title:
On the Galactic chemical evolution of sulphur. Sulphur abundances from
  the [S i] 1082 nm line in giants

abstract:
  Context. The Galactic chemical evolution of sulphur is still under debate. At
low metallicities some studies find no correlation between [S/Fe] and [Fe/H],
others find [S/Fe] increasing towards lower metallicities, and still others
find a combination of the two. Each scenario has different implications for the
Galactic chemical evolution of sulphur.
  Aims. To contribute to the discussion on the Galactic chemical evolution of
sulphur by deriving sulphur abundances from non-LTE insensitive spectral
diagnostics in Disk and Halo stars with homogeneously determined stellar
parameters.
  Methods. We derive Teff from photometric colours, logg from stellar
isochrones and Bayesian estimation, and [Fe/H] and [S/Fe] from spectrum
synthesis. We derive [S/Fe] from the [S i] 1082 nm line in 39 mostly cool and
metal-poor giants, using 1D LTE MARCS model atmospheres to model our
high-resolution NIR spectra obtained with the VLT, NOT and Gemini South
telescopes.
  Results. We derive homogeneous stellar parameters for 29 stars. Our results
argue for a chemical evolution of sulphur that is typical for alpha-elements,
contrary to some previous studies. Our abundances are systematically higher by
about 0.1 dex in comparison to other studies that arrived at similar
conclusions using other sulphur diagnostics.
  Conclusions. We find the [S i] line to be a valuable diagnostic of sulphur
abundances in cool giants down to [Fe/H] ~ -2.3. We argue that a homogeneous
determination of stellar parameters is necessary, since the derived abundances
are sensitive to them. Our results ([S/Fe]) show reasonable agreement with
predictions of contemporary models of Galactic chemical evolution. In these
models sulphur is predominantly created in massive stars by oxygen burning, and
ejected in the ISM during Type II SNe explosions. Systematic differences with
previous studies likely fall within modelling uncertainties.


title: Simplicity of UHF and Cuntz algebras on $L^p$~spaces

abstract:
  We prove that, for $p \in [1, \infty),$ and integers $d$ at least 2, the
$L^p$ analog ${\mathcal{O}}_d^p$ of the Cuntz algebra ${\mathcal{O}}_d$ is a
purely infinite simple amenable Banach algebra.
  The proof requires what we call the spatial $L^p$ UHF algebras, which are
analogs of UHF algebras acting on $L^p$ spaces. As for the usual UHF
C*-algebras, they have associated supernatural numbers. For fixed $p \in [1,
\infty),$ we prove that any spatial $L^p$ UHF algebra is simple and amenable,
and that two such algebras are isomorphic if and only if they have the same
supernatural number (equivalently, the same scaled ordered $K_0$-group). For
distinct $p_1, p_2 \in [1, \infty),$ we prove that no spatial $L^{p_1}$ UHF
algebra is isomorphic to any spatial $L^{p_2}$ UHF algebra.


title:
Numerical Stability Improvements for the Pseudo-Spectral EM PIC
  Algorithm

abstract:
  The pseudo-spectral analytical time-domain (PSATD) particle-in-cell (PIC)
algorithm solves the vacuum Maxwell's equations exactly, has no Courant
time-step limit (as conventionally defined), and offers substantial flexibility
in plasma and particle beam simulations. It is, however, not free of the usual
numerical instabilities, including the numerical Cherenkov instability, when
applied to relativistic beam simulations. This paper presents several
approaches that, when combined with digital filtering, almost completely
eliminate the numerical Cherenkov instability. The paper also investigates the
numerical stability of the PSATD algorithm at low beam energies.

categories: physics.plasm-ph math.NA physics.acc-ph physics.comp-ph


title:
Bipartite entanglement induced by classically-constrained quantum
  dissipative dynamics

abstract:
  The properties of some complex many body systems can be modeled by
introducing in the dissipative dynamics of each single component a set of
kinetic constraints that depend on the state of the neighbor systems. Here, we
characterize this kind of dynamics for two quantum systems whose independent
dissipative evolutions are defined by a Lindblad equation. The constraints are
introduced through a set of projectors that restrict the action of each single
dissipative Lindblad channel to the state of the other system. Conditions that
guaranty a classical interpretation of the kinetic constraints are found. The
generation and evolution of entanglement is studied for two optical qubits
systems. Classically constrained dissipation leads to a stationary state whose
degree of entanglement depends on the initial state. Nevertheless,
independently of the initial conditions, a maximal entangled state is generated
when both systems are subjected to the action of local Hamiltonian fields that
do not commutate with the constraints. The underlying physical mechanism is
analyzed in detail.


title:
Non-Markovian quantum jumps from measurements in bipartite Markovian
  dynamics

abstract:
  The quantum jump approach allows to characterize the stochastic dynamics
associated to an open quantum system submitted to a continuous measurement
action. In this paper we show that this formalism can consistently be extended
to non-Markovian system dynamics. The results rely in studying a measurement
process performed on a bipartite arrangement characterized by a Markovian
Lindblad evolution. Both a renewal and non-renewal extensions are found. The
general structure of non-local master equations that admit an unravelling in
terms of the corresponding non-Markovian trajectories are also found. Studying
a two-level system dynamics, it is demonstrated that non-Markovian effects such
as an environment-to-system flow of information may be present in the ensemble
dynamics.


title: Graphes parfaits : structure et algorithmes

abstract:
  This work is the PhD thesis of Nicolas Trotignon, written in 2004 under the
supervision of Fr\'ed\'eric Maffray. It is motivated by the desire for a better
understanding of perfect graphs. The proof of the Claude Berge's perfect graph
conjecture in 2002 by Chudnovsky, Robertson, Seymour and Thomas has shed a new
light on this field of combinatorics. But some questions are still unsettled,
particulary the existence of a combinatorial algorithm for the coloring of
perfect graphs.
  An even pair of a graph is a pair of vertices such that every path joining
them has even length. As proved by Fonlupt and Uhry, the contraction of an even
pair preserves the chromatic number, and when applied recursively may lead to
an optimal coloring. We prove a conjecture of Everett and Reed saying that this
method works for a class of perfect graphs: Artemis graphs. This yields a
coloring algorithm for Artemis graphs with complexity $O(n^2m)$.
  We give an $O(n^9)$ algorithm for the recognition of Artemis graphs. Other
recognition algorithms are also given, each of them based on subgraph detection
routines for Berge graphs. We show that these subgraph detection problems are
NP-complete when extended to general graphs.


title:
Unique continuation for fractional Schr\"odinger operators in three and
  higher dimensions

abstract:
  We prove the unique continuation property for the differential inequality
$|(-\Delta)^{\alpha/2}u|\leq|V(x)u|$, where $0<\alpha<n$ and $V\in
L_{\textrm{loc}}^{n/\alpha,\infty}(\mathbb{R}^n)$, $n\geq3$.


title:
The effects of intense magnetic fields on Landau levels in a neutron
  star

abstract:
  In this paper, an approximate method of calculating the Fermi energy of
electrons ($E_{F}(e)$) in a high-intensity magnetic field, based on the
analysis of the distribution of a neutron star magnetic field, has been
proposed. In the interior of a Neutron star, different forms of intense
magnetic field could exist simultaneously and a high electron Fermi energy
could be generated by the release of magnetic field energy. The calculation
results show that: $E_{F}(e)$ is related to density $\rho$, the mean electron
number per baryon $Y_{e}$ and magnetic field strength $B$.


title: Markovian embedding of non-Markovian quantum collisional models

abstract:
  A wide class of non-Markovian completely positive master equations can be
formulated on the basis of quantum collisional models. In this phenomenological
approach the dynamics of an open quantum system is modeled through an ensemble
of stochastic realizations that consist in the application at random times of a
(collisional) completely positive transformation over the system state. In this
paper, we demonstrate that these kinds of models can be embedded in bipartite
Markovian Lindblad dynamics consisting of the system of interest and an
auxiliary one. In contrast with phenomenological formulations, here the
stochastic ensemble dynamics an the inter-event time interval statistics are
obtained from a quantum measurement theory after assuming that the auxiliary
system is continuously monitored in time. Models where the system
inter-collisional dynamics is non-Markovian [B. Vacchini, Phys. Rev. A 87,
030101(R) (2013)] are also obtained from the present approach. The formalism is
exemplified through bipartite dynamics that leads to non-Markovian system
effects such as an environment-to-system back flow of information.


title:
A Robust Alternating Direction Method for Constrained Hybrid Variational
  Deblurring Model

abstract:
  In this work, a new constrained hybrid variational deblurring model is
developed by combining the non-convex first- and second-order total variation
regularizers. Moreover, a box constraint is imposed on the proposed model to
guarantee high deblurring performance. The developed constrained hybrid
variational model could achieve a good balance between preserving image details
and alleviating ringing artifacts. In what follows, we present the
corresponding numerical solution by employing an iteratively reweighted
algorithm based on alternating direction method of multipliers. The
experimental results demonstrate the superior performance of the proposed
method in terms of quantitative and qualitative image quality assessments.


title: Asymptotic normality of some graph sequences

abstract:
  For a simple finite graph G denote by {G \brace k} the number of ways of
partitioning the vertex set of G into k non-empty independent sets (that is,
into classes that span no edges of G). If E_n is the graph on n vertices with
no edges then {E_n \brace k} coincides with {n \brace k}, the ordinary Stirling
number of the second kind, and so we refer to {G \brace k} as a graph Stirling
number.
  Harper showed that the sequence of Stirling numbers of the second kind, and
thus the graph Stirling sequence of E_n, is asymptotically normal ---
essentially, as n grows, the histogram of ({E_n \brace k})_{k \geq 0}, suitably
normalized, approaches the density function of the standard normal
distribution.
  In light of Harper's result, it is natural to ask for which sequences
(G_n)_{n \geq 0} of graphs is there asymptotic normality of ({G_n \brace k})_{k
\geq 0}. Do and Galvin conjectured that if for each n, G_n is acylic and has n
vertices, then asymptotic normality occurs, and they gave a proof under the
added condition that G_n has no more than o(\sqrt{n/\log n}) components.
  Here we settle Do and Galvin's conjecture in the affirmative, and
significantly extend it, replacing "acyclic" in their conjecture with
"co-chromatic with a quasi-threshold graph, and with negligible chromatic
number". Our proof combines old work of Navon and recent work of Engbers,
Galvin and Hilyard on the normal order problem in a Weyl algebra, and work of
Kahn on the matching polynomial of a graph.


title: Maximal Ergodic Inequalities for Banach Function Spaces

abstract:
  We analyse the Transfer Principle, which is used to generate weak type
maximal inequalities for ergodic operators, and extend it to the general case
of $\sigma$-compact locally compact Hausdorff groups acting
measure-preservingly on $\sigma$-finite measure spaces. We show how the
techniques developed here generate various weak type maximal inequalities on
different Banach function spaces, and how the properties of these function
spaces influence the weak type inequalities that can be obtained. Finally, we
demonstrate how the techniques developed imply almost sure pointwise
convergence of a wide class of ergodic averages.


title: Diffraction of light by a nanowire

abstract:
  A general scattering problem of a plane electromagnetic wave on an infinite
cylindrical rod is formulated and solved in a form of Bessel functions series
expansion. The conductivity account via Ohm law directly in Maxwell equation
leads to complex wavenumber and hence the complex arguments of Bessel functions
inside the cylinder. The general formula for averaged by period Pointing vector
is derived. For numerical calculations asymptotics of Bessel functions are
used. Dependence of scattered wave intensity as function of angle and frequency
is presented for different values of the rod radius.


title:
Electron interaction, charging and screening in grain boundaries in
  graphene

abstract:
  Electronic, transport, and spin properties of grain boundaries (GBs) are
investigated in electrostatically doped graphene at finite electron densities
within the Hartree and Hubbard approximations. We demonstrate that depending on
the character of the GBs, the states residing on them can have a metallic
character with a zero group velocity or can be fully populated losing the
ability to carry a current. These states show qualitatively different features
in charge accumulation and spin polarization. We also demonstrate that the
semiclassical Thomas-Fermi approach provides a satisfactory approximation to
the calculated self-consistent potential. The conductance of GBs is reduced due
to enhanced backscattering from this potential.


title: A classifying space for commutativity in Lie groups

abstract:
  In this article we consider a space B_{com}G assembled from commuting
elements in a Lie group G first defined in [Adem, Cohen, Torres-Giese 2012]. We
describe homotopy-theoretic properties of these spaces using homotopy colimits,
and their role as a classifying space for transitionally commutative bundles.
We prove that ZxB_{com}U is a loop space and define a notion of commutative
K-theory for bundles over a finite complex X which is isomorphic to
[X,ZxB_{com}U]. We compute the rational cohomology of B_{com}G for G equal to
any of the classical groups U(n), SU(n) and Sp(n), and exhibit the rational
cohomologies of B_{com}U, B_{com}SU and B_{com}Sp as explicit polynomial rings.


title:
Information filtering via hybridization of similarity preferential
  diffusion processes

abstract:
  The recommender system is one of the most promising ways to address the
information overload problem in online systems. Based on the personal
historical record, the recommender system can find interesting and relevant
objects for the user within a huge information space. Many physical processes
such as the mass diffusion and heat conduction have been applied to design the
recommendation algorithms. The hybridization of these two algorithms has been
shown to provide both accurate and diverse recommendation results. In this
paper, we proposed two similarity preferential diffusion processes. Extensive
experimental analyses on two benchmark data sets demonstrate that both
recommendation and accuracy and diversity are improved duet to the similarity
preference in the diffusion. The hybridization of the similarity preferential
diffusion processes is shown to significantly outperform the state-of-art
recommendation algorithm. Finally, our analysis on network sparsity show that
there is significant difference between dense and sparse system, indicating
that all the former conclusions on recommendation in the literature should be
reexamined in sparse system.


title: Casimir torque in weak coupling

abstract:
  In this paper, dedicated to Johan H{\o}ye on the occasion of his 70th
birthday, we examine manifestations of Casimir torque in the weak-coupling
approximation, which allows exact calculations so that comparison with the
universally applicable, but generally uncontrolled, proximity force
approximation may be made. In particular, we examine Casimir energies between
planar objects characterized by $\delta$-function potentials, and consider the
torque that arises when angles between the objects are changed. The results
agree very well with the proximity force approximation when the separation
distance between the objects is small compared with their sizes. In the
opposite limit, where the size of one object is comparable to the separation
distance, the shape dependence starts becoming irrelevant. These calculations
are illustrative of what to expect for the torques between, for example,
conducting planar objects, which eventually should be amenable to both improved
theoretical calculation and experimental verification.


title:
Weighted Hardy-Littlewood average operators on bilateral grand Lebesgue
  spaces

abstract:
  We obtain in this short article the non-asymptotic exact estimations for the
norm of (generalized) weighted Hardy-Littlewood average integral operator in
the so-called Bilateral Grand Lebesgue Spaces. We also give examples to show
the sharpness of these inequalities.


title: Rovelli' s relational quantum mechanics, monism and quantum becoming

abstract:
  In this paper I present and defend Rovelli's relation quantum mechanics from
some foreseeable objections, so as to clarify its philosophical implications
vis a vis rival interpretations. In particular I ask whether RQM presupposes a
hidden recourse to both a duality of evolutions and of ontology (the
relationality of quantum world and the intrinsicness of the classical world,
which in the limit must be recovered from the former). I then concentrate on
the pluralistic, antimonistic metaphysical consequences of the theory, due to
the impossibility of assigning a state to the quantum universe. Finally, in the
last section I note interesting consequences of RQM with respect to the
possibility of defining a local, quantum relativistic becoming (in flat
spacetimes).Given the difficulties of having the cosmic form of becoming that
would be appropriate for priority monism, RQM seems to present an important
advantage with respect to monistic views, at least as far as the possibility of
explaining our experience of time is concerned.


title: The (7,4)-conjecture in finite groups

abstract:
  The first open case of the Brown, Erd\H{o}s, S\'os conjecture is equivalent
to the following; For every $c>0$ there is a threshold $n_0$ so that if a
quasigroup has order $n\geq n_0$ then for every subset of triples of the form
$(a,b,ab),$ denoted by $S,$ if $|S|\geq cn^2$ then there is a seven-element
subset of the quasigroup which spans at least four triples of the selected
subset $S.$ In this paper we prove the conjecture for finite groups.


title:
Charm mixing as input for model-independent determinations of the CKM
  phase gamma

abstract:
  The coherence factor and average strong phase difference of D0 and D0bar
decay amplitudes to the same final state play an important role in the
precision determination of the CKM parameter gamma using B- -> DK- and related
decay modes. So far, this important input from the charm sector could only be
obtained from measurements based on quantum-correlated DDbar pairs produced at
the charm threshold. We propose to constrain these parameters using charm
mixing, using the large charm samples available at the B factories and LHCb. We
demonstrate for the example of D0->Kpipipi that a substantial improvement in
the precision of the coherence factor and average strong phase difference can
be obtained with this method, using existing data.


title: Ramification of local rings along valuations

abstract:
  In this paper we discuss stable forms of extensions of algebraic local rings
along a valuation in all dimensions over a field k of characteristic zero, and
generalize a formula of Ghezzi, H\`a and Kashcheyeva describing the extension
of associated graded rings along the valuation for stable extensions of regular
algebraic local rings of dimension two to arbitrary ground fields k of
characteristic zero. We discuss the failure of this result in positive
characteristic.


title: Near-optimal Frequency-weighted Interpolatory Model Reduction

abstract:
  This paper develops an interpolatory framework for weighted-$\mathcal{H}_2$
model reduction of MIMO dynamical systems. A new representation of the
weighted-$\mathcal{H}_2$ inner products in MIMO settings is introduced and used
to derive associated first-order necessary conditions satisfied by optimal
weighted-$\mathcal{H}_2$ reduced-order models. Equivalence of these new
interpolatory conditions with earlier Riccati-based conditions given by Halevi
is also shown. An examination of realizations for equivalent
weighted-$\mathcal{H}_2$ systems leads then to an algorithm that remains
tractable for large state-space dimension. Several numerical examples
illustrate the effectiveness of this approach and its competitiveness with
Frequency Weighted Balanced Truncation and an earlier interpolatory approach,
the Weighted Iterative Rational Krylov Algorithm.


title: Asymptotic density and the Ershov hierarchy

abstract:
  We classify the asymptotic densities of the $\Delta^0_2$ sets according to
their level in the Ershov hierarchy. In particular, it is shown that for $n
\geq 2$, a real $r \in [0,1]$ is the density of an $n$-c.e.\ set if and only if
it is a difference of left-$\Pi_2^0$ reals. Further, we show that the densities
of the $\omega$-c.e.\ sets coincide with the densities of the $\Delta^0_2$
sets, and there are $\omega$-c.e.\ sets whose density is not the density of an
$n$-c.e. set for any $n \in \omega$.


title:
On the Heat Kernel under the Ricci Flow Coupled with the Harmonic Map
  Flow

abstract:
  We estimate the heat kernel on a closed Riemannian manifold $M$, with
$dim(M)\geq 3$, evolving under the Ricci-harmonic map flow and the result
depends on some constants arising from a Sobolev imbedding theorem. In a
special case, when the scalar curvature satisfies a certain natural inequality,
we obtain, as a corollary, a bound similar to the one known for the fixed
metric case.


title:
Gradient estimates for the heat equation under the Ricci-Harmonic Map
  flow

abstract:
  The paper establishes a series of gradient estimates for positive solutions
to the heat equation on a manifold $M$ evolving under the Ricci flow, coupled
with the harmonic map flow between $M$ and a second manifold $N$. We prove
Li-Yau type Harnack inequalities and we consider the cases when $M$ is a
complete manifold without boundary and when $M$ is compact, without boundary.


title: Position eigenstates via application of an operator on the vacuum

abstract:
  The squeezed states are states of minimum uncertainty, but unlike the
coherent states, in which the uncertainty in the position and the momentum are
the same, these allow to reduce the uncertainty, either in the position or in
the momentum, while maintaining the principle of uncertainty in its minimum. It
seems that this property of the squeezed states would allow you to get the
position eigenstates as a limit case of them, doing null the uncertainty in the
position and infinite at the momentum. However, there are two equivalent ways
to define the squeezed states, which lead to different expressions for the
limit states. In this work, we analyze these two definitions of the squeezed
states and show the advantages and disadvantages of using such definition to
find the position eigenstates. With this idea in mind, but leaving aside the
definitions of the squeezed states, we find an operator applied to the vacuum
that gives us the position eigenstates. We also analyze some properties of the
squeezed states, based on the new expressions obtained for the eigenstates of
the position.


title:
Empirical distribution of good channel codes with non-vanishing error
  probability (extended version)

abstract:
  This paper studies several properties of channel codes that approach the
fundamental limits of a given (discrete or Gaussian) memoryless channel with a
non-vanishing probability of error. The output distribution induced by an
$\epsilon$-capacity-achieving code is shown to be close in a strong sense to
the capacity achieving output distribution. Relying on the concentration of
measure (isoperimetry) property enjoyed by the latter, it is shown that regular
(Lipschitz) functions of channel outputs can be precisely estimated and turn
out to be essentially non-random and independent of the actual code. It is also
shown that the output distribution of a good code and the capacity achieving
one cannot be distinguished with exponential reliability. The random process
produced at the output of the channel is shown to satisfy the asymptotic
equipartition property. Using related methods it is shown that quadratic forms
and sums of $q$-th powers when evaluated at codewords of good AWGN codes
approach the values obtained from a randomly generated Gaussian codeword.


title: A decomposition for additive functional of Levy processes

abstract:
  Motivated by the recent results of Nualart and Xu \cite{Nualart} concerning
limits laws for occupation times of one dimensional symmetric stable processes,
this paper proves a decomposition for functionals of one dimensional symmetric
L\'evy processes under certain conditions on the characteristic exponent and
computes the moments of the decomposition.


title:
Global existence of solutions to the Einstein-massive scalar field
  equations with a cosmological constant for a perfect fluid on the flat
  Robertson-Walker space-time

abstract:
  In many cases a massive nonlinear scalar field can lead to accelerated
expansion in cosmological models. This paper contains mathematical results on
this subject for flat Robertson-Walker space-time. Global existence to the
coupled Einstein-massive scalar field system which rules the dynamics of a kind
of pure matter in the presence of a massive scalar field and cosmological
constant is proved, under the assumption that the scalar field ? is a
non-decreasing function, in Robertson-Walker1 space-time; asymptotic behaviour
are investigated in the case of a cosmological constant bounded from below by a
strictly negative constant depending only on the massive scalar field.


title: The collapse of supertasks

abstract:
  A supertask consists in the performance of an infinite number of actions in a
finite time. I show that any attempt to carry out a supertask will produce a
divergence of the curvature of spacetime, resulting in the formation of a black
hole. I maintain that supertasks, contrarily to a popular view among
philosophers, are physically impossible. Supertasks, literally, collapse under
their own weight.


title:
Delay Minimization for Instantly Decodable Network Coding in Persistent
  Channels with Feedback Intermittence

abstract:
  In this paper, we consider the problem of minimizing the multicast decoding
delay of generalized instantly decodable network coding (G-IDNC) over
persistent forward and feedback erasure channels with feedback intermittence.
In such an environment, the sender does not always receive acknowledgement from
the receivers after each transmission. Moreover, both the forward and feedback
channels are subject to persistent erasures, which can be modelled by a two
state (good and bad states) Markov chain known as Gilbert-Elliott channel
(GEC). Due to such feedback imperfections, the sender is unable to determine
subsequent instantly decodable packets combination for all receivers. Given
this harsh channel and feedback model, we first derive expressions for the
probability distributions of decoding delay increments and then employ these
expressions in formulating the minimum decoding problem in such environment as
a maximum weight clique problem in the G-IDNC graph. We also show that the
problem formulations in simpler channel and feedback models are special cases
of our generalized formulation. Since this problem is NP-hard, we design a
greedy algorithm to solve it and compare it to blind approaches proposed in
literature. Through extensive simulations, our adaptive algorithm is shown to
outperform the blind approaches in all situations and to achieve significant
improvement in the decoding delay, especially when the channel is highly
persistent


title: Holographic Vitrification

abstract:
  We establish the existence of stable and metastable stationary black hole
bound states at finite temperature and chemical potentials in global and planar
four-dimensional asymptotically anti-de Sitter space. We determine a number of
features of their holographic duals and argue they represent structural
glasses. We map out their thermodynamic landscape in the probe approximation,
and show their relaxation dynamics exhibits logarithmic aging, with aging rates
determined by the distribution of barriers.


title: Rational points on intersections of cubic and quadric hypersurfaces

abstract:
  We investigate the Hasse principle for complete intersections cut out by a
quadric and cubic hypersurface defined over the rational numbers.


title: Corrigendum: "On the Floer homology of cotangent bundles"

abstract:
  We fix an orientation issue which appears in our previous paper about the
isomorphism between Floer homology of cotangent bundles and loop space
homology. When the second Stiefel-Whitney class of the underlying manifold does
not vanish on 2-tori, this isomorphism requires the use of a twisted version of
the Floer complex.


title: Lectures on the free period Lagrangian action functional

abstract:
  In this expository article we study the question of the existence of periodic
orbits of prescribed energy for classical Hamiltonian systems on compact
configuration spaces. We use a variational approach, by studying how the
behavior of the free period Lagrangian action functional changes when the
energy crosses certain values, known as the Ma\~n\'e critical values.


title: On The Spaces of Fibonacci Difference Null and Convergent Sequences

abstract:
  In the present paper, by using the band matrix F defined by the Fibonacci
sequence, we introduce the sequence sequence spaces c_0(F) and c(F). Also, we
give some inclusion relations and construct the bases of the spaces c_0(F) and
c(F). Finally, we compute the alpha-, beta-, gamma-duals of these spaces and
characterize the classes (c_0(F),X) and (c(F),X) for certain choice of the
sequence space X.


title: Conformal invariance of dimer heights on isoradial double graphs

abstract:
  An isoradial graph is a planar graph in which each face is inscribable into a
circle of common radius. We study the 2-dimensional perfect matchings on a
bipartite isoradial graph, obtained from the union of an isoradial graph and
its interior dual graph. Using the isoradial graph to approximate a
simply-connected domain bounded by a simple closed curve, by letting the mesh
size go to zero, we prove that in the scaling limit, the distribution of height
is conformally invariant and converges to a Gaussian free field.


title:
Compactness of matrix operators on some sequence spaces derived by
  Fibonacci numbers

abstract:
  In this paper, we apply the Hausdorff measure of noncompactness to obtain the
necessary and sufficient conditions for certain matrix operators on the
Fibonacci difference sequence spaces l_{p}(F) and l_{infinite}(F) to be
compact, where 1<=p<infinite.


title: Universal deformation rings and tame blocks

abstract:
  Let k be an algebraically closed field of positive characteristic, and let W
be the ring of infinite Witt vectors over k. Suppose G is a finite group and B
is a block of kG of infinite tame representation type. We find all finitely
generated kG-modules V that belong to B and whose endomorphism ring is
isomorphic to k and determine the universal deformation ring R(G,V) for each of
these modules.


title:
Some New Paranormed Difference Sequence Spaces Derived by Fibonacci
  Numbers

abstract:
  In this study, we define new paranormed sequence spaces by the sequences of
Fibonacci numbers. Furthermore, we compute the $\alpha-,\beta-$ and $\gamma-$
duals and obtain bases for these sequence spaces. Besides this, we characterize
the matrix transformations from the new paranormed sequence spaces to the
Maddox's spaces $c_{0}(q),c(q),\ell(q)$ and $\ell_{\infty}(q)$.


title: Cornered Heegaard Floer homology

abstract:
  Bordered Floer homology assigns invariants to 3-manifolds with boundary, such
that the Heegaard Floer homology of a closed 3-manifold, split into two pieces,
can be recovered as a tensor product of the bordered invariants of the pieces.
We construct cornered Floer homology invariants of 3-manifolds with
codimension-2 corners, and prove that the bordered Floer homology of a
3-manifold with boundary, split into two pieces with corners, can be recovered
as a tensor product of the cornered invariants of the pieces.


title: Kondo lattice model: from local to non-local descriptions

abstract:
  In this paper, we study the influence of spatial fluctuations in a
two-dimentional Kondo-Lattice model (KLM) with anti-ferromagnetic couplings. To
accomplish this, we first present an implementation of the dual-fermion (DF)
approach based on the hybridization expansion continuous-time quantum Monte
Carlo impurity solver (CT-HYB), which allows us to consistently compare the
local and non-local descriptions of this model. We find that, the inclusion of
non-locality restores the self-energy dispersion of the conduction electrons,
{\it i.e.} the $\vec{k}$ dependence of $\Sigma(\vec{k}, i\omega_{n})$. The
anti-ferromagnetic correlations result in an additional symmetry in
$\Sigma(\vec{k}, i\omega_{n})$, which is well described by the N\'eel
antiferromagnetic wave-vector. A "metal"-"anti-ferromagnetic insulator"-"Kondo
insulator" transition is observed at finite temperatures, which is driven by
the competition of the effective RKKY interaction (at the weak coupling regime)
and the Kondo singlet formation mechanism (at the strong coupling regime). Away
from half-filling, the anti-ferromagnetic phase becomes unstable against hole
doping. The system tends to develop a ferromagnetic phase with the spin
susceptibility $\chi_{s}(Q)$ peaking at $Q=\Gamma$. However, for small $J/t$,
no divergence of $\chi_{s}(\Gamma)$ is really observed, thus, we find no sign
of long-range ferromagnetism in the hole-doped two-dimension KLM. The
ferromagnetism is found to be stable at larger $J/t$ regime. Interestingly, we
find the local approximation employed in this work, {\it i.e.} the dynamical
mean-field theory (DMFT), is still a very good description of the KLM,
especially in the hole-doped case. However, at half-filling, the non-local
fluctuation effect is indeed pronounced. We observe a strong reduction of the
critical coupling strength for the onset of the Kondo insulating phase.


title: A complementary construction using mutually unbiased bases

abstract:
  We present a construction for complementary pairs of arrays that exploits a
set of mutually-unbiased bases, and enumerate these arrays as well as the
corresponding set of complementary sequences obtained from the arrays by
projection. We also sketch an algorithm to uniquely generate these sequences.
The pairwise squared inner-product of members of the sequence set is shown to
be $\frac{1}{2}$. Moreover, a subset of the set can be viewed as a codebook
that asymptotically achieves $\sqrt{\frac{3}{2}}$ times the Welch bound.


title: Robustness of large-scale stochastic matrices to localized perturbations

abstract:
  Upper bounds are derived on the total variation distance between the
invariant distributions of two stochastic matrices differing on a subset W of
rows. Such bounds depend on three parameters: the mixing time and the minimal
expected hitting time on W for the Markov chain associated to one of the
matrices; and the escape time from W for the Markov chain associated to the
other matrix. These results, obtained through coupling techniques, prove
particularly useful in scenarios where W is a small subset of the state space,
even if the difference between the two matrices is not small in any norm.
Several applications to large-scale network problems are discussed, including
robustness of Google's PageRank algorithm, distributed averaging and consensus
algorithms, and interacting particle systems.


title: Data assimilation of fuel moisture in WRF-SFIRE

abstract:
  Fuel moisture is a major influence on the behavior of wildland fires and an
important underlying factor in fire risk. We present a method to assimilate
spatially sparse fuel moisture observations from remote automatic weather
stations (RAWS) into the moisture model in WRF-SFIRE. WRF-SFIRE is a coupled
atmospheric and fire behavior model which simulates the evolution of fuel
moisture in idealized fuel species based on atmospheric state. The proposed
method uses a modified trend surface model to estimate the fuel moisture field
and its uncertainty based on currently available observations. At each grid
point of WRF-SFIRE, this information is combined with the model forecast using
a nonlinear Kalman filter, leading to an updated estimate of fuel moisture. We
demonstrate the effectiveness of the method with tests in two real-world
situations: a region in Southern California, where two large Santa Ana fires
occurred recently, and on a domain enclosing Colorado.


title: Semisimplicity of the Lyapunov spectrum for irreducible cocycles

abstract:
  Let $G$ be a semisimple Lie group acting on a space $X$, let $\mu$ be a
compactly supported measure on $G$, and let $A$ be a strongly irreducible
linear cocycle over the action of $G$. We then have a random walk on $X$, and
let $T$ be the associated shift map. We show that the cocycle $A$ over the
action of $T$ is conjugate to a block conformal cocycle.
  This statement is used in the recent paper by Eskin-Mirzakhani on the
classifications of invariant measures for the SL(2,R) action on moduli space.
The ingredients of the proof are essentially contained in the papers of
Guivarch and Raugi and also Goldsheid and Margulis.


title:
Effect of in-medium spectral density of $D$ and $D^*$ mesons on the
  $J/\psi$ dissociation in hadronic matter

abstract:
  The one-loop self-energy of the $D$ and $D^*$ mesons in a hot hadronic medium
is evaluated using the real time formalism of thermal field theory. The
interaction of the heavy open-charm mesons with the thermalized constituents
$(\pi,K,\eta)$ of the hadronic matter is treated in the covariant formalism of
heavy meson chiral perturbation theory. The imaginary parts are extracted from
the discontinuities of the self-energy function across the unitary and the
Landau cuts. The non-zero contribution from the latter to the spectral density
of $D$ and $D^*$ mesons opens a number of subthreshold decay channels of the
$J/\psi$ leading to a significant increase in the dissociation width in
hadronic matter.


title: Instrumentation for the Energy Frontier

abstract:
  The Instrumentation Frontier was set up as a part of the Snowmass 2013
Community Summer Study to examine the instrumentation R&D needed to support
particle physics research over the coming decade. This report summarizes the
findings of the Energy Frontier subgroup of the Instrumentation Frontier.


title:
Signature of a topological phase transition in the Josephson
  supercurrent through a topological insulator

abstract:
  Topological insulators (TIs) hold great promise for realizing zero-energy
Majorana states in solid-state systems. Recently, several groups reported
experimental data suggesting that signatures of Majorana modes in topological
insulator Josephson junctions (TIJJs) have -- indeed -- been observed. To
verify this claim, one needs to study the topological properties of low-energy
Andreev-bound states (ABS) in TIs of which the Majorana modes are a special
case. It has been shown theoretically that topologically non-trivial low-energy
ABS are also present in TIJJs with doped topological insulators up to some
critical level of doping at which the system undergoes a topological phase
transition. Here, we present first experimental evidence for this topological
transition in the bulk band of a doped TI. Our theoretical calculations, and
numerical modeling link abrupt changes in the critical current of top-gated
TIJJs to moving the chemical potential in the charge-accumulation region on the
surface of the doped TI across a band-inversion point. We demonstrate that the
critical-current changes originate from a shift of the spatial location of
low-energy ABS from the surface to the boundary between topologically-trivial
and band-inverted regions after the transition. The appearance of a decay
channel for surface ABS is related to the vanishing of the band effective mass
in the bulk and thus exemplifies the topological character of surface ABS as
boundary modes. Importantly, the mechanism suggest a means of manipulating
Majorana modes in future experiments.


title: Continuous and holomorphic functions with values in closed operators

abstract:
  We systematically derive general properties of continuous and holomorphic
functions with values in closed operators, allowing in particular for operators
with empty resolvent set. We provide criteria for a given operator-valued
function to be continuous or holomorphic. This includes sufficient conditions
for the sum and product of operator-valued holomorphic functions to be
holomorphic.
  Using graphs of operators, operator-valued functions are identified with
functions with values in subspaces of a Banach space. A special role is thus
played by projections onto closed subspaces of a Banach space, which depend
holomorphically on a parameter.


title: On time-reversibility of linear stochastic models

abstract:
  Reversal of the time direction in stochastic systems driven by white noise
has been central throughout the development of stochastic realization theory,
filtering and smoothing. Similar ideas were developed in connection with
certain problems in the theory of moments, where a duality induced by time
reversal was introduced to parametrize solutions. In this latter work it was
shown that stochastic systems driven by arbitrary second-order stationary
processes can be similarly time-reversed. By combining these two sets of ideas
we present herein a generalization of time-reversal in stochastic realization
theory.


title: Universal Lattice Basis

abstract:
  We report on the utility of using Shannons Sampling theorem to solve Quantum
Mechanical systems. We show that by extending the logic of Shannons
interpolation theorem we can define a Universal Lattice Basis, which has
superior interpolating properties compared to traditional methods. This basis
is orthonormal, semi-local, has a Euclidean norm, and a simple analytic
expression for the derivatives. Additionally, we can define a bounded domain
for which band-limited functions, such as Gaussians, show quadratic convergence
in the representation error in respect to the sampling frequency. This theory
also extends to the periodic domain and we illustrate the simple analytic forms
of the periodic semi-local basis and derivatives. Additionally, we show that
this periodic basis is equivalent to the space defined by the Fast Fourier
Transform. This novel basis has great utility in solving quantum mechanical
problems for which the wave functions are known to be naturally band-limited.
Several numerical examples in single and multi-dimensions are given to show the
convergence and equivalence of the periodic and bounded domains for compact
states.


title:
Quantum phase transitions and thermodynamics of the power-law Kondo
  model

abstract:
  We revisit the physics of a Kondo impurity coupled to a fermionic host with a
diverging power-law density of states near the Fermi level, $\rho(\omega) \sim
|\omega|^r$, with exponent $-1<r<0$. Using the analytical understanding of
several fixed points, based partially on powerful mappings between models with
bath exponents $r$ and $(-r)$, combined with accurate numerical renormalization
group calculations, we determine thermodynamic quantities within the stable
phases, and also near the various quantum phase transitions. Antiferromagnetic
Kondo coupling leads to strong screening with a negative zero-temperature
impurity entropy, while ferromagnetic Kondo coupling can induce a stable
fractional spin moment. We formulate the quantum field theories for all
critical fixed points of the problem, which are fermionic in nature and allow
for a perturbative renormalization-group treatment.


title:
Hyperentanglement purification and concentration assisted by diamond NV
  centers inside photonic crystal cavities

abstract:
  Hyperentanglement has attracted much attention for its fascinating
applications in quantum communication. However, it is impossible to purify a
pair of photon systems in a mixed hyperentangled state with errors in two
degrees of freedom using linear optical elements only, far different from all
the existing entanglement purification protocols in a degree of freedom (DOF)
for quantum systems. Here, we investigate the possibility of purifying a
spatial-polarization mixed hyperentangled Bell state with the errors in both
the spatial mode and polarization DOFs, resorting to the nonlinear optics of a
nitrogen-vacancy (NV) center in a diamond embedded in a photonic crystal cavity
coupled to a waveguide. We present the first hyperentanglement purification
protocol for purifying a pair of two-photon systems in a mixed hyperentangled
Bell state with the errors in two DOFs. Besides, we propose an efficient
hyperentanglement concentration protocol for a partially hyperentangled Bell
pure state, which has the maximal success probability in principle. These two
protocols are useful in long-distance quantum communication with
hyperentanglement


title: Hyper-parallel photonic quantum computation with coupled quantum dots

abstract:
  It is well known that a parallel quantum computer is more powerful than a
classical one. So far, there are some important works about the construction of
universal quantum logic gates, the key elements in quantum computation.
However, they are focused on operating on one degree of freedom (DOF) of
quantum systems. Here, we investigate the possibility of achieving scalable
hyper-parallel quantum computation based on two DOFs of photon systems. We
construct a deterministic hyper-controlled-not (hyper-CNOT) gate operating on
both the spatial-mode and the polarization DOFs of a two-photon system
simultaneously, by exploiting the giant optical circular birefringence induced
by quantum-dot spins in double-sided optical microcavities as a result of
cavity quantum electrodynamics (QED). This hyper-CNOT gate is implemented by
manipulating the four qubits in the two DOFs of a two-photon system without
auxiliary spatial modes or polarization modes. It reduces the operation time
and the resources consumed in quantum information processing, and it is more
robust against the photonic dissipation noise, compared with the integration of
several cascaded CNOT gates in one DOF.


title: Set Representations of Linegraphs

abstract:
  Let $G$ be a graph with vertex set $V(G)$ and edge set $E(G)$. A family
$\mathcal{S}$ of nonempty sets $\{S_1,\ldots,S_n\}$ is a set representation of
$G$ if there exists a one-to-one correspondence between the vertices $v_1,
\ldots, v_n$ in $V(G)$ and the sets in $\mathcal{S}$ such that $v_iv_j \in
E(G)$ if and only if $S_i\cap S_j\neq \es$. A set representation $\mathcal{S}$
is a distinct (respectively, antichain, uniform and simple) set representation
if any two sets $S_i$ and $S_j$ in $\mathcal{S}$ have the property $S_i\neq
S_j$ (respectively, $S_i\nsubseteq S_j$, $|S_i|=|S_j|$ and $|S_i\cap
S_j|\leqslant 1$). Let $U(\mathcal{S})=\bigcup_{i=1}^n S_i$. Two set
representations $\mathcal{S}$ and $\mathcal{S}'$ are isomorphic if
$\mathcal{S}'$ can be obtained from $\mathcal{S}$ by a bijection from
$U(\mathcal{S})$ to $U(\mathcal{S}')$. Let $F$ denote a class of set
representations of a graph $G$. The type of $F$ is the number of equivalence
classes under the isomorphism relation. In this paper, we investigate types of
set representations for linegraphs. We determine the types for the following
categories of set representations: simple-distinct, simple-antichain,
simple-uniform and simple-distinct-uniform.


title:
Maximal Subalgebras for Modular Graded Lie Superalgebras of Odd Cartan
  Type

abstract:
  The purpose of this paper is to determine all maximal graded subalgebras of
the four infinite series of finite-dimensional graded Lie superalgebras of odd
Cartan type over an algebraically closed field of characteristic $p>3$. All
maximal graded subalgebras consist of three types (\MyRoman{1}), (\MyRoman{2})
and (\MyRoman{3}). Maximal graded subalgebras of type (\MyRoman{3}) fall into
reducible maximal graded subalgebras and irreducible maximal graded
subalgebras. In this paper we classify maximal graded subalgebras of types
(\MyRoman{1}), (\MyRoman{2}) and reducible maximal g raded subalgebras.The
classification of irreducible maximal graded subalgebras is reduced to that of
the irreducible maximal subalgebras of the classical Lie superalgebra
$\mathfrak{p}(n)$.


title:
Precisely aligned graphene grown on hexagonal boron nitride by catalyst
  free chemical vapor deposition

abstract:
  To grow precisely aligned graphene on h-BN without metal catalyst is
extremely important, which allows for intriguing physical properties and
devices of graphene/h-BN hetero-structure to be studied in a controllable
manner. In this report, such hetero-structures were fabricated and investigated
by atomic resolution scanning probe microscopy. Moirre patterns are observed
and the sensitivity of moirre interferometry proves that the graphene grains
can align precisely with the underlying h-BN lattice within an error of less
than 0.05 degree. The occurrence of moirre pattern clearly indicates that the
graphene locks into h-BN via van der Waals epitaxy with its interfacial stress
greatly released. It is worthy to note that the edges of the graphene grains
are primarily oriented along the armchair direction. The field effect mobility
in such graphene flakes exceeds 20,000 cm2/V.s at ambient condition. This work
opens the door of atomic engineering of graphene on h-BN, and sheds light on
fundamental research as well as electronic applications based on graphene/h-BN
hetero-structure.


title: On the average character degree of finite groups

abstract:
  We prove that if the average of the degrees of the irreducible characters of
a finite group $G$ is less than 16/5, then $G$ is solvable. This solves a
conjecture of I.M. Isaacs, M. Loukaki, and the first author. We discuss related
questions.


title: Further results on the nullity of signed graphs

abstract:
  The nullity of a graph is the multiplicity of the eigenvalues zero in its
spectrum. A signed graph is a graph with a sign attached to each of its edges.
In this paper, we obtain the coefficient theorem of the characteristic
polynomial of a signed graph, give two formulae on the nullity of signed graphs
with cut-points. As applications of the above results, we investigate the
nullity of the bicyclic signed graph $\Gamma(\infty(p,q,l))$, obtain the
nullity set of unbalanced bicyclic signed graphs, and thus determine the
nullity set of bicyclic signed graphs.


title: On rotating star solutions to non-isentropic Euler-Poisson equations

abstract:
  This paper investigates rotating star solutions to the Euler-Poisson
equations with a non-isentropic equation of state. As a first step, the
equation for gas density with a prescribed entropy and angular velocity
distribution is studied. The resulting elliptic equation is solved either by
the method of sub and supersolutions or by a variational method, depending on
the value of the adiabatic index. The reverse problem of determining angular
velocity from gas density is also considered.


title: Triplets of Closely Embedded Hilbert Spaces

abstract:
  We obtain a general concept of triplet of Hilbert spaces with closed
(unbounded) embeddings instead of continuous (bounded) ones. The construction
starts with a positive selfadjoint operator $H$, that is called the Hamiltonian
of the system, which is supposed to be one-to-one but may not have a bounded
inverse, and for which a model is obtained. From this model we get the abstract
concept and show that its basic properties are the same with those of the
model. Existence and uniqueness results, as well as left-right symmetry, for
these triplets of closely embedded Hilbert spaces are obtained. We motivate
this abstract theory by a diversity of problems coming from homogeneous or
weighted Sobolev spaces, Hilbert spaces of holomorphic functions, and weighted
$L^2$ spaces. An application to weak solutions for a Dirichlet problem
associated to a class of degenerate elliptic partial differential equations is
presented. In this way, we propose a general method of proving the existence of
weak solutions that avoids coercivity conditions and Poincar\'e-Sobolev type
inequalities.


title: Dynamic and Thermodynamic Stability of Relativistic, Perfect Fluid Stars

abstract:
  We consider perfect fluid bodies (stars) in general relativity, characterized
by particle number density and entropy per particle. A star is said to be in
dynamic equilibrium if it is a stationary, axisymmetric solution to the
Einstein-fluid equations with circular flow. We prove that for a star in
dynamic equilibrium, the necessary and sufficient condition for thermodynamic
equilibrium (extremum of total entropy S) is constancy of angular velocity
(\Omega), redshifted temperature, and redshifted chemical potential. Friedman
previously identified positivity of canonical energy, E, as a criterion for
dynamic stability and argued that all rotating stars are dynamically unstable
to sufficiently nonaxisymmetric perturbations (the CFS instability), so our
main focus is on axisymmetric stability. We show that for a star in dynamic
equilibrium, mode stability holds with respect to all axisymmetric
perturbations if E is positive on a certain subspace, V, of axisymmetric
Lagrangian perturbations that, in particular, have no Lagrangian change in
angular momentum density. Conversely, if E fails to be positive on V, then
there exist perturbations that can't become asymptotically stationary at late
times. We further show that for a star in thermodynamic equilibrium, the
canonical energy in the rotating frame, E_r, is related to second order changes
in ADM mass, M, and angular momentum, J, by E_r = \delta^2 M - \Omega \delta^2
J. Thus, positivity of E_r for perturbations with \delta J = 0 is a necessary
condition for thermodynamic stability (local maximum of S). For axisymmetric
perturbations we have E = E_r, so a necessary condition for thermodynamic
stability with respect to axisymmetric perturbations is positivity of E on all
perturbations with \delta J = 0, not merely on the perturbations in V. Many of
our results are in close parallel to results of Hollands and Wald for the
theory of black holes.


title:
Symmetric reflection line resonator for semiconductor circuit quantum
  electrodynamics

abstract:
  We have designed and fabricated a half-wavelength reflection line resonator
(RLR) that consists of a pair of two coupled microstrip lines on a GaAs/AlGaAs
heterostructure. By changing the top gate voltage on a square of two
dimensional electron gas under the resonator, a large range of the quality
factors can be obtained. Energy loss in the two-dimensional electron gas can be
minimized, thus realizing a versatile resonator suitable for integration with
semiconductor quantum circuits.


title: Homogeneous Transformation Groups of the Sphere

abstract:
  In this paper, we study the structure of homogeneous subgroups of the
homeomorphism group of the sphere, which are defined as closed groups of
homeomorphisms of the sphere that contain the rotation group. We prove two
structure theorems about the behaviour and properties of such groups and
present a diagram of the structure of these groups partly on the basis of these
results. In addition, we prove a number of explicit relations between the
groups in the diagram.


title: Removable singularities of the CscK metric

abstract:
  In this paper, we consider a CscK metric defined away from divisor and with
metric upper bound and lower bound going to zero in certain rate. And we'll
prove that this "nicely" behaved metric is a smooth CscK metric across the
divisor.


title: Degenerate Bose Gas: A New Tool for Accurate Frequency Measurement

abstract:
  We propose a new way of detecting frequencies using superradiant Rayleigh
scattering from degenerate Bose gases. A measurement of the time evolution of
population at the initial momentum state could determine an unknown frequency
with respect to a known one at which the pump laser's frequency modulates. A
range of frequencies from kHz to MHz could be determined with a fractional
uncertainty of 10^{-6}.


title: The orientation dependence of quasar spectral energy distributions

abstract:
  We investigate the orientation dependence of the spectral energy
distributions in a sample of radio-loud quasars. Selected specifically to study
orientation issues, the sample contains 52 sources with redshifts in the range
0.16<z<1.4 and measurements of radio core dominance, a radio orientation
indicator. Measured properties include monochromatic luminosities at a range of
wavelengths between the infrared and X-rays, integrated infrared luminosity,
spectral slopes, and the covering fraction of the obscuring circumnuclear dust.
We estimate dust covering fraction assuming that the accretion disk emits
anisotropically and discuss the shortcomings and technical difficulties of this
calculation. Luminosities are found to depend on orientation, with face-on
sources factors of a 2-3 brighter than more edge-on sources, depending on
wavelength. The degree of anisotropy varies very little with wavelength such
that the overall shape of the spectral energy distribution does not vary
significantly with orientation. In the infrared, we do not observe a decrease
in anisotropy with increasing wavelength. The spectral slopes and estimates of
covering fraction are not significantly orientation dependent. We construct
composite spectral energy distributions as a function of radio core dominance
and find that these illustrate the results determined from the measured
properties.


title:
Hamiltonian systems with an infinite number of localized travelling
  waves

abstract:
  In many Hamiltonian systems, propagation of steadily travelling solitons or
kinks is prohibited because of resonances with linear excitations. We show that
Hamiltonian systems with resonances may admit an infinite number of travelling
solitons or kinks if the closest to the real axis singularities in the complex
upper half-plane of limiting asymptotic solution are of the form
$z_\pm=\pm\alpha+i\beta$, $\alpha\ne 0$. This quite a general statement is
illustrated by examples of the fifth-order Korteweg--de Vries-type equation,
the discrete cubic-quintic Klein--Gordon equation, and the nonlocal double
sine--Gordon equations.


title: Hyper-Kamiokande Physics Opportunities

abstract:
  We propose the Hyper-Kamiokande (Hyper-K) detector as a next generation un-
derground water Cherenkov detector. It will serve as a far detector of a long
base- line neutrino oscillation experiment envisioned for the upgraded J-PARC
beam, and as a detector capable of observing, far beyond the sensitivity of the
Super-Kamiokande (Super-K) detector, proton decays, atmospheric neutrinos, and
neutrinos from astro- physical origins. The current baseline design of Hyper-K
is based on the highly suc- cessful Super-K detector, taking full advantage of
a well-proven technology. Hyper-K consists of two cylindrical tanks lying
side-by-side, the outer dimensions of each tank being 48(W) x54(H) x 250(L) m3.
The total (fiducial) mass of the detector is 0.99 (0.56) million metric tons,
which is about 20 (25) times larger than that of Super-K.
  This set of three one- page whitepapers prepared for the US Snowmass process
describes the opportunities for future physics discoveries at the Hyper-K
facility with beam, atmospheric and astrophysical neutrinos.


title: Haptic Science and Technology

abstract:
  Haptic technology, or haptics, is a tactile feedback technology which takes
advantage of a user's sense of touch by applying forces, vibrations, and/or
motions upon the user. This mechanical stimulation may be used to assist in the
creation of virtual objects (objects existing only in a computer simulation),
for control of such virtual objects, and for the enhancement of the remote
control of machines and devices. It has been described as for the sense of
touch what computer graphics does for vision. Although haptic devices are
capable of measuring bulk or reactive forces that are applied by the user, it
should not be confused with touch or tactile sensors that measure the pressure
or force exerted by the user to the interface.


title:
A Solution to the Network Challenges of Data Recovery in Erasure-coded
  Distributed Storage Systems: A Study on the Facebook Warehouse Cluster

abstract:
  Erasure codes, such as Reed-Solomon (RS) codes, are being increasingly
employed in data centers to combat the cost of reliably storing large amounts
of data. Although these codes provide optimal storage efficiency, they require
significantly high network and disk usage during recovery of missing data. In
this paper, we first present a study on the impact of recovery operations of
erasure-coded data on the data-center network, based on measurements from
Facebook's warehouse cluster in production. To the best of our knowledge, this
is the first study of its kind available in the literature. Our study reveals
that recovery of RS-coded data results in a significant increase in network
traffic, more than a hundred terabytes per day, in a cluster storing multiple
petabytes of RS-coded data.
  To address this issue, we present a new storage code using our recently
proposed "Piggybacking" framework, that reduces the network and disk usage
during recovery by 30% in theory, while also being storage optimal and
supporting arbitrary design parameters. The implementation of the proposed code
in the Hadoop Distributed File System (HDFS) is underway. We use the
measurements from the warehouse cluster to show that the proposed code would
lead to a reduction of close to fifty terabytes of cross-rack traffic per day.


title: Compact Lambert Type Operators Between Two l^p Spaces

abstract:
  In this paper we investigate compactness of weighted Lambert type operators
between two Lp spaces


title:
People Are the Answer to Security: Establishing a Sustainable
  Information Security Awareness Training (ISAT) Program in Organization

abstract:
  Educating the users on the essential of information security is very vital
and important to the mission of establishing a sustainable information security
in any organization and institute. At the University Technology Malaysia (UTM),
we have recognized the fact that, it is about time information security should
no longer be a lacking factor in productivity, both information security and
productivity must work together in closed proximity. We have recently
implemented a broad campus information security awareness program to educate
faculty member, staff, students and non-academic staff on this essential topic
of information security. The program consists of training based on web,
personal or individual training with a specific monthly topic, campus
campaigns, guest speakers and direct presentations to specialized groups. The
goal and the objective are to educate the users on the challenges that are
specific to information security and to create total awareness that will change
the perceptions of people thinking and ultimately their reactions when it comes
to information security. In this paper, we explain how we created and
implemented our information security awareness training (ISAT) program and
discuss the impediment we encountered along the process. We explore different
methods of deliveries such as target audiences, and probably the contents as we
believe might be vital to a successful information security program. Finally,
we discuss the importance and the flexibility of establishing a sustainable
information security training program that could be adopted to meet current and
future needs and demands while still relevant to our current users.


title:
Enhancing the Conventional Information Security Management Maturity
  Model (ISM3) in Resolving Human Factors in Organization Information Sharing

abstract:
  Information sharing in organization has been considered as an important
approach in increasing organizational efficiency, performance and decision
making. With the present and advances in information and communication
technology, sharing information and exchanging of data across organizations has
become more feasible in organization. However, information sharing has been a
complex task over the years and identifying factors that influence information
sharing across organization has becomes crucial and critical. Researchers have
taken several methods and approaches to resolve problems in information sharing
at all levels without a lasting solution, as sharing is best understood as a
practice that reflects behavior, social, economic, legal and technological
influences. Due to the limitation of the conventional ISM3 standards to address
culture, social, legislation and human behavior, the findings in this paper
suggest that, a centralized information structure without human practice,
distribution of information and coordination is not effective. This paper
reviews the previous information sharing research, outlines the factors
affecting information sharing and the different practices needed to improve the
management of information security by recommending several combinations of
information security and coordination mechanism for reducing uncertainty during
sharing of information .This thesis proposes information security management
protocol (ISMP) as an enhancement towards ISM3 to resolve the above problems.
This protocol provides a means for practitioners to identify key factors
involved in successful information sharing.....


title: Distributed-element circuit model of edge magnetoplasmon transport

abstract:
  We report experimental and theoretical studies of edge magnetoplasmon (EMP)
transport in quantum Hall (QH) devices. We develop a model that allows us to
calculate the transport coefficients of EMPs in QH devices with various
geometries. In our model, a QH system is described as a chiral
distributed-element (CDE) circuit, where the effects of Coulomb interaction are
represented by an electrochemical capacitance distributed along unidirectional
transmission lines. We measure the EMP transport coefficients through single-
and coupled-edge channels, a quantum point contact, and single- and
double-cavity structures. These measured transmission spectra can be reproduced
well by simulations using the corresponding CDE circuits. By fitting the
experimental results with the simulations, we deduce the circuit parameters
that characterize the electrostatic environment around the edge channels in a
realistic QH system. The observed gate-voltage dependences of the EMP transport
properties in gate-defined structures are explained in terms of the gate tuning
of the circuit parameters in CDE circuits.


title: Th\'eories homotopiques des 2-cat\'egories

abstract:
  This text develops a homotopy theory of 2-categories analogous to
Grothendieck's homotopy theory of categories developed in "Pursuing Stacks". We
define the notion of "basic localizer of 2-Cat", 2-categorical generalization
of Grothendieck's notion of basic localizer, and we show that the homotopy
theories of $Cat$ and 2-$Cat$ are equivalent in a remarkably strong sense:
there is an isomorphism, compatible with localization, between the ordered
classes of basic localizers of $Cat$ and 2-$Cat$. It follows that weak homotopy
equivalences in 2-$Cat$ can be characterised in an internal way, without
mentioning topological spaces or simplicial sets.


title: Reconstruction and uniqueness of moving obstacles

abstract:
  We study the uniqueness and accuracy of the numerical solution of the problem
of reconstruction of the shape and trajectory of a reflecting obstacle moving
in an inhomogeneous medium from travel times, start and end points, and initial
angles of ultrasonic rays reflecting at the obstacle. The speed of sound in the
domain when there is no obstacle present is known and provided as an input
parameter which together with the other initial data enables the algorithm to
trace ray paths and find their reflection points. The reflection points
determine with high-resolution the shape and trajectory of the obstacle. The
method has predictable computational complexity and performance and is very
efficient when it is parallelized and optimized because only a small portion of
the domain is reconstructed.


title:
Design of Minimum Correlated, Maximal Clique Sets of One-Dimensional
  Uni-polar (Optical) Orthogonal Codes

abstract:
  This paper proposes an algorithm to search a family of multiple sets of
minimum correlated one dimensional uni-polar (optical) orthogonal codes
(1-DUOC) or optical orthogonal codes (OOC) with fixed as well as variable code
parameters. The cardinality of each set is equal to upper bound. The codes
within a set can be searched for general values of code length, code weight,
auto-correlation constraint and cross-correlation constraint. Each set forms a
maximal clique of the codes within given range of correlation properties .
These one-dimensional uni-polar orthogonal codes can find their application as
signature sequences for spectral spreading purpose in incoherent optical code
division multiple access (CDMA) systems.


title:
Quasistationarity in a long-range interacting model of particles moving
  on a sphere

abstract:
  We consider a long-range interacting system of $N$ particles moving on a
spherical surface under an attractive Heisenberg-like interaction of infinite
range, and evolving under deterministic Hamilton dynamics. The system may also
be viewed as one of globally coupled Heisenberg spins. In equilibrium, the
system has a continuous phase transition from a low-energy magnetized phase, in
which the particles are clustered on the spherical surface, to a high-energy
homogeneous phase. The dynamical behavior of the model is studied analytically
by analyzing the Vlasov equation for the evolution of the single-particle
distribution, and numerically by direct simulations. The model is found to
exhibit long lived non-magnetized quasistationary states (QSSs) which in the
thermodynamic limit are dynamically stable within an energy range where the
equilibrium state is magnetized. For finite $N$, these states relax to
equilibrium over a time that increases algebraically with $N$. In the
dynamically unstable regime, non-magnetized states relax fast to equilibrium
over a time that scales as $\log N$. These features are retained in presence of
a global anisotropy in the magnetization.


title: Online Regenerator Placement

abstract:
  Connections between nodes in optical networks are realized by lightpaths. Due
to the decay of the signal, a regenerator has to be placed on every lightpath
after at most $d$ hops, for some given positive integer $d$. A regenerator can
serve only one lightpath. The placement of regenerators has become an active
area of research during recent years, and various optimization problems have
been studied. The first such problem is the Regeneration Location Problem
($\prb$), where the goal is to place the regenerators so as to minimize the
total number of nodes containing them. We consider two extreme cases of online
$\prb$ regarding the value of $d$ and the number $k$ of regenerators that can
be used in any single node. (1) $d$ is arbitrary and $k$ unbounded. In this
case a feasible solution always exists. We show an $O(\log \abs{X} \cdot \log
d)$-competitive randomized algorithm for any network topology, where $X$ is the
set of paths of length $d$. The algorithm can be made deterministic in some
cases. We show a deterministic lower bound of $\Omega \lb$, where $E$ is the
edge set. (2) $d=2$ and $k=1$. In this case there is not necessarily a solution
for a given input. We distinguish between feasible inputs (for which there is a
solution) and infeasible ones. In the latter case, the objective is to satisfy
the maximum number of lightpaths. For a path topology we show a lower bound of
$\sqrt{l}/2$ for the competitive ratio (where $l$ is the number of internal
nodes of the longest lightpath) on infeasible inputs, and a tight bound of 3
for the competitive ratio on feasible inputs.


title:
Many countable support iterations of proper forcings preserve Souslin
  trees

abstract:
  We show that many countable support iterations of proper forcings preserve
Souslin trees. We establish sufficient conditions in terms of games and we draw
connections to other preservation properties. We present a proof of
preservation properties in countable support interations in the so-called Case
A that does not need a division into forcings that add reals and those who do
not.


title: Counting gamma rays in the directions of galaxy clusters

abstract:
  Emission of AGNs and neutral pion decay - are the two most natural
mechanisms, that could make a galaxy cluster be a source of gamma-rays in the
GeV regime. We revisited this problem by using 52.5-month FERMI-LAT data above
10 GeV and stacking 55 clusters from the HIFLUGS sample of the X-ray brightest
clusters. The choice of >10 GeV photons is optimal from the point of view of
angular resolution, while the sample selection optimizes the chances of
detecting signatures of the neutral pion decay, arising from hadronic
interactions of relativistic protons with an intra-cluster medium, which scale
with the X-ray flux. In the stacked data we detected a signal for the central
0.25 deg circle at the level of 4.3 sigma. An evidence for a spatial extent of
the signal is marginal. A subsample of cool-core clusters has higher count rate
1.9+/-0.3 per cluster compared to the subsample of non-cool core clusters
1.3+/-0.2. Several independent arguments suggest that the contribution of AGNs
to the observed signal is substantial if not dominant. No strong support for
the large contribution of pion decay was found. In terms of a limit on the
relativistic protons energy density, we got an upper limit of ~1.5% relative to
the gas thermal energy density, provided that the spectrum of relativistic
protons is hard (s=4.1 in dN/dp=p^-s). This estimate assumes that relativistic
and thermal components are mixed. For softer spectra the limits are weaker.


title:
Reducing intrinsic decoherence in a superconducting circuit by quantum
  error detection

abstract:
  A fundamental challenge for quantum information processing is reducing the
impact of environmentally-induced errors. Quantum error detection (QED)
provides one approach to handling such errors, in which errors are rejected
when they are detected. Here we demonstrate a QED protocol based on the idea of
quantum un-collapsing, using this protocol to suppress energy relaxation due to
the environment in a three-qubit superconducting circuit. We encode quantum
information in a target qubit, and use the other two qubits to detect and
reject errors caused by energy relaxation. This protocol improves the storage
time of a quantum state by a factor of roughly three, at the cost of a reduced
probability of success. This constitutes the first experimental demonstration
of an algorithm-based improvement in the lifetime of a quantum state stored in
a qubit.


title: New constructions of quaternary bent functions

abstract:
  In this paper, a new construction of quaternary bent functions from
quaternary quadratic forms over Galois rings of characteristic 4 is proposed.
Based on this construction, several new classes of quaternary bent functions
are obtained, and as a consequence, several new classes of quadratic binary
bent and semi-bent functions in polynomial forms are derived. This work
generalizes the recent work of N. Li, X. Tang and T. Helleseth.


title: Numerical studies of dynamo action in a turbulent shear flow - I

abstract:
  We perform numerical experiments to study the shear dynamo problem where we
look for the growth of large--scale magnetic field due to non--helical stirring
at small scales in a background linear shear flow, in previously unexplored
parameter regimes. We demonstrate the large--scale dynamo action in the limit
when the fluid Reynolds number (${\rm Re}$) is below unity whereas the magnetic
Reynolds number (${\rm Rm}$) is above unity; the exponential growth rate scales
linearly with shear, which is consistent with earlier numerical works. The
limit of low ${\rm Re}$ is particularly interesting, as seeing the dynamo
action in this limit would provide enough motivation for further theoretical
investigations, which may focus the attention to this analytically more
tractable limit of ${\rm Re} < 1$ as compared to more formidable limit of ${\rm
Re} > 1$. We also perform simulations in the regimes when, (i) both (${\rm
Re}$, ${\rm Rm}$) $< 1$; (ii) ${\rm Re} > 1$ & ${\rm Rm} < 1$, and compute all
components of the turbulent transport coefficients ($\alpha_{ij}$ and
$\eta_{ij}$) using the test--field method. A reasonably good agreement is seen
between our results and the results of earlier analytical works (Sridhar &
Singh 2010; Singh & Sridhar 2011) in the similar parameter regimes.


title: Split functions, Fourier transforms and multipliers

abstract:
  We study the effect of a splitting operator S_t on the L^p norm of the
Fourier transform of a function f and on the operator norm of a Fourier
multiplier m. Most of our results assume p is an even integer, and are often
stronger when f or m has compact support.


title: More effects of Dirac low-mode removal

abstract:
  In previous studies we have shown that hadrons, except for a pion, survive
the removal of the lowest lying Dirac eigenmodes from the valence quark
propagators. The low-modes are tied to the dynamical breaking of chiral
symmetry and we found chiral symmetry to be restored by means of matching
masses of chiral partners, like, e.g., the vector and axial vector currents.
Here we investigate the influence of removing the lowest part of the Dirac
spectrum on the locality of the Dirac operator. Moreover, we analyze the
influence of low-mode truncation on the quark momenta and thereupon on the
hadron spectrum and, finally, introduce a reweighting scheme to extend the
truncation to the sea quark sector.


title:
Generation and Manipulation of Localized Modes in Floquet Topological
  Insulators

abstract:
  We investigate Floquet Topological Insulators in the presence of
spatially-modulated light. We extend on previous work to show that light can be
used to generate and control localized modes in the bulk of these systems. We
provide examples of bulk modes generated through modulation of different
properties of the light, such as its phase, polarization and frequency. We show
that these effects may be realized in a variety of systems, including a
zincblende model and graphene, and also provide a generalization of these
results to three dimensional systems.


title:
Nonlinear degradation enhanced transport of morphogens performing
  subdiffusion

abstract:
  We study a morphogen gradient formation under nonlinear degradation and
subdiffusive transport. In the long time limit we obtain the nonlinear effect
of degradation enhanced diffusion, resulting from the interaction of
non-Markovian subdiffusive transport with a nonlinear reaction. We find the
stationary profile of power-law type, which has implications for robustness,
with the shape of the profile being controlled by the anomalous exponent. Far
away from the source of morphogens, any changes in rate of production are not
felt.


title:
Introduction to Graphene Electronics -- A New Era of Digital Transistors
  and Devices

abstract:
  The speed of silicon-based transistors has reached an impasse in the recent
decade, primarily due to scaling techniques and the short-channel effect.
Conversely, graphene (a revolutionary new material possessing an atomic
thickness) has been shown to exhibit a promising value for electrical
conductivity. Graphene would thus appear to alleviate some of the drawbacks
associated with silicon-based transistors. It is for this reason why such a
material is considered one of the most prominent candidates to replace silicon
within nano-scale transistors. The major crux here, is that graphene is
intrinsically gapless, and yet, transistors require a band-gap pertaining to a
well-defined ON/OFF logical state. Therefore, exactly as to how one would
create this band-gap in graphene allotropes is an intensive area of growing
research. Existing methods include nano-ribbons, bilayer and multi-layer
structures, carbon nanotubes, as well as the usage of the graphene substrates.
Graphene transistors can generally be classified according to two working
principles. The first is that a single graphene layer, nanoribbon or carbon
nanotube can act as a transistor channel, with current being transported along
the horizontal axis. The second mechanism is regarded as tunneling, whether
this be band-to-band on a single graphene layer, or vertically between adjacent
graphene layers. The high-frequency graphene amplifier is another talking point
in recent research, since it does not require a clear ON/OFF state, as with
logical electronics. This paper reviews both the physical properties and
manufacturing methodologies of graphene, as well as graphene-based electronic
devices, transistors, and high-frequency amplifiers from past to present
studies. Finally, we provide possible perspectives with regards to future
developments.


title: Path-integral approach to the Wigner-Kirkwood expansion

abstract:
  We study the high-temperature behavior of quantum-mechanical path integrals.
Starting from the Feynman-Kac formula, we derive a new functional
representation of the Wigner-Kirkwood perturbation expansion for quantum
Boltzmann densities. As shown by its applications to different potentials, the
presented expansion turns out to be quite efficient in generating analytic form
of the higher-order expansion coefficients. To put some flesh on the bare bones
we apply the expansion to obtain basic thermodynamic functions of the
one-dimensional anharmonic oscillator. Further salient issues, such as
generalization to the Bloch density matrix and comparison with the more
customary world-line formulation are discussed.

categories: cond-mat.stat-mech math-ph math.MP quant-ph


title:
Ionization State of Inter-Stellar Medium in Galaxies: Evolution,
  SFR-M_star-Z Dependence, and Ionizing Photon Escape

abstract:
  We present a systematic study for ionization state of inter-stellar medium in
galaxies at z=0-3 with ~140,000 SDSS galaxies and 108 intermediate to high
redshift galaxies from the literature, using an ionization-parameter sensitive
line ratio of [OIII]5007/[OII]3727 and photoionization models. We confirm that
z=2-3 galaxies show an [OIII]/[OII] ratio significantly higher than a typical
star-forming galaxy of SDSS by a factor of >~10, and the photoionization models
reveal that these high-z galaxies have an ionization parameter of log(qion/cm
s^{-1})~7.6-9.0, a factor of ~4-10 higher than local galaxies. For galaxies at
any redshift, we identify a correlation between the [OIII]/[OII] ratio and
galaxy global properties of star-formation rate (SFR), stellar mass (M_star),
and metallicity (Z). We extend the fundamental metallicity relation (FMR) and
develop the fundamental ionization relation (FIR), a four-dimensional relation
of ionization parameter, SFR, M_star, and Z. The intermediate and high-z
galaxies up to z~3 follow the FIR defined with the local galaxies, in contrast
with the FMR whose possible evolution from z~2 to 3 is reported. We find that
the FMR evolution of z~2-3 appears, if one omits ionization parameter
differences, and that the FMR evolution does not exist for an average
metallicity solution of z~3 galaxies with a high-ionization parameter.
Interestingly, all of two local Lyman-continuum emitting galaxies (LyC leakers)
have a high [OIII]/[OII] ratio, indicating a positive correlation between
[OIII]/[OII] and ionizing photon escape fraction (fesc), which is successfully
explained by our photoionization models. Because [OIII]/[OII] ratios of z~2-3
galaxies, especially Ly-alpha emitters (LAEs), are comparable to, or higher
than, those of the local LyC leakers, these high-z galaxies are candidates of
Lyman-continuum emitting objects. (abridged)


title:
Simulation of pumping mechanism of H2O-masers in circumstellar envelopes
  of late-type stars

abstract:
  The radiative transfer problem is considered in dense gas-dust clouds.
Physical parameters are adopted in simulations corresponding to gas-dust clouds
in the circumstellar envelopes of late-type stars. An one-dimensional
plane-parallel slab geometry of the cloud is considered. The radiative transfer
problem is solved using the accelerated lambda iteration technique. The
rotational levels of the five lowest vibrational levels of H2O-molecule are
considered in the simulations. The level populations of H2O-molecule are
computed as a function of distance in the cloud. The conditions of the level
population inversion occurrence are investigated. In particular, the factors
controlling the population inversion in the 22.2 GHz maser line are considered.
A radiative excitation of the molecules by external radiation field of a star
is considered together with the collisional pumping of the maser.


title:
Optimal stochastic control and optimal consumption and portfolio with
  G-Brownian motion

abstract:
  By the calculus of Peng's G-sublinear expectation and G-Brownian motion on a
sublinear expectation space $(\Omega, {\cal H}, \hat{\mathbb{E}})$, we first
set up an optimality principle of stochastic control problem. Then we
investigate an optimal consumption and portfolio decision with a volatility
ambiguity by the derived verification theorem. Next the two-fund separation
theorem is explicitly obtained. And an illustrative example is provided.


title: Equivalence of string and fusion loop-spin structures

abstract:
  The importance of the fusion relation of loops was recognized in the context
of spin structures on the loop space by Stolz and Teichner and further
developed by Waldorf. On a spin manifold M the equivalence classes of `fusive'
spin structures on the loop space LM, incorporating the fusion property, strong
regularity and reparameterization-invariance, are shown to be in 1-1
correspondence with equivalence classes of string structures on M. The
identification is through the affine space of `string' cohomology classes
considered by Redden.


title: A Note on Holographic Weyl Anomaly and Entanglement Entropy

abstract:
  We develop a general approach to simplify the derivation of the holographic
Weyl anomaly. As an application, we derive the holographic Weyl anomaly from
general higher derivative gravity in asymptotically $AdS_{5}$ and $AdS_{7}$.
Interestingly, to derive all the central charges of 4d and 6d CFTs, we make no
use of equations of motion. Following Myers' idea, we propose a formula of
holographic entanglement entropy for higher derivative gravity in
asymptotically $AdS_5$. Applying this formula, we obtain the correct universal
term of entanglement entropy for 4d CFTs. It turns out that our formula is the
leading term of Dong's proposal in asymptotically $AdS_5$. Since only the
leading term contributes to the universal log term, we actually prove that
Dong's proposal yields the correct universal term of entanglement entropy for
4d CFTs. This is a nontrivial test of Dong's proposal.


title: An Error-Resilient Redundant Subspace Correction Method

abstract:
  As we stride toward the exascale era, due to increasing complexity of
supercomputers, hard and soft errors are causing more and more problems in
high-performance scientific and engineering computation. In order to improve
reliability (increase the mean time to failure) of computing systems, a lot of
efforts have been devoted to developing techniques to forecast, prevent, and
recover from errors at different levels, including architecture, application,
and algorithm. In this paper, we focus on algorithmic error resilient iterative
linear solvers and introduce a redundant subspace correction method. Using a
general framework of redundant subspace corrections, we construct iterative
methods, which have the following properties: (1) Maintain convergence when
error occurs assuming it is detectable; (2) Introduce low computational
overhead when no error occurs; (3) Require only small amount of local
(point-to-point) communication compared to traditional methods and maintain
good load balance; (4) Improve the mean time to failure. With the proposed
method, we can improve reliability of many scientific and engineering
applications. Preliminary numerical experiments demonstrate the efficiency and
effectiveness of the new subspace correction method.


title: Learning to Rank for Blind Image Quality Assessment

abstract:
  Blind image quality assessment (BIQA) aims to predict perceptual image
quality scores without access to reference images. State-of-the-art BIQA
methods typically require subjects to score a large number of images to train a
robust model. However, subjective quality scores are imprecise, biased, and
inconsistent, and it is challenging to obtain a large scale database, or to
extend existing databases, because of the inconvenience of collecting images,
training the subjects, conducting subjective experiments, and realigning human
quality evaluations. To combat these limitations, this paper explores and
exploits preference image pairs (PIPs) such as "the quality of image $I_a$ is
better than that of image $I_b$" for training a robust BIQA model. The
preference label, representing the relative quality of two images, is generally
precise and consistent, and is not sensitive to image content, distortion type,
or subject identity; such PIPs can be generated at very low cost. The proposed
BIQA method is one of learning to rank. We first formulate the problem of
learning the mapping from the image features to the preference label as one of
classification. In particular, we investigate the utilization of a multiple
kernel learning algorithm based on group lasso (MKLGL) to provide a solution. A
simple but effective strategy to estimate perceptual image quality scores is
then presented. Experiments show that the proposed BIQA method is highly
effective and achieves comparable performance to state-of-the-art BIQA
algorithms. Moreover, the proposed method can be easily extended to new
distortion categories.


title: Gravitation, Equivalence Principle, and Quantum Mechanics

abstract:
  Gravitation, according to General Relativity, is an attribute of space-time's
geometry and hence not a force in the Newtonian sense. This is a consequence of
Einstein's equivalence principle, which so far passed all experimental tests
with high precision. However, the search for possible violations continues, for
they, as the case may be, are expected to point towards more fundamental
theoretical extensions of General Relativity. In particular, it is expected
that useful insights are gained by studying the interaction between
gravitational fields and genuine quantum-mechanical systems, like atoms or
molecules. But this raises some fundamental issues, for General Relativity and
Quantum Theory rest on partially incompatible sets of concepts. This article
tries to explain in an elementary fashion how these issues recently entered
modern research in atom interferometry. A shorter and editorially adapted
version of this paper will appear in "Spektrum der Wissenschaft" -- the German
edition of "Scientific American".


title: Optimizing the MapReduce Framework on Intel Xeon Phi Coprocessor

abstract:
  With the ease-of-programming, flexibility and yet efficiency, MapReduce has
become one of the most popular frameworks for building big-data applications.
MapReduce was originally designed for distributed-computing, and has been
extended to various architectures, e,g, multi-core CPUs, GPUs and FPGAs. In
this work, we focus on optimizing the MapReduce framework on Xeon Phi, which is
the latest product released by Intel based on the Many Integrated Core
Architecture. To the best of our knowledge, this is the first work to optimize
the MapReduce framework on the Xeon Phi.
  In our work, we utilize advanced features of the Xeon Phi to achieve high
performance. In order to take advantage of the SIMD vector processing units, we
propose a vectorization friendly technique for the map phase to assist the
auto-vectorization as well as develop SIMD hash computation algorithms.
Furthermore, we utilize MIMD hyper-threading to pipeline the map and reduce to
improve the resource utilization. We also eliminate multiple local arrays but
use low cost atomic operations on the global array for some applications, which
can improve the thread scalability and data locality due to the coherent L2
caches. Finally, for a given application, our framework can either
automatically detect suitable techniques to apply or provide guideline for
users at compilation time. We conduct comprehensive experiments to benchmark
the Xeon Phi and compare our optimized MapReduce framework with a
state-of-the-art multi-core based MapReduce framework (Phoenix++). By
evaluating six real-world applications, the experimental results show that our
optimized framework is 1.2X to 38X faster than Phoenix++ for various
applications on the Xeon Phi.


title:
Description of cross peaks induced by intermolecular vibrational energy
  transfer in two-dimensional infrared spectroscopy

abstract:
  In the present work, the analytical description of an intermolecular
vibrational energy transfer, analyzed by two dimensional infrared spectroscopy,
is established. The energy transfer process takes place between the dark
combination states of low frequency modes pertaining to different molecules.
The appearance of the cross peaks results from coherent transfer between these
combination states and an optically active state of the acceptor molecule. Such
a process has recently been observed experimentally between the nitrile groups
of acetonitrile-d3 and benzonitrile molecules. This molecular system will be
used as a model for the simulations of their two-dimensional infrared spectra.
The dependence of the cross-peak growth, which is a signature of the
intermolecular energy transfer, will be discussed in detail as a function of
the molecular dynamical constants.


title: Spectral radius and Hamiltonian properties of graphs

abstract:
  Let $G$ be a graph with minimum degree $\delta$. The spectral radius of $G$,
denoted by $\rho(G)$, is the largest eigenvalue of the adjacency matrix of $G$.
In this note we mainly prove the following two results. (1) Let $G$ be a graph
on $n\geq 4$ vertices with $\delta\geq 1$. If $\rho(G)> n-3$, then $G$ contains
a Hamilton path unless $G\in\{K_1\vee (K_{n-3}+2K_1),K_2\vee 4K_1,K_1\vee
(K_{1,3}+K_1)\}$. (2) Let $G$ be a graph on $n\geq 14$ vertices with $\delta
\geq 2$. If $\rho(G)\geq \rho(K_2\vee (K_{n-4}+2K_1))$, then $G$ contains a
Hamilton cycle unless $G= K_2\vee (K_{n-4}+2K_1)$. As corollaries of our first
result, two previous theorems due to Fiedler and Nikiforov and Lu et al. are
obtained, respectively. Our second result refines another previous theorem of
Fiedler and Nikiforov.


title: Exponential and power laws in public procurement markets

abstract:
  For the first time ever, we analyze a unique public procurement database,
which includes information about a number of bidders for a contract, a final
price, an identification of a winner and an identification of a contracting
authority for each of more than 40,000 public procurements in the Czech
Republic between 2006 and 2011, focusing on the distributional properties of
the variables of interest. We uncover several scaling laws -- the exponential
law for the number of bidders, and the power laws for the total revenues and
total spendings of the participating companies, which even follows the Zipf's
law for the 100 most spending institutions. We propose an analogy between
extensive and non-extensive systems in physics and the public procurement
market situations. Through an entropy maximization, such the analogy yields
some interesting results and policy implications with respect to the
Maxwell-Boltzmann and Pareto distributions in the analyzed quantities.


title:
Polarons, Dressed Molecules, and Itinerant Ferromagnetism in ultracold
  Fermi gases

abstract:
  In this review, we discuss the properties of a few impurity atoms immersed in
a gas of ultracold fermions, the so-called Fermi polaron problem. On one side,
this many-body system is appealing because it can be described almost exactly
with simple diagrammatic and/or variational theoretical approaches. On the
other, it provides quantitatively reliable insight into the phase diagram of
strongly interacting population imbalanced quantum mixtures. In particular, we
show that the polaron problem can be applied to study itinerant ferromagnetism,
a long standing problem in quantum mechanics.


title: Least Product Relative Error Estimation

abstract:
  A least product relative error criterion is proposed for multiplicative
regression models. It is invariant under scale transformation of the outcome
and covariates. In addition, the objective function is smooth and convex,
resulting in a simple and uniquely defined estimator of the regression
parameter. It is shown that the estimator is asymptotically normal and that the
simple plugging-in variance estimation is valid. Simulation results confirm
that the proposed method performs well. An application to body fat calculation
is presented to illustrate the new method.