title: Sparse model from optimal nonuniform embedding of time series

abstract:
  An approach to obtaining a parsimonious polynomial model from time series is
proposed. An optimal minimal nonuniform time series embedding schema is used to
obtain a time delay kernel. This scheme recursively optimizes an objective
functional that eliminates maximum number of false nearest neighbors between
successive state space reconstruction cycles. A polynomial basis is then
constructed from this time delay kernel. A sparse model from this polynomial
basis is obtained by solving a regularized least squares problem. The
constraint satisfaction problem is made computationally tractable by keeping
the ratio between number of constraints to number of variable small by using
fewer samples spanning all regions of the reconstructed state space. This helps
the structure selection process from an exponentially large combinatorial
search space. A forward stagewise algorithm is then used for fast discovery of
the optimization path. Results are presented for Mackey-Glass system.


title: Free energy of a Lovelock holographic superconductor

abstract:
  We study thermodynamics of black hole solutions in Lanczos-Lovelock AdS
gravity in d+1 dimensions coupled to nonlinear electrodynamics and a
Stueckelberg scalar field. This class of theories is used in the context of
gauge/gravity duality to describe a high-temperature superconductor in d
dimensions. Larger number of coupling constants in the gravitational side is
necessary to widen a domain of validity of physical quantities in a dual QFT.
We regularize the gravitational action and find the finite conserved quantities
for a planar black hole with scalar hair. Then we derive the quantum
statistical relation in the Euclidean sector of the theory, and obtain the
exact formula for the free energy of the superconductor in the holographic
quantum field theory. Our result is analytic and it includes the effects of
backreaction of the gravitational field. We further discuss on how this formula
could be used to analyze second order phase transitions through the
discontinuities of the free energy, in order to classify holographic
superconductors in terms of the parameters in the theory.


title: Canonical magnetic insulators with isotropic magnetoelectric coupling

abstract:
  We have performed an exhaustive representation-theory-based search for the
simplest structures allowing isotropic magnetoelectric coupling. We find 30
such structures, all sharing a common pattern of atomic displacements in the
direction of atomic magnetic moments. We focus on one of these 30 canonical
structures and find that it is generically realized in a class of fractionally
substituted pyrochlore compounds with an all-in-all-out magnetic order.
Furthermore, we find that these substituted pyrochlore compounds have a
substantial Chern-Simons orbital magnetoelectric component (\theta=0.1--0.2).
While this component is also formally present in strong Z_2 topological
insulators (\theta=\pi), its effects are observable there only if time-reversal
symmetry is broken at the surface.


title:
Open heavy-flavour production in pp and Pb-Pb collisions at the LHC,
  measured with ALICE at central rapidity

abstract:
  The ALICE experiment studies nucleus-nucleus collisions at the LHC in order
to investigate the properties of QCD matter at extreme energy densities. The
measurement of open charm and open beauty production allows to investigate the
interaction of heavy quarks with the hot and dense medium formed in high-energy
nucleus-nucleus collisions. In particular, in-medium energy loss is predicted
to be different for gluons, light quarks and heavy quarks and to depend on the
medium energy density and size. ALICE has measured open heavy-flavour particle
production at central rapidity in several decay channels in Pb-Pb and pp
collisions at sqrt{s_NN} = 2.76 TeV and sqrt{s} = 2.76, 7 TeV respectively. The
results obtained from the reconstruction of D meson decays at central rapidity
and from electrons from heavy-flavour hadron decay will be presented.


title:
On Barriers and the Gap between Active and Passive Replication (Full
  Version)

abstract:
  Active replication is commonly built on top of the atomic broadcast
primitive. Passive replication, which has been recently used in the popular
ZooKeeper coordination system, can be naturally built on top of the
primary-order atomic broadcast primitive. Passive replication differs from
active replication in that it requires processes to cross a barrier before they
become primaries and start broadcasting messages. In this paper, we propose a
barrier function tau that explains and encapsulates the differences between
existing primary-order atomic broadcast algorithms, namely semi-passive
replication and Zookeeper atomic broadcast (Zab), as well as the differences
between Paxos and Zab. We also show that implementing primary-order atomic
broadcast on top of a generic consensus primitive and tau inherently results in
higher time complexity than atomic broadcast, as witnessed by existing
algorithms. We overcome this problem by presenting an alternative,
primary-order atomic broadcast implementation that builds on top of a generic
consensus primitive and uses consensus itself to form a barrier. This algorithm
is modular and matches the time complexity of existing tau-based algorithms.


title:
Note on the nature of the transition between a system in an equilibrium
  state and a system in a non-equilibrium state (and vice-versa)

abstract:
  The transition from a non-equilibrium state to an equilibrium state is
characterized not only by the disappearance of the entropy production, but
mainly by the disappearance of the organized currents, due to the gradients
present in a non-equilibrium system. Their disappearance is necessary to obtain
maximum entropy in the equilibrium state.


title: One dimensional Newton's equation with variable mass

abstract:
  We revisit Newton's equation of motion in one dimension when the moving
particle has a variable mass m(x,t) depending both on position (x) and time
(t). Geometrically the mass function is identified with one of the metric
function in a 1+1-dimensional spacetime. As a reflection of the equivalence
principle geodesics equation gives the Newton's law of motion leaving the right
hand side to be supplemented by the external forces. The resulting equation
involves the speed of light so that our equation of motion addresses a wider
scope than the customary classical mechanics. In the limit of infinite light
speed which amounts to instantaneous interaction we recover the classical
results.


title: Thermoelectricity of Wigner crystal in a periodic potential

abstract:
  We study numerically the thermoelectricity of the classical Wigner crystal
placed in a periodic potential and being in contact with a thermal bath modeled
by the Langevin dynamics. At low temperatures the system has sliding and pinned
phases with the Aubry transition between them. We show that in the Aubry pinned
phase the dimensionless Seebeck coefficient can reach very high values of
several hundreds. At the same time the charge and thermal conductivity of
crystal drop significantly inside this phase. Still we find that the largest
values of $ZT$ factor are reached in the Aubry phase and for the studied
parameter range we obtain $ZT \leq 4.5$. We argue that this system can provide
an optimal regime for reaching high $ZT$ factors and realistic modeling of
thermoelecriticy. Possible experimental realizations of this model are
discussed.


title:
How to Extend Karolyi and Nagy's BRILLIANT Proof of the
  Zeilberger-Bressoud q-Dyson Theorem in order to Evaluate ANY Coefficient of
  the q-Dyson Product

abstract:
  We show how to extend the Karolyi-Nagy beautiful proof of the
Zeilberger-Bressoud q-Dyson theorem, (first proved by Zeilberger and Bressoud
in 1985, and originally conjectured by George Andrews in 1975), that states
that the constant term of a certain Laurent polynomial equals the q-multinomial
coefficient, how to evaluate any other specific coefficient. The algorithm
implies that any such coefficient is always a certain rational function (that
the algorithm finds) times the q-multinomial coefficient.


title:
Spectroscopy of the short-hard GRB 130603B: The host galaxy and
  environment of a compact object merger

abstract:
  Short duration gamma-ray bursts (SGRBs) are thought to be related to the
violent merger of compact objects, such as neutron stars or black holes, which
makes them promising sources of gravitational waves. The detection of a
'kilonova'-like signature associated to the Swift-detected GRB 130603B has
suggested that this event is the result of a compact object merger. Our
knowledge on SGRB has been, until now, mostly based on the absence of supernova
signatures and the analysis of the host galaxies to which they cannot always be
securely associated. Further progress has been significantly hampered by the
faintness and rapid fading of their optical counterparts (afterglows), which
has so far precluded spectroscopy of such events. Afterglow spectroscopy is the
key tool to firmly determine the distance at which the burst was produced,
crucial to understand its physics, and study its local environment. Here we
present the first spectra of a prototypical SGRB afterglow in which both
absorption and emission features are clearly detected. Together with
multiwavelength photometry we study the host and environment of GRB 130603B.
From these spectra we determine the redshift of the burst to be z =
0.3565+/-0.0002, measure rich dynamics both in absorption and emission, and a
substantial line of sight extinction of A_V = 0.86+/-0.15 mag. The GRB was
located at the edge of a disrupted arm of a moderately star forming galaxy with
near-solar metallicity. Unlike for most long GRBs (LGRBs), N_HX / A_V is
consistent with the Galactic ratio, indicating that the explosion site differs
from those found in LGRBs. The merger is not associated with the most
star-forming region of the galaxy; however, it did occur in a dense region,
implying a rapid merger or a low natal kick velocity for the compact object
binary.


title:
Galaxy And Mass Assembly (GAMA): Resolving the role of environment in
  galaxy evolution

abstract:
  We present observations of 18 galaxies from the Galaxy And Mass Assembly
(GAMA) survey made with the SPIRAL optical integral field unit (IFU) on the
Anglo-Australian Telescope. The galaxies are selected to have a narrow range in
stellar mass (6x10^9Msolar < M* <2x10^10 Msolar) in order to focus on the
effects of environment. Local galaxy environments are measured quantitatively
using 5th nearest neighbour surface densities. We find that the total star
formation rates (SFR) measured from the IFU data are consistent with total SFRs
measured from aperture correcting either GAMA or Sloan Digital Sky Survey
single-fibre observations. The mean differences are SFR_GAMA/SFR_IFU =
1.26+/-0.23, sigma=0.90 and for the Sloan Digital Sky Survey we similarly find
SFR_Brinchmann/SFR_IFU = 1.34+/-0.17, sigma=0.67. Examining the relationships
with environment, we find off-centre and clumpy Halpha emission is not
significantly dependent on environment, being present in 2/7 (29^+20_-11 per
cent) galaxies in high-density environments (>0.77 Mpc^-2), and 5/11
(45^+15_-13 per cent) galaxies in low-density environments (<0.77 Mpc^-2). We
find a weak but not significant relationship of the total star formation rates
of star-forming galaxies with environment. Due to the size of our sample and
the scatter observed we do not draw a definitive conclusion about a possible
SFR dependence on environment. Examining the spatial distribution of the Halpha
emission, we find no evidence for a change in shape or amplitude of the radial
profile of star-forming galaxies with environment. If these observations are
borne out in larger samples this would infer that any environment-driven
star-formation suppression must either act very rapidly (the
`infall-and-quench' model) or that galaxies must evolve in a density-dependent
manner (an `in-situ evolution' model).


title:
On the classification of projectively flat Finsler metrics with constant
  flag curvature

abstract:
  In this paper, we study locally projectively flat Finsler metrics with
constant flag curvature ${\bf K}$. We prove those are totally determined by
their behaviors at the origin by solving some nonlinear PDEs. The
classifications when ${\bf K}=0$, ${\bf K}=-1$ and ${\bf K} =1$ are given
respectively in an algebraic way. Further, we construct a new projectively flat
Finsler metric with flag curvature ${\bf K}=1$ determined by a Minkowskian norm
with double square roots at the origin. As an application of our main theorems,
we give the classification of locally projectively flat spherical symmetric
Finsler metrics much easier than before. ----Comments are welcome.


title: On Hensel's roots and a factorization formula in Z[[x]]

abstract:
  Given an odd prime $p$, we provide formulas for the Hensel lifts of
polynomial roots modulo $p$, and give an explicit factorization over the ring
of formal power series with integer coefficients for certain reducible
polynomials whose constant term is of the form $p^w$ with $w>1$. All of our
formulas are given in terms of partial Bell polynomials and rely on the
inversion formula of Lagrange.


title: Weak density of orbit equivalence classes of free group actions

abstract:
  It is proven that the orbit-equivalence class of any essentially free
probability-measure-preserving action of a free group $G$ is weakly dense in
the space of actions of $G$.


title:
Dihadron production in semi-inclusive DIS from transversely polarized
  protons

abstract:
  Transverse Momentum Dependent (TMD) dihadron production, including vector
meson production, allows access to various TMD distribution and fragmentation
functions. Dihadron production is complementary to single hadron semi-inclusive
DIS measurements, pairing the same distribution functions with different
fragmentation functions. While dihadrons present unique measurement
opportunities, the TMD dihadron cross section is significantly more complex
than that for single hadron production, due to the polarization in the final
state. Various theoretical advances, which further clarify the complexity, will
be highlighted. The HERMES analysis of the transverse target moments of the TMD
dihadron cross section allows the first test of a particular prediction of the
Lund/Artru string fragmentation model, specifically that the favored Collins
fragmentation function has opposite sign in single hadron production versus
vector meson production. The status and results of this analysis will be
discussed and an extension of the Lund/Artru model for disfavored fragmentation
will also be presented.


title:
Condensed phase effects on the electronic momentum distribution in the
  warm dense matter regime

abstract:
  We report ab initio calculations of the valence electron momentum
distribution function n(p) and dynamic structure factor for warm dense Be at
Mbar pressures. We observe an unexpected, strong reshaping of the Compton
profile upon increasing density, even well before any significant
core-wavefunction overlap or electride behavior occurs. We propose that this
nonperturbative effect, which is due to a growing influence on n(p) of the
orthogonalization of valence and core electron wave- functions with increasing
density, is observable by inelastic x-ray scattering at x-ray free-electron
lasers and large-scale laser-shock heating facilities, and may also be more
generally important for thermodynamic properties of dense, partially-ionized
plasmas.


title:
Ionization in Atmospheres of Brown Dwarfs and Extrasolar Planets V:
  Alfv\'{e}n Ionization

abstract:
  Observations of continuous radio and sporadic X-ray emission from low-mass
objects suggest they harbour localized plasmas in their atmospheric
environments. For low-mass objects, the degree of thermal ionization is
insufficient to qualify the ionized component as a plasma, posing the question:
what ionization processes can efficiently produce the required plasma that is
the source of the radiation? We propose Alfv\'{e}n ionization as a mechanism
for producing localized pockets of ionized gas in the atmosphere, having
sufficient degrees of ionization ($\geq10^{-7}$) that they constitute plasmas.
We outline the criteria required for Alfv\'{e}n ionization and demonstrate it's
applicability in the atmospheres of low-mass objects such as giant gas planets,
brown dwarfs and M-dwarfs for both solar and sub-solar metallicities. We find
that Alfv\'{e}n ionization is most efficient at mid to low atmospheric
pressures where a seed plasma is easier to magnetize and the pressure gradients
needed to drive the required neutral flows are the smallest. For the model
atmospheres considered, our results show that degrees of ionization of
$10^{-6}-1$ can be obtained as a result of Alfv\'{e}n ionization. Observable
consequences include continuum Bremsstrahlung emission, superimposed with
spectral lines from the plasma ion species (e.g. He, Mg, H$_{2}$ or CO lines).
Forbidden lines are also expected from the metastable population. The presence
of an atmospheric plasma opens the door to a multitude of plasma and chemical
processes not yet considered in current atmospheric models. The occurrence of
Alfv\'{e}n ionization may also be applicable to other astrophysical
environments such as protoplanetary disks.


title: Quantum cluster characters of Hall algebras

abstract:
  The aim of the present paper is to introduce a generalized quantum cluster
character, which assigns to each object V of a finitary Abelian category C over
a finite field FF_q and any sequence ii of simple objects in C the element
X_{V,ii} of the corresponding algebra P_{C,ii} of q-polynomials. We prove that
if C was hereditary, then the assignments V-> X_{V,ii} define algebra
homomorphisms from the (dual) Hall-Ringel algebra of C to the P_{C,ii}, which
generalize the well-known Feigin homomorphisms from the upper half of a quantum
group to q-polynomial algebras.
  If C is the representation category of an acyclic valued quiver (Q,d) and
ii=(ii_0,ii_0), where ii_0 is a repetition-free source-adapted sequence, then
we prove that the ii-character X_{V,ii} equals the quantum cluster character
X_V introduced earlier by the second author in [29] and [30]. Using this
identification, we deduce a quantum cluster structure on the quantum unipotent
cell corresponding to the square of a Coxeter element. As a corollary, we prove
a conjecture from the joint paper [5] of the first author with A. Zelevinsky
for such quantum unipotent cells. As a byproduct, we construct the quantum
twist and prove that it preserves the triangular basis introduced by A.
Zelevinsky and the first author in [6].


title:
Sudakov Double Logarithms Resummation in Hard Processes in Small-x
  Saturation Formalism

abstract:
  In this manuscript, we present a complete study of the Sudakov double
logarithms resummation for various hard processes in eA and pA collisions in
the small-x saturation formalism. We first employ a couple of slightly
different formalisms to perform the one-loop analysis of the Higgs boson
production process in pA collisions, and demonstrate that Sudakov-type
logarithms arise as the leading correction and that they can be systematically
resummed in addition to the usual small-x resummation. We further study the
Sudakov double logarithms for other processes such as heavy quark pair
production and back-to-back dijet production in eA and pA collisions through
detailed calculation of the corresponding one-loop diagrams. As the most
important contribution from the one-loop correction, the Sudakov factor should
play an important role in the phenomenological study of saturation physics in
the pA programs at RHIC and the LHC.


title:
Inelastic Collisions of Solitary Waves in Anisotropic Bose-Einstein
  Condensates: Sling-Shot Events and Expanding Collision Bubbles

abstract:
  We study experimentally and theoretically the dynamics of apparent dark
soliton stripes in an elongated Bose-Einstein condensate. We show that for the
trapping strengths corresponding to our experimental setup, the transverse
confinement along one of the tight directions is not strong enough to arrest
the formation of solitonic vortices or vortex rings. These solitonic vortices
and vortex rings, when integrated along the transverse direction, appear as
dark soliton stripes along the longitudinal direction thereby hiding their true
character. The latter significantly modifies the interaction dynamics during
collision events and can lead to apparent examples of inelasticity and what may
appear experimentally even as a merger of two dark soliton stripes. We explain
this feature by means of the interaction of two solitonic vortices leading to a
sling shot event with one of the solitonic vortices being ejected at a
relatively large speed. Furthermore we observe expanding collision bubbles
which consist of repeated inelastic collisions of a dark soliton stripe pair
with an {\it increasing} time interval between collisions.


title:
Compatibility of the Feigin-Frenkel Isomorphism and the Harish-Chandra
  Isomorphism for jet algebras

abstract:
  Let $\fg$ be a simple finite-dimensional complex Lie algebra with a Cartan
subalgebra $\fh$ and Weyl group $W$. Let $\fg_n$ denote the Lie algebra of
$n$-jets on $\fg$. A theorem of Rais and Tauvel and Geoffriau identifies the
centre of the category of $\fg_n$-modules with the algebra of functions on the
variety of $n$-jets on the affine space $\fh^*/W$. On the other hand, a theorem
of Feigin and Frenkel identifies the centre of the category of critical level
smooth modules of the corresponding affine Kac-Moody algebra with the algebra
of functions on the ind-scheme of opers for the Langlands dual group. We prove
that these two isomorphisms are compatible by defining the higher residue of
opers with irregular singularities. We also define generalized Verma and
Wakimoto modules and relate them by a nontrivial morphism.


title: The natural measure of a symbolic dynamical system

abstract:
  This study investigates the natural or intrinsic measure of a symbolic
dynamical system $\Sigma$. The measure $\mu([i_{1},i_{2},...,i_{n}])$ of a
pattern $[i_{1},i_{2},...,i_{n}]$ in $\Sigma$ is an asymptotic ratio of
$[i_{1},i_{2},...,i_{n}]$, which arises in all patterns of length $n$ within
very long patterns, such that in a typical long pattern, the pattern
$[i_{1},i_{2},...,i_{n}]$ appears with frequency
$\mu([i_{1},i_{2},...,i_{n}])$. When $\Sigma=\Sigma(A)$ is a shift of finite
type and $A$ is an irreducible $N\times N$ non-negative matrix, the measure
$\mu$ is the Parry measure. $\mu$ is ergodic with maximum entropy. The result
holds for sofic shift $\mathcal{G}=(G,\mathcal{L})$, which is irreducible. The
result can be extended to $\Sigma(A)$, where $A$ is a countably infinite matrix
that is irreducible, aperiodic and positive recurrent. By using the Krieger
cover, the natural measure of a general shift space is studied in the way of a
countably infinite state of sofic shift, including context free shift. The
Perron-Frobenius Theorem for non-negative matrices plays an essential role in
this study.


title:
Birational geometry in the study of dynamics of automorphisms and
  Brody/Mori/Lang hyperbolicity

abstract:
  We survey our recent papers (some being joint ones) about the relation
between the geometry of a compact K\"ahler manifold and the existence of
automorphisms of positive entropy on it. We also use the language of log
minimal model program (LMMP) in biraitonal geometry, but not its more
sophisticated technical part. We give applications of LMMP to positivity of log
canonical divisor of a Mori / Brody / Lang hyperbolic (quasi-) projective
(singular) variety.


title: Double-dimers, the Ising model and the hexahedron recurrence

abstract:
  We define and study a recurrence relation in ${\mathbb Z}^3$, called the
hexahedron recurrence, which is similar to the octahedron recurrence (Hirota
bilinear difference equation) and cube recurrence (Miwa equation). Like these
examples, solutions to the hexahedron recurrence are partition sums for edge
configurations on a certain graph, and have a natural interpretation in terms
of cluster algebras. We give an explicit correspondence between monomials in
the Laurent expansions arising in the recurrence with certain double-dimer
configurations of a graph. We compute limit shapes for the corresponding
double-dimer configurations.
  The Kashaev difference equation arising in the Ising model star-triangle
relation is a special case of the hexahedron recurrence. In particular this
reveals the cluster nature underlying the Ising model. The above relation
allows us to prove a Laurent phenomenon for the Kashaev difference equation.


title: $Z_c(4025)$ as the hadronic molecule with hidden charm

abstract:
  We have studied the loosely bound $D^*\bar{D}^*$ system. Our results indicate
that the recently observed charged charmonium-like structure $Z_c(4025)$ can be
an ideal $D^*\bar{D}^*$ molecular state. We have also investigated its pionic,
dipionic, and radiative decays. We stress that both the scalar isovector
molecular partner $Z_{c0}$ and three isoscalar partners ${\tilde Z}_{c0,c1,c2}$
should also exist if $Z_c(4025)$ is a $D^*\bar{D}^*$ molecular state {in the
framework of the one-pion-exchange model}. $Z_{c0}$ can be searched for in the
channel $e^+e^-\to Y \to Z_{c0}(4025)\left(\pi\pi\right)_{P-wave}$ where $Y$
can be Y(4260) or any other excited $1^{--}$ charmonium or charmonium-like
states such as Y(4360), Y(4660) etc. The isoscalar $D^*\bar{D}^*$ molecular
states ${\tilde Z}_{c0,c2}$ with $0^+(0^{++})$ and $0^+(2^{++})$ can be
searched for in the three pion decay channel $e^+e^-\to Y \to {\tilde
Z}_{c0,c2} \left(3\pi\right)^{I=0}_{P-wave}$. The isoscalar molecular state
${\tilde Z}_{c1}$ with $0^-(1^{+-})$ can be searched for in the channel
${\tilde Z}_{c1}\eta$. Experimental discovery of these partner states will
firmly establish the molecular picture.


title: Generalized conditional entropy in bipartite quantum systems

abstract:
  We analyze, for a general concave entropic form, the associated conditional
entropy of a quantum system A+B, obtained as a result of a local measurement on
one of the systems (B). This quantity is a measure of the average mixedness of
A after such measurement, and its minimum over all local measurements is shown
to be the associated entanglement of formation between A and a purifying third
system C. In the case of the von Neumann entropy, this minimum determines also
the quantum discord. For classically correlated states and mixtures of a pure
state with the maximally mixed state, we show that the minimizing measurement
can be determined analytically and is universal, i.e., the same for all concave
forms. While these properties no longer hold for general states, we also show
that in the special case of the linear entropy, an explicit expression for the
associated conditional entropy can be obtained, whose minimum among projective
measurements in a general qudit-qubit state can be determined analytically, in
terms of the largest eigenvalue of a simple 3x3 correlation matrix. Such
minimum determines the maximum conditional purity of A, and the associated
minimizing measurement is shown to be also universal in the vicinity of maximal
mixedness. Results for X states, including typical reduced states of spin pairs
in XY chains at weak and strong transverse fields, are also provided and
indicate that the measurements minimizing the von Neumann and linear
conditional entropies are typically coincident in these states, being
determined essentially by the main correlation. They can differ, however,
substantially from that minimizing the geometric discord.


title: Chiral spin liquid in a two-dimensional two-component helical magnet

abstract:
  A low-temperature method is developed, suited for the two-dimensional
two-component classical helical magnet. Four phases on the phase diagram as
functions of temperature and helicity parameter of the Hamiltonian are found.
Among the three ordered phases two show magnetic order: the usual algebraic
correlations of the magnetization and the algebraic correlations of the
magnetization in the frame rotating according with the helical order. A chiral
spin liquid phase emerges directly from the paramagnetic phase and has a scalar
parity-breaking pitch of the magnetization as the order parameter. The chiral
phase transition is found to be of a continuous second order type with a
modified by the long-range interaction Ising universality class. All the
critical exponents are calculated in the second and the third order of an
$\epsilon$-expansion. A new scaling relationship replacing the Josephson's one
is found.


title: Interacting bubble clouds and their sonochemical production

abstract:
  Acoustically driven air pockets trapped in artificial crevices on a sur- face
can emit bubbles which organize in (interacting) bubble clusters. With
increasing driving power Fernandez Rivas et al. [Angew. Chem. Int. Ed., 2010]
observed three different behaviors: clusters close to the very pits out of
which they had been created, clusters pointing toward each other, and merging
clusters. The latter behavior is highly undesired for technological purposes as
it is associated with a reduction of the radical production and an enhancement
of the erosion of the reactor walls. The dependence on the control parameters
such as the distance of the pits and the conditions for cluster-merging are
examined. The underlying mechanism, governed by the secondary Bjerknes forces,
turns out to be strongly influenced by the nonlinearity of the bubble
oscillations and not directly by the number of nucleated bubbles. The Bjerknes
forces are found to dampen the bubble oscillations, thus reducing the radical
production. Therefore, the increased number of bubbles at high power could be
the key to understand the experimental observation that, after a certain power
threshold, any further increase of the driving does not improve the
sonochemical efficiency.


title:
[Fe II] 1.64 um Features of Jets and Outflows from Young Stellar Objects
  in the Carina Nebula

abstract:
  We present [Fe II] 1.64 {\mu}m imaging observations for jets and outflows
from young stellar objects (YSOs) over the northern part (~ 24'x45') of the
Carina Nebula, a massive star forming region. The observations were performed
with IRIS2 of Anglo-Australian Telescope and the seeing was ~1.5"+-0.5". Eleven
jet and outflow features are detected at eight different regions, and are named
as Ionized Fe Objects (IFOs). One Herbig-Haro object candidate missed in Hubble
Space Telescope H{\alpha} observations is newly identified as HHc-16, referring
our [Fe II] images. IFOs have knotty or longish shapes, and the detection rate
of IFOs against previously identified YSOs is 1.4 %, which should be treated as
a lower limit. Four IFOs show an anti-correlated peak intensities in [Fe II]
and H{\alpha}, where the ratio I([Fe II])/I(H{\alpha}) is higher for longish
IFOs than for knotty IFOs. We estimate the outflow mass loss rate from the [Fe
II] flux, using two different methods. The jet-driving objects are identified
for three IFOs (IFO-2, -4, and -7), for which we study the relations between
the outflow mass loss rate and the YSO physical parameters from the radiative
transfer model fitting. The ratios of the outflow mass loss rate over the disk
accretion rate are consistent for IFO-4 and -7 with the previously reported
values (10^-2-10^+1), while it is higher for IFO-2. This excess may be from the
underestimation of the disk accretion rate. The jet-driving objects are likely
to be low- or intermediate-mass stars. Other YSO physical parameters, such as
luminosity and age, show reasonable relations or trends.


title:
Absolute Proper Motion of IRAS 00259+5625 with VERA : Indication of
  Superbubble Expansion Motion

abstract:
  We present the first measurement of the absolute proper motions of IRAS
00259+5625 (CB3, LBN594) associated with the HI loop called the "NGC281
superbubble" that extends from the Galactic plane over ~300 pc toward
decreasing galactic latitude. The proper motion components measured with VERA
are (mu_alpha cos(delta), mu_delta) = (-2.48 +/- 0.32, -2.85 +/- 0.65) mas
yr^{-1}, converted into (mu_l cos(b), mu_b) = (-2.72 +/- 0.32, -2.62 +/- 0.65)
mas yr^{-1} in the Galactic coordinates. The measured proper motion
perpendicular to the Galactic plane (mu_b) shows vertical motion away from the
Galactic plane with a significance of about ~4-sigma. As for the source
distance, the distance measured with VERA is marginal, 2.4^{+1.0}_{-0.6} kpc.
Using the distance, an absolute vertical motion (v_{b}) of -17.9 +/- 12.2 km
s^{-1} is determined with ~1.5-sigma significance. The tendency of the large
vertical motion is consistent with previous VLBI results for NGC 281 associated
with the same superbubble. Thus, our VLBI results indicate the superbubble
expansion motion whose origin is believed to be sequential supernova
explosions.


title: On the hot spots conjecture for acute triangles

abstract:
  We show that the hot spots conjecture of J. Rauch holds for acute triangles
if one of the angles is not larger than $\pi/6$. More precisely, we show that
the second Neumann eigenfunction on those acute triangles has no maximum or
minimum inside the domain. We first simplify the problem by showing that
absence of critical points on two sides implies no critical points inside a
triangle. This result applies to any acute triangle and might help prove the
conjecture for arbitrary acute triangles. Then we show that there are no
critical points on two sides assuming one small angle. We also establish
simplicity for the second Neumann eigenvalue for all non-equilateral triangles.


title:
Transformation process of the magnetron-sputtered Ag$_2$O film in
  hydrogen annealing

abstract:
  The current paper mainly addresses the effect of the hydrogen partial
pressure on the microstructure and transformation of the Ag$_2$O film. The
transformation process and mechanism were also analyzed in detail. Increasing
the hydrogen partial pressure can accelerate the transformation of Ag$_2$O to
Ag and lower the critical transformation temperature of the film due to the
enhanced hydrogen reduction, and to both of the lowered activation energy of
the reaction of Ag$_2$O with hydrogen and enhanced lattice strain of the
Ag$_2$O film, respectively. Hydrogen-involved reaction in the whole hydrogen
annealing process is mainly hydrogen reduction reaction with Ag$_2$O. The
diffusion of hydrogen and gaseous H$_2$O molecules is accompanied with the
whole hydrogen annealing process.


title: Cavity linewidth narrowing with dark-state polaritons

abstract:
  We perform a quantum-theoretical treatment of cavity linewidth narrowing with
intracavity electromagnetically induced transparency (EIT). By means of
intracavity EIT, the photons in the cavity are in the form of cavity
polaritons: bright-state polariton and dark-state polariton. Strong coupling of
the bright-state polariton to the excited state induces an effect known as
vacuum Rabi splitting, whereas the dark-state polariton decoupled from the
excited state induce a narrow cavity transmission window. Our analysis would
provide a quantum theory of linewidth narrowing with a quantum field pulse at
the single-photon level.


title:
On the formation of the peculiar low-mass X-ray binary IGR J17480$-$2446
  in Terzan 5

abstract:
  IGR J17480$-$2446 is an accreting X-ray pulsar in a low-mass X-ray binary
harbored in the Galactic globular cluster Terzan 5. Compared with other
accreting millisecond pulsars, IGR J17480$-$2446 is peculiar in its low spin
frequency (11 Hz), which suggests that it might be a mildly recycled neutron
star at the very early phase of mass transfer. However, this model seems to be
in contrast with the low field strength deduced from the kiloHertz
quasi-periodic oscillations observed in IGR J17480$-$2446. Here we suggest an
alternative interpretation, assuming that the current binary system was formed
during an exchange encounter either between a binary (which contains a recycled
neutron star) and the current donor, or between a binary and an isolated,
recycled neutron star. In the resulting binary, the spin axis of the neutron
star could be parallel or anti-parallel with the orbital axis. In the later
case, the abnormally low frequency of IGR J17480$-$2446 may result from the
spin-down to spin-up evolution of the neutron star. We also briefly discuss the
possible observational implications of the pulsar in this scenario.


title: Structural Changes in Data Communication in Wireless Sensor Networks

abstract:
  Wireless sensor networks are an important technology for making distributed
autonomous measures in hostile or inaccessible environments. Among the
challenges they pose, the way data travel among them is a relevant issue since
their structure is quite dynamic. The operational topology of such devices can
often be described by complex networks. In this work, we assess the variation
of measures commonly employed in the complex networks literature applied to
wireless sensor networks. Four data communication strategies were considered:
geometric, random, small-world, and scale-free models, along with the shortest
path length measure. The sensitivity of this measure was analyzed with respect
to the following perturbations: insertion and removal of nodes in the geometric
strategy; and insertion, removal and rewiring of links in the other models. The
assessment was performed using the normalized Kullback-Leibler divergence and
Hellinger distance quantifiers, both deriving from the Information Theory
framework. The results reveal that the shortest path length is sensitive to
perturbations.


title:
A Challenging Solar Eruptive Event of 18 November 2003 and the Causes of
  the 20 November Geomagnetic Superstorm. II. CMEs, Shock Waves, and Drifting
  Radio Bursts

abstract:
  We continue our study (Grechnev et al. (2013), doi:10.1007/s11207-013-0316-6;
Paper I) on the 18 November 2003 geoffective event. To understand possible
impact on geospace of coronal transients observed on that day, we investigated
their properties from solar near-surface manifestations in extreme ultraviolet,
LASCO white-light images, and dynamic radio spectra. We reconcile near-surface
activity with the expansion of coronal mass ejections (CMEs) and determine
their orientation relative to the earthward direction. The kinematic
measurements, dynamic radio spectra, and microwave and X-ray light curves all
contribute to the overall picture of the complex event and confirm an
additional eruption at 08:07 - 08:20 UT close to the solar disk center presumed
in Paper I. Unusual characteristics of the ejection appear to match those
expected for a source of the 20 November superstorm but make its detection in
LASCO images hopeless. On the other hand, none of the CMEs observed by LASCO
seem to be a promising candidate for a source of the superstorm being able to
produce, at most, a glancing blow on the Earth's magnetosphere. Our analysis
confirms free propagation of shock waves revealed in the event and reconciles
their kinematics with "EUV waves" and dynamic radio spectra up to decameters.


title:
Population synthesis of young isolated neutron stars: the effect of
  fallback disk accretion and magnetic field evolution

abstract:
  The spin evolution of isolated neutron stars (NSs) is dominatd by their
magnetic fields. The measured braking indices of young NSs show that the
spin-down mechanism due to magnetic dipole radiation with constant magnetic
fields is inadequate. Assuming that the NS magnetic field is buried by
supernova fallback matter and re-emerges after accretion stops, we carry out
Monte-Carlo simulation of the evolution of young NSs, and show that most of the
pulsars have the braking indices ranging from -1 to 3. The results are
compatible with the observational data of NSs associated with supernova
remnants. They also suggest that the initial spin periods of NSs might occupy a
relatively wide range.


title: The spt-Crank for Ordinary Partitions

abstract:
  The spt-function $spt(n)$ was introduced by Andrews as the weighted counting
of partitions of $n$ with respect to the number of occurrences of the smallest
part. Andrews, Garvan and Liang defined the spt-crank of an $S$-partition which
leads to combinatorial interpretations of the congruences of $spt(n)$ mod 5 and
7. Let $N_S(m,n)$ denote the net number of $S$-partitions of $n$ with spt-crank
$m$. Andrews, Garvan and Liang showed that $N_S(m,n)$ is nonnegative for all
integers $m$ and positive integers $n$, and they asked the question of finding
a combinatorial interpretation of $N_S(m,n)$. In this paper, we introduce the
structure of doubly marked partitions and define the spt-crank of a doubly
marked partition. We show that $N_S(m,n)$ can be interpreted as the number of
doubly marked partitions of $n$ with spt-crank $m$. Moreover, we establish a
bijection between marked partitions of $n$ and doubly marked partitions of $n$.
A marked partition is defined by Andrews, Dyson and Rhoades as a partition with
exactly one of the smallest parts marked. They consider it a challenge to find
a definition of the spt-crank of a marked partition so that the set of marked
partitions of $5n+4$ and $7n+5$ can be divided into five and seven equinumerous
classes. The definition of spt-crank for doubly marked partitions and the
bijection between the marked partitions and doubly marked partitions leads to a
solution to the problem of Andrews, Dyson and Rhoades.


title:
Optics of semiconductors and insulators: Role of local-field effects
  revised

abstract:
  We show that by nullifying the short-wave response to the long-wave
excitation (local-field-effects), the adiabatic time-dependent
density-functional theory (TDDFT) of optics of semiconductors and insulators
can be brought into excellent agreement with experiment. This indicates that
the wing elements [($\Gv,\0v)$ and $(\0v,\Gv)$, $\Gv\ne\0v$] of both the
Kohn-Sham (KS) density-response function $\chi^s$ and the exchange-correlation
kernel $f^{xc}$ are greatly overestimated by the existing approximations to the
static DFT and TDDFT, respectively, to the extent that zero is a better
approximation for them than the corresponding values provided by current
theories. The head element of $f^{xc}$ is thereby fixed by the static
macroscopic dielectric constant $\epsilon_M$. Our method yields accurate
optical spectra including both the weakly and strongly bound excitons, while
its computational cost is extremely low, since only the head element of the KS
response matrix and the static dielectric constant are needed.


title: Effective Mass of Holographic Brownian Particle in Rotating Plasma

abstract:
  The dynamic of string fluctuation under rotating BTZ black hole is studied
using the method of \cite{Son:2009vu}. We compare the result with previous
computation in \cite{Atmaja:2012jg}, with a different method, for the case of
co-rotating string. The result gives definite answer that the end of string
identified as an external quark at the boundary behaves as Brownian particle
with mass is given an effective mass $M_{eff}$ equal to the zero temperature
mass of external quark $M_0$ times Lorentz factor $\gamma$ to the power three.
We also extend the computation for general case of rotating black hole where
the metric is asymptotically $AdS_3$ and the fluctuation is taken only along
the co-rotating motion. It shows that the effective mass of the external quark
is in general given by $\gamma^3 M_0$.


title:
On Generalized Bayesian Data Fusion with Complex Models in Large Scale
  Networks

abstract:
  Recent advances in communications, mobile computing, and artificial
intelligence have greatly expanded the application space of intelligent
distributed sensor networks. This in turn motivates the development of
generalized Bayesian decentralized data fusion (DDF) algorithms for robust and
efficient information sharing among autonomous agents using probabilistic
belief models. However, DDF is significantly challenging to implement for
general real-world applications requiring the use of dynamic/ad hoc network
topologies and complex belief models, such as Gaussian mixtures or hybrid
Bayesian networks. To tackle these issues, we first discuss some new key
mathematical insights about exact DDF and conservative approximations to DDF.
These insights are then used to develop novel generalized DDF algorithms for
complex beliefs based on mixture pdfs and conditional factors. Numerical
examples motivated by multi-robot target search demonstrate that our methods
lead to significantly better fusion results, and thus have great potential to
enhance distributed intelligent reasoning in sensor networks.


title: A reverse Schwarz--Pick inequality

abstract:
  We prove a kind of "reverse Schwarz--Pick lemma" for holomorphic self-maps of
the disk. The result becomes especially clear-cut for inner functions and casts
new light on their derivatives.


title:
Ultra-compact modulators based on novel CMOS-compatible plasmonic
  materials

abstract:
  We propose several planar layouts of ultra-compact plasmonic waveguide
modulators that utilize alternative CMOS-compatible materials. The modulation
is efficiently achieved by tuning the carrier concentration in a transparent
conducting oxide layer, thereby tuning the waveguide either in plasmonic
resonance or off-resonance. Resonance significantly increases the absorption
coefficient of the plasmonic waveguide, which enables larger modulation depth.
We show that an extinction ratio of 86 dB/um can be achieved, allowing for a
3-dB modulation depth in less than one micron at the telecommunication
wavelength. Our multilayer structures can potentially be integrated with
existing plasmonic and photonic waveguides as well as novel semiconductor-based
hybrid photonic/electronic circuits.


title:
Infinitely many nonlocal symmetries and conservation laws for the
  (1+1)-dimensional Sine-Gordon equation

abstract:
  Infinitely many nonlocal symmetries and conservation laws of the
(1+1)-dimensional Sine-Gordon (SG) equation are derived in terms of its
B\"acklund transformation (BT). Some special nonlocal symmetries and nonlocal
conservation laws are obtained from the linearized equations of the SG equation
and its BT. Furthermore, one can derive infinitely many nonlocal symmetries
from a known nonlocal symmetry, but also infinitely many nonlocal conservation
laws from a known nonlocal conservation law. In addition, infinitely many local
and nonlocal conservation laws can be directed generated from BT through the
parameter expansion procedure.


title: Featured trends in e$^{-}+$Mn electron elastic scattering

abstract:
  The impacts of both exchange interaction and electron correlation, as well as
their combined impact, on electron elastic scattering off a semifilled shell
Mn(...$3d^{5}$$4s^{2}$, $^{6}S$) atom are theoretically studied in the electron
energy range of $\epsilon= 0-25$ eV. Corresponding elastic scattering phase
shifts $\delta_{\ell}(\epsilon)$ as well as partial $\sigma_{\ell}(\epsilon)$
and total $\sigma(\epsilon)$ cross sections are found to be subject to a strong
correlation impact. The latter is shown to be drastically different for
oppositely spin-polarized scattered electrons, in some cases, thereby bringing
significant differences in corresponding $\delta_{\ell}(\epsilon)$s,
$\sigma_{\ell}(\epsilon)$s, and $\sigma(\epsilon)$s between said electrons.
This is proven to be an inherent features of electron scattering off a
semifilled shell atom in general. Electron correlation is accounted for in the
framework of the self-energy part $\Sigma$ of the Green function of a scattered
electron concept. The latter is calculated both in the second-order
perturbation theory in the Coulomb interelectron interaction as well as beyond
it by solving the Dyson equation for $\Sigma$. The significance of the "Dyson"
correlation corrections in e$^{-}+$Mn scattering is unraveled. They are shown
to aggravate noticeably the inherent differences between elastic scattering
phase shifts and cross sections of spin-up ($\uparrow$) and spin-down
($\downarrow$) polarized electrons scattered off a spin-polarized Mn atom, in
some cases. In particular, the existence of a narrow resonant maximum in
$\sigma^{\downarrow}(\epsilon)$ near $\epsilon \approx 8$ eV but the absence of
such in $\sigma^{\uparrow}(\epsilon)$ in e$^{-}+$Mn scattering is predicted.


title: Tests in adaptive regression via the Kac-Rice formula

abstract:
  We derive an exact p-value for testing a global null hypothesis in a general
adaptive regression problem. The general approach uses the Kac-Rice formula, as
described in (Adler & Taylor 2007). The resulting formula is exact in finite
samples, requiring only Gaussianity of the errors. We apply the formula to the
lasso, group lasso, and principal components and matrix completion problems. In
the case of the lasso, the new test relates closely to the recently proposed
covariance test of Lockhart et al. (2013).


title: Fourth generation Majorana neutrino, dark matter and Higgs physics

abstract:
  We consider extensions of the standard model with fourth generation fermions
(SM4) in which extra symmetries are introduced such that the transitions
between the fourth generation fermions and the ones in the first three
generations are forbidden. In these models, the stringent lower bounds on the
masses of fourth generation quarks from direct searches are relaxed, and the
lightest fourth neutrino is allowed to be stable and light enough to trigger
the Higgs boson invisible decay. In addition, the fourth Majorana neutrino can
be a subdominant but highly detectable dark matter component. We perform a
global analysis of the current LHC data on the Higgs production and decay in
this type of SM4. The results show that the mass of the lightest fourth
Majorana neutrino is confined in the range $\sim 41-59$ GeV. Within the allowed
parameter space, the predicted effective cross-section for spin-independent
DM-nucleus scattering is $\sim 3\times 10^{-48}-6\times 10^{-46}
\text{cm}^{2}$, which is close to the current Xenon100 upper limit and is
within the reach of the Xenon1T experiment in the near future. The predicted
spin-dependent cross sections can also reach $\sim 8\times
10^{-40}\text{cm}^{2}$.


title:
Fuchsian Groups, Circularly Ordered Groups, and Dense Invariant
  Laminations on the Circle

abstract:
  We propose a program to study groups acting faithfully on S^1 in terms of
number of pairwise transverse dense invariant laminations. We give some
examples of groups which admit a small number of invariant laminations as an
introduction to such groups. Main focus of the present paper is to characterize
Fuchsian groups in this scheme. We prove a group acting on S^1 is conjugate to
a Fuchsian group if and only if it admits three very-full laminations with a
variation of the transversality condition. Some partial results toward a
similar characterization of hyperbolic 3-manifold groups which fiber over the
circle have been obtained. This work was motivated by the universal circle
theory for tautly foliated 3-manifolds developed by Thurston and
Calegari-Dunfield.


title:
Crack Formation in the Presence of an Electric Field in Droplets of
  Laponite Gel

abstract:
  When a colloidal gel dries through evaporation, cracks are usually formed,
which often reveal underlying processes at work during desiccation. Desiccating
colloid droplets of few hundred $\mu l$ size show interesting effects of
pattern formation and cracking which makes this an active subject of current
research. Since aqueous gels of clay are known to be strongly affected by an
electric field, one may expect crack patterns to exhibit a field effect. In the
present study we allow droplets of laponite gel to dry under a radial electric
field. This gives rise to highly reproducible patterns of cracks, which depend
on the strength, direction and time of exposure to the electric field. For a
continuously applied DC voltage, cracks always appear on dissipation of a
certain constant amount of energy. If the field is switched off before cracks
appear, the observed results are shown to obey a number of empirical scaling
relations, which enable us to predict the time of appearance and the number of
cracks under specified conditions.


title:
Sur une conjecture de Kato et Kuzumaki concernant les hypersurfaces de
  Fano

abstract:
  Nous montrons que les corps p-adiques et les corps de nombres totalement
imaginaires v\'erifient la propri\'et\'e C_1^1 conjectur\'ee par Kato et
Kuzumaki en 1986. Autrement dit, si k est l'un de ces corps et f(x_0, ..., x_n)
est un polyn\^ome homog\`ene de degr\'e au plus n \`a coefficients dans k, tout
\'el\'ement de k s'\'ecrit comme produit de normes depuis des extensions finies
de k dans lesquelles f admet un z\'ero non trivial. Nous \'etablissons aussi la
conjecture d'Ax sur les corps pseudo-alg\'ebriquement clos parfaits pour les
corps dont le groupe de Galois absolu est un pro-p-groupe.
  -----
  We prove that p-adic fields as well as totally imaginary number fields
satisfy the C_1^1 property conjectured by Kato and Kuzumaki in 1986. In other
words, if k denotes such a field and f(x_0, ..., x_n) is a homogeneous
polynomial of degree at most n with coefficients in k, every element of k may
be written as a product of norms from finite extensions of k in which f
possesses a nontrivial zero. As a by-product of the proof, we also establish
Ax's conjecture about perfect pseudo-algebraically closed fields for fields
whose absolute Galois group is a pro-p-group.


title:
Effect of assessment error and private information on stern-judging in
  indirect reciprocity

abstract:
  Stern-judging is one of the best-known assessment rules in indirect
reciprocity. Indirect reciprocity is a fundamental mechanism for the evolution
of cooperation. It relies on mutual monitoring and assessments, i.e.,
individuals judge, following their own assessment rules, whether other
individuals are "good" or "bad" according to information on their past
behaviors. Among many assessment rules, stern-judging is known to provide
stable cooperation in a population, as observed when all members in the
population know all about others' behaviors (public information case) and when
the members never commit an assessment error. In this paper, the effect of
assessment error and private information on stern-judging is investigated. By
analyzing the image matrix, which describes who is good in the eyes of whom in
the population, we analytically show that private information and assessment
error cause the collapse of stern-judging: all individuals assess other
individuals as "good" at random with a probability of 1/2.


title:
Quasiisometries of negatively curved homogeneous manifolds associated
  with Heisenberg groups

abstract:
  We study quasiisometries between negatively curved homogeneous manifolds
associated with diagonalizable derivations on Heisenberg algebras. We classify
these manifolds up to quasiisometry, and show that all quasiisometries between
such manifolds (except when they are complex hyperbolic spaces) are almost
similarities. We prove these results by studying the quasisymmetric maps on the
ideal boundary of these manifolds.


title: Quasiconformal maps on model Filiform groups

abstract:
  We describe all quasiconformal maps on the higher (real and complex) model
Filiform groups equipped with the Carnot metric, including non-smooth ones.
These maps have very special forms. In particular, they are all biLipschitz and
preserve multiple foliations. The results in this paper have implications to
the large scale geometry of nilpotent Lie groups and negatively curved solvable
Lie groups.


title: Rigidity of quasiconformal maps on Carnot groups

abstract:
  We show that quasiconformal maps on many Carnot groups must be biLipschitz.
In particular, this is the case for 2-step Carnot groups with reducible first
layer. These results have implications for the rigidity of quasiisometries
between negatively curved solvable Lie groups.


title: A slow bar in the dwarf irregular galaxy NGC 3741

abstract:
  Using the Tremaine-Weinberg method, we measure the speed of the HI bar seen
in the disk of NGC 3741. NGC 3741 is an extremely gas rich galaxy with an
{H\,{\sc i}} disk which extends to about 8.3 times its Holmberg radius. It is
also highly dark matter-dominated. Our calculated value of the pattern speed
$\Omega_p$ is 17.1 $\pm$ 3.4 km $\textrm{s}^{-1}\textrm{kpc}^{-1}$. We also
find the ratio of the co-rotation radius to the bar semi-major axis to be (1.6
$\pm$ 0.3), indicating a slow bar. This is consistent with bar models in which
dynamical friction results in a slow bar in dark matter dominated galaxies.


title: Irreducible Characters of Kac-Moody Lie superalgebras

abstract:
  Generalizing the super duality formalism for finite-dimensional Lie
superalgebras of type $ABCD$, we establish an equivalence between parabolic BGG
categories of a Kac-Moody Lie superalgebra and a Kac-Moody Lie algebra. The
characters for a large family of irreducible highest weight modules over a
symmetrizable Kac-Moody Lie superalgebra are then given in terms of
Kazhdan-Lusztig polynomials for the first time. We formulate a notion of
integrable modules over a symmetrizable Kac-Moody Lie superalgebra via super
duality, and show that these integrable modules form a semisimple tensor
subcategory, whose Littlewood-Richardson tensor product multiplicities coincide
with those in the Kac-Moody algebra setting.


title: Quasiconformal maps on non-rigid Carnot groups

abstract:
  We study quasiconformal maps on non-rigid Carnot groups equipped with Carnot
metric. We show that for most non-rigid Carnot groups N, all quasiconformal
maps on N must be biLipschitz.


title:
Dipole-dipole interactions in protein-protein complexes: a quantum
  mechanical study of the ubiquitin-Dsk2 complex

abstract:
  Quantum mechanical calculations are performed on the proteins that constitute
the ubiquitin-Dsk2 complex whose atomic structure has been experimentally
determined by NMR spectroscopy (PDB id 1WR1). The results indicate that the
dipole moment vectors of the two proteins are aligned in a head-to-tail
orientation while forming and angle of ~130{\deg}. Hence, attractive
dipole-dipole interactions not only stabilize the protein-protein complex but
they are likely to favor the correct orientation of the proteins during the
formation of the complex.


title:
Divergence of Dynamical Conductivity at Certain Percolative
  Superconductor-Insulator Transitions

abstract:
  Random inductor-capacitor (LC) networks can exhibit percolative
superconductor-insulator transitions (SITs). We use a simple and efficient
algorithm to compute the dynamical conductivity \sigma(\omega,p) of one type of
LC network on large (4000 x 4000) square lattices, where \delta=p-p_c is the
tuning parameter for the SIT. We confirm that the conductivity obeys a scaling
form, so that the characteristic frequency scales as \Omega ~ |\delta|^{\nu z}
with \nu z \approx 1.91, the superfluid stiffness scales as \Upsilon ~
|\delta|^t with t \approx 1.3, and the electric susceptibility scales as \chi_E
~ |\delta|^{-s} with s = 2\nu z - t \approx 2.52. In the insulating state, the
low-frequency dissipative conductivity is exponentially small, whereas in the
superconductor, it is linear in frequency. The sign of Im \sigma(\omega) at
small \omega changes across the SIT. Most importantly, we find that right at
the SIT Re \sigma(\omega) ~ \omega^{t/\nu z-1} ~ \omega^{-0.32}, so that the
conductivity diverges in the DC limit, in contrast with most other classical
and quantum models of SITs.


title: Some examples of quasiisometries of nilpotent Lie groups

abstract:
  We construct quasiisometries of nilpotent Lie groups. In particular, for any
simply connected nilpotent Lie group N, we construct quasiisometries from N to
itself that is not at finite distance from any map that is a composition of
left translations and automorphisms. We also construct biLipschitz maps of the
Heisenberg groups that send vertical lines to non-vertical curves.


title: Separability and Dynamical Symmetry of Quantum Dots

abstract:
  The separability and Runge-Lenz-type dynamical symmetry of the internal
dynamics of certain two-electron Quantum Dots, found by Simonovi\'c et al. [1],
is traced back to that of the perturbed Kepler problem. A large class of
axially symmetric perturbing potentials which allow for separation in parabolic
coordinates can easily be found. Apart of the 2:1 anisotropic harmonic trapping
potential considered in [1], they include a constant electric field parallel to
the magnetic field (Stark effect), the ring-shaped Hartmann potential, etc. The
harmonic case is studied in detail.


title: On extensions of completely simple semigroups by groups

abstract:
  An example of an extension of a completely simple semigroup U by a group H is
given which cannot be embedded into the wreath product of U by H. On the other
hand, every central extension of U by H is shown to be embeddable in the wreath
product of U by H, and any extension of U by H is proved to be embeddable in a
semidirect product of a completely simple semigroup V by H where the maximal
subgroups of V are direct powers of those of U.


title: Precoloring extension involving pairs of vertices of small distance

abstract:
  In this paper, we consider coloring of graphs under the assumption that some
vertices are already colored. Let $G$ be an $r$-colorable graph and let
$P\subset V(G)$. Albertson [J.\ Combin.\ Theory Ser. B \textbf{73} (1998),
189--194] has proved that if every pair of vertices in $P$ have distance at
least four, then every $(r+1)$-coloring of $G[P]$ can be extended to an
$(r+1)$-coloring of $G$, where $G[P]$ is the subgraph of $G$ induced by $P$. In
this paper, we allow $P$ to have pairs of vertices of distance at most three,
and investigate how the number of such pairs affects the number of colors we
need to extend the coloring of $G[P]$. We also study the effect of pairs of
vertices of distance at most two, and extend the result by Albertson and Moore
[J.\ Combin.\ Theory Ser. B \textbf{77} (1999) 83--95].


title: Multigraphs with $\Delta \ge 3$ are Totally-$(2\Delta-1)$-choosable

abstract:
  The \emph{total graph} $T(G)$ of a multigraph $G$ has as its vertices the set
of edges and vertices of $G$ and has an edge between two vertices if their
corresponding elements are either adjacent or incident in $G$. We show that if
$G$ has maximum degree $\Delta(G)$, then $T(G)$ is $(2\Delta(G)-1)$-choosable.
We give a linear-time algorithm that produces such a coloring. The best
previous general upper bound for $\Delta(G) > 3$ was
$\floor{\frac32\Delta(G)+2}$, by Borodin et al. When $\Delta(G)=4$, our
algorithm gives a better upper bound. When $\Delta(G)\in\{3,5,6\}$, our
algorithm matches the best known bound. However, because our algorithm is
significantly simpler, it runs in linear time (unlike the algorithm of Borodin
et al.).


title:
Engineered optical nonlinearities and enhanced light transmission in
  soft-matter systems with tunable polarizabilities

abstract:
  In this work, we demonstrate that the nonlinear response of certain
soft-matter systems can be tailored at will by appropriately engineering their
optical polarizability. In particular, we deliberately synthesize stable
colloidal suspensions with negative polarizabilities, and observe for the first
time robust propagation and enhanced transmission of self-trapped light over
long distances that would have been otherwise impossible in conventional
suspensions with positive polarizabilities. What greatly facilitates this
behavior is an induced saturable nonlinear optical response introduced by the
thermodynamic properties of these colloidal systems. This in turn leads to a
substantial reduction in scattering via self-activated transparency effects.
Our results may open up new opportunities in developing soft-matter systems
with tunable optical nonlinearities.


title: A field theoretic model for static friction

abstract:
  We present a field theoretic model for friction, where the friction
coefficient between two surfaces may be calculated based on elastic properties
of the surfaces. We assume that the geometry of contact surface is not unusual.
We verify Amonton's laws to hold that friction force is proportional to the
normal load.This model gives the opportunity to calculate the static
coefficient of friction for a few cases, and show that it is in agreement with
observed values. Furthermore we show that the coefficient of static friction is
independent of apparent surface area in first approximation.


title:
Energy and centrality dependence of chemical freeze-out parameters from
  models

abstract:
  One of the main goals of heavy-ion collision experiments is to study the
structure of the QCD phase diagram. The QCD phase diagram is typically plotted
as temperature ($T$) vs. baryon chemical potential ($\mu_{B}$). The statistical
thermal model THERMUS compared to experimental data provides chemical
freeze-out parameters such as temperature, baryon chemical potential and
strangeness saturation factor ($\gamma_{s}$). However, the values of these
parameters depend on models and their underlying assumptions, such as the
nature of the ensemble used, particle ratios vs. particle yields, and the
treatment of feed-down contributions to particle yields. In these proceedings,
we report on a systematic study of chemical freeze-out parameters using
THERMUS, as a function of collision centrality and collision energies
($\sqrt{s_{NN}} =7.7-200$ GeV). These studies are performed with the string
melting version of A Multi-Phase Transport (AMPT) model. A comparison is
presented of freeze-out parameters between grand-canonical vs. strangeness
canonical ensembles, particle yields vs. ratios, with and without feed-down
contributions to the particle yields. The main aim is to evaluate the
sensitivity of the thermal model fits to various model assumptions. This is an
important study for understanding corresponding experimental results from the
beam energy scan program at RHIC.


title:
Excitation- and state-transfer through spin chains in the presence of
  spatially correlated noise

abstract:
  We investigate the influence of environmental noise on spin networks and spin
chains. In addition to the common model of an independent bath for each spin in
the system we also consider noise with a finite spatial correlation length. We
present the emergence of new dynamics and decoherence-free subspaces with
increasing correlation length for both dephasing and dissipating environments.
This leads to relaxation blocking of one spin by uncoupled surrounding spins.
We then consider perfect state transfer through a spin chain in the presence of
decoherence and discuss the dependence of the transfer quality on spatial noise
correlation length. We identify qualitatively different features for dephasing
and dissipative environments in spin-transfer problems.


title:
Multilepton Signatures of the Higgs Boson through its Production in
  Association with a Top-quark Pair

abstract:
  We consider the possible production of the Higgs Boson in association with a
top-quark pair and its subsequent decay into a tau-lepton pair or a W-boson
pair. This process can give rise to many signatures of the Higgs boson. These
signatures can have electrons, muons, tau jets, bottom jets and/or light
flavour jets. We analyze the viability of some of these signatures. We will
look at those signatures where the background is minimal. In particular, we
explore the viability of the signatures "isolated 4 electron/muon" and
"isolated 3 electron/muon + a jet" The jet can be due to a light flavour
quark/gluon, a bottom quark, or a tau lepton. Of all these signatures, we find
that "isolated 3 electron/muon + a tau jet", with an extra bottom jet, can be
an excellent signature of this mode of the Higgs boson production. We show that
this signature may be visible within a year, once the Large Hadron Collider
(LHC) restarts. Some of the other signatures would also be observable after the
LHC accumulates sufficient luminosity.


title:
Nonperturbative analysis of the evolution of cosmological perturbations
  through a nonsingular bounce

abstract:
  In bouncing cosmology, the primordial fluctuations are generated in a cosmic
contraction phase before the bounce into the current expansion phase. For a
nonsingular bounce, curvature and anisotropy grow rapidly during the bouncing
phase, raising questions about the reliability of perturbative analysis. In
this paper, we study the evolution of adiabatic perturbations in a nonsingular
bounce by nonperturbative methods including numerical simulations of the
nonsingular bounce and the covariant formalism for calculating nonlinear
perturbations. We show that the bounce is disrupted in regions of the universe
with significant inhomogeneity and anisotropy over the background energy
density, but is achieved in regions that are relatively homogeneous and
isotropic. Sufficiently small perturbations, consistent with observational
constraints, can pass through the nonsingular bounce with negligible alteration
from nonlinearity. We follow scale invariant perturbations generated in a
matter-like contraction phase through the bounce. Their amplitude in the
expansion phase is determined by the growing mode in the contraction phase, and
the scale invariance is well preserved across the bounce.


title:
Influence of the voltage taps position on the self-field DC and AC
  transport characterization of HTS superconducting tapes

abstract:
  The current-voltage (I-V) curve is the basic characteristic of a
superconducting wire or tape. Measuring I-V curves is generally problematic
when samples have poor stabilization. Soldering voltage taps to an active part
of the conductor affects the effectiveness of the local cooling and/or can be
difficult to do in certain devices such as fault current limiters and cables
where the tapes are closely packed. In order to overcome these problems,
voltage taps can be placed outside the active area of the superconductor. We
proved both by simulations and experiments that this arrangement leads to the
same results as the standard four point method and it provides more detailed
information for sample protection. The same arrangement can also be used for AC
transport loss measurement. However in this case particular care has to be
taken because the eddy current loss in the current leads contributes to the
total measured loss. We used numerical simulations to evaluate the contribution
of the eddy current loss to the measured AC loss. With help of simulations one
can determine whether the contribution of the eddy current loss is significant
and possibly optimize the current leads to reduce that loss contribution.


title:
Choice number of complete multipartite graphs $K_{3*3,2*(k-5),1*2}$ and
  $K_{4,3*2,2*(k-6),1*3}$

abstract:
  A graph $G$ is called \emph{chromatic-choosable} if its choice number is
equal to its chromatic number, namely $Ch(G)=\chi(G)$. Ohba has conjectured
that every graph $G$ satisfying $|V(G)|\leq 2\chi(G)+1$ is chromatic-choosable.
Since each $k$-chromatic graph is a subgraph of a complete $k$-partite graph,
we see that Ohba's conjecture is true if and only if it is true for every
complete multipartite graph. However, the only complete multipartite graphs for
which Ohba's conjecture has been verified are:
  $K_{3*2,2*(k-3),1}$, $K_{3,2*(k-1)}$, $K_{s+3,2*(k-s-1),1*s}$,
$K_{4,3,2*(k-4),1*2}$, and $K_{5,3,2*(k-5),1*3}$.
  In this paper, we show that Ohba's conjecture is true for two new classes of
complete multipartite graphs: graphs with three parts of size 3 and graphs with
one part of size 4 and two parts of size 3. Namely, we prove that
$Ch(K_{3*3,2*(k-5),1*2})=k$ and $Ch(K_{4,3*2,2*(k-6),1*3})=k$ (for $k\geq 5$
and $k\geq 6$, respectively).


title:
Perspectives of Micro-Pattern Gaseous Detector Technologies for Future
  Physics Projects

abstract:
  A centenary after the invention of the basic principle of gas amplification,
gaseous detectors - are still the first choice whenever the large area coverage
with low material budget is required. Advances in photo-lithography and
micro-processing techniques in the chip industry during the past two decades
triggered a major transition in the field of gas detectors from wire structures
to Micro-Pattern Gas Detector (MPGD) concepts, revolutionizing cell-size
limitations for many gas detector applications. The high radiation resistance
and excellent spatial and time resolution make them an invaluable tool to
confront future detector challenges at the frontiers of research. The design of
the new micro-pattern devices appears suitable for industrial production. In
2008, the RD51 collaboration at CERN has been established to further advance
technological developments of MPGDs and associated electronic-readout systems,
for applications in basic and applied research. This review provides an
overview of the state-of-the-art of the MPGD technologies and summarizes recent
activities for the next generation of colliders within the framework of the
RD51 collaboration.


title:
Reactivity Boundaries to Separate the Fate of a Chemical Reaction
  Associated with Multiple Saddles

abstract:
  Reactivity boundaries that divide the origin and destination of trajectories
are crucial of importance to reveal the mechanism of reactions, which was
recently found to exist robustly even at high energies for index-one saddles
[Phys. Rev. Lett. 105, 048304 (2010)]. Here we revisit the concept of the
reactivity boundary and propose a more general definition that can involve a
single reaction associated with a bottleneck made up of higher index saddles
and/or several saddle points with different indices, where the normal form
theory, based on expansion around a single stationary point, does not work. We
numerically demonstrate the reactivity boundary by using a reduced model system
of the $H^+_5$ cation where the proton exchange reaction takes place through a
bottleneck made up of two index-two saddle points and two index-one saddle
points. The cross section of the reactivity boundary in the reactant region of
the phase space reveals which initial conditions are effective in making the
reaction happen, and thus sheds light on the reaction mechanism.


title: Reentrant classicality of a damped system

abstract:
  For a free particle, the coupling to its environment can be the relevant
mechanism to induce quantum behavior as the temperature is lowered. We study
general linear environments with a spectral density proportional to {\omega}^s
at low frequencies and consider in particular the specific heat of the free
damped particle. For super-Ohmic baths with s>=2, a reentrant classical
behavior is found. As the temperature is lowered, the specific heat decreases
from the classical value of k_B/2, thereby indicating the appearence of quantum
effects. However, the classical value of the specific heat is restored as the
temperature approaches zero. This surprising behavior is due to the suppressed
density of bath degrees of freedom at low frequencies. For s<2, the specific
heat at zero temperature increases linearly with s from -k_B/2 to k_B/2. An
Ohmic bath, s=1, is thus very special in the sense that it represents the only
case where the specific heat vanishes at zero temperature.


title:
Structural, Vibrational, Elastic and Topological Properties of PaN Under
  Pressure

abstract:
  Electronic, structural, vibrational and elastic properties of PaN have been
studied both at ambient and high pressures, using first principles methods with
several commonly used parameterizations of the exchange-correlation energy. The
generalized gradient approximation (GGA) reproduces the ground state properties
satisfactorily. Under pressure PaN is found to undergo a structural transition
from NaCl to the R-3m structure near 58 GPa. The high pressure behavior of the
acoustic phonon branch along the (1,0,0) and (1,1,0) directions, and the C44
elastic constant are anomalous, which signals the structural transition. With
GGA exchange-correlation, a topological transition in the charge density occurs
near the structural transition which may be regarded as a quantum phase
transition, where the order parameter obeys a mean field scaling law. However,
the topological transition is absent when other exchange-correlation
functionals are invoked (local density approximation (LDA) and hybrid
functional). Therefore, this constitutes an example of GGA and LDA leading to
qualitatively different predictions, and it is of great interest to examine
experimentally whether this topological transition occurs.


title:
Laser Beam Profile Influence on LIBS Analytical Capabilities: Single vs.
  Multimode Beam

abstract:
  Single vs. multimode laser beams have been compared for laser ablation on
steel samples. Laser plasma properties and analytical capabilities (precision,
limit of detection) were used as key parameters for comparison. Peak fluence at
focal spot has been observed to be higher for Gaussian beam despite ~14-fold
lower pulse energy. A comparison of Gaussian and multimode beams with equal
energy was carried out in order to estimate influence of beam profile only.
Single mode lasing (Gaussian beam) results in better reproducibility of
analytical signals compared to multimode lasing while laser energy
reproducibility was the same for both cases. Precision improvements were
attributed to more stable laser ablation due to better reproducibility of beam
profile fluence at laser spot. Plasma temperature and electron density were
higher for Gaussian laser beam. Calibration curves were obtained for four
elements under study (Cr, Mn, Si, Cu). Two sampling (drilling and scanning
procedures) and two optical detection schemes (side-view and optical fiber)
were used to compare Gaussian and multimode beam profile influence on
analytical capabilities of LIBS. We have found that multimode beam sampling was
strongly influenced by surface effects (impurities, defects etc.). For all
sampling and detection schemes, better precision was obtained if Gaussian beam
was used for sampling. In case of single-spot sampling better limits of
detection were achieved for multimode beam. If laser sources have same
wavelength and equal energy than quality of laser beam became a crucial
parameter which determined plasma properties and analytical capabilities of
LIBS


title:
Gradient Magnitude Similarity Deviation: A Highly Efficient Perceptual
  Image Quality Index

abstract:
  It is an important task to faithfully evaluate the perceptual quality of
output images in many applications such as image compression, image restoration
and multimedia streaming. A good image quality assessment (IQA) model should
not only deliver high quality prediction accuracy but also be computationally
efficient. The efficiency of IQA metrics is becoming particularly important due
to the increasing proliferation of high-volume visual data in high-speed
networks. We present a new effective and efficient IQA model, called gradient
magnitude similarity deviation (GMSD). The image gradients are sensitive to
image distortions, while different local structures in a distorted image suffer
different degrees of degradations. This motivates us to explore the use of
global variation of gradient based local quality map for overall image quality
prediction. We find that the pixel-wise gradient magnitude similarity (GMS)
between the reference and distorted images combined with a novel pooling
strategy the standard deviation of the GMS map can predict accurately
perceptual image quality. The resulting GMSD algorithm is much faster than most
state-of-the-art IQA methods, and delivers highly competitive prediction
accuracy.


title: Rotating hybrid compact stars

abstract:
  Starting from equations of state of nucleonic and color-superconducting quark
matter and assuming a first-order phase transition between these, we construct
an equation of state of stellar matter, which contains three phases: a
nucleonic phase, as well as two-flavor and three-flavor color-superconducting
phases of quarks. Static sequences of the corresponding hybrid stars include
massive members with masses of $\sim 2 M_{\odot}$ and radii in the range of
$13< R < 16$ km. We investigate the integral parameters of rapidly rotating
stars and obtain evolutionary sequences that correspond to constant rest-mass
stars spinning down by electromagnetic and gravitational radiation. Physically
new transitional sequences are revealed that are distinguished by a phase
transition from nucleonic to color-superconducting matter for some
configurations that are located between the static and Keplerian limits. The
snapshots of internal structure of the star, displaying the growth or shrinkage
of superconducting volume as the star's spin changes, are displayed for
constant rest mass stars. We further obtain evolutionary sequences of rotating
supramassive compact stars and construct pre-collapse models that can be used
as initial data to simulate a collapse of color-superconducting hybrid stars to
a black hole.


title:
Corrections for tribimaximal, bimaximal and democratic neutrino mixing
  matrices

abstract:
  In this work we analyze the corrections to tribimaximal (TBM), bimaximal (BM)
and democratic (DC) mixing matrices for explaining large reactor mixing angle
$\theta_{13}$ and checking the consistency with other neutrino mixing angles.
The corrections are parameterized in terms of small orthogonal rotations (R)
with corresponding modified PMNS matrix of the form $R_{ij}\cdot U \cdot
R_{kl}$ where $R_{ij}$ is rotation in ij sector and U is any one of these
special matrices. We showed the rotations $R_{13}\cdot U \cdot R_{23}$,
$R_{12}\cdot U \cdot R_{13}$ for BM and $R_{13}\cdot U \cdot R_{13}$ for TBM
perturbative case successfully fit all neutrino mixing angles within $1\sigma$
range. The perturbed PMNS matrix $R_{12}\cdot U \cdot R_{13}$ for DC, TBM and
$R_{23}\cdot U \cdot R_{23}$ for TBM case is successful in producing mixing
angles at 2$\sigma$ level. The other rotation schemes are either excluded or
successful in producing mixing angles at $3\sigma$ level.


title:
Specht's problem for associative affine algebras over commutative
  Noetherian rings

abstract:
  In a series of papers \cite{BRV1}, \cite{BRV2}, \cite{BRV3} we introduced
full quivers and pseudo-quivers of representations of algebras, and used them
as tools in describing PI-varieties of algebras. In this paper we apply them to
obtain a complete proof of Belov's solution of Specht's problem for affine
algebras over an arbitrary Noetherian ring. The inductive step relies on a
theorem that enables one to find a "$\bar q$-characteristic
coefficient-absorbing polynomial in each T-ideal $\Gamma$," i.e., a
non-identity of the representable algebra $A$ arising from $\Gamma$, whose
ideal of evaluations in $A$ is closed under multiplication by $\bar q$-powers
of the characteristic coefficients of matrices corresponding to the generators
of $A$, where $\bar q$ is a suitably large power of the order of the base
field. The passage to an arbitrary Noetherian base ring $C$ involves localizing
at finitely many elements a kind of $C$, and reducing to the field case by a
local-global principle.


title:
Local scaling asymptotics in phase space and time in Berezin-Toeplitz
  quantization

abstract:
  This paper deals with the local semiclassical asymptotics of a quantum
evolution operator in the Berezin-Toeplitz scheme, when both time and phase
space variables are subject to appropriate scalings in the neighborhood of the
graph of the underlying classical dynamics. Global consequences are then drawn
regarding the scaling asymptotics of the trace of the quantum evolution as a
function of time.


title:
Correlation effects and phonon modes softening with doping in
  Ba1-xKxBiO3

abstract:
  Monoclinic crystal structure of the undoped BaBiO3 can be described as a
cubic perovskite distorted by a frozen breathing and tilting phonon modes of
BiO6 octahedra. The phonon mode softening is experimentally observed [M. Braden
et al., Europhysics Letters (EPL) 34, 531 (1996)] in Ba1-xKxBiO3 through
potassium doping followed by a transition into an ideal cubic perovskite
structure at x = 0.37 close to the appearance of superconductivity. In our
previous paper [D. Korotin et al., Journal of Physics: Condensed Matter 24,
415603 (2012)] we demonstrated that it is necessary to take into account
correlation effects by DFT+U method in Wannier functions basis to obtain a good
agreement between the calculated and experimental values of crystal structure
distortion and energy gap in BaBiO3. In the present work with the same method
we calculated the breathing mode phonon frequencies as a function of potassium
doping level in Ba1-xKxBiO3. Obtained frequencies are in a good agreement with
experimental values and the breathing mode softening with doping effect is
reproduced while calculations without consideration of correlation effects
failed to do so. We shown that the cubic crystal structure becomes stable at x
= 0.30 in agreement with the experimental transition to cubic perovskite at x =
0.37. The possible connections between the correlation effects, phonon mode
softening, and superconductivity in Ba1-xKxBiO3 are discussed.


title: Phase Retrieval for Sparse Signals: Uniqueness Conditions

abstract:
  In a variety of fields, in particular those involving imaging and optics, we
often measure signals whose phase is missing or has been irremediably
distorted. Phase retrieval attempts the recovery of the phase information of a
signal from the magnitude of its Fourier transform to enable the reconstruction
of the original signal. A fundamental question then is: "Under which conditions
can we uniquely recover the signal of interest from its measured magnitudes?"
In this paper, we assume the measured signal to be sparse. This is a natural
assumption in many applications, such as X-ray crystallography, speckle imaging
and blind channel estimation. In this work, we derive a sufficient condition
for the uniqueness of the solution of the phase retrieval (PR) problem for both
discrete and continuous domains, and for one and multi-dimensional domains.
More precisely, we show that there is a strong connection between PR and the
turnpike problem, a classic combinatorial problem. We also prove that the
existence of collisions in the autocorrelation function of the signal may
preclude the uniqueness of the solution of PR. Then, assuming the absence of
collisions, we prove that the solution is almost surely unique on 1-dimensional
domains. Finally, we extend this result to multi-dimensional signals by solving
a set of 1-dimensional problems. We show that the solution of the
multi-dimensional problem is unique when the autocorrelation function has no
collisions, significantly improving upon a previously known result.


title:
Membership in social networks and the application in information
  filtering

abstract:
  During the past a few years, users' membership in the online system (i.e. the
social groups that online users joined) are wildly investigated. Most of these
works focus on the detection, formulation and growth of online communities. In
this paper, we study users' membership in a coupled system which contains
user-group and user-object bipartite networks. By linking users' membership
information and their object selection, we find that the users who have
collected only a few objects are more likely to be "influenced" by the
membership when choosing objects. Moreover, we observe that some users may join
many online communities though they collected few objects. Based on these
findings, we design a social diffusion recommendation algorithm which can
effectively solve the user cold-start problem. Finally, we propose a
personalized combination of our method and the hybrid method in [PNAS 107, 4511
(2010)], which leads to a further improvement in the overall recommendation
performance.


title:
Information filtering in sparse online systems: recommendation via
  semi-local diffusion

abstract:
  With the rapid growth of the Internet and overwhelming amount of information
and choices that people are confronted with, recommender systems have been
developed to effectively support users' decision-making process in the online
systems. However, many recommendation algorithms suffer from the data sparsity
problem, i.e. the user-object bipartite networks are so sparse that algorithms
cannot accurately recommend objects for users. This data sparsity problem makes
many well-known recommendation algorithms perform poorly. To solve the problem,
we propose a recommendation algorithm based on the semi-local diffusion process
on a user-object bipartite network. The numerical simulation on two sparse
datasets, Amazon and Bookcross, show that our method significantly outperforms
the state-of-the-art methods especially for those small-degree users. Two
personalized semi-local diffusion methods are proposed which further improve
the recommendation accuracy. Finally, our work indicates that sparse online
systems are essentially different from the dense online systems, all the
algorithms and conclusions based on dense data should be rechecked again in
sparse data.


title:
Constraints on 3-flavor QCD order parameters from eta to pi+pi-pi0 decay
  width

abstract:
  Quark condensate and pseudoscalar decay constant in the chiral limit are the
principal order parameters of spontaneous chiral symmetry breaking in QCD. Yet
their three flavor values are still only weakly constrained by analyses using
experimental data. We try to obtain such constraints by statistical methods
from the decay width of the eta to pi+pi-pi0 decay in the framework of resummed
chiral perturbation theory. We rely on recent estimates of the isospin
violating parameter R, which is proportional to the difference of the u and d
quark masses. Alternatively, we relax the assumption and try to extract
information on R as well.


title:
Terrace-like structure in the above-threshold ionization spectrum of an
  atom in an IR+XUV two-color laser field

abstract:
  Based on the frequency-domain theory, we investigate the above-threshold
ionization (ATI) process of an atom in a two-color laser field with infrared
(IR) and extreme ultraviolet (XUV) frequencies, where the photon energy of the
XUV laser is close to or larger than the atomic ionization threshold. By using
the channel analysis, we find that the two laser fields play different roles in
an ionization process, where the XUV laser determines the ionization
probability by the photon number that the atom absorbs from it, while the IR
laser accelerates the ionized electron and hence widens the electron kinetic
energy spectrum. As a result, the ATI spectrum presents a terrace-like
structure. By using the saddle-point approximation, we obtain a classical
formula which can predict the cutoff of each plateau in the terrace-like ATI
spectrum. Furthermore, we find that the difference of the heights between two
neighboring plateaus in the terrace-like structure of the ATI spectrum
increases as the frequency of the XUV laser increases.


title: Geometric structure for the tangent bundle of direct limit manifolds

abstract:
  We equip the direct limit of tangent bundles of paracompact finite
dimensional manifolds with a structure of convenient vector bundle with
structural group $GL(\infty,\mathbb{R})
=\underrightarrow{\lim}GL(\mathbb{R}^{n})$.


title: Outliers in the Single Ring Theorem

abstract:
  This text is about spiked models of non Hermitian random matrices. More
specifically, we consider matrices of the type $A+P$, where the rank of $P$
stays bounded as the dimension goes to infinity and where the matrix $A$ is a
non Hermitian random matrix, satisfying an isotropy hypothesis: its
distribution is invariant under the left and right actions of the unitary
group. The macroscopic eigenvalue distribution of such matrices is governed by
the so called Single Ring Theorem, due to Guionnet, Krishnapur and Zeitouni. We
first prove that if $P$ has some eigenvalues out of the maximal circle of the
single ring, then $A+P$ has some eigenvalues (called outliers) in the
neighborhood of those of $P$, which is not the case for the eigenvalues of $P$
in the inner cycle of the single ring. Then, we study the fluctuations of the
outliers of $A$ around the eigenvalues of $P$ and prove that they are
distributed as the eigenvalues of some finite dimensional random matrices. Such
facts had already been noticed for Hermitian models. More surprising facts are
that outliers can here have very various rates of convergence to their limits
(depending on the Jordan Canonical Form of $P$) and that some correlations can
appear between outliers at a macroscopic distance from each other (a fact
already noticed by Knowles and Yin in the Hermitian case, but only in the case
of non Gaussian models, whereas spiked Gaussian matrices belong to our model
and can have such correlated outliers). Our first result generalizes a previous
result by Tao for matrices with i.i.d. entries, whereas the second one (about
the fluctuations) is new.


title: Group theoretical construction of planar Noncommutative Phase Spaces

abstract:
  Noncommutative phase spaces are generated and classified in the framework of
centrally extended anisotropic planar kinematical Lie groups as well as in the
framework of noncentrally extended planar absolute time Lie groups. Through
these constructions the coordinates of the phase spaces do not commute due to
the presence of naturally introduced fields giving rise to minimal couplings.
By symplectic realizations methods, physical interpretations of generators
coming from the obtained structures are given.


title: Curvilinear Grids for WENO Methods in Astrophysical Simulations

abstract:
  We investigate the applicability of curvilinear grids in the context of
astrophysical simulations and WENO schemes. With the non-smooth mapping
functions from Calhoun et al. (2008), we can tackle many astrophysical problems
which were out of scope with the standard grids in numerical astrophysics. We
describe the difficulties occurring when implementing curvilinear coordinates
into our WENO code, and how we overcome them. We illustrate the theoretical
results with numerical data. The WENO finite difference scheme works only for
high Mach number flows and smooth mapping functions whereas the finite volume
scheme gives accurate results even for low Mach number flows and on non-smooth
grids.


title: L-functions as distributions

abstract:
  We define an axiomatic class of L-functions extending the Selberg class. We
show in particular that one can recast the traditional conditions of an Euler
product, analytic continuation and functional equation in terms of
distributional identities akin to Weil's explicit formula. The generality of
our approach enables some new applications; for instance, we show that the
L-function of any cuspidal automorphic representation of GL_3(A_Q) has
infinitely many zeros of odd order.


title:
Fundamental limits and near-optimal design of graphene modulators and
  non-reciprocal devices

abstract:
  The potential of graphene for use in photonic applications was evidenced by
recent demonstrations of modulators, polarisation rotators, and isolators.
These promising yet preliminary results raise crucial questions: what is the
optimal performance achievable by more complex designs using multilayer
structures, graphene patterning, metal additions, or a combination of these
approaches, and how can this optimum design be achieved in practice? Today, the
complexity of the problem, which is magnified by the variability in graphene
parameters, leaves the design of these new devices to time-consuming and
suboptimal trial-and-error procedures. We address this issue by first
demonstrating that the relevant figures of merit for the devices above are
subject to absolute theoretical upper bounds. Strikingly these limits are
related only to the conductivity tensor of graphene; thus, we can provide
essential roadmap information such as the best possible device performance
versus wavelength and graphene quality. Second, based on the theory developed,
physical insight, and detailed simulations, we demonstrate how structures
closely approaching these fundamental limits can be designed, demonstrating the
possibility of significant improvement. These results are believed to be of
paramount importance for the design of graphene-based modulators, rotators, and
isolators and are also directly applicable to other 2-dimensional materials.


title: Electrical Detection of Spin Wave Resonance in a Permalloy Thin Strip

abstract:
  We investigated the microwave-induced DC response of spin wave resonance
(SWR) in a permalloy thin strip via electrical detection. Our experimental
results obtained by sweeping the external field reveal that: 1. the amplitude
of SWR signals depend on the direction of external field and, 2. unlike the DC
response of ferromagnetic resonance, SWR spectra are always anti-symmetrical.
The spin dynamics are discussed based on these unusual signals in resonant
condition.


title:
A structure-based model fails to probe the mechanical unfolding pathways
  of the titin I27 domain

abstract:
  We discuss the use of a structure based C$\alpha$-Go model and Langevin
dynamics to study in detail the mechanical properties and unfolding pathway of
the titin I27 domain. We show that a simple Go-model does detect correctly the
origin of the mechanical stability of this domain. The unfolding free energy
landscape parameters $x_u$ and $\Delta G^{\ddagger}$, extracted from
dependencies of unfolding forces on pulling speeds, are found to agree
reasonably well with experiments. We predict that above $v=10^4$ nm/s the
additional force-induced intermediate state is populated at an end-to-end
extension of about $75 \mathring{A}$. The force-induced switch in the unfolding
pathway occurs at the critical pulling speed $v_{crit} \approx 10^6-10^7$ nm/s.
We argue that this critical pulling speed is an upper limit of the interval
where Bell's theory works. However, our results suggest that the Go-model fails
to reproduce the experimentally observed mechanical unfolding pathway properly,
yielding an incomplete picture of the free energy landscape. Surprisingly, the
experimentally observed intermediate state with the A strand detached is not
populated in Go-model simulations over a wide range of pulling speeds. The
discrepancy between simulation and experiment is clearly seen from the early
stage of the unfolding process which shows the limitation of the Go model in
reproducing unfolding pathways and deciphering the complete picture of the free
energy landscape.