and potassium, we find
that the p-H2 ground-state is a liquid with a significantly large superfluid
fraction of ~30%. The appearance of p-H2 superfluid response is due to the fact
that the interactions between Na atoms and H2 molecules are less attractive
than between H2 molecules. This induces a considerable reduction of the
hydrogen density which favours the stabilization of the liquid phase.


title:
A Tracker for the Mu3e Experiment based on High-Voltage Monolithic
  Active Pixel Sensors

abstract:
  The Mu3e experiment searches for the lepton flavour violating decay mu+ ->
e+e-e+, aiming for a branching fraction sensitivity of 10^-16. This requires an
excellent momentum resolution for low energy electrons, high rate capability
and a large acceptance. In order to minimize multiple scattering, the amount of
material has to be as small as possible. These challenges can be met with a
tracker built from high-voltage monolithic active pixel sensors (HV-MAPS),
which can be thinned to 50 um and which incorporate the complete read-out
electronics on the sensor chip. To further minimise material, the sensors are
supported by a mechanical structure built from 25 um thick Kapton foil and
cooled with gaseous helium.


title:
Measurement of the $^{1}H$($\vec{\gamma}$, $\vec{p}$)$\pi^{0}$ reaction
  using a novel nucleon spin polarimeter

abstract:
  We report the first large-acceptance measurement of polarization transfer
from a polarized photon beam to a recoiling nucleon, pioneering a novel
polarimetry technique with wide application to future nuclear and hadronic
physics experiments. The commissioning measurement of polarization transfer in
the $^{1}H$($\vec{\gamma}$,$\vec{p}$)$\pi^{0}$ reaction in the range
$0.4<E_{\gamma}<1.4$ GeV is highly selective regarding the basic
parameterizations used in partial wave analyses to extract the nucleon
excitation spectrum. The new data strongly favor the recently proposed
Chew-Mandelstam formalism.


title: The NOvA Experiment: Overview and Status

abstract:
  The NO$\nu$A experiment is a long-baseline accelerator based neutrino
oscillation experiment. It uses the upgraded Fermilab NuMI beam and measures
electron-neutrino appearance and muon-neutrino disappearance at its far
detector in Ash River, Minnesota. Goals of the experiment include measurements
of $\theta_{13}$, the neutrino-mass hierarchy and the CP-violating phase.
NO$\nu$A has begun to take data this year and will have its first physics
results in 2014. This talk provides an overview of the scientific reach of the
NO$\nu$A experiment, the status of detector construction and physics analysis
and a first glimpse of far-detector data.


title:
Comment on "Semiclassical and Quantum Analysis of a Focussing Free
  Particle Hermite Wavefunction", by Paul Strange (arXiv:1309.6753 [quant-ph])

abstract:
  In the recent and very enjoyable paper (Paul Strange, "Semiclassical and
Quantum Analysis of a Focussing Free Particle Hermite Wavefunction",
arXiv:1309.6753[quant-ph]), Professor Strange has studied a particular solution
of the free particle Schroedinger equation in which the time and space
dependence are not separable. After recognizing the fact that "The Schroedinger
equation has an identical mathematical form to the paraxial wave equation
[...]", he claims to "describe and try to gain insight into an exotic,
apparently accelerating solution of the free particle Schroedinger equation
that is square integrable and which also displays some unusual
characteristics." It is the main aim of this short note to show that the
wavefunction described by Prof. Strange is simply one particular Hermite-Gauss
solution of the paraxial wave equation and even more "exotic" examples can be
found by considering, e.g., Laguerre-Gauss solutions.


title:
Effects of the composition on transonic properties of accretion flows
  around black holes

abstract:
  We study the properties of a steady, multi-species, low angular momentum
accretion flow around a Schwarzschild black hole. Each species is described by
a relativistic equation of state. We find that the transonic properties depend
strongly on the composition of the flow. We find that an electron-positron pair
plasma is the least relativistic one. This flow produces only one sonic point
very close to the event horizon and does not show multiple critical points for
any angular momentum or energy. When the baryons are present, the number of
critical points depend on the specific energy content. Since the number of
critical points decide whether the flow will have non-linearities or shock
waves, our results implies that whether or not standing shocks forms will
depend on the flow composition. Thus, for instance, a pure electron-positron
pair plasma will never undergo a shock transition, while mixing it with some
baryons (common in outflows and jets, for example) as in a completely ionized
gas, will have shocks. We study in detail how the baryon loading affects the
shock properties and discuss implication in astrophysical observations.


title: Prefactor Reduction of the Guruswami-Sudan Interpolation Step

abstract:
  The concept of prefactors is considered in order to decrease the complexity
of the Guruswami-Sudan interpolation step for generalized Reed-Solomon codes.
It is shown that the well-known re-encoding projection due to Koetter et al.
leads to one type of such prefactors. The new type of Sierpinski prefactors is
introduced. The latter are based on the fact that many binomial coefficients in
the Hasse derivative associated with the Guruswami-Sudan interpolation step are
zero modulo the base field characteristic. It is shown that both types of
prefactors can be combined and how arbitrary prefactors can be used to derive a
reduced Guruswami-Sudan interpolation step.


title:
Discovery of higher order reentrant modes by constructing a cylindrical
  symmetric ring and post cavity resonator

abstract:
  Analysis of the properties of resonant modes in a reentrant cavity structure
comprising of a post and a ring was undertaken and verified experimentally. In
particular we show the existence of higher order reentrant cavity modes in such
a structure. Results show that the new cavity has two re-entrant modes, one
which has a better displacement sensitivity than the single post resonator and
the other with a reduced sensitivity. The more sensitive mode is better than
the single post resonator by a factor of 2 to 1.5 when the gap spacing is below
100 $ \mu$m. This type of cavity has the potential to operate as a highly
sensitive transducer for a variety of precision measurement applications, in
particular applications which require coupling to more than one sensitive
transducer mode.


title: On groups with slow intersection growth

abstract:
  Intersection growth concerns the asymptotic behavior of the index of the
intersection of all subgroups of a group that have index at most n. In this
note we show that the intersection growth of some groups may not be a nicely
behaved function by showing the following seemingly contradictory results: (a)
for any group G the intersection growth function i_G(n) is super linear
infinitely often; and (b) for any increasing function f there exists a group G
such that i_G below f infinitely often.


title: Missing solution in a Cornell potential

abstract:
  Missing bound-state solutions for fermions in the background of a Cornell
potential consisting of a mixed scalar-vector-pseudoscalar coupling is
examined. Charge-conjugation operation, degeneracy and localization are
discussed.


title: Modelling the relative velocities of isolated pairs of galaxies

abstract:
  We study the comoving relative velocities, v12, of model isolated galaxy
pairs at z=0.5. For this purpose, we use the predictions from the GALFORM
semi-analytical model of galaxy formation and evolution based on a Lambda cold
dark matter cosmology consistent with the results from WMAP7. In real space, we
find that isolated pairs of galaxies are predicted to form an angle t with the
line-of-sight that is uniformily distributed as expected if the Universe is
homogeneous and isotropic. We also find that isolated pairs of galaxies
separated by a comoving distance between 1 and 3 Mpc/h are predicted to have
<v12>=0. For galaxies in this regime, the distribution of the angle t is
predicted to change minimally from real to redshift space, with a change
smaller than 5% in <sin^2 t>. However, the distances defining the comoving
regime strongly depends on the applied isolation criteria.


title:
Transfer of planar orders onto a sphere: formation and properties of
  complex topological defects

abstract:
  General topological principles how to transfer the planar orders onto a
sphere are considered. Formation of extended topological defects (ETDs), which
have a reconstructed inner structure surrounded by perfect initial order, is
discussed. Topological charge of the ETD can be determined from the shape of a
characteristic polygon bounding the defect. Relation between the total
topological charge of all defects in the spherical structure and the type of
initial planar order is found. It is also demonstrated that in the spherical
hexagonal crystal a dislocation located in the ETD area is actually absorbed by
it, because the order outside the defect doesn't display existence of
dislocation in any way. For the case of singly connected spherical hexagonal
order arising from mutual repulsion of N particles (N < 1000) only
triangulation of the order inside the ETD regions recovers the linear scars
which represent a narrow parts of wider ETD areas.


title: Powerful energy harvester based on resonant-tunneling quantum wells

abstract:
  We analyze a heat engine based on a hot cavity connected via quantum wells to
electronic reservoirs. We discuss the output power as well as the efficiency
both in the linear and nonlinear regime. We find that the device delivers a
large power of about 0.18 W/cm^2 for a temperature difference of 1 K nearly
doubling the power than can be extracted from a similar heat engine based on
quantum dots. At the same time, the heat engine also has a good efficiency
although reduced from the quantum dot case. Due to the large level spacings
that can be achieved in quantum wells, our proposal opens the route towards
room-temperature applications of nanoscale heat engines.


title: Schr\"odinger Spacetimes with Screen and Reduced Entanglement

abstract:
  We study a particular class of type II string vacua which become
Schr\"odinger like spacetime in the IR region but are conformally AdS in
asymptotic UV region. These solutions are found to possess some unique
properties such as the presence of a spacetime `screen'. This Schr\"odinger
(spacetime) screen is however very different from a black-hole horizon. It
requires the presence of finite chemical potential and a negative charge
density in the Schr\"odinger CFT. We find that these vacua give rise to reduced
entanglement entropy as compared to Lifshitz-AdS counterpart, perhaps due to
the screening effects.


title:
Hidden regular variation of moving average processes with heavy-tailed
  innovations

abstract:
  We look at joint regular variation properties of MA($\infty$) processes of
the form $\mathbf{X} = (X_k, k \in \mathbb{Z})$ where $X_k =
\sum_{j=0}^{\infty} \psi_j Z_{k-j}$ and the sequence of random variables $(Z_i,
i \in \mathbb{Z})$ are i.i.d. with regularly varying tails. We use the setup of
$\mathbb{M}_{\mathbb{O}}$-convergence and obtain hidden regular variation
properties for $\mathbf{X}$ under suitable summability conditions on the
constant coefficients $(\psi_j : j \geq 0)$. Our approach emphasizes continuity
properties of mappings and produces regular variation in sequence space.


title: A Simple Proof of Maxwell Saturation for Coupled Scalar Recursions

abstract:
  Low-density parity-check (LDPC) convolutional codes (or spatially-coupled
codes) were recently shown to approach capacity on the binary erasure channel
(BEC) and binary-input memoryless symmetric channels. The mechanism behind this
spectacular performance is now called threshold saturation via spatial
coupling. This new phenomenon is characterized by the belief-propagation
threshold of the spatially-coupled ensemble increasing to an intrinsic noise
threshold defined by the uncoupled system. In this paper, we present a simple
proof of threshold saturation that applies to a wide class of coupled scalar
recursions. Our approach is based on constructing potential functions for both
the coupled and uncoupled recursions. Our results actually show that the fixed
point of the coupled recursion is essentially determined by the minimum of the
uncoupled potential function and we refer to this phenomenon as Maxwell
saturation. A variety of examples are considered including the
density-evolution equations for: irregular LDPC codes on the BEC, irregular
low-density generator matrix codes on the BEC, a class of generalized LDPC
codes with BCH component codes, the joint iterative decoding of LDPC codes on
intersymbol-interference channels with erasure noise, and the compressed
sensing of random vectors with i.i.d. components.


title: The quasiparticle band gap in the topological insulator Bi2Te3

abstract:
  We present a theoretical study of dispersion of states which form the bulk
band-gap edges in the three-dimensional topological insulator Bi2Te3. Within
density functional theory, we analyze the effect of atomic positions varying
within the error range of the available experimental data and approximation
chosen for the exchange-correlation functional on the bulk band gap and k-space
location of valence- and conduction-band extrema. For each set of the positions
with different exchange-correlation functionals, we show how many-body
corrections calculated within a one-shot GW approach affect the mentioned
characteristics of electronic structure of Bi2Te3. We thus also illustrate to
what degree the one-shot GW results are sensitive to the reference one-particle
band structure in the case of bismuth telluride. We found that for this
topological insulator the GW corrections enlarge the fundamental band gap and
for certain atomic positions and reference band structure bring its value in
close agreement with experiment.


title: An Image-Based Fluid Surface Pattern Model

abstract:
  This work aims at generating a model of the ocean surface and its dynamics
from one or more video cameras. The idea is to model wave patterns from video
as a first step towards a larger system of photogrammetric monitoring of marine
conditions for use in offshore oil drilling platforms. The first part of the
proposed approach consists in reducing the dimensionality of sensor data made
up of the many pixels of each frame of the input video streams. This enables
finding a concise number of most relevant parameters to model the temporal
dataset, yielding an efficient data-driven model of the evolution of the
observed surface. The second part proposes stochastic modeling to better
capture the patterns embedded in the data. One can then draw samples from the
final model, which are expected to simulate the behavior of previously observed
flow, in order to determine conditions that match new observations. In this
paper we focus on proposing and discussing the overall approach and on
comparing two different techniques for dimensionality reduction in the first
stage: principal component analysis and diffusion maps. Work is underway on the
second stage of constructing better stochastic models of fluid surface dynamics
as proposed here.


title:
Unexpected z-Direction Ising Antiferromagnetic Order in a frustrated
  Spin-1/2 $J_1-J_2$ XY Model on the Honeycomb Lattice

abstract:
  Using the density matrix renormalization group (DMRG) on wide cylinders, we
study the phase diagram of the spin-1/2 XY model on the honeycomb lattice, with
first-neighbor ($J_1 = 1$) and frustrating second-neighbor ($J_2>0$)
interactions. For the intermediate frustration regime $0.22\lesssim
J_2\lesssim0.36$, we find a surprising antiferromagnetic Ising phase, with
ordered moments pointing along the z axis, despite the absence of any S_z_z
interactions in the Hamiltonian. Surrounding this phase as a function of $J_2$
are antiferromagnetic phases with the moments pointing in the $x-y$ plane for
small $J_2$ and a close competition between an $x-y$ plane magnetic collinear
phase and a dimer phase for large values of $J_2$. We do not find any spin
liquid phases in this model.


title: Procrustes problems and Parseval quasi-dual frames

abstract:
  Parseval frames have particularly useful properties, and in some cases, they
can be used to reconstruct signals which were analyzed by a non-Parseval frame.
In this paper, we completely describe the degree to which such reconstruction
is feasible. Indeed, notice that for fixed frames $\cF$ and $\cX$ with
synthesis operators $F$ and $X$, the operator norm of $FX^*-I$ measures the
(normalized) worst-case error in the reconstruction of vectors when analyzed
with $\cX$ and synthesized with $\cF$. Hence, for any given frame $\cF$, we
compute explicitly the infimum of the operator norms of $FX^*-I$, where $\cX$
is any Parseval frame. The $\cX$'s that minimize this quantity are called
Parseval quasi-dual frames of $\cF$. Our treatment considers both finite and
infinite Parseval quasi-dual frames.


title:
Effects of spontaneous symmetry break in the origin of non-analytic
  behavior of entanglement at quantum phase transitions

abstract:
  We present an example where Spontaneous Symmetry Breaking may effect not only
the behavior of the entanglement at Quantum Phase Transitions, but also the
origin of the non-analyticity. In particular, in the XXZ model, we study the
non analyticities in the concurrence between two spins, which was claimed to be
accidental, since it had its origin in the optimization involved in the
concurrence definition. We show that when one takes in account the effect of
the Spontaneous Symmetry Breaking, even tough the values of the entanglement
measure does not change, the origin the the non-analytical behavior changes: it
is not due to the optimization process anymore and in this sense it is a
"natural" non-analyticity. This is a much more subtle influence of the
Spontaneous Symmetry Breaking not noticed before. However the non-analytical
behavior still suggests a second order quantum phase transition and not the
first order that occurs and we explain why. We also show that the value of
entanglement between one site and the rest of the chain does change when taking
into account the Spontaneous Symmetry Breaking.


title:
Noncommutative determinants, Cauchy-Binet formulae, and Capelli-type
  identities II. Grassmann and quantum oscillator algebra representation

abstract:
  We prove that, for $X$, $Y$, $A$ and $B$ matrices with entries in a
non-commutative ring such that $[X_{ij},Y_{k\ell}]=-A_{i\ell} B_{kj}$,
satisfying suitable commutation relations (in particular, $X$ is a Manin
matrix), the following identity holds: $ \mathrm{coldet} X \mathrm{coldet} Y =
< 0 | \mathrm{coldet} (a A + X (I-a^{\dagger} B)^{-1} Y) |0 > $. Furthermore,
if also $Y$ is a Manin matrix, $ \mathrm{coldet} X \mathrm{coldet} Y =\int
\mathcal{D}(\psi, \psi^{\dagger}) \exp [ \sum_{k \geq 0} \frac{1}{k+1}
(\psi^{\dagger} A \psi)^{k} (\psi^{\dagger} X B^k Y \psi) ] $. Notations: $ < 0
|$, $| 0 >$, are respectively the bra and the ket of the ground state,
$a^{\dagger}$ and $a$ the creation and annihilation operators of a quantum
harmonic oscillator, while $\psi^{\dagger}_i$ and $\psi_i$ are Grassmann
variables in a Berezin integral. These results should be seen as a
generalization of the classical Cauchy-Binet formula, in which $A$ and $B$ are
null matrices, and of the non-commutative generalization, the Capelli identity,
in which $A$ and $B$ are identity matrices and
$[X_{ij},X_{k\ell}]=[Y_{ij},Y_{k\ell}]=0$.


title:
Leavitt path algebras with at most countably many irreducible
  representatios

abstract:
  Let E be an arbitrary directed graph with no restrictions on the number of
vertices and edges and let K be any field. We give necessary and sufficient
conditions for the Leavitt path algebra L_K(E) to be of countable irreducible
representation type, that is, we determine when L_K(E)has at most countably
many distinct isomorphism classes of simple left L_K(E-modules. It is also
shown that L_K(E) has dinitely many isomorphism classes of simple left modules
if and only if L_K(E) is a semi-artinian von Neumann regular ring with at most
finitely many ideals. Equivalent conditions on the graph E are also given.
Examples are constructed showing that for each (finite or infinite) cardinal m
there exists a Leavitt path algebra L having exactly m distinct isomorphism
classes of simple left modules.


title: Harmonic oscillator: an analysis via Fourier series

abstract:
  The Fourier series method is used to solve the homogeneous equation governing
the motion of the harmonic oscillator. It is shown that the general solution to
the problem can be found in a surprisingly simple way for the case of the
simple harmonic oscillator. It is also shown that the damped harmonic
oscillator is susceptible to the analysis.


title: Critical Transitions In a Model of a Genetic Regulatory System

abstract:
  We consider a model for substrate-depletion oscillations in genetic systems,
based on a stochastic differential equation with a slowly evolving external
signal. We show the existence of critical transitions in the system. We apply
two methods to numerically test the synthetic time series generated by the
system for early indicators of critical transitions: a detrended fluctuation
analysis method, and a novel method based on topological data analysis
(persistence diagrams).

categories: nlin.CD cs.CE cs.CG math.AP q-bio.GN q-bio.QM


title:
A cold-atoms based processor for deterministic quantum computation with
  one qubit in intractably large Hilbert spaces

abstract:
  We propose the use of Rydberg interactions and ensembles of cold atoms in
mixed state for the implementation of a protocol for deterministic quantum
computation with one quantum bit (DQC1) that can be readily operated in high
dimensional Hilbert spaces. We propose an experimental test for the scalability
of the protocol and to study the physics of discord. Furthermore we develop a
scheme to add control to non-trivial unitaries that will enable the study of
many-body physics with ensembles in mixed states.


title: The obstruction to the existence of a loopless star product

abstract:
  We show that there is an obstruction to the existence of a star product
defined by Kontsevich graphs without directed cycles.


title: The divergence of the BFGS and Gauss Newton Methods

abstract:
  We present examples of divergence for the BFGS and Gauss Newton methods.
These examples have objective functions with bounded level sets and other
properties concerning the examples published recently in this journal, like
unit steps and convexity along the search lines. As these other examples, the
iterates, function values and gradients in the new examples fit into the
general formulation in our previous work {\it On the divergence of line search
methods, Comput. Appl. Math. vol.26 no.1 (2007)}, which also presents an
example of divergence for Newton's method.


title: Two-Nucleon Systems in a Finite Volume

abstract:
  I present the formalism and methodology for determining the nucleon-nucleon
scattering parameters from the finite volume spectra obtained from lattice
quantum chromodynamics calculations. Using the recently derived energy
quantization conditions and the experimentally determined scattering
parameters, the bound state spectra for finite volume systems with overlap with
the 3S1-3D3 channel are predicted for a range of volumes. It is shown that the
extractions of the infinite-volume deuteron binding energy and the low-energy
scattering parameters, including the S-D mixing angle, are possible from
Lattice QCD calculations of two-nucleon systems with boosts of |P| <= 2pi
sqrt{3}/L in volumes with spatial extents L satisfying fm <~ L <~ 14 fm.


title: Zero temperature limits of Gibbs states for almost-additive potentials

abstract:
  This paper is devoted to study ergodic optimisation problems for
almost-additive sequences of functions (rather than a fixed potential) defined
over countable Markov shifts (that is a non-compact space). Under certain
assumptions we prove that any accumulation point of a family of Gibbs
equilibrium measures is a maximising measure. Applications are given in the
study of the joint spectral radius and to multifractal analysis of Lyapunov
exponent of non-conformal maps.


title:
Prospects on the search for invisible Higgs decays in the ZH channel at
  the LHC and HL-LHC: A Snowmass White Paper

abstract:
  We show prospects on a search for invisible decays of a Higgs boson at the
Large Hadron Collider (LHC) and High Luminosity LHC (HL-LHC). This search is
performed on a Higgs boson produced in association with a Z boson. We expect
that the branching ratio of 17-22% (6-14%) could be excluded at 95% confidence
level with 300 fb^{-1} (3000 fb^{-1}) of data at sqrt(s)=14 TeV. The range
indicates different assumptions on the control of systematic uncertainties.
Interpretations with Higgs-portal dark matter models are also considered.


title: Ultracold Heteronuclear Mixture of Ground and Excited State Atoms

abstract:
  We report on the realization of an ultracold mixture of lithium atoms in the
ground state and ytterbium atoms in the excited metastable 3P2 state. Such a
mixture can support broad magnetic Feshbach resonances which may be utilized
for the production of ultracold molecules with an electronic spin degree of
freedom, as well as novel Efimov trimers. We investigate the interaction
properties of the mixture in the presence of an external magnetic field and
find an upper limit for the background interspecies two-body inelastic decay
coefficient of K'2 < 3e-12 cm^3/s for the 3P2 m_J=-1 substate. We calculate the
dynamic polarizabilities of the Yb 3P2 magnetic substates for a range of
wavelengths, and find good agreement with our measurements at 1064nm. Our
calculations also allow the identification of magic frequencies where Yb ground
and metastable states are identically trapped and the determination of the
interspecies van der Waals coefficients.


title: A Computer Verification of a Conjecture About Erd\"os-Mordell Curve

abstract:
  In this paper we consider Erd\"os-Mordell inequality and its extension in the
plane of triangle to the Erd\"os-Mordell curve. Algebraic equation of this
curve is derived, and using modern computer tools in mathematics, we verified
one conjecture that relates to Erd\"os-Mordell curve.


title:
Measurements of B -> DK decays to constrain the CKM Unitarity Triangle
  angle \gamma and related results at LHCb

abstract:
  Constraints on the CKM angle \gamma are presented from GLW, ADS, and GGSZ
analyses of B+- -> D K+- at the LHCb experiment. The branching fractions of B0
-> D0bar K+ \pi- and Bs -> D0bar K- \pi+ are also reported, measured relative
to the related mode B0 -> D0bar \pi+ \pi-.


title:
Vibrationally coherent crossing and coupling of electronic states during
  internal conversion in beta-carotene

abstract:
  Coupling of nuclear and electronic degrees of freedom mediates energy flow in
molecules after optical excitation. The associated coherent dynamics in
polyatomic systems, however, remain experimentally unexplored. Here, we
combined transient absorption spectroscopy with electronic population control
to reveal nuclear wavepacket dynamics during the S2-S1 internal conversion in
beta-carotene. We show that passage through a conical intersection is
vibrationally coherent and thereby provides direct feedback on the role of
different vibrational coordinates in the breakdown of the Born-Oppenheimer
approximation.


title: Heavy Flavor Suppression: Boltzmann vs Langevin

abstract:
  The propagation of heavy flavor through the quark gluon plasma has been
treated commonly within the framework of Langevin dynamics, i.e. assuming the
heavy flavor momentum transfer is much smaller than the light one. On the other
hand a similar suppression factor $R_{AA}$ has been observed experimentally for
light and heavy flavors. We present a thorough study of the approximations
involved by Langevin equation by mean of a direct comparison with the full
collisional integral within the framework of Boltzmann transport equation. We
have compared the results obtained in both approaches which can differ
substantially for charm quark leading to quite different values extracted for
the heavy quark diffusion coefficient. In the case of bottom quark the
approximation appears to be quite reasonable.


title: Improved interpolation inequalities on the sphere

abstract:
  This paper contains a review of available methods for establishing improved
interpolation inequalities on the sphere for subcritical exponents. Pushing
further these techniques we also establish some new results, clarify the range
of applicability of the various existing methods and state several explicit
estimates.


title: Weak Topological Insulators in PbTe/SnTe Superlattices

abstract:
  It is desirable to realize topological phases in artificial structures by
engineering electronic band structures. In this paper, we investigate
$(PbTe)_m(SnTe)_{2n-m}$ superlattices along [001] direction and find a robust
weak topological insulator phase for a large variety of layer numbers m and
2n-m. We confirm this topologically non-trivial phase by calculating Z2
topological invariants and topological surface states based on the
first-principles calculations. We show that the folding of Brillouin zone due
to the superlattice structure plays an essential role in inducing topologically
non-trivial phases in this system. This mechanism can be generalized to other
systems in which band inversion occurs at multiple momenta, and gives us a
brand-new way to engineer topological materials in artificial structures.


title: All-optical quantum information processing using Rydberg gates

abstract:
  In this work we propose a hybrid scheme to implement a photonic controlled-z
(CZ) gate using photon storage in highly-excited Rydberg states, which controls
the effective photon-photon interaction using resonant microwave fields. Our
scheme decouples the light propagation from the interaction and exploits the
spatial properties of the dipole blockade phenomenon to realize a CZ gate with
minimal loss and mode distortion. Excluding the coupling efficiency, fidelities
exceeding 95% are achievable and are found to be mainly limited by motional
dephasing and the finite lifetime of the Rydberg levels.


title: Renormalization, Freezing Phase Transitions and Fibonacci Quasicrystals

abstract:
  We examine the renormalization operator determined by the Fibonacci
substitution. We exhibit a fixed point and determine its stable leaf (under
iteration of the operator). Then, we study the thermodynamic formalism for po-
tentials in this stable leaf, and prove they have a freezing phase transition,
with ground state supported on the attracting quasi-crystal associated to the
Fibonacci substitution


title: Maximizing Utility Among Selfish Users in Social Groups

abstract:
  We consider the problem of a social group of users trying to obtain a
"universe" of files, first from a server and then via exchange amongst
themselves. We consider the selfish file-exchange paradigm of give-and-take,
whereby two users can exchange files only if each has something unique to offer
the other. We are interested in maximizing the number of users who can obtain
the universe through a schedule of file-exchanges. We first present a practical
paradigm of file acquisition. We then present an algorithm which ensures that
at least half the users obtain the universe with high probability for $n$ files
and $m=O(\log n)$ users when $n\rightarrow\infty$, thereby showing an
approximation ratio of 2. Extending these ideas, we show a $1+\epsilon_1$ -
approximation algorithm for $m=O(n)$, $\epsilon_1>0$ and a $(1+z)/2
+\epsilon_2$ - approximation algorithm for $m=O(n^z)$, $z>1$, $\epsilon_2>0$.
Finally, we show that for any $m=O(e^{o(n)})$, there exists a schedule of file
exchanges which ensures that at least half the users obtain the universe.


title:
Combining parametric, semi-parametric, and non-parametric survival
  models with stacked survival models

abstract:
  For estimating conditional survival functions, non-parametric estimators can
be preferred to parametric and semi-parametric estimators due to relaxed
assumptions that enable robust estimation. Yet, even when misspecified,
parametric and semi-parametric estimators can possess better operating
characteristics in small sample sizes due to smaller variance than
non-parametric estimators. Fundamentally, this is a bias-variance tradeoff
situation in that the sample size is not large enough to take advantage of the
low bias of non-parametric estimation. Stacked survival models estimate an
optimally weighted combination of models that can span parametric,
semi-parametric, and non-parametric models by minimizing prediction error. An
extensive simulation study demonstrates that stacked survival models
consistently perform well across a wide range of scenarios by adaptively
balancing the strengths and weaknesses of individual candidate survival models.
In addition, stacked survival models perform as good as, or better than, the
model selected through cross-validation. Lastly, stacked survival models are
applied to a well-known German breast cancer study.


title:
Stationary Cycling Induced by Switched Functional Electrical Stimulation
  Control

abstract:
  Functional electrical stimulation (FES) is used to activate the dysfunctional
lower limb muscles of individuals with neuromuscular disorders to produce
cycling as a means of exercise and rehabilitation. However, FES-cycling is
still metabolically inefficient and yields low power output at the cycle crank
compared to able-bodied cycling. Previous literature suggests that these
problems are symptomatic of poor muscle control and non-physiological muscle
fiber recruitment. The latter is a known problem with FES in general, and the
former motivates investigation of better control methods for FES-cycling.In
this paper, a stimulation pattern for quadriceps femoris-only FES-cycling is
derived based on the effectiveness of knee joint torque in producing forward
pedaling. In addition, a switched sliding-mode controller is designed for the
uncertain, nonlinear cycle-rider system with autonomous state-dependent
switching. The switched controller yields ultimately bounded tracking of a
desired trajectory in the presence of an unknown, time-varying, bounded
disturbance, provided a reverse dwell-time condition is satisfied by
appropriate choice of the control gains and a sufficient desired cadence.
Stability is derived through Lyapunov methods for switched systems, and
experimental results demonstrate the performance of the switched control system
under typical cycling conditions.


title: The NIFFTE project

abstract:
  The Neutron Induced Fission Fragment Tracking Experiment (NIFFTE) is a
double-sided Time Projection Chamber (TPC) with micromegas readout designed to
measure the energy-dependent neutron-induced fission cross sections of the
major and minor actinides with unprecedented accuracy. The NIFFTE project
addresses the challenge of minimizing major sources of systematic uncertainties
from previous fission chamber measurements such as: target and beam
non-uniformities, misidentification of alpha and light charged particles as
fission fragments, and uncertainties inherent to the reference standards used.
In-beam tests of the NIFFTE TPC at the Los Alamos Neutron Science Center
(LANSCE) started in 2010 and have continued in 2011, 2012 and 2013. An overview
of the NIFFTE TPC status and performance at LANSCE will be presented.


title: Dynamical phase diagram of Gaussian BEC wave packets in optical lattices

abstract:
  We study the dynamics of self-trapping in Bose-Einstein condensates (BECs)
loaded in deep optical lattices with Gaussian initial conditions, when the
dynamics is well described by the Discrete Nonlinear Schr\"odinger Equation
(DNLS). In the literature an approximate dynamical phase diagram based on a
variational approach was introduced to distinguish different dynamical regimes:
diffusion, self-trapping and moving breathers. However, we find that the actual
DNLS dynamics shows a completely different diagram than the variational
prediction. We numerically calculate a detailed dynamical phase diagram
accurately describing the different dynamical regimes. It exhibits a complex
structure which can readily be tested in current experiments in BECs in optical
lattices and in optical waveguide arrays. Moreover, we derive an explicit
theoretical estimate for the transition to self-trapping in excellent agreement
with our numerical findings, which may be a valuable guide as well for future
studies on a quantum dynamical phase diagram based on the Bose-Hubbard
Hamiltonian.


title: A Holographic Path to the Turbulent Side of Gravity

abstract:
  We study the dynamics of a 2+1 dimensional relativistic viscous conformal
fluid in Minkowski spacetime. Such fluid solutions arise as duals, under the
"gravity/fluid correspondence", to 3+1 dimensional asymptotically anti-de
Sitter (AAdS) black brane solutions to the Einstein equation. We examine
stability properties of shear flows, which correspond to hydrodynamic
quasinormal modes of the black brane. We find that, for sufficiently high
Reynolds number, the solution undergoes an inverse turbulent cascade to long
wavelength modes. We then map this fluid solution, via the gravity/fluid
duality, into a bulk metric. This suggests a new and interesting feature of the
behavior of perturbed AAdS black holes and black branes, which is not readily
captured by a standard quasinormal mode analysis. Namely, for sufficiently
large perturbed black objects (with long-lived quasinormal modes), nonlinear
effects transfer energy from short to long wavelength modes via a turbulent
cascade within the metric perturbation. As long wavelength modes have slower
decay, this lengthens the overall lifetime of the perturbation. We also discuss
various implications of this behavior, including expectations for higher
dimensions, and the possibility of predicting turbulence in more general
gravitational scenarios.


title:
On the congruence $1^m + 2^m + \dotsb + m^m \equiv n \pmod{m}$ with $n |
  m$

abstract:
  We show that if the congruence above holds and $n\mid m$, then the quotient
$Q:=m/n$ satisfies $\sum_{p\mid Q} \frac{Q}{p}+1 \equiv 0\pmod{Q}$, where $p$
is prime. The only known solutions of the latter congruence are $Q=1$ and the
eight known primary pseudoperfect numbers $2,6,42, 1806, 47058, 2214502422,
52495396602,$ and $8490421583559688410706771261086$. Fixing $Q$, we prove that
the set of positive integers $n$ satisfying the congruence in the title, with
$m=Q n$, is empty in case $Q=52495396602$, and in the other eight cases has an
asymptotic density between bounds in $(0,1)$ that we provide.


title: Nucleon axial charge in 2+1-flavor dynamical DWF lattice QCD

abstract:
  The current status of some nucleon isovector observables, the vector charge,
\(g_V\), axial charge, \(g_A\), quark momentum fraction, \(\langle x
\rangle_{u-d}\), and quark helicity fraction, \(\langle x \rangle_{\Delta u -
\Delta d}\), calculated using recent RBC/UKQCD 2+1-flavor dynamical domain-wall
fermions (DWF) lattice QCD ensembles are reported: with Iwasaki gauge action at
inverse lattice spacing, \(a^{-1}\), of about 1.7 GeV, linear lattice extent,
\(L\), of about 2.7 fm, pion mass, \(m_\pi\), of about 420 and 330 MeV, and
with Iwasaki\(\times\)DSDR gauge action at \(a^{-1}\) of about 1.4 GeV, \(L\)
of about 4.6 fm, and \(m_\pi\) of about 250 and 170 MeV. The calculations have
been refined with enhanced statistics, in particular through successful
application of the all-mode-averaging (AMA) technique for the 170- and 330-MeV
ensembles. As a result, the precision agreement seen in the charge ratio,
\(g_A/g_V\), for 420-MeV and 250-MeV ensembles that share the finite-size
scaling parameter \(m_\pi L\) of about 5.8 is more significant with new values
of 1.17(2) and 1.18(4) respectively. We also studied the dependence on the
source-sink separation in the lightest ensemble of 170-MeV, by comparing the
cases with the separation of about 1.0 and 1.3 fm and did not see any
dependence: contamination from the excited states are well under control in our
choice of source and sink smearing. The axial charge, \(g_A\) and the ratio,
\(g_A/g_V\), shows a long-range autocorrelation that extends the entire range
of configurations that were so far analyzed, almost 700 hybrid Molecular
Dynamics time, in the lightest ensemble of \(m_\pi=170\) MeV. The other
observables do not show any autocorrelation with the interval of 16
trajectories.


title:
Exploring Vortex Dynamics in the Presence of Dissipation: Analytical and
  Numerical Results

abstract:
  In this paper, we systematically examine the stability and dynamics of
vortices under the effect of a phenomenological dissipation used as a
simplified model for the inclusion of the effect of finite temperatures in
atomic Bose-Einstein condensates. An advantage of this simplified model is that
it enables an analytical prediction that can be compared directly (and
favorably) to numerical results. We then extend considerations to a case of
considerable recent experimental interest, namely that of a vortex dipole and
observe good agreement between theory and numerical computations in both the
stability properties (eigenvalues of the vortex dipole stationary states) and
the dynamical evolution of such configurations.


title:
The stability of barycentric interpolation at the Chebyshev points of
  the second kind

abstract:
  We present a new analysis of the stability of the first and second
barycentric formulae for interpolation at the Chebyshev points of the second
kind. Our theory shows that the second formula is more stable than previously
thought and our experiments confirm its stability in practice. % OLD: We also
explain that the first barycentric formula has accuracy problems which are not
properly taken into account in the current literature. We also extend our
current understanding regarding the accuracy problems of the first barycentric
formula.


title: Sudden change of quantum discord for a system of two qubits

abstract:
  It is known that quantum discord might experience a sudden transition in its
dynamics when calculated for certain Bell-diagonal states (BDS) that are in
interaction with their surroundings. We examine this phenomenon known as the
sudden change of quantum discord, considering the case of two qubits
independently interacting with dephasing reservoirs. We first numerically
demonstrate that, for a class of initial states which can be chosen arbitrarily
close to BDS, the transition is in fact not sudden, although it might
numerically appear so if not studied carefully. Then, we provide an extension
of this discussion covering the X-shaped density matrices. Our findings suggest
that the transition of quantum discord might be sudden only for an highly
idealized zero-measure subset of states within the set of all possible initial
conditions of two qubits.


title:
Coulomb Corrections to the Parameters of the Landau-Pomeranchuk-Migdal
  Effect Theory and its Analogue

abstract:
  Using the Coulomb correction to the screening angular parameter of the
Moliere multiple scattering theory, we obtained analytically and numerically
the Coulomb corrections to the parameters of the Migdal LPM effect theory. We
showed that these corrections allow to eliminate the discrepancy between the
predictions of the LPM effect theory and its measurement at least for high Z
targets and also to further improve the agreement between the predictions of
the LPM effect theory analogue for a thin layer of matter and experimental
data.


title: On Weighted Dirac Combs Supported Inside Model Sets

abstract:
  In this paper we prove that given a weakly almost periodic measure $\mu$
supported inside some model set $\Lambda(W)$ with closed window $W$, then the
strongly almost periodic component $\mu_S$ and the null weakly almost periodic
component $\mu_0$ are both supported inside $\Lambda(W)$. As a consequence we
prove that given any translation bounded measure $\omega$, supported inside
some model set, then each of the pure point diffraction spectrum
$\hat{\gamma}_{pp}$ and the continuous diffraction spectrum $\hat{\gamma}_c$ is
either trivial or have a relatively dense support.


title: Projective Dimension of String and Cycle Hypergraphs

abstract:
  We present a closed formula and a simple algorithmic procedure to compute the
projective dimension of square-free monomial ideals associated to string or
cycle hypergraphs. As an application, among these ideals we characterize all
the Cohen-Macaulay ones.


title:
Bibliometric-enhanced Retrieval Models for Big Scholarly Information
  Systems

abstract:
  Bibliometric techniques are not yet widely used to enhance retrieval
processes in digital libraries, although they offer value-added effects for
users. In this paper we will explore how statistical modelling of scholarship,
such as Bradfordizing or network analysis of coauthorship network, can improve
retrieval services for specific communities, as well as for large, cross-domain
large collections. This paper aims to raise awareness of the missing link
between information retrieval (IR) and bibliometrics / scientometrics and to
create a common ground for the incorporation of bibliometric-enhanced services
into retrieval at the digital library interface.


title: Software Interfaces: On The Impact of Interface Design Anomalies

abstract:
  Interfaces are recognized as an important mechanism to define contracts
governing interactions between semi-independent software modules. Well-designed
interfaces significantly reduce software complexity and ease maintainability by
fostering modularization, hiding implementation details and minimizing the
impact caused by changes in the software implementation. However, designing
good interfaces is not a trivial task. The presence of interface design defects
often yield increased development cost, lower code quality and reduced
development productivity. Despite their importance, currently there are only a
few research efforts that investigate the quality of interface design. In this
paper, we identify and characterize common interface design anomalies and
illustrate them via examples taken from well-known open source applications. In
order to quantify the presence of interface design anomalies and estimate their
impact on the interface design quality, as well on the software quality
attributes, such as maintainability, we conduct an empirical study covering 9
open source projects. Building on our empirical results, we develop a set of
recommendations to improve interface design.


title:
Slepton mass splittings and cLFV in the SUSY seesaw in the light of
  recent experimental results

abstract:
  Following recent experimental developments, in this study we re-evaluate if
the interplay of high- and low-energy lepton flavour violating observables
remains a viable probe to test the high-scale type-I supersymmetric seesaw. Our
analysis shows that fully constrained supersymmetric scenarios no longer allow
to explore this interplay, since recent LHC data precludes the possibility of
having sizeable slepton mass differences for a slepton spectrum sufficiently
light to be produced, and in association to BR(mu -> e gamma) within
experimental reach. However, relaxing the strict universality of supersymmetric
soft-breaking terms, and fully exploring heavy neutrino dynamics, still allows
to have slepton mass splittings O(few %), for slepton masses accessible at the
LHC, with associated mu -> e gamma rates within future sensitivity. For these
scenarios, we illustrate how the correlation between high- and low-energy
lepton flavour violating observables allows to probe the high-scale
supersymmetric seesaw.


title:
Robust Computation of Dipole Electromagnetic Fields in
  Arbitrarily-Anisotropic, Planar-Stratified Environments

abstract:
  We develop a general-purpose formulation, based on two-dimensional spectral
integrals, for computing electromagnetic fields produced by
arbitrarily-oriented dipoles in planar-stratified environments, where each
layer may exhibit arbitrary and independent anisotropy in both the (complex)
permittivity and permeability. Among the salient features of our formulation
are (1) computation of eigenmodes (characteristic plane waves) supported in
arbitrarily anisotropic media in a numerically robust fashion, (2)
implementation of an hp-adaptive refinement for the numerical integration to
evaluate the radiation and weakly-evanescent spectra contributions, and (3)
development of an adaptive extension of an integral convergence acceleration
technique to compute the strongly-evanescent spectrum contribution. While other
semianalytic techniques exist to solve this problem, none have full
applicability to media exhibiting arbitrary double anisotropies in each layer,
where one must account for the whole range of possible phenomena such as mode
coupling at interfaces and non-reciprocal mode propagation. Brute-force
numerical methods can tackle this problem but only at a much higher
computational cost. The present formulation provides an efficient and robust
technique for field computation in arbitrary planar-stratified environments. We
demonstrate the formulation for a number of problems related to geophysical
exploration.


title:
Radiation pressure confinement - II. Application to the broad line
  region in active galactic nuclei

abstract:
  Active galactic nuclei (AGN) are characterized by similar broad emission
lines properties at all luminosities ($10^{39}$-$10^{47}$ erg s$^{-1}$). What
produces this similarity over a vast range of $10^8$ in luminosity?
Photoionization is inevitably associated with momentum transfer to the
photoionized gas. Yet, most of the photoionized gas in the Broad Line Region
(BLR) follows Keplerian orbits, which suggests that the BLR originates from gas
with a large enough column for gravity to dominate. The photoionized surface
layer of the gas must develop a pressure gradient due to the incident radiation
force. We present solutions for the structure of such a hydrostatic
photoionized gas layer in the BLR. The gas is stratified, with a low-density
highly-ionized surface layer, a density rise inwards, and a uniform-density
cooler inner region, where the gas pressure reaches the incident radiation
pressure. This radiation pressure confinement (RPC) of the photoionized layer
leads to a universal ionization parameter $U\sim 0.1$ in the inner photoionized
layer, independent of luminosity and distance. Thus, RPC appears to explain the
universality of the BLR properties in AGN. We present predictions for the BLR
emission per unit covering factor, as a function of distance from the ionizing
source, for a range of ionizing continuum slopes and gas metallicity. The
predicted mean strength of most lines (excluding H$\beta$), and their different
average-emission radii, are consistent with the available observations.


title: Intermediate inflation on the brane and warped DGP models

abstract:
  Brane and warped Dvali-Gabadadze-Porrati inflationary universe models in the
context of intermediate inflation are studied. In both models we consider that
the energy density is a standard scalar field and we discuss the evolution of
the universe during the slow-roll inflation. Also, we describe the conditions
for these models. The corresponding Wilkinson Microwave Anisotropy Probe seven
year data are utilized to fix some parameters in our models. Our results are
compared to those found in General Relativity.


title: Approximation Algorithms for the Max-Buying Problem with Limited Supply

abstract:
  We consider the Max-Buying Problem with Limited Supply, in which there are
$n$ items, with $C_i$ copies of each item $i$, and $m$ bidders such that every
bidder $b$ has valuation $v_{ib}$ for item $i$. The goal is to find a pricing
$p$ and an allocation of items to bidders that maximizes the profit, where
every item is allocated to at most $C_i$ bidders, every bidder receives at most
one item and if a bidder $b$ receives item $i$ then $p_i \leq v_{ib}$. Briest
and Krysta presented a 2-approximation for this problem and Aggarwal et al.
presented a 4-approximation for the Price Ladder variant where the pricing must
be non-increasing (that is, $p_1 \geq p_2 \geq \cdots \geq p_n$). We present an
$e/(e-1)$-approximation for the Max-Buying Problem with Limited Supply and, for
every $\varepsilon > 0$, a $(2+\varepsilon)$-approximation for the Price Ladder
variant.


title:
Observation of plastoferrite character and semiconductor to metal
  transition in soft ferromagnetic Li0.5Mn0.5Fe2O4ferrite

abstract:
  We prepared Li0.5Mn0.5Fe2O4 ferrite through chemical reaction in highly
acidic solution and subsequent sintering of chemical routed powder at
temperatures > 800 0C. Surface morphology showed plastoferrite character for
sintering temperature > 1000 0C. Mechanical softening of metal-oxygen bonds at
higher measurement temperatures stimulated delocalization of charge carriers,
which were strongly localized in A and B sites of the spinel structure at lower
temperatures. The charge delocalization process has activated semiconductor to
metallic transition in ac conductivity curves, obeyed by Jonscher power law and
Drude equation, respectively. Metallic state is also confirmed by the frequency
dependence of dielectric constant curves.


title:
The charged current neutrino cross section for solar neutrinos, and
  background to \BBz\ experiments

abstract:
  Solar neutrinos can interact with the source isotope in neutrinoless double
beta decay experiments through charged current and neutral current
interactions. The charged-current product nucleus will then beta decay with a
Q-value larger than the double beta decay Q-value. As a result, this process
can populate the region of interest and be a background to the double beta
decay signal. In this paper we estimate the solar neutrino capture rates on
three commonly used double beta decay isotopes, \nuc{76}{Ge}, \nuc{130}{Te},
and \nuc{136}{Xe}. We then use the decay scheme of each product nucleus to
estimate the possible background rates in those materials. As half-life
sensitivities in future experiments approach $10^{28}$ y, this background will
have to be considered.


title: A Statistical Learning Based System for Fake Website Detection

abstract:
  Existing fake website detection systems are unable to effectively detect fake
websites. In this study, we advocate the development of fake website detection
systems that employ classification methods grounded in statistical learning
theory (SLT). Experimental results reveal that a prototype system developed
using SLT-based methods outperforms seven existing fake website detection
systems on a test bed encompassing 900 real and fake websites.


title:
Exploration and Exploitation in Visuomotor Prediction of Autonomous
  Agents

abstract:
  This paper discusses various techniques to let an agent learn how to predict
the effects of its own actions on its sensor data autonomously, and their
usefulness to apply them to visual sensors. An Extreme Learning Machine is used
for visuomotor prediction, while various autonomous control techniques that can
aid the prediction process by balancing exploration and exploitation are
discussed and tested in a simple system: a camera moving over a 2D greyscale
image.


title:
A Classification of Configuration Spaces of Planar Robot Arms with
  Application to a Continuous Inverse Kinematics Problem

abstract:
  Using results on the topology of moduli space of polygons [Jaggi, 92;
Kapovich and Millson, 94], it can be shown that for a planar robot arm with $n$
segments there are some values of the base-length, $z$, at which the
configuration space of the constrained arm (arm with its end effector fixed)
has two disconnected components, while at other values the constrained
configuration space has one connected component. We first review some of these
known results.
  Then the main design problem addressed in this paper is the construction of
pairs of continuous inverse kinematics for arbitrary robot arms, with the
property that the two inverse kinematics agree when the constrained
configuration space has a single connected component, but they give distinct
configurations (one in each connected component) when the configuration space
of the constrained arm has two components. This design is made possible by a
fundamental theoretical contribution in this paper -- a classification of
configuration spaces of robot arms such that the type of path that the system
(robot arm) takes through certain critical values of the forward kinematics
function is completely determined by the class to which the configuration space
of the arm belongs. This classification result makes the aforesaid design
problem tractable, making it sufficient to design a pair of inverse kinematics
for each class of configuration spaces (three of them in total).
  We discuss the motivation for this work, which comes from a more extensive
problem of motion planning for the end effector of a robot arm requiring us to
continuously sample one configuration from each connected component of the
constrained configuration spaces.
  We demonstrate the low complexity of the presented algorithm through a
Javascript + HTML5 based implementation available at
http://hans.math.upenn.edu/~subhrabh/nowiki/robot_arm_JS-HTML5/arm.html


title:
Prospects For Precision Measurements with Reactor Antineutrinos at Daya
  Bay

abstract:
  In 2012 the Daya Bay experiment made an unambiguous observation of reactor
antineutrino disappearance over kilometer-long baselines and determined that
the neutrino mixing angle $\theta_{13}$ is non-zero. The measurements of Daya
Bay have provided the most precise determination of $\theta_{13}$ to date. This
whitepaper outlines the prospects for precision studies of reactor
antineutrinos at Daya Bay in the coming years. This includes precision
measurements of sin$^2 2\theta_{13}$ and $\Delta m^2_{ee}$ to $<$3%,
high-statistics measurement of reactor flux and spectrum, and non-standard
physics searches.


title: Production and spectroscopy of hadrons containing a b quark at ATLAS

abstract:
  We present studies of the production and spectroscopy of some members of the
B-hadron family. We reconstruct B ground states in their hadronic decay modes
with a J/{\psi} or {\Upsilon} in the final state. These studies are based on
the 2011 7 TeV dataset collected by the ATLAS detector.


title:
A graphics processor-based intranuclear cascade and evaporation
  simulation

abstract:
  Monte Carlo simulations of the transport of protons in human tissue have been
deployed on graphics processing units (GPUs) with impressive results. To
provide a more complete treatment of non-elastic nuclear interactions in these
simulations, we developed a fast intranuclear cascade-evaporation simulation
for the GPU. This can be used to model non-elastic proton collisions on any
therapeutically relevant nuclei at incident energies between 20 and 250 MeV.
Predictions are in good agreement with Geant4.9.6p2. It takes approximately 2 s
to calculate $1\times 10^6$ 200 MeV proton-$^{16}$O interactions on a NVIDIA
GTX680 GPU. A speed-up factor of $\sim$20 relative to one Intel i7-3820 core
processor thread was achieved.


title: A General Formula for the Mismatch Capacity

abstract:
  The fundamental limits of channels with mismatched decoding are addressed. A
general formula is established for the mismatch capacity of a general channel,
defined as a sequence of conditional distributions with a general decoding
metrics sequence. We deduce an identity between the Verd\'{u}-Han general
channel capacity formula, and the mismatch capacity formula applied to Maximum
Likelihood decoding metric. Further, several upper bounds on the capacity are
provided, and a simpler expression for a lower bound is derived for the case of
a non-negative decoding metric. The general formula is specialized to the case
of finite input and output alphabet channels with a type-dependent metric. The
closely related problem of threshold mismatched decoding is also studied, and a
general expression for the threshold mismatch capacity is obtained. As an
example of threshold mismatch capacity, we state a general expression for the
erasures-only capacity of the finite input and output alphabet channel. We
observe that for every channel there exists a (matched) threshold decoder which
is capacity achieving. Additionally, necessary and sufficient conditions are
stated for a channel to have a strong converse. Csisz\'{a}r and Narayan's
conjecture is proved for bounded metrics, providing a positive answer to the
open problem introduced in [1], i.e., that the "product-space" improvement of
the lower random coding bound, $C_q^{(\infty)}(W)$, is indeed the mismatch
capacity of the discrete memoryless channel $W$. We conclude by presenting an
identity between the threshold capacity and $C_q^{(\infty)}(W)$ in the DMC
case.


title: Ramond singular vectors and Jack superpolynomials

abstract:
  The explicit formula for the superconformal singular vectors in the
Neveu-Schwarz sector has been obtained recently, via its symmetric polynomial
representation, as a sum of Jack superpolynomials. Here we present the
analogous, but slightly more complicated, closed-form expression for the Ramond
singular vectors.


title:
Short-term synaptic plasticity in the deterministic Tsodyks-Markram
  model leads to unpredictable network dynamics

abstract:
  Short-Term Synaptic Plasticity (STSP) strongly affects the neural dynamics of
cortical networks. The Tsodyks and Markram (TM) model for STSP accurately
accounts for a wide range of physiological responses at different types of
cortical synapses. Here, we report for the first time a route to chaotic
behavior via a Shilnikov homoclinic bifurcation that dynamically organises some
of the responses in the TM model. In particular, the presence of such a
homoclinic bifurcation strongly affects the shape of the trajectories in the
phase space and induces highly irregular transient dynamics; indeed, in the
vicinity of the Shilnikov homoclinic bifurcation, the number of population
spikes and their precise timing are unpredictable and highly sensitive to the
initial conditions. Such an irregular deterministic dynamics has its
counterpart in stochastic/network versions of the TM model: the existence of
the Shilnikov homoclinic bifurcation generates complex and irregular spiking
patterns and --acting as a sort of springboard-- facilitates transitions
between the down-state and unstable periodic orbits. The interplay between the
(deterministic) homoclinic bifurcation and stochastic effects may give rise to
some of the complex dynamics observed in neural systems.


title:
Largest integral simplices with one interior integral point: Solution of
  Hensley's conjecture and related results

abstract:
  For each dimension $d$, $d$-dimensional integral simplices with exactly one
interior integral point have bounded volume. This was first shown by Hensley.
Explicit volume bounds were determined by Hensley, Lagarias and Ziegler,
Pikhurko, and Averkov. In this paper we determine the exact upper volume bound
for such simplices and characterize the volume-maximizing simplices. We also
determine the sharp upper bound on the coefficient of asymmetry of an integral
polytope with a single interior integral point. This result confirms a
conjecture of Hensley from 1983. Moreover, for an integral simplex with
precisely one interior integral point, we give bounds on the volumes of its
faces, the barycentric coordinates of the interior integral point and its
number of integral points. Furthermore, we prove a bound on the lattice
diameter of integral polytopes with a fixed number of interior integral points.
The presented results have applications in toric geometry and in integer
optimization.


title: Effect of equation of state and composition on relativistic flows

abstract:
  The thermal state of the fluid is governed by the ratio of the thermal and
the rest energy. This brings the composition of the fluid into the picture.
Although, fluid composed of lighter particles (e.g: electron-positron pair
plasma) at same temperature, is more relativistic compared to fluids with
finite baryon loading, but this is not necessarily true when baryon poor
transonic fluid are compared with each other. It can be shown that the
transonic pair-fluid is the least relativistic. This has far reaching
consequences on accreting flows around compact objects and are expected to have
similar effect on relativistic outflows and explosive events as well.


title: Lithium abundance evolution in open clusters: Hyades, NGC752, and M67

abstract:
  Mixing mechanisms bring the Li from the base of the convective zone to deeper
and warmer layers where it is destroyed. These mechanisms are investigated by
comparing observations of Li abundances in stellar atmospheres to models of
stellar evolution. Observations in open cluster are especially suitable for
this comparison, since their age and metallicity are homogeneous among their
members and better determined than in field stars. In this work, we compare the
evolution of Li abundances in three different clusters: the Hyades, NGC752, and
M67. Our models are calculated with microscopic diffusion and transport of
chemicals by meridional circulation, and calibrated on the Sun. These
comparisons allow us to follow the evolution of Li abundance as a function of
stellar mass in each cluster and as a function of the age by comparing this
evolution in each cluster. We evaluate the efficiency of the mixing mechanisms
used in the models, and we try to identify the lacking mechanisms to reproduce
the observed evolution of Li abundance.


title: The effects of rounding errors in the nodes on barycentric interpolation

abstract:
  We analyze the effects of rounding errors in the nodes on barycentric
interpolation. These errors are particularly relevant for the first barycentric
formula with the Chebyshev points of the second kind. Here, we propose a method
for reducing them.


title:
Proceedings of the Twenty-Ninth Conference on Uncertainty in Artificial
  Intelligence (2013)

abstract:
  This is the Proceedings of the Twenty-Ninth Conference on Uncertainty in
Artificial Intelligence, which was held in Bellevue, WA, August 11-15, 2013


title: Lorentz violation in a uniform newtonian gravitational field

abstract:
  Lorentz invariance is one of the fundamental principles of physics, and, as
such, it must be experimentally tested. The purpose of this work is to obtain,
within the Standard-Model Extension, the dynamics of a Lorentz-violating spinor
in a uniform newtonian gravitational field. This is achieved by treating the
spinor as a test particle and introducing the gravitational field through a
uniformly accelerated observer. The nonrelativistic hamiltonian is obtained and
some experimental consequences are discussed. One unexpected outcome of this
work is that the gravitational field helps disentangling bounds on coefficients
for Lorentz violation.


title: Two-way quantum cryptography at different wavelengths

abstract:
  We study the security of two-way quantum cryptography at different
wavelengths of the electromagnetic spectrum, from the optical range down to the
microwave range. In particular, we consider a two-way quantum communication
protocol where Gaussian-modulated thermal states are subject to random Gaussian
displacements and finally homodyned. We show how its security threshold (in
reverse reconciliation) is extremely robust with respect to the preparation
noise and able to outperform the security thresholds of one-way protocols at
any wavelength. As a result, improved security distances are now accessible for
implementing quantum key distribution at the very challenging regime of
infrared frequencies.


title: Theoretical evolution of Rossby number for solar analog stars

abstract:
  Magnetic fields of late-type stars are presumably generated by a dynamo
mechanism at the interface layer between the radiative interior and the outer
convective zone. The Rossby number, which is related to the dynamo process,
shows an observational correlation with activity. It represents the ratio
between the rotation period of the star and the local convective turnover time.
The former is well determined from observations but the latter is estimated by
an empirical iterated function depending on the color index (B-V) and the
mixing-length parameter. We computed the theoretical Rossby number of stellar
models with the TGEC code, and analyze its evolution with time during the main
sequence. We estimated a function for the local convective turnover time
corresponding to a mixing-length parameter inferred from a solar model, and
compare our results to the estimated Rossby number of 33 solar analogs and
twins, observed with the spectropolarimeters ESPaDOnS@CFHT and Narval@LBT.


title: Structures and Lagrangian statistics of the Taylor-Green Dynamo

abstract:
  The evolution of a Taylor-Green forced magnetohydrodynamic (MHD) system
showing dynamo activity is analyzed via direct numerical simulations. The
statistical properties of the velocity and magnetic field in Eulerian
coordinates and along trajectories of fluid elements (Lagrangian coordinates)
are found to change between the kinematic, non-linear and saturated regime.
Fluid element (tracer) trajectories change from chaotic quasi-isotropic
(kinematic phase) to mean magnetic field aligned (saturated phase). The
probability density functions (PDFs) of the magnetic field change from strongly
non-Gaussian in the kinematic to quasi-Gaussian PDFs in the saturated regime so
that their flatness give a precise handle on the definition of the limiting
points of the three regimes. Also the statistics of the fluctuations of the
kinetic and magnetic energy along fluid trajectories change. All this goes
along with a dramatic increase of the correlation time of velocity and magnetic
field fluctuations experienced by tracers significantly exceeding one turbulent
large-eddy turn-over time. A remarkable consequence is an intermittent scaling
regime of the Lagrangian magnetic field structure functions at unusually long
time scales.


title: Quantum circuits cannot control unknown operations

abstract:
  One of the essential building blocks of classical computer programs is the
"if" clause, which executes a subroutine depending on the value of a control
variable. Similarly, several quantum algorithms rely on applying a unitary
operation conditioned on the state of a control system. Here we show that this
control cannot be performed by a quantum circuit if the unitary is completely
unknown. However, this no-go theorem does not prevent implementing quantum
control of unknown unitaries in practice, as any physical implementation of an
unknown unitary provides additional information that makes the control
possible. We then argue that one should extend the quantum circuit formalism to
capture this possibility in a straightforward way. This is done by allowing
unknown unitaries to be applied to subspaces and not only to subsystems.


title: The Membrane Paradigm and Firewalls

abstract:
  Following the Membrane Paradigm, we show that the stretched horizon of a
black hole retains information about particles thrown into the hole for a time
of order the scrambling time m ln(m/M_P), after the particles cross the
horizon. One can, for example, read off the proper time at which a particle
anti-particle pair thrown into the hole, annihilates behind the horizon, if
this time is less than the scrambling time. If we believe that the
Schwarzschild geometry exterior to the horizon is a robust thermodynamic
feature of the quantum black hole, independent of whether it is newly formed,
or has undergone a long period of Hawking decay, then this classical
computation shows that the "firewall" resolution of the AMPS paradox is not
valid.


title: Experimental Realization of a Three-Dimensional Dirac Semimetal

abstract:
  The three dimensional (3D) Dirac semimetal, which has been predicted
theoretically, is a new electronic state of matter. It can be viewed as 3D
generalization of graphene, with a unique electronic structure in which
conduction and valence band energies touch each other only at isolated points
in momentum space (i.e. the 3D Dirac points), and thus it cannot be classified
either as a metal or a semiconductor. In contrast to graphene, the Dirac points
of such a semimetal are not gapped by the spin-orbit interaction and the
crossing of the linear dispersions is protected by crystal symmetry. In
combination with broken time-reversal or inversion symmetries, 3D Dirac points
may result in a variety of topologically non-trivial phases with unique
physical properties. They have, however, escaped detection in real solids so
far. Here we report the direct observation of such an exotic electronic
structure in cadmium arsenide (Cd3As2) by means of angle-resolved photoemission
spectroscopy (ARPES). We identify two momentum regions where electronic states
that strongly disperse in all directions form narrow cone-like structures, and
thus prove the existence of the long sought 3D Dirac points. This electronic
structure naturally explains why Cd3As2 has one of the highest known bulk
electron mobilities. This realization of a 3D Dirac semimetal in Cd3As2 not
only opens a direct path to a wide spectrum of applications, but also offers a
robust platform for engineering topologically-nontrivial phases including Weyl
semimetals and Quantum Spin Hall systems.


title: When does a physical system compute?

abstract:
  Computing is a high-level process of a physical system. Recent interest in
non-standard computing systems, including quantum and biological computers, has
brought this physical basis of computing to the forefront. There has been,
however, no consensus on how to tell if a given physical system is acting as a
computer or not; leading to confusion over novel computational devices, and
even claims that every physical event is a computation. In this paper we
introduce a formal framework that can be used to determine whether or not a
physical system is performing a computation. We demonstrate how the abstract
computational level interacts with the physical device level, drawing the
comparison with the use of mathematical models to represent physical objects in
experimental science. This powerful formulation allows a precise description of
the similarities between experiments, computation, simulation, and technology,
leading to our central conclusion: physical computing is the use of a physical
system to predict the outcome of an abstract evolution. We give conditions that
must be satisfied in order for computation to be occurring, and illustrate
these with a range of non-standard computing scenarios. The framework also
covers broader computing contexts, where there is no obvious human computer
user. We define the critical notion of a 'computational entity', and show the
role this plays in defining when computing is taking place in physical systems.


title: Theoretical Issues in Flavor Physics

abstract:
  Quark and lepton flavor physics presents us with a basic question: Can we
understand the pattern of masses and mixings of the known quarks and leptons,
and how do present and proposed measurements help to advance that goal? Topics
discussed include the apparent suppression of new flavor-changing effects, the
status of quark and lepton mixing, the implications of new measurements of CP
asymmetries in heavy quark decays, the impications of forthcoming experiments
on the muon's anomalous magnetic moment and its transitions to an electron, and
what we can hope to learn from electric dipole moments.


title:
An inverse radiative transfer in refractive media equipped with a
  magnetic field

abstract:
  We study the reconstruction of the attenuation and absorption coefficients in
a stationary linear transport equation from knowledge of albedo operator in
dimension $n\geq 3$ on a Riemannian manifold in the presence of a magnetic
field. We show the direct boundary value problem is well posed under two types
of subcritical conditions. We obtain uniqueness and non-uniqueness results of
the reconstruction under some restrictions. Finally, stability estimates are
also established.


title: On the Feature Discovery for App Usage Prediction in Smartphones

abstract:
  With the increasing number of mobile Apps developed, they are now closely
integrated into daily life. In this paper, we develop a framework to predict
mobile Apps that are most likely to be used regarding the current device status
of a smartphone. Such an Apps usage prediction framework is a crucial
prerequisite for fast App launching, intelligent user experience, and power
management of smartphones. By analyzing real App usage log data, we discover
two kinds of features: The Explicit Feature (EF) from sensing readings of
built-in sensors, and the Implicit Feature (IF) from App usage relations. The
IF feature is derived by constructing the proposed App Usage Graph (abbreviated
as AUG) that models App usage transitions. In light of AUG, we are able to
discover usage relations among Apps. Since users may have different usage
behaviors on their smartphones, we further propose one personalized feature
selection algorithm. We explore minimum description length (MDL) from the
training data and select those features which need less length to describe the
training data. The personalized feature selection can successfully reduce the
log size and the prediction time. Finally, we adopt the kNN classification
model to predict Apps usage. Note that through the features selected by the
proposed personalized feature selection algorithm, we only need to keep these
features, which in turn reduces the prediction time and avoids the curse of
dimensionality when using the kNN classifier. We conduct a comprehensive
experimental study based on a real mobile App usage dataset. The results
demonstrate the effectiveness of the proposed framework and show the predictive
capability for App usage prediction.


title: Coexistence of phases and the observability of random graphs

abstract:
  In a recent Letter, Yang et al. [Phys. Rev. Lett. 109, 258701 (2012)]
introduced the concept of observability transitions: the percolation-like
emergence of a macroscopic observable component in graphs in which the state of
a fraction of the nodes, and of their first neighbors, is monitored. We show
how their concept of depth-L percolation---where the state of nodes up to a
distance L of monitored nodes is known---can be mapped unto multitype random
graphs, and use this mapping to exactly solve the observability problem for
arbitrary L. We then demonstrate a non-trivial coexistence of an observable and
of a non-observable extensive component. This coexistence suggests that
monitoring a macroscopic portion of a graph does not prevent a macroscopic
event to occur unbeknown to the observer. We also show that real complex
systems behave quite differently with regard to observability depending on
whether they are geographically-constrained or not.


title: Link polynomial calculus and the AENV conjecture

abstract:
  Using the recently proposed differential hierarchy (Z-expansion) technique,
we obtain a general expression for the HOMFLY polynomials in two arbitrary
symmetric representations of link families, including Whitehead and Borromean
links. Among other things, this allows us to check and confirm the recent
conjecture of arXiv:1304.5778 that the large representation limit (the same as
considered in the knot volume conjecture) of this quantity matches the
prediction from mirror symmetry consideration. We also provide, using the
evolution method, the HOMFLY polynomial in two arbitrary symmetric
representations for an arbitrary member of the one-parametric family of
2-component 3-strand links, which includes the Hopf and Whitehead links.


title: Experimental Challenges of the European Strategy for Particle Physics

abstract:
  In planning for the Phase II upgrades of CMS and ATLAS major considerations
are: 1)being able to deal with degradation of tracking and calorimetry up to
the radiation doses to be expected with an integrated luminosity of 3000
$fb^{-1}$ and 2)maintaining physics performance at a pileup level of ~140. Here
I report on work started within the context of the CMS Forward Calorimetry Task
Force and continuing in an expanded CERN RD52 R$&$D program integrating timing
(i.e. measuring the time-of-arrival of physics objects) as a potential tool for
pileup mitigation and ideas for Forward Calorimetry. For the past 4 years our
group has focused on precision timing at the level of 10-20 picoseconds in an
environment with rates of $~10^6-10^7$ Hz/$cm^2 $ as is appropriate for the
future running of the LHC (HL-LHC era). A time resolution of 10-20 picoseconds
is one of the few clear criteria for pileup mitigation at the LHC, since the
interaction time of a bunch crossing has an rms of 170 picosec. While work on
charged particle timing in other contexts (i.e. ALICE R$&$D) is starting to
approach this precision, there have been essentially no technologies that can
sustain performance at these rates. I will present results on a tracker we
developed within the DOE Advanced Detector R$&$D program which is now meeting
these requirements. I will also review some results from Calorimeter Projects
developed within our group (PHENIX EMCAL and ATLAS ZDC) which achieved
calorimeter timing precision< 100 picoseconds.


title: Asymptotic statistics of cycles in surrogate-spatial permutations

abstract:
  We propose an extension of the Ewens measure on permutations by choosing the
cycle weights to be asymptotically proportional to the degree of the symmetric
group. This model is primarily motivated by a natural approximation to the
so-called spatial random permutations recently studied by V. Betz and D.
Ueltschi (hence the name "surrogate-spatial"), but it is of substantial
interest in its own right. We show that under the suitable (thermodynamic)
limit both measures have the similar critical behaviour of the cycle statistics
characterized by the emergence of infinitely long cycles. Moreover, using a
greater analytic tractability of the surrogate-spatial model, we obtain a
number of new results about the asymptotic distribution of the cycle lengths
(both small and large) in the full range of subcritical, critical and
supercritical domains. In particular, in the supercritical regime there is a
parametric "phase transition" from the Poisson-Dirichlet limiting distribution
of ordered cycles to the occurrence of a single giant cycle. Our techniques are
based on the asymptotic analysis of the corresponding generating functions
using Polya's Enumeration Theorem and complex variable methods.


title:
LAr1-ND: Testing Neutrino Anomalies with Multiple LArTPC Detectors at
  Fermilab

abstract:
  This white paper describes LAr1-ND and the compelling physics it brings first
in Phase 1 and next towards the full LAr1 program. In addition, LAr1-ND serves
as a key step in the development toward large-scale LArTPC detectors. Its
development goals will encompass testing existing and possibly innovative
designs for LBNE while at the same time providing a training ground for teams
working towards LBNE combining timely neutrino physics with experience in
detector development.


title: Higgs Decays in Gauge Extensions of the Standard Model

abstract:
  We explore the phenomenology of virtual spin-1 contributions to the h to
gamma gamma and h to Z gamma decay rates in gauge extensions of the standard
model. We consider generic lorentz and gauge invariant vector
self-interactions, which can have non-trivial structure after diagonalizing the
quadratic part of the action. Such features are phenomenologically relevant in
models where the electroweak gauge bosons mix with additional spin-1 fields,
such as occurs in little higgs models, extra dimensional models, strongly
coupled variants of electroweak symmetry breaking, and other gauge extensions
of the standard model. In models where non-renormalizable operators mix field
strengths of gauge groups, the one-loop higgs decay amplitudes can be
logarithmically divergent, and we provide power counting for the size of the
relevant counter-term. We provide an example calculation in a 4-site moose
model that contains degrees of freedom that model the effects of vector and
axial vector resonances arising from TeV scale strong dynamics.


title:
Threshold Resummation and the Determinations of Parton Distribution
  Functions

abstract:
  The precise knowledge of parton distribution functions (PDFs) is
indispensable to the accurate calculation of hadron-initiated QCD hard
scattering observables. Much of our information on PDFs is extracted by
comparing deep inelastic scattering (DIS) and lepton pair production (LPP) data
to convolutions of the PDFs with the partonic cross sections of these
processes. It is known that partonic cross sections receive large corrections
in regions of phase space near partonic thresholds that can be resummed using
threshold resummation techniques. The effect of threshold resummation on DIS
and LPP differs because partonic thresholds for the two processes occur in
different kinematic regions. Recent global fits for PDFs have included DIS data
from the large Bjorken x and moderate Q^2 region where threshold effects have
been shown to be large. The present project explores the effects of
simultaneously incorporating threshold resummation in both DIS and LPP and to
evaluate the effects of such additions on global fits.


title:
The Emergence of Animal Social Complexity: theoretical and biobehavioral
  evidence

abstract:
  This paper will introduce a theory of emergent animal social complexity using
various results from computational models and empirical results. These results
will be organized into a vertical model of social complexity. This will support
the perspective that social complexity is in essence an emergent phenomenon
while helping to answer two interrelated questions. The first of these involves
how behavior is integrated at units of analysis larger than the individual
organism. The second involves placing aggregate social events into the context
of processes occurring within individual organisms over time (e.g. genomic and
physiological processes). By using a complex systems perspective, five
principles of social complexity can be identified. These principles suggest
that lower-level mechanisms give rise to high-level mechanisms, ultimately
resulting in metastable networks of social relations. These network structures
then constrain lower-level phenomena ranging from transient, collective social
groups to physiological regulatory mechanisms within individual organisms. In
conclusion, the broader implications and drawbacks of applying the theory to a
diversity of natural populations will be discussed.


title:
Observation of electron antineutrino disappearance by the Daya Bay
  Reactor Neutrino Experiment

abstract:
  This presentation describes a measurement of the neutrino mixing parameter,
sin^2(2theta_13), from the Daya Bay Reactor Neutrino Experiment. Disappearance
of electron antineutrinos at a distance of ~2 km from a set of six reactors,
where the reactor flux is constrained by near detectors, has been clearly
observed. The result, based on the ratio of observed to expected rate of
antineutrinos, using 139 days of data taken between December 24, 2011 and May
11, 2012, is sin^2(2theta_13) = 0.089 +/- 0.010(stat.) +/- 0.005(syst.).
Improvements in sensitivity from inclusion of additional data, spectral
analysis, and improved calibration are expected in the future.


title: Bound entangled states with extremal properties

abstract:
  Following recent work of Beigi and Shor, we investigate PPT states that are
"heavily entangled." We first exploit volumetric methods to show that in a
randomly chosen direction, there are PPT states whose distance in trace norm
from separable states is (asymptotically) at least 1/4. We then provide
explicit examples of PPT states which are nearly as far from separable ones as
possible. To obtain a distance of 2-{\epsilon} from the separable states, we
need a dimension of 2^{poly(\log(1/\epsilon))}, as opposed to
2^{poly(1/\epsilon)} given by the construction of Beigi and Shor. We do so by
exploiting the so called {\it private states}, introduced earlier in the
context of quantum cryptography. We also provide a lower bound for the distance
between private states and PPT states and investigate the distance between pure
states and the set of PPT states.


title: Intersection growth in groups

abstract:
  The intersection growth of a group $G$ is the asymptotic behavior of the
index of the intersection of all subgroups of $G$ with index at most $n$, and
measures the Hausdorff dimension of $G$ in profinite metrics. We study
intersection growth in free groups and special linear groups and relate
intersection growth to quantifying residual finiteness.


title:
Constraining primordial magnetic fields with distortions of the
  black-body spectrum of the cosmic microwave background: pre- and
  post-decoupling contributions

abstract:
  Observational limits on $y$- and $\mu$-type distortions can constrain
properties of magnetic fields in the early universe. For a Gaussian, random,
and non-helical field, $\mu$ and $y$ are calculated a function of the
present-day strength of the field, $B_0$, smoothed over a certain Gaussian
width, $k_c^{-1}$, and spectral index, $n_B$, defined by $P_B(k)\propto
k^{n_B}$. For $n_B=-2.9$ and $k_c^{-1}=1 {\rm Mpc}$, the COBE/FIRAS limit on
$\mu$ yields $B_0<40$ nG, whereas the projected PIXIE limit on $\mu$ would
yield $B_0<0.8$ nG. For non-scale-invariant spectra, constraints can be
stronger. For $B_0=1$ nG with $k_c^{-1}=1 {\rm Mpc}$, the COBE/FIRAS limit on
$\mu$ excludes a wide range of spectral indices given by $n_B>-2.6$. After
decoupling, energy dissipation is due to ambipolar diffusion and decaying MHD
turbulence, creating a $y$-type distortion. The distortion is completely
dominated by decaying MHD turbulence, and is of order $y\approx 10^{-7}$ for a
few nG field smoothed over the damping scale at the decoupling epoch,
$k_{d,dec}\approx 290 (B_0/1 {\rm nG})^{-1} {\rm Mpc}^{-1}$. This contribution
is as large as those of the known contributions such as reionization and
virialized objects at lower redshifts. The projected PIXIE limit on $y$ would
exclude $B_0>1.0$ and 0.6 nG for $n_B=-2.9$ and -2.3, respectively, and
$B_0>0.6$ nG for $n_B\geq 2$. The current limits on the optical depth to
Thomson scattering restrict the predicted $y$-type distortion to be $y\lesssim
10^{-8}$. (Abridged)


title:
Threshold resummation in direct photon production and its implications
  on the large-x gluon PDF

abstract:
  Currently, the gluon distribution function is mainly constrained by jet data.
Yet, its high-x behaviour is largely unknown. This kinematic region is
important, for instance, for the understanding of the production of a massive
state at forward rapidities at the LHC. In the past, single inclusive direct
photon data from fixed target experiments was used to constrain the gluon
distribution due to its dominant contribution from the $qg \rightarrow\gamma q$
subprocess in proton-proton collisions. Due to disagreement with its
theoretical predictions at next-to-leading order (NLO) in perturbative QCD
(pQCD), direct photon data have been excluded from global fits. This talk will
discuss an improvement to such theoretical predictions by including
\emph{threshold resummation} at next-to-leading logarithmic accuracy (NLL) and
its impact on gluon distribution at large-x using Bayesian reweighting
technique.


title:
Tertiary classes for a one-parameter variation of flat connections on a
  smooth manifold

abstract:
  In this note, we extend the theory of Chern-Cheeger-Simons to construct
canonical invariants for a one-parameter family of flat connections on a smooth
manifold. These invariants lie in degrees $(2p-2)$-cohomology with
$\C/\Z$-cohomology, for $p\geq 2$. Furthermore, they are shown to be rigid in a
variation of paths (parametrising flat connections), in degrees at least three.


title: Near-field thermal transistor

abstract:
  Using a block of three separated solid elements, a thermal source and drain
together with a gate made of an insulator-metal transition material exchanging
near-field thermal radiation, we introduce a nanoscale analog of a field-effect
transistor which is able to control the flow of heat exchanged by evanescent
thermal photons between two bodies. By changing the gate temperature around its
critical value, the heat flux exchanged between the hot body (source) and the
cold body (drain) can be reversibly switched, amplified, and modulated by a
tiny action on the gate. Such a device could find important applications in the
domain of nanoscale thermal management and it opens up new perspectives
concerning the development of contactless thermal circuits intended for
information processing using the photon current rather than the electric
current.


title:
Quantum criticality of geometric phase in coupled optical cavity arrays
  under linear quench

abstract:
  The atoms trapped in microcavities and interacting through the exchange of
virtual photons can be modeled as an anisotropic Heisenberg spin-1/2 lattice.
We study the dynamics of the geometric phase of this system under the linear
quenching process of laser field detuning which shows the XX criticality of the
geometric phase in presence of single Rabi frequency oscillation. We also study
the quantum criticality for different quenching rate in the presence of single
or two Rabi frequencies oscillation in the system.


title: The nucleolus of large majority games

abstract:
  Members of a shareholder meeting or legislative committee have greater or
smaller voting power than meets the eye if the nucleolus of the induced
majority game differs from the voting weight distribution. We establish a new
sufficient condition for the weight and power distributions to be equal; and we
characterize the limit behavior of the nucleolus in case all relative weights
become small.


title: Message passing optimization of Harmonic Influence Centrality

abstract:
  This paper proposes a new measure of node centrality in social networks, the
Harmonic Influence Centrality, which emerges naturally in the study of social
influence over networks. Using an intuitive analogy between social and
electrical networks, we introduce a distributed message passing algorithm to
compute the Harmonic Influence Centrality of each node. Although its design is
based on theoretical results which assume the network to have no cycle, the
algorithm can also be successfully applied on general graphs.


title: The Cosmic Evolution of Fermi BL Lacertae Objects

abstract:
  Fermi has provided the largest sample of gamma-ray selected blazars to date.
In this work we use a uniformly selected set of 211 BL Lacertae (BL Lac)
objects detected by it Fermi during its first year of operation. We have
obtained redshift constraints for 206 out of the 211 BL Lacs in our sample
making it the largest and most complete sample of BL Lacs available in the
literature. We use this sample to determine the luminosity function of BL Lacs
and its evolution with cosmic time. We find that for most BL Lac classes, the
evolution is positive with a space density peaking at modest redshift (z~1.2).
The low-luminosity, high-synchrotron peaked (HSP) BL Lacs are an exception,
showing strong negative evolution, with number density increasing for
z$\lesssim$0.5. Since this rise corresponds to a drop-off in the density of
flat-spectrum radio quasars (FSRQs), a possible interpretation is that these
HSPs represent an accretion-starved end-state of an earlier merger-driven
gas-rich phase. We additionally find that the known BL Lac correlation between
luminosity and photon spectral index persists after correction for the
substantial observational selection effects with implications for the so called
`blazar sequence'. Finally, estimating the beaming corrections to the
luminosity function, we find that BL Lacs have an average Lorentz factor of
$\gamma=6.1^{+1.1}_{-0.8}$, and that most are seen within 10$^{\circ}$ of the
jet axis.