title: Violation of a new Wigner inequality with high angular momenta

abstract:
  In the study of systems that cannot be described classically, the Wigner
inequality, has received only a small amount of attention. In this paper we
extend the Wigner inequality - originally derived in 1969 - and show how it may
be used to contradict local realism with only coincidence detections in the
absence of two-outcome measurements - that is, for any system where only one
possible result of a pair of potential outcomes can be registered. It thus
encapsulates a much broader class of measurement schemes than could previously
violate a local-realistic inequality. This is possible due to an assumption of
"extended fairness" on the measurement outcomes, which we posit is highly
plausible. We then apply this inequality to a recently constructed setup with
access to entangled pairs of photons with very high angular momenta, in which
no previously derived local-realistic inequality could successfully be used
without making very broad assumptions. To our knowledge this experiment
constitutes a violation of local realism with the largest quanta to date. We
thus demonstrate the versatility of this inequality under very lossy
conditions.


title:
Anisotropic conductivity and weak localization in HgTe quantum well with
  normal energy spectrum

abstract:
  The results of experimental study of interference induced magnetoconductivity
in narrow quantum well HgTe with the normal energy spectrum are presented.
Analysis is performed with taking into account the conductivity anisotropy. It
is shown that the fitting parameter \tau_\phi corresponding to the phase
relaxation time increases in magnitude with the increasing conductivity
(\sigma) and decreasing temperature following the 1/T law. Such a behavior is
analogous to that observed in usual two-dimensional systems with simple energy
spectrum and corresponds to the inelasticity of electron-electron interaction
as the main mechanism of the phase relaxation. However, it drastically differs
from that observed in the wide HgTe quantum wells with the inverted spectrum,
in which \tau_\phi being obtained by the same way is practically independent of
\sigma. It is presumed that a different structure of the electron
multicomponent wave function for the inverted and normal quantum wells could be
reason for such a discrepancy.


title: Multispecies Virial Expansions

abstract:
  We study the virial expansion of mixtures of countably many different types
of particles. The main tool is the Lagrange-Good inversion formula, which has
other applications such as counting coloured trees or studying probability
generating functions in multi-type branching processes. We prove that the
virial expansion converges absolutely in a domain of small densities. In
addition, we establish that the virial coefficients can be expressed in terms
of two-connected graphs.


title: Avoiding dissipation in a system of three quantum harmonic oscillators

abstract:
  We analyze the symmetries in an open quantum system composed by three coupled
and detuned harmonic oscillators in the presence of a common heat bath. It is
shown analytically how to engineer the couplings and frequencies of the system
so as to have several degrees of freedom unaffected by decoherence,
irrespective of the specific spectral density or initial state of the bath.
This partial thermalization allows observing asymptotic entanglement at
moderate temperatures, even in the nonresonant case. This latter feature cannot
be seen in the simpler situation of only two oscillators, highlighting the
richer structural variety of the three-body case. When departing from the
strict conditions for partial thermalization, a hierarchical structure of
dissipation rates for the normal modes is observed, leading to a long transient
where quantum correlations such as the quantum discord are largely preserved,
as well as to synchronous dynamics of the oscillators quadratures.


title:
Dissipative ground-state preparation of a spin chain by a structured
  environment

abstract:
  We propose a dissipative method to prepare the ground state of the isotropic
XY spin Hamiltonian in a transverse field. Our model consists of a spin chain
with nearest-neighbour interactions and an additional collective coupling of
the spins to a damped harmonic oscillator. The latter provides an effective
environment with a Lorentzian spectral density and can be used to drive the
chain asymptotically towards its multipartite-entangled ground state at a rate
that depends on the degree of non-Markovianity of the evolution. We also
present a detailed proposal for the experimental implementation with a chain of
trapped ions. The protocol does not require individual addressing, concatenated
pulses, or multi-particle jump operators, and is capable of generating the
desired target state in small ion chains with very high fidelities.


title:
Two new SB2 binaries with main sequence B-type pulsators in the Kepler
  field

abstract:
  Context: OB stars are important in the chemistry and evolution of the
Universe, but the sample of targets well understood from an asteroseismological
point of view is still too limited to provide feedback on the current
evolutionary models. Our study extends this sample with two spectroscopic
binary systems. AIMS. Our goal is to provide orbital solutions, fundamental
parameters and abundances from disentangled high-resolution high
signal-to-noise spectra, as well as to analyse and interpret the variations in
the Kepler light curve of these carefully selected targets. This way we
continue our efforts to map the instability strips of beta Cep and SPB stars
using the combination of high-resolution ground-based spectroscopy and
uninterrupted space-based photometry. Methods: We fit Keplerian orbits to
radial velocities measured from selected absorption lines of high-resolution
spectroscopy using synthetic composite spectra to obtain orbital solutions. We
use revised masks to obtain optimal light curves from the original pixel-data
from the Kepler satellite, which provided better long term stability compared
to the pipeline processed light curves. We use various time-series analysis
tools to explore and describe the nature of variations present in the light
curve. Results: We find two eccentric double-lined spectroscopic binary systems
containing a total of three main sequence B-type stars (and one F-type
component) of which at least one in each system exhibits light variations. The
light curve analysis (combined with spectroscopy) of the system of two B stars
points towards the presence of tidally excited g modes in the primary
component. We interpret the variations seen in the second system as classical g
mode pulsations driven by the kappa mechanism in the B type primary, and
explain the unexpected power in the p mode region as a result of nonlinear
resonant mode excitation.


title: On radiation reaction and the Abraham-Lorentz-Dirac equation

abstract:
  It is underlined that the Lienard-Wiechert solutions indicate that after the
external force is instantly removed from a small charged particle, the field in
its close neighborhood becomes a Lorentz boosted Coulomb field. It suggests
that the force of the self-field on the particle should instantaneously vanish
after a sudden removal of the external force. A minimal modification of
Abraham-Lorentz-Dirac equation is searched seeking to implement this property.
A term assuring this behavior is added to the equation by maintaining Lorentz
covariance and vanishing scalar product with the four-velocity. The simple
Dirac constant force example does not show runaway acceleration.


title: Digraph functors which admit both left and right adjoints

abstract:
  For our purposes, two functors {\Lambda} and {\Gamma} are said to be
respectively left and right adjoints of each other if for any digraphs G and H,
there exists a homomorphism of {\Lambda}(G) to H if and only if there exists a
homomorphism of G to {\Gamma}(H). We investigate the right adjoints
characterised by Pultr in [A. Pultr, The right adjoints into the categories of
relational systems, in Reports of the Midwest Category Seminar, IV, volume 137
of Lecture Notes in Mathematics, pages 100-113, Berlin, 1970]. We find
necessary conditions for these functors to admit right adjoints themselves. We
give many examples where these necessary conditions are satisfied, and the
right adjoint indeed exists. Finally, we discuss a connection between these
right adjoints and homomorphism dualities.


title:
Spontaneous exchange bias in a nanocomposite of
  BiFeO$_3$-Bi$_2$Fe$_4$O$_9$

abstract:
  We have observed a large as well as path-dependent spontaneous exchange bias
(H$_{SEB}$) ($\sim$30-60 mT) in a nanocomposite of BiFeO$_3$-Bi$_2$Fe$_4$O$_9$
across 5-300 K when it is measured in an unmagnetized state following
zero-field cooling and appropriate demagnetization. The path dependency yields
a variation in the exchange bias depending on the sign of the starting field
and the path followed in tracing the hysteresis loop. The asymmetry thus
observed - $\Delta$H$_{SEB}$ - is found to be decreasing nonmonotonically
across 5-300 K with a peak around 200 K. The $\Delta$H$_{SEB}$ together with
large H$_{SEB}$ could have significant ramification in tuning the exchange bias
driven effects and consequent applications.


title: Entropy Current Formalism for Supersymmetric Theories

abstract:
  The recent developments in fluid/gravity correspondence give a new impulse to
the study of fluid dynamics of supersymmetric theories. In that respect, the
entropy current formalism requires some modifications in order to be adapted to
supersymmetric theories and supergravities. We formulate a new entropy current
in superspace with the properties: 1) it is conserved off-shell for non
dissipative fluids, 2) it is invariant under rigid supersymmetry
transformations 3) it is covariantly closed in local supersymmetric theories 4)
it reduces to its bosonic expression on space-time.


title: CP-violating Phases in Active-Sterile Solar Neutrino Oscillations

abstract:
  Effects of CP-violating phases in active-sterile solar neutrino oscillations
are discussed in a general scheme of 3+N_{s} mixing, without any constraint on
the mixing between the three active and the N_{s} sterile neutrinos, assuming
only a realistic hierarchy of neutrino mass-squared differences. A generalized
Parke formula describing the neutrino oscillation probabilities inside the Sun
is calculated. The validity of the analytical calculation and the probability
variation due to the unknown CP-violating phases are illustrated with a
numerical calculation of the evolution equation in the case of 3+1 neutrino
mixing.


title: Loop-deformed Poincar\'e algebra

abstract:
  In this essay we present evidence suggesting that loop quantum gravity leads
to deformation of the local Poincar\'e algebra within the limit of high
energies. This deformation is a consequence of quantum modification of
effective off-shell hypersurface deformation algebra. Surprisingly, the form of
deformation suggests that the signature of space-time changes from Lorentzian
to Euclidean at large curvatures. We construct particular realization of the
loop-deformed Poincar\'e algebra and find that it can be related to curved
momentum space, which indicates the relationship with recently introduced
notion of relative locality. The presented findings open a new way of testing
loop quantum gravity effects.


title:
Water deuterium fractionation in the inner regions of two solar type
  protostars

abstract:
  The [HDO]/[H2O] ratio is a crucial parameter for probing the history of water
formation. So far, it has been measured for only three solar type protostars
and yielded different results, possibly pointing to a substantially different
history in their formation. In the present work, we report new interferometric
observations of the HDO 4 2,2 - 4 2,3 line for two solar type protostars,
IRAS2A and IRAS4A, located in the NGC1333 region. In both sources, the detected
HDO emission originates from a central compact unresolved region. Comparison
with previously published interferometric observations of the H218$O 3 1,3 - 2
2,0 line shows that the HDO and H$_2$O lines mostly come from the same region.
A non-LTE LVG analysis of the HDO and H218$O line emissions, combined with
published observations, provides a [HDO]/[H2O] ratio of 0.3 - 8 % in IRAS2A and
0.5 - 3 % in IRAS4A.
  First, the water fractionation is lower than that of other molecules such as
formaldehyde and methanol in the same sources. Second, it is similar to that
measured in the solar type protostar prototype, IRAS16293-2422, and,
surprisingly enough, larger than that measured in NGC1333 IRAS4B. {The
comparison of the measured values towards IRAS2A and IRAS4A with the
predictions of our gas-grain model GRAINOBLE gives similar conclusions to those
for IRAS 16293, arguing that these protostars {share} a similar chemical
history, although they are located in different clouds.


title:
Anomalous reduction of the Lorenz ratio at the quantum critical point in
  YbAgGe

abstract:
  We report measurements of the electrical and thermal transport on the
hexagonal heavy-fermion metal YbAgGe for temperatures $T\geq$ 40 mK and in
magnetic fields $H\parallel ab$ up to 14 T. This distorted Kagome-lattice
system displays a series of magnetic states and a quantum critical point at
$H_c =4.5$ T. The Lorenz ratio $L(T)/L_0$ displays a marked reduction only
close to $H_c$. A $T$-linear contribution below 120 mK, present at all
different fields, allows to extrapolate the Lorenz ratio towards T=0. At the
critical field this yields $L/L_0=0.92\pm 0.03$, suggesting a violation of the
Wiedemann-Franz law due to strong inelastic scattering.


title:
Temporal and spatial expansion of a multidimensional model for electron
  acceleration in the bubble regime

abstract:
  An extended analytical model for particle dynamics in fields of a
highly-nonlinear plasma wake field (the bubble or blow out regime) is derived.
A recently proposed piecewise model (Kostyukov et al., New J. Phys., {\bf 12},
045009 (2010)) is generalized to include a time dependent bubble radius and
full field solution in the acceleration direction. Incorporation of the cavity
dynamics in the model is required to simulate the particle trapping properly.
On the other hand, it is shown that the previously reported piecewise model
does not reproduce the formation of a mono energetic peak in the particle
spectrum. The mono energetic electron beams are recovered only when the full
longitudinal field gradient is included in the model.


title: Neutron matter from chiral effective field theory interactions

abstract:
  The neutron-matter equation of state constrains the properties of many
physical systems over a wide density range and can be studied systematically
using chiral effective field theory (EFT). In chiral EFT, all many-body forces
among neutrons are predicted to next-to-next-to-next-to-leading order (N3LO).
We present details and additional results of the first complete N3LO
calculation of the neutron-matter energy, which includes the subleading
three-nucleon as well as the leading four-nucleon forces, and provides
theoretical uncertainties. In addition, we discuss the impact of our results
for astrophysics: for the supernova equation of state, the symmetry energy and
its density derivative, and for the structure of neutron stars. Finally, we
give a first estimate for the size of the N3LO many-body contributions to the
energy of symmetric nuclear matter, which shows that their inclusion will be
important in nuclear structure calculations.


title:
Spintronic Switches for Ultra Low Energy On-Chip and Inter-Chip
  Current-Mode Interconnects

abstract:
  Energy-efficiency and design-complexity of high-speed on-chip and inter-chip
data-interconnects has emerged as the major bottleneck for high-performance
computing-systems. As a solution, we propose an ultra-low energy interconnect
design-scheme using nano-scale spintorque switches. In the proposed method,
data is transmitted in the form of current-pulses, with amplitude of the order
of few micro-amperes that flows across a small terminal-voltage of less than
50mV. Sub-nanosecond spintorque switching of scaled nano-magnets can be used to
receive and convert such high-speed current-mode signal into binary
voltage-levels using magnetic-tunnel-junction (MTJ), with the help of simple
CMOS inverter. As a result of low-voltage, low-current signaling and minimal
signal-conversion overhead, the proposed technique can facilitate highly
compact and simplified designs for multi-gigahertz inter-chip and on-chip
data-communication links. Such links can achieve more than ~100x higher
energy-efficiency, as compared to state of the art CMOS interconnects.


title:
Period-index and u-invariant questions for function fields over complete
  discretely valued fields

abstract:
  Let K be a complete discretely valued field and F the function field of a
curve over K. If the characteristic of the residue field k of K is p > 0, then
we give a bound for the Brauer p-simension of F in terms of the p-rank of k. If
k is a perfect field of characteristic 2, we show that the u-invaraint of F is
at most 8.


title: Adjoint functors in graph theory

abstract:
  We survey some uses of adjoint functors in graph theory pertaining to
colourings, complexity reductions, multiplicativity, circular colourings and
tree duality. The exposition of these applications through adjoint functors
unifies the presentation to some extent, and also raises interesting questions.


title:
Generalized projected dynamics for non-system observables of
  non-equilibrium quantum impurity models

abstract:
  The reduced dynamics formalism has recently emerged as a powerful tool to
study the dynamics of non-equilibrium quantum impurity models in strongly
correlated regimes. Examples include the non-equilibrium Anderson impurity
model near the Kondo crossover temperature and the non-equilibrium Holstein
model, for which the formalism provides an accurate description of the reduced
density matrix of the system for a wide range of timescales. In this work, we
generalize the formalism to allow for non-system observables such as the
current between the impurity and leads. We show that the equation of motion for
the reduced observable of interest can be closed with the equation of motion
for the reduced density matrix and demonstrate the new formalism for a generic
resonant level model.


title: Inclics, galaxies, star configurations and Waldschmidt constants

abstract:
  This paper introduces complexes of linear varieties, called inclics (for
INductively Constructible LInear ComplexeS). As examples, we study galaxies
(these are constructed starting with a star configuration to which we add
general points in a larger projective space). By assigning an order of
vanishing (i.e., a multiplicity) to each member of the complex, we obtain fat
linear varieties (fat points if all of the linear varieties are points). The
scheme theoretic union of these fat linear varieties gives an inclic scheme
$X$. For such a scheme, we show there is an inductive procedure for computing
the Hilbert function of its defining ideal $I_X$, regardless of the choice of
multiplicities. As an application, we show how our results allow the
computation of the Hilbert functions of, for example, symbolic powers
$(I_X)^{(m)}$ for arbitrary $m$ of many new examples of radical ideals $(I_X)$,
and we explicitly compute the Waldschmidt constants $\gamma(I_X)$ for galactic
inclics $X$.


title:
Hexagonal warping on optical conductivity of surface states in
  Topological Insulator Bi_{2}Te_{3}

abstract:
  ARPES studies of the protected surface states in the Topological Insulator $%
Bi_{2}Te_{3}$ have revealed the existence of an important hexagonal warping
term in its electronic band structure. This term distorts the shape of the
Dirac cone from a circle at low energies to a snowflake shape at higher
energies. We show that this implies important modifications of the interband
optical transitions which no longer provide a constant universal background as
seen in graphene. Rather the conductivity shows a quasilinear increase with a
slightly concave upward bending as energy is increased. Its slope increases
with increasing magnitude of the hexagonal distortion as does the magnitude of
the jump at the interband onset. The energy dependence of the density of states
is also modified and deviates downward from linear with increasing energy.


title: Universality and conformal non-invariance in self-affine rough surfaces

abstract:
  We show numerically that the roughness and growth exponents of a wide range
of rough surfaces, such as random deposition with relaxation (RDR), ballistic
deposition (BD) and restricted solid-on-solid model (RSOS), are independent of
the underlying regular (square, triangular, honeycomb) or random (Voronoi)
lattices. In addition we show that the universality holds also at the level of
statistical properties of the iso-height lines on different lattices. This
universality is revealed by calculating the fractal dimension, loop correlation
exponent and the length distribution exponent of the individual contours. We
also indicate that the hyperscaling relations are valid for the iso-height
lines of all the studied Gaussian and non-Gaussian self-affine rough surfaces.
Finally using the direct method of Langlands et.al we show that the contour
lines of the rough surfaces are not conformally invariant except when we have
simple Gaussian free field theory with zero roughness exponent.


title:
A characterization of causal automorphisms on two-dimensional Minkowski
  spacetime

abstract:
  It is shown that causal automorphisms on two-dimensional Minkowski spacetime
can be characterized by the invariance of the wave equations.


title: Heavy quark pair production in high energy pA collisions: Quarkonium

abstract:
  Quarkonium production in high-energy proton (deuteron)-nucleus collisions is
investigated in the color glass condensate framework. We employ the color
evaporation model assuming that the quark pair produced from dense small-x
gluons in the nuclear target bounds into a quarkonium outside the target. The
unintegrated gluon distribution at small Bjorken x in the nuclear target is
treated with the Balitsky-Kovchegov equation with running coupling corrections.
For the gluons in the proton, we examine two possible descriptions,
unintegrated gluon distribution and ordinary collinear gluon distribution. We
present the transverse momentum spectrum and nuclear modification factor for
J/psi production at RHIC and LHC energies, and those for Upsilon(1S) at LHC
energy, and discuss the nuclear modification factor and the momentum broadening
by changing the rapidity and the initial saturation scale.


title:
Sequential Randomized Algorithms for Convex Optimization in the Presence
  of Uncertainty

abstract:
  In this paper, we propose new sequential randomized algorithms for convex
optimization problems in the presence of uncertainty. A rigorous analysis of
the theoretical properties of the solutions obtained by these algorithms, for
full constraint satisfaction and partial constraint satisfaction, respectively,
is given. The proposed methods allow to enlarge the applicability of the
existing randomized methods to real-world applications involving a large number
of design variables. Since the proposed approach does not provide a priori
bounds on the sample complexity, extensive numerical simulations, dealing with
an application to hard-disk drive servo design, are provided. These simulations
testify the goodness of the proposed solution.


title: Analytic structure of $\phi^4$ theory using light-by-light sum rules

abstract:
  We apply a sum rule for the forward light-by-light scattering process within
the context of the $\phi^4$ quantum field theory. As a consequence of the sum
rule a stringent causality criterion is presented and the resulting constraints
are studied within a particular resummation of graphs. Such resummation is
demonstrated to be consistent with the sum rule to all orders of perturbation
theory. We furthermore show the appearance of particular non-perturbative
solutions within such approximation to be a necessary requirement of the sum
rule. For a range of values of the coupling constant, these solutions manifest
themselves as a physical bound state and a $K$-matrix pole. For another domain
however, they appear as tachyon solutions, showing the inconsistency of the
approximation in this region.


title:
A database for quarkonium and open heavy-flavour production in hadronic
  collisions with HepData

abstract:
  We report on the creation of a database for quarkonium and open heavy-flavour
production in hadronic collisions. This database, made as a collaboration
between HepData and the ReteQuarkonii network of the integrating activity I3HP2
of the 7th Framework Programme, provides an up-to-date review on quarkonia and
open heavy-flavour existing data. We first present the physics motivation for
this project, which is connected to the aim of the ReteQuarkonii network,
studies of open heavy-flavour hadrons and quarkonia in nucleus-nucleus
collisions. Then we give a general overview of the database and describe the
HepData database for particle physics, which is the framework of the quarkonia
database. Finally we describe the functionalities of the database with as
example the comparison of the production cross section for the J/$\psi$ meson
at different energies.


title: Quasi-Exact Solvability and Deformations of Sl(2) Algebra

abstract:
  Algebraic structure of a class of differential equations including Heun is
shown to be related with the deformations of sl(2) algebra. These include both
quadratic and cubic ones. The finite dimensional representation of cubic
algebra is explicitly shown to describe a quasi-exactly solvable system, not
connected with sl(2) symmetry. Known finite dimensional representations of
sl(2) emerge under special conditions. We answer affirmatively the question
raised by Turbiner: Are there quasi- exactly solvable problems which can not be
represented in terms of sl(2) generators? and give the explicit deformed
symmetry underlying this system.


title:
Intrinsic Correlated Electronic Structure of CrO2 Revealed by Hard X-ray
  Photoemission Spectroscopy

abstract:
  Bulk-sensitive hard x-ray photoemission spectroscopy (HAXPES) reveals for
as-grown epitaxial films of half-metallic ferromagnetic CrO2(100) a pronounced
screening feature in the Cr 2p3/2 core level and an asymmetry in the O 1s core
level. This gives evidence of a finite, metal-type Fermi edge, which is
surprisingly not observed in HAXPES. A spectral weight shift in HAXPES away
from the Fermi energy is attributed to single-ion recoil effects due to high
energy photoelectrons. In conjunction with inverse PES the intrinsic correlated
Mott-Hubbard-type electronic structure is unravelled, yielding an averaged
Coulomb correlation energy Uav ~ 3.2 eV.


title:
Spin states of iron impurities in magnesium oxide under pressure: A
  possible intermediate state

abstract:
  Ferropericlase (Mg,Fe)O is a major lower mantle mineral, and studying its
properties is a fundamental step toward understanding the Earth's interior.
Here, we performed a first-principles investigation on the properties of iron
as an isolated impurity in magnesium oxide, which is the condition of
ferropericlase under which iron-iron interactions could be neglected. The
calculations were carried using the all-electron full-potential linearized
augmented plane wave method within the density functional theory in the
generalized gradient approximation plus the on-site Hubbard correction. We
present the electronic and magnetic properties, electric and magnetic hyperfine
splitting of this impurity in high and low spin states for several charge
states at zero pressure, which were then extended to high pressures. For the
impurity in the neutral charge state, our results indicated that there is a
metastable intermediate spin state (S=1), in addition to the high (S=2) and low
(S=0) spin states. Those results were discussed in the context of an
intermediate spin state, experimentally identified in ferrosilicate perovskite.


title:
New perspectives on neutron star and black hole spectroscopy and dynamic
  tides

abstract:
  We elaborate on a powerful tidal interaction formalism where the multipole
dynamics is kept generic and encoded in a linear response function. This
response function is the gravitational counterpart of the atomic spectrum and
can become of similar importance with the rise of gravitational wave astronomy.
We find that the internal dynamics of nonrotating neutron stars admit a
harmonic oscillator formulation yielding a simple interpretation of tides. A
preliminary investigation of the black holes case is given. Our results fill
the gap between Love numbers and dynamic tides.


title: Characterization Of Left Artinian Algebras Through Pseudo Path Algebras

abstract:
  In this paper, using pseudo path algebras, we generalize Gabriel's Theorem on
elementary algebras to left Artinian algebras over a field $k$ when it is
splitting over its radical, in particular, when the dimension of the quotient
algebra decided by the $n$'th Hochschild cohomology is less than 2 (for
example, $k$ is finite or char$k=0$). Using generalized path algebras, the
generalized Gabriel's Theorem is given for finite dimensional algebras with
2-nilpotent radicals which is splitting over its radical. As a tool, the
so-called pseudo path algebras are introduced as a new generalization of path
algebras, which can cover generalized path algebras (see Fact 2.5).
  The main result is that (i) for a left Artinian $k$-algebra $A$ and $r=r(A)$
the radical of $A$, when the quotient algebra $A/r$ can be lifted, it holds
that $A\cong PSE_k(\Delta,\mathcal{A},\rho)$ with $J^{s}\subset<\rho>\subset J$
for some $s$ (Theorem 3.2); (ii) for a finite dimensional $k$-algebra $A$ with
$r=r(A)$ 2-nilpotent radical, when the quotient algebra $A/r$ can be lifted, it
holds that $A\cong k(\Delta,\mathcal{A},\rho)$ with $\widetilde
J^{2}\subset<\rho>\subset\widetilde J^{2}+\widetilde J\cap$
\textrm{Ker}$\widetilde{\varphi}$ (Theorem 4.3), where $\Delta$ is the quiver
of $A$ and $\rho$ is a set of relations.
  Meantime, the uniqueness of the quivers and generalized path algebra/pseudo
path algebras satisfying the isomorphism relations is obtained in the case when
the ideals generated by the relations are admissible (see Theorem 3.5 and 4.4).


title:
Fluctuations and correlations of a driven tracer in a hard-core lattice
  gas

abstract:
  We consider a driven tracer particle (TP) in a bath of hard-core particles
undergoing continuous exchanges with a reservoir. We develop an analytical
framework which allows us to go beyond the standard force-velocity relation
used for this minimal model of active microrheology and quantitatively analyze,
for any density of the bath particles, the fluctuations of the TP position and
their correlations with the occupation number of the bath particles. We obtain
an exact Einstein-type relation which links these fluctuations in the absence
of a driving force and the bath particles density profiles in the linear
driving regime. For the one-dimensional case we also provide an approximate but
very accurate explicit expression for the variance of the TP position and show
that it can be a non-monotoneous function of the bath particles density:
counter-intuitively, an increase of the density may increase the dispersion of
the TP position. We show that this non trivial behavior, which could in
principle be observed in active microrheology experiments, is induced by subtle
cross-correlations quantified by our approach.


title: Decomposition of direct images of logarithmic differentials

abstract:
  The purpose of this note is to give a short proof of a theorem of Koll\'ar
that the derived direct image of the canonical sheaf splits into a sum of its
cohomology sheaves. This is deduced from a stronger decomposition theorem for
direct images of sheaves of logarithmic differentials, together with the weak
semistable reduction theorem.


title:
OPE of the pseudoscalar gluonium correlator in massless QCD to
  three-loop order

abstract:
  In this paper analytical results are presented for higher order corrections
to coefficient functions of the operator product expansion (OPE) for the
correlator of two pseudoscalar gluonium operators \tilde{O}_1=G^{\mu
\nu}\tilde{G}_{\mu \nu}. The Wilson coefficient in front of the scalar gluon
condensate operator O_1=-1/4 G^{\mu \nu}G_{\mu \nu} is given at three-loop
accuracy. The leading coefficient C_0 in front of the unity operator O_0=1 has
been calculated up to three-loop order some time ago but has been checked
independently in this work. It is interesting to see that the coefficient C_1
in the pseudoscalar case is finite, whereas contact terms appear in C_0 in this
case and in both coefficients C_0 and C_1 in the cases of the scalar gluonium
correlator and the energy momentum tensor correlator. For the corresponding
Renormalization Group invariant Wilson coefficients which are also constructed
the results are partially extended to four-loop accuracy. All results are given
in the MSbar-scheme at zero temperature.


title: Sensors and Navigation Algorithms for Flight Control of Tethered Kites

abstract:
  We present the sensor setup and the basic navigation algorithm used for the
flight control of the SkySails towing kite system. Starting with brief
summaries on system setup and equations of motion of the tethered kite system,
we subsequently give an overview of the sensor setup, present the navigation
task and discuss challenges which have to be mastered. In the second part we
introduce in detail the inertial navigation algorithm which has been used for
operational flights for years. The functional capability of this algorithm is
illustrated by experimental flight data. Finally we suggest a modification of
the algorithms as further development step in order to overcome certain
limitations.


title: Large deviations of the interference in the Ginibre network model

abstract:
  Under different assumptions on the distribution of the fading random
variables, we derive large deviation estimates for the tail of the interference
in a wireless network model whose nodes are placed, over a bounded region of
the plane, according to the $\beta$-Ginibre process, $0<\beta\leq 1$. The
family of $\beta$-Ginibre processes is formed by determinantal point processes,
with different degree of repulsiveness, which converge in law to a homogeneous
Poisson process, as $\beta \to 0$. In this sense the Poisson network model may
be considered as the limiting uncorrelated case of the $\beta$-Ginibre network
model. Our results indicate the existence of two different regimes. When the
fading random variables are bounded or Weibull superexponential, large values
of the interference are typically originated by the sum of several equivalent
interfering contributions due to nodes in the vicinity of the receiver.
  In this case, the tail of the interference has, on the log-scale, the same
asymptotic behavior for any value of $0<\beta\le 1$, but it differs (again on a
log-scale) from the asymptotic behavior of the tail of the interference in the
Poisson network model.
  When the fading random variables are exponential or subexponential, instead,
large values of the interference are typically originated by a single
dominating interferer node and, on the log-scale, the asymptotic behavior of
the tail of the interference is essentially insensitive to the distribution of
the nodes. As a consequence, on the log-scale, the asymptotic behavior of the
tail of the interference in any $\beta$-Ginibre network model, $0<\beta\le 1$,
is the same as in the Poisson network model.


title:
Multi-wavelength Observations of the Giant X-ray Flare Galaxy NGC 5905:
  signatures of tidal disruption

abstract:
  NGC 5905 is one of the few galaxies with no prior evidence for an AGN in
which an X-ray flare, due to the tidal disruption of a star by the massive
black hole in the center of the galaxy, was detected by the RASS in 1990-91.
Here we present analysis of late-time follow-up observations of NGC 5905 using
Chandra, Spitzer VLA 3 GHz and 8 GHz archival data and GMRT 1.28 GHz radio
observations. The X-ray image shows no compact source that could be associated
with an AGN. Instead, the emission is extended -- likely due to nuclear star
formation and the total measured X-ray luminosity is comparable to the X-ray
luminosity determined from the 2002 Chandra observations. Diffuse X-ray
emission was detected close to the circum-nuclear star forming ring. The
Spitzer 2006 mid-infrared spectrum also shows strong evidence of nuclear star
formation but no clear AGN signatures. The semi-analytical models of Tommasin
et. al. 2010 together with the measured [OIV]/[NeII] line ratio suggest that at
most only 5.6% of the total IR Flux at 19 $\mu$m is being contributed by the
AGN. The GMRT 1.28 GHz observations reveal a nuclear source. In the much higher
resolution VLA 3 GHz map, the emission has a double lobed structure of size
2.7'' due to the circumnuclear star forming ring. The GMRT 1.28 GHz peak
emission coincides with the center of the circumnuclear ring. We did not detect
any emission in the VLA 8 GHz (1996) archival data. The 3 $\sigma$ upper limits
for the radio afterglow of the TDE at 1.28 GHz, 3 GHz and 8 GHz are 0.17 mJy,
0.09 mJy and 0.09 mJy, respectively. Our studies thus show that (i) NGC 5905
has a declining X-ray flux consistent with a TDE, (ii) the IR flux is dominated
by nuclear star formation, (iii) the nuclear radio emission observed from the
galaxy is due to circumnuclear star formation, (iv) no compact radio emission
associated with a radio afterglow from the TDE is detected.


title: Doping Mechanisms in Graphene-MoS2 Hybrids

abstract:
  We present a joint theoretical and experimental investigation of charge
doping and electronic potential landscapes in hybrid structures composed of
graphene and semiconducting single layer MoS2. From first-principles
simulations we find electron doping of graphene due to the presence of rhenium
impurities in MoS2. Furthermore, we show that MoS2 edges give rise to charge
reordering and a potential shift in graphene, which can be controlled through
external gate voltages. The interplay of edge and impurity effects allows the
use of the graphene-MoS2 hybrid as a photodetector. Spatially resolved
photocurrent signals can be used to resolve potential gradients and local
doping levels in the sample.


title: The Gauss map for Lagrangean and isoclinic surfaces

abstract:
  Simple properties of the Gauss map characterise important classes of surfaces
in $\Rq$: $R$-surfaces, the real version of plane complex curves; Lagrangean
surfaces; isoclinic surfaces.


title: Two-dimensional bipolar junction transistors

abstract:
  Recent development in fabrication technology of planar two-dimensional (2D)
materials has brought up possibilities of numerous novel applications. Our
recent analysis has revealed that by definition of p-n junctions through
appropriate patterned doping of 2D semiconductors, ideal exponential I-V
characteristics may be expected. However, the theory of 2D junctions turns out
to be very much different to that of the standard bulk junctions. Based on this
theory of 2D diodes, here we construct for the first time, a model to describe
the 2D Bipolar Junction Transistors (2D-BJTs). We derive the small-signal
equivalent model, and estimate the performance of a 2D-BJT device based on
Graphone as the example material. A current gain of about 138 and maximum
threshold frequency of 77GHz, together with a power-delay product of only 4fJ
per 1um lateral width is expected at an operating voltage of 5V. Also, we
derive necessary formulae and a new approximate solution for continuity
equation in the 2D configuration, which have been verified against numerical
solutions.


title:
Trace distance and linear entropy of qubit states: Role of initial
  qubit-environment correlations

abstract:
  The role of initial qubit-environment correlations on trace distance between
two qubit states is studied in the framework of non--Markovian pure dephasing.
The growth of mixedness of reduced state quantified by linear entropy is shown
to be related to the degree of initial qubit--environment correlations.


title: Nonommutative wormholes in $f(R)$ gravity

abstract:
  This paper discusses several new exact solutions of static wormholes in
$f(R)$ gravity with a noncommutative-geometry background, which replaces
point-like structures by smeared objects. In the first part of the paper we
assume the power-law form $f(R)=aR^n$ and discuss several solutions
corresponding to different values of the exponent. The second part of the paper
assumes a particular form of the shape function that also yields a viable
solution. This investigation generalizes some of our previous work in $f(R)$
gravity, as well as in noncommutative geometry.


title:
Classification of Realizations of Lie Algebras of Vector Fields on a
  Circle

abstract:
  Finite-dimensional subalgebras of a Lie algebra of smooth vector fields on a
circle, as well as piecewise-smooth global transformations of a circle on
itself, are considered. A canonical forms of realizations of two- and
three-dimensional noncommutative algebras are obtained. It is shown that all
other realizations of smooth vector fields are reduced to this form using
global transformations. Some combinatorial formulas for the number of
inequivalent realizations of these algebras are obtained.


title: Local geometry of surfaces in $\mathbf R^4$

abstract:
  The indicatrix or curvature ellipse and the characteristic curve of a surface
in $\mathbf R^4$ are presented, as well as the projective duality connecting
them. The characterisation of points in the surfaces as elliptic, parabolic and
hyperbolic points, and the inflection points, are also discussed.


title:
EMCCD photometry reveals two new variable stars in the crowded central
  region of the globular cluster NGC 6981

abstract:
  Two previously unknown variable stars in the crowded central region of the
globular cluster NGC 6981 are presented. The observations were made using the
Electron Multiplying CCD (EMCCD) camera at the Danish 1.54m Telescope at La
Silla, Chile.The two variables were not previously detected by conventional CCD
imaging because of their proximity to a bright star. This discovery
demonstrates that EMCCDs are a powerful tool for performing high-precision
time-series photometry in crowded fields and near bright stars, especially when
combined with difference image analysis (DIA).


title: Combinatorial Walrasian Equilibrium

abstract:
  We study a combinatorial market design problem, where a collection of
indivisible objects is to be priced and sold to potential buyers subject to
equilibrium constraints.The classic solution concept for such problems is
Walrasian Equilibrium (WE), which provides a simple and transparent pricing
structure that achieves optimal social welfare. The main weakness of the WE
notion is that it exists only in very restrictive cases. To overcome this
limitation, we introduce the notion of a Combinatorial Walrasian equilibium
(CWE), a natural relaxation of WE. The difference between a CWE and a
(non-combinatorial) WE is that the seller can package the items into
indivisible bundles prior to sale, and the market does not necessarily clear.
  We show that every valuation profile admits a CWE that obtains at least half
of the optimal (unconstrained) social welfare. Moreover, we devise a poly-time
algorithm that, given an arbitrary allocation X, computes a CWE that achieves
at least half of the welfare of X. Thus, the economic problem of finding a CWE
with high social welfare reduces to the algorithmic problem of social-welfare
approximation. In addition, we show that every valuation profile admits a CWE
that extracts a logarithmic fraction of the optimal welfare as revenue.
Finally, these results are complemented by strong lower bounds when the seller
is restricted to using item prices only, which motivates the use of bundles.
The strength of our results derives partly from their generality - our results
hold for arbitrary valuations that may exhibit complex combinations of
substitutes and complements.


title: Excited Hadrons, Heavy Quarks and QCD thermodynamics

abstract:
  We show how excited states in QCD can be profitably used to build up the
Polyakov loop in the fundamental representation at temperatures below the
hadron-quark-gluon crossover. The conditions under which a Hagedorn temperature
for the Polyakov loop can be defined are analysed.


title: Differential Evolution for Many-Particle Adaptive Quantum Metrology

abstract:
  We devise powerful algorithms based on differential evolution for adaptive
many-particle quantum metrology. Our new approach delivers adaptive quantum
metrology policies for feedback control that are orders-of-magnitude more
efficient and surpass the few-dozen-particle limitation arising in methods
based on particle-swarm optimization. We apply our method to the
binary-decision-tree model for quantum-enhanced phase estimation as well as to
a new problem: a decision tree for adaptive estimation of the unknown bias of a
quantum coin in a quantum walk and show how this latter case can be realized
experimentally.


title:
Identifying low-dimensional dynamics in Type-I edge-localised-mode
  processes in JET plasmas

abstract:
  Edge localised mode (ELM) measurements from reproducibly similar plasmas in
the Joint European Torus (JET) tokamak, which differ only in their gas puffing
rate, are analysed in terms of the pattern in the sequence of inter-ELM time
intervals. It is found that the category of ELM defined empirically as Type I -
typically more regular, less frequent, and having larger amplitude than other
ELM types - embraces substantially different ELMing processes. By quantifying
the structure in the sequence of inter-ELM time intervals using delay time
plots, we reveal transitions between distinct phase space dynamics, implying
transitions between distinct underlying physical processes. The control
parameter for these transitions between these different ELMing processes is the
gas puffing rate.


title: Quench Dynamics of Edge States in 2-D Topological Insulator Ribbons

abstract:
  We study the dynamics of edge states of the two dimensional BHZ Hamiltonian
in a ribbon geometry following a sudden quench to the quantum critical point
separating the topological insulator phase from the trivial insulator phase.
The effective edge state Hamiltonian is a collection of decoupled qubit-like
two-level systems which get coupled to bulk states following the quench. We
notice a pronounced collapse and revival of the Loschmidt echo for low-energy
edge states illustrating the oscillation of the state between the two edges. We
also observe a similar collapse and revival in the spin Hall current carried by
these edge states, leading to a persistence of its time-averaged value.


title:
Single vector-like top partner production in the Left-Right Twin Higgs
  model at TeV energy $e\gamma$ colliders

abstract:
  The left-right twin Higgs model contains a new vector-like heavy top quark,
which mixes with the SM-like top quark. In this work, we studied the single
vector-like top partner production via process $e^{-}\gamma \rightarrow
\nu_{e}\bar{T}b$ at the International Linear Collider. We calculated the
production cross section at tree level and displayed the relevant differential
distributions. The result shows that there will be 125 events produced each
year with $\sqrt{s}$=2TeV and the integrated luminosity $\mathcal L_{int}\simeq
500fb^{-1}$, and the b-quark tagging and the relevant missing energy $\met$ cut
will be helpful to detect this new effect.


title:
Stability estimates for the inverse boundary value problem by partial
  Cauchy data

abstract:
  In this paper we study the inverse conductivity problem with partial data in
dimension $n\geq 3$. We derive stability estimates for this inverse problem if
the conductivity has $C^{1,\sigma}(\bar\Omega)\cap H^{3/2+\sigma}(\Omega)$
regularity for $0<\sigma<1$.


title: Balancing conditions in global tropical geometry

abstract:
  We study tropical geometry in the global setting using Berkovich's
deformation retraction. We state and prove the generalized balancing conditions
in this setting. Starting with a strictly semi-stable formal scheme, we
calculate certain sheaves of vanishing cycles using analytic \'etale
cohomology, then we interpret the tropical weights via these cycles. We obtain
the balancing condition for tropical curves on the skeleton associated to the
formal scheme in terms of the intersection theory on the special fiber. Our
approach works over any complete discrete valuation field.


title: Quasicrystalline order and a crystal-liquid state in a soft-core fluid

abstract:
  A two-dimensional system of soft particles interacting via a two-length-scale
potential is studied. Density functional theory and Brownian dynamics
simulations reveal a fluid phase and two crystalline phases with different
lattice spacing. Of these the larger lattice spacing phase can form an exotic
periodic state with a fraction of highly mobile particles: a crystal liquid.
Near the transition between this phase and the smaller lattice spacing phase,
quasicrystalline structures may be created by a competition between linear
instability at one scale and nonlinear selection of the other.

categories: cond-mat.soft cond-mat.mtrl-sci cond-mat.stat-mech nlin.PS


title:
Yielding and microstructure in a 2D jammed material under shear
  deformation

abstract:
  The question of how a disordered material's microstructure translates into
macroscopic mechanical response is central to understanding and designing
materials like pastes, foams and metallic glasses. Here, we examine a 2D soft
jammed material under cyclic shear, imaging the structure of ~50,000 particles.
Below a certain strain amplitude, the structure becomes conserved at long
times, while above, it continually rearranges. We identify the boundary between
these regimes as a yield strain, defined without rheological measurement. Its
value is consistent with a simultaneous but independent measurement of yielding
by stress-controlled bulk rheometry. While there are virtually no irreversible
rearrangements in the steady state below yielding, we find a largely stable
population of plastic rearrangements that are reversed with each cycle. These
results point to a microscopic view of mechanical properties under cyclic
deformation.


title: Proof of a Conjecture on Permutation Polynomials over Finite Fields

abstract:
  Let $k$ be a positive integer and $S_{2k}={\tt x}+{\tt x}^4+...+{\tt
x}^{4^{2k-1}}\in\Bbb F_2[{\tt x}]$. It was recently conjectured that ${\tt
x}+S_{2k}^{4^{2k}}+S_{2k}^{4^k+3}$ is a permutation polynomial of $\Bbb
F_{4^{3k}}$. In this note, the conjecture is confirmed and a generalization is
obtained.


title: MIMAC: A micro-tpc matrix for dark matter directional detection

abstract:
  The dark matter directional detection opens a new field in cosmology bringing
the possibility to build a map of nuclear recoils that would be able to explore
the galactic dark matter halo giving access to a particle characterization of
such matter and the shape of the halo. The MIMAC (MIcro-tpc MAtrix of Chambers)
collaboration has developed in the last years an original prototype detector
based on the direct coupling of large pixelized micromegas with a devoted fast
self-triggered electronics showing the feasibility of a new generation of
directional detectors. The discovery potential of this search strategy is
discussed and illustrated. In June 2012, the first bi-chamber prototype has
been installed at Modane Underground Laboratory (LSM) and the first underground
background events, the gain stability and calibration are shown.


title:
Four-dimensional aether-like Lorentz-breaking QED revisited and problem
  of ambiguities

abstract:
  In this paper, we consider the perturbative generation of the CPT-even
aether-like Lorentz-breaking term in the extended Lorentz-breaking QED within
different approaches and discuss its ambiguities.


title: LHC Higgs Signatures from Topflavor Seesaw Mechanism

abstract:
  We study LHC Higgs signatures from topflavor seesaw realization of
electroweak symmetry breaking with a minimal gauge extension SU(2) x SU(2) x
U(1). This elegant renormalizable construction singles out top quark sector
(instead of all other light fermions) to join the new SU(2) gauge force. It
predicts extra vector-like spectator quarks (T, B), new gauge bosons (W', Z'),
and a pair of neutral Higgs bosons (h, H). We demonstrate that for the lighter
Higgs boson h of mass 125GeV, this model predicts modified Higgs signal rates
in h --> \gamma\gamma, WW*, ZZ* channels via gluon fusions, in h --> tau tau
mode via vector boson fusions, and in h --> bb mode via gauge boson associate
productions. We perform a global fit for our theory by including both direct
search data (LHC and Tevatron) and indirect precision constraints. We further
analyze the LHC discovery potential for detecting the heavier Higgs state H.


title: Origin of the insulating state in honeycomb iridates and rhodates

abstract:
  A burning question in the emerging field of spin-orbit driven insulating
iridates, such as Na2IrO3 and Li2IrO3 is whether the observed insulating state
should be classified as a Mott-Hubbard insulator derived from a half-filled
relativistic j_eff=1/2 band or as a band insulator where the gap is assisted by
spin-orbit interaction, or Coulomb correlations, or both. The difference
between these two interpretations is that only for the former, strong
spin-orbit coupling (lambda >~ W, where W is the band width) is essential. We
have synthesized the isostructural and isoelectronic Li2RhO3 and report its
electrical resistivity and magnetic susceptibility. Remarkably it shows
insulating behavior together with fluctuating effective S=1/2 moments, similar
to Na2IrO3 and Li2IrO3, although in Rh4+ (4d5) the spin-orbit coupling is
greatly reduced. We show that this behavior has non-relativistic one-electron
origin (although Coulomb correlations assist in opening the gap), and can be
traced down to formation of quasi-molecular orbitals, similar to those in
Na2IrO3.


title: Multimode pulsation of the ZZ Ceti star GD 154

abstract:
  We present the results of a comparative period search on different
time-scales and modelling of the ZZ Ceti (DAV) star GD 154. We determined six
frequencies as normal modes and four rotational doublets around the ones having
the largest amplitude. Two normal modes at 807.62 and 861.56 microHz have never
been reported before. A rigorous test revealed remarkable intrinsic amplitude
variability of frequencies at 839.14 and 861.56 microHz over a 50 d time-scale.
In addition, the multimode pulsation changed to monoperiodic pulsation with an
843.15 microHz dominant frequency at the end of the observing run. The 2.76
microHz average rotational split detected led to a determination of a 2.1 d
rotational period for GD 154. We searched for model solutions with effective
temperatures and log g close to the spectroscopically determined ones. The
best-fitting models resulting from the grid search have M_H between 6.3 x 10^-5
and 6.3 x 10^-7 M*, which means thicker hydrogen layer than the previous
studies suggested. Our investigations show that mode trapping does not
necessarily operate in all of the observed modes and the best candidate for a
trapped mode is at 2484 microHz.


title: Bootstrap percolation on Galton-Watson trees

abstract:
  Bootstrap percolation is a type of cellular automaton which has been used to
model various physical phenomena, such as ferromagnetism. For each natural
number $r$, the $r$-neighbour bootstrap process is an update rule for vertices
of a graph in one of two states: `infected' or `healthy'. In consecutive
rounds, each healthy vertex with at least $r$ infected neighbours becomes
itself infected. Percolation is said to occur if every vertex is eventually
infected.
  Usually, the starting set of infected vertices is chosen at random, with all
vertices initially infected independently with probability $p$. In that case,
given a graph $G$ and infection threshold $r$, a quantity of interest is the
critical probability, $p_c(G,r)$, at which percolation becomes likely to occur.
In this paper, we look at infinite trees and, answering a problem posed by
Balogh, Peres and Pete, we show that for any $b \geq r$ and for any $\epsilon >
0$ there exists a tree $T$ with branching number $\br(T) = b$ and critical
probability $p_c(T,r) < \epsilon$. However, this is false if we limit ourselves
to the well-studied family of Galton--Watson trees. We show that for every $r
\geq 2$ there exists a constant $c_r>0$ such that if $T$ is a Galton--Watson
tree with branching number $\br(T) = b \geq r$ then p_c(T,r) > \frac{c_r}{b}
e^{-\frac{b}{r-1}}.
  We also show that this bound is sharp up to a factor of $O(b)$ by giving an
explicit family of Galton--Watson trees with critical probability bounded from
above by $C_r e^{-\frac{b}{r-1}}$ for some constant $C_r>0$.


title: Stability of trapped degenerate dipolar Bose and Fermi gases

abstract:
  Trapped degenerate dipolar Bose and Fermi gases of cylindrical symmetry with
the polarization vector along the symmetry axis are only stable for the
strength of dipolar interaction below a critical value. In the case of bosons,
the stability of such a dipolar Bose-Einstein condensate (BEC) is investigated
for different strengths of contact and dipolar interactions using variational
approximation and numerical solution of a mean-field model. In the disk shape,
with the polarization vector perpendicular to the plane of the disk, the atoms
experience an overall dipolar repulsion and this fact should contribute to the
stability. However, a complete numerical solution of the dynamics leads to the
collapse of a strongly disk-shaped dipolar BEC due to the long-range
anisotropic dipolar interaction. In the case of fermions, the stability of a
trapped single-component degenerate dipolar Fermi gas is studied including the
Hartree-Fock exchange and Brueckner-Goldstone correlation energies in the local
density approximation valid for a large number of atoms. Estimates for the
maximum allowed number of polar Bose and Fermi molecules in BEC and degenerate
Fermi gas are given.


title:
Asymmetric Illumination of a Circumbinary Disk in the Presence of a
  Low-Mass Companion

abstract:
  The model of an young star with a protoplanetary disk and a low-mass
companion, which is moving on a circular orbit, inclined to the disk plane, is
considered. The hydrodynamic models of such a system were calculated by SPH
method. It was shown the distortions in the disk, caused by the orbital motion
of the companion, lead to the strong dependence of illumination conditions of
the disk on the azimuth (because of extinction between the star and the disk
surface) and, therefore, it leads to the appearance of large-scale asymmetry in
images of disks. The calculations showed the dependence of the illumination on
the azimuth was stronger in the central part of the disk than on the periphery.
Bright and dark domains are located not symmetry with respect to the line of
nodes. The sizes and locations of the domains are depended on the model
parameters as well as on the phase of the orbital period. The bright and dark
domains do not follow the companion, but they make small amplitude oscillations
with respect to some direction. The properties of the model, which were written
above, open new opportunities of searching low-mass companions in the vicinity
of young stars. The stars with protoplanetary disks, which are observed face-on
or under the small inclination angle i, are the best ones for this purpose.


title: Linear codes on posets with extension property

abstract:
  We investigate linear and additive codes in partially ordered Hamming-like
spaces that satisfy the extension property, meaning that automorphisms of
ideals extend to automorphisms of the poset. The codes are naturally described
in terms of translation association schemes that originate from the groups of
linear isometries of the space. We address questions of duality and invariants
of codes, establishing a connection between the dual association scheme and the
scheme defined on the dual poset (they are isomorphic if and only if the poset
is self-dual). We further discuss invariants that play the role of weight
enumerators of codes in the poset case. In the case of regular rooted trees
such invariants are linked to the classical problem of tree isomorphism. We
also study the question of whether these invariants are preserved under
standard operations on posets such as the ordinal sum and the like.


title:
Fidelity of photon propagation in electromagnetically induced
  transparency in the presence of four-wave mixing

abstract:
  We study the effects of the four-wave mixing (4WM) in a quantum memory scheme
based on electromagnetically induced transparency (EIT). We treat the problem
of field propagation on the quantum mechanical level, which allows us to
calculate the fidelity for propagation for a quantum light pulse such as a
single photon. While 4WM can be beneficial for classical, all-optical
information storage, the quantum noise associated with the signal amplification
and idler generation is in general detrimental for a quantum memory. We
identify a range of parameters where 4WM makes a single photon quantum memory
impossible.


title: Discontinuous Galerkin methods for nonvariational problems

abstract:
  We extend the finite element method introduced by Lakkis and Pryer [2011] to
approximate the solution of second order elliptic problems in nonvariational
form to incorporate the discontinuous Galerkin (DG) framework. This is done by
viewing the NVFEM as a mixed method whereby the finite element Hessian is an
auxiliary variable in the formulation. Representing the finite element Hessian
in a discontinuous setting yields a linear system of the same size and having
the same sparsity pattern of the compact DG methods for variational elliptic
problems. Furthermore, the system matrix is very easy to assemble, Thus this
approach greatly reduces the computational complexity of the discretisation
compared to the continuous approach.
  We conduct a stability and consistency analysis making use of the unified
framework set out in Arnold et. al. [2001]. We also give an apriori analysis of
the method. The analysis applies to any consistent representation of the finite
element Hessian, thus is applicable to the previous works making use of
continuous Galerkin approximations.


title: Synaptic Scaling Balances Learning in a Spiking Model of Neocortex

abstract:
  Learning in the brain requires complementary mechanisms: potentiation and
activity-dependent homeostatic scaling. We introduce synaptic scaling to a
biologically-realistic spiking model of neocortex which can learn changes in
oscillatory rhythms using STDP, and show that scaling is necessary to balance
both positive and negative changes in input from potentiation and atrophy. We
discuss some of the issues that arise when considering synaptic scaling in such
a model, and show that scaling regulates activity whilst allowing learning to
remain unaltered.


title: Reentrant cluster glass behavior in La2CoMnO6 nanoparticles

abstract:
  Magnetic study on La2CoMnO6 nanoparticles revealed multiple magnetic
transitions at 218 K, 135 K and below 38 K and the nature of the low
temperature transition was unclear [J Appl Phys 111, 024102 2012]. Presence of
mixed valance states of Co and Mn has been confirmed from the XPS measurement
and its presence along with antisite disorder affects in reducing the
saturation magnetization of the nanoparticles. The zero field cooled and field
cooled bifurcation in dc magnetization, relaxation in zero field cooled
magnetization and large enhancement in coercive field below the glassy
temperature has been discussed. Frequency dependence of ac susceptibility using
power law has revealed cluster glass behavior. Further, the dc field
superimposed on ac susceptibility and absence of memory effect in ac
susceptibility has suggested the existence of non interacting clusters
comprising of competing interactions below 38 K. Competing magnetic
interactions due to the presence of mixed valances and antisite disorder found
to establish a reentered cluster glassy state in the nanoparticles.


title: Gossips and Prejudices: Ergodic Randomized Dynamics in Social Networks

abstract:
  In this paper we study a novel model of opinion dynamics in social networks,
which has two main features. First, agents asynchronously interact in pairs,
and these pairs are chosen according to a random process. We refer to this
communication model as "gossiping". Second, agents are not completely
open-minded, but instead take into account their initial opinions, which may be
thought of as their "prejudices". In the literature, such agents are often
called "stubborn". We show that the opinions of the agents fail to converge,
but persistently undergo ergodic oscillations, which asymptotically concentrate
around a mean distribution of opinions. This mean value is exactly the limit of
the synchronous dynamics of the expected opinions.


title: On Number of Almost Blank Subframes in Heterogeneous Cellular Networks

abstract:
  In heterogeneous cellular scenarios with macrocells, femtocells or picocells
users may suffer from significant co-channel cross-tier interference. To manage
this interference 3GPP introduced almost blank subframe (ABSF), a subframe in
which the interferer tier is not allowed to transmit data. Vulnerable users
thus get a chance to be scheduled in ABSFs with reduced cross-tier
interference. We analyze downlink scenarios using stochastic geometry and
formulate a condition for the required number of ABSFs based on base station
placement statistics and user throughput requirement. The result is a
semi-analytical formula that serves as a good initial estimate and offers an
easy way to analyze impact of network parameters. We show that while in
macro/femto scenario the residue ABSF interference can be well managed, in
macro/pico scenario it affects the number of required ABSFs strongly. The
effect of ABSFs is subsequently demonstrated via user throughput simulations.
Especially in the macro/pico scenario, we find that using ABSFs is advantageous
for the system since victim users no longer suffer from poor performance for
the price of relatively small drop in higher throughput percentiles.


title: Critical solutions in topologically gauged N=8 CFTs in three dimensions

abstract:
  In this paper we discuss some special (critical) background solutions that
arise in topological gauged ${\mathcal N}=8$ three-dimensional CFTs with SO(N)
gauge group. These solutions solve the TMG equations (containing the parameters
$\mu$ and $l$) for a certain set of values of $\mu l$ obtained by varying the
number of scalar fields with a VEV. Apart from Minkowski, chiral round $AdS_3$
and null-warped $AdS_3$ (or Schr\"odinger(z=2)) we identify also a more exotic
solution recently found in $TMG$ by Ertl, Grumiller and Johansson. We also
discuss the spectrum, symmetry breaking pattern and the supermultiplet
structure in the various backgrounds and argue that some properties are due to
their common origin in a conformal phase. Some of the scalar fields, including
all higgsed ones, turn out to satisfy three-dimensional singleton field
equations. Finally, we note that topologically gauged ${\mathcal N}=6$ ABJ(M)
theories have a similar, but more restricted, set of background solutions.


title:
Sobolev and isoperimetric inequalities for submanifolds in weighted
  ambient spaces

abstract:
  In this paper, we prove a Sobolev and isoperimetric inequalities for
submanifold in weighted manifold. Our results generalize the Hoffman-Spruck's
inequalities.


title: Algorithms for Large-scale Whole Genome Association Analysis

abstract:
  In order to associate complex traits with genetic polymorphisms, genome-wide
association studies process huge datasets involving tens of thousands of
individuals genotyped for millions of polymorphisms. When handling these
datasets, which exceed the main memory of contemporary computers, one faces two
distinct challenges: 1) Millions of polymorphisms come at the cost of hundreds
of Gigabytes of genotype data, which can only be kept in secondary storage; 2)
the relatedness of the test population is represented by a covariance matrix,
which, for large populations, can only fit in the combined main memory of a
distributed architecture. In this paper, we present solutions for both
challenges: The genotype data is streamed from and to secondary storage using a
double buffering technique, while the covariance matrix is kept across the main
memory of a distributed memory system. We show that these methods sustain
high-performance and allow the analysis of enormous dataset


title:
Colored bosons on top FBA and angular cross section for $t \bar t$
  production

abstract:
  With full data set that corresponds to an integrated luminosity of 9.4
fb$^{-1}$, CDF has updated the top quark forward-backward asymmetry (FBA) as
functions of rapidity difference $|\Delta y|$ and $t\bar t$ invariant mass
$M_{t\bar t}$. Beside the sustained inconsistency between experiments and
standard model (SM) predictions at large $|\Delta y|$ and $M_{t\bar t}$, an
unexpected large first Legendre moment with $a_1= 0.39\pm 0.108 $ is found. In
order to solve the large top FBA, we study the contributions of color triplet
scalar and color octet vector boson. We find that the top FBA at $|\Delta y|
>1$ and $M_{t\bar t} > 450$ GeV in triplet and octet model could be enhanced to
be around 30% and 20%, whereas the first Legendre moment is $a^{\bf Di}_1=
0.38$ and $a^{\bf Axi}_1= 0.23$, respectively.


title:
The parabolic Anderson model in a dynamic random environment: space-time
  ergodicity for the quenched Lyapunov exponent

abstract:
  We continue our study of the parabolic Anderson equation $\partial
u(x,t)/\partial t = \kappa\Delta u(x,t) + \xi(x,t)u(x,t)$, $x\in\Z^d$, $t\geq
0$, where $\kappa \in [0,\infty)$ is the diffusion constant, $\Delta$ is the
discrete Laplacian, and $\xi$ plays the role of a \emph{dynamic random
environment} that drives the equation. The initial condition $u(x,0)=u_0(x)$,
$x\in\Z^d$, is taken to be non-negative and bounded. The solution of the
parabolic Anderson equation describes the evolution of a field of particles
performing independent simple random walks with binary branching: particles
jump at rate $2d\kappa$, split into two at rate $\xi \vee 0$, and die at rate
$(-\xi) \vee 0$. We assume that $\xi$ is stationary and ergodic under
translations in space and time, is not constant and satisfies
$\E(|\xi(0,0)|)<\infty$, where $\E$ denotes expectation w.r.t.\ $\xi$. Our main
object of interest is the quenched Lyapunov exponent $\lambda_0 (\kappa) =
\lim_{t\to\infty} \frac{1}{t}\log u(0,t)$. In earlier work we showed that under
certain mild space-time mixing assumptions the limit exists $\xi$-a.s., is
finite and continuous on $[0,\infty)$, is globally Lipschitz on $(0,\infty)$,
is not Lipschitz at 0, and satisfies $\lambda_0(0) = \E(\xi(0,0))$ and
$\lambda_0(\kappa) > \E(\xi(0,0))$ for $\kappa \in (0,\infty)$.In the present
paper we show that $\lim_{\kappa\to\infty} \lambda_0(\kappa) =\E(\xi(0,0))$
under an additional space-time mixing condition on $\xi$. This result shows
that the parabolic Anderson model exhibits space-time ergodicity in the limit
of large diffusivity. This fact is interesting because there are choices of
$\xi$ that fulfill our assumption for which the annealed Lyapunov exponent
$\lambda_1(\kappa) = \lim_{t\to\infty} \frac{1}{t}\log \E(u(0,t))$ is infinite
on $[0,\infty)$, a situation that is referred to as strongly catalytic
behavior.


title:
Elaboration of the alpha-Model Derived from the BCS Theory of
  Superconductivity

abstract:
  The single-band alpha-model of superconductivity [H. Padamsee, et al., J. Low
Temp. Phys. {\bf 12}, 387 (1973)] is a popular model that was adapted from the
single-band Bardeen-Cooper-Schrieffer (BCS) theory of superconductivity mainly
to allow fits to electronic heat capacity versus temperature T data that
deviate from the BCS prediction. The model assumes that the normalized
superconducting order parameter Delta(T)/Delta(0) and therefore the normalized
London penetration depth lambda_L(T)/lambda_L(0) are the same as in BCS theory,
calculated using the BCS value alpha_BCS = 1.764 of alpha = Delta(0)/(kB Tc),
where kB is Boltzmann's constant and Tc is the superconducting transition
temperature. On the other hand, to calculate the electronic free energy,
entropy, heat capacity and thermodynamic critical field versus T, the
alpha-model takes alpha to be an adjustable parameter. Here we write the BCS
equations and limiting behaviors for the superconducting state thermodynamic
properties explicitly in terms of alpha, as needed for calculations within the
alpha-model, and present plots of the results versus T and alpha that are
compared with the respective BCS predictions. Mechanisms such as gap anisotropy
and strong coupling that can cause deviations of the thermodynamics from the
BCS predictions, especially the heat capacity jump at Tc, are considered.
Extensions of the alpha-model that have appeared in the literature such as the
two-band model are also discussed. Tables of values of Delta(T)/Delta(0) and
lambda_L(T)/lambda_L(0) calculated from the BCS theory using alpha = alpha_BCS
are provided, which are the same in the alpha-model by assumption. Tables of
values of the entropy, heat capacity and thermodynamic critical field versus T
for seven values of alpha including alpha_BCS are also presented.


title: Extrapolation-based implicit-explicit general linear methods

abstract:
  For many systems of differential equations modeling problems in science and
engineering, there are natural splittings of the right hand side into two
parts, one non-stiff or mildly stiff, and the other one stiff. For such systems
implicit-explicit (IMEX) integration combines an explicit scheme for the
non-stiff part with an implicit scheme for the stiff part.
  In a recent series of papers two of the authors (Sandu and Zhang) have
developed IMEX GLMs, a family of implicit-explicit schemes based on general
linear methods. It has been shown that, due to their high stage order, IMEX
GLMs require no additional coupling order conditions, and are not marred by
order reduction.
  This work develops a new extrapolation-based approach to construct practical
IMEX GLM pairs of high order. We look for methods with large absolute stability
region, assuming that the implicit part of the method is A- or L-stable. We
provide examples of IMEX GLMs with optimal stability properties. Their
application to a two dimensional test problem confirms the theoretical
findings.


title:
A Participatory Universe of J. A. Wheeler as an Intentional Correlate of
  Embodied Subjects and an Example of Purposiveness in Physics

abstract:
  This paper investigates the role of human subjectivity and its delimiters in
articulating the universe in physics and cosmology. As a case study, we reflect
upon the complex of ideas of the so called Participatory Universe by later J.
A. Wheeler. The objective of the paper is to explicate the role of the human
agency as a centre of disclosure and manifestation of the universe as well the
as teleology of scientific representation of the world implied by the intrinsic
purposiveness of human actions.


title: Sensitivity of measured fission yields on prompt-neutron corrections

abstract:
  The amount of emitted prompt neutrons from the fission fragments increases as
a function of excitation energy. Yet it is not fully understood whether the
increase in \nu(A) as a function of E_{n} is mass dependent. The share of
excitation energies among the fragments is still under debate, but there are
reasons to believe that the excess in neutron emission originates only from the
heavy fragments, leaving \nu_{light}(A) almost unchanged. In this work we
investigated the consequences of a mass-dependent increase in \nu(A) on the
final mass and energy distributions. The assumptions on \nu(A) are essential
when analysing measurements based on the 2E-technique. This choice showed to be
significant on the measured observables. For example, the post-neutron emission
mass yield distribution revealed changes up to 10-30%. The outcome of this work
pinpoint the urgent need to determine \nu(A) experimentally, and in particular,
how \nu(A) changes as a function of incident-neutron energy. Until then, many
fission yields in the data libraries could be largely affected, since they were
analysed based on another assumption on the neutron emission.


title: Local characterization of 1d topologically ordered states

abstract:
  We consider 1d Hamiltonian systems whose ground states display symmetry
protected topological order. We show that ground states within the topological
phase cannot be connected with each other through LOCC between a bipartition of
the system. Our claim is demonstrated by analyzing the entanglement spectrum
and Renyi entropies of different physical systems providing examples for
symmetry protected topological phases. Specifically, we consider spin-1/2
Cluster-Ising model and a class of spin-1 models undergoing quantum phase
transitions to the Haldane phase. Our results provide a probe for
simmetry-protected topological order, that holds true even at the system's
local scale. Therefore our analysis can serve as as local experimental test for
topological order.


title:
Binary Frequencies in a Sample of Globular Clusters. I. Methodology and
  Initial Results

abstract:
  Binary stars are thought to be a controlling factor in globular cluster
evolution, since they can heat the environmental stars by converting their
binding energy to kinetic energy during dynamical interactions. Through such
interaction, the binaries determine the time until core collapse. To test
predictions of this model, we have determined binary fractions for 35 clusters.
Here we present our methodology with a representative globular cluster NGC
4590. We use HST archival ACS data in the F606W and F814W bands and apply
PSF-fitting photometry to obtain high quality color-magnitude diagrams. We
formulate the star superposition effect as a Poisson probability distribution
function, with parameters optimized through Monte-Carlo simulations. A
model-independent binary fraction of (6.2 +- 0.3)% is obtained by counting
stars that extend to the red side of the residual color distribution after
accounting for the photometric errors and the star superposition effect. A
model-dependent binary fraction is obtained by constructing models with a known
binary fraction and an assumed binary mass-ratio distribution function. This
leads to a binary fraction range of 6.8% to 10.8%, depending on the assumed
shape to the binary mass ratio distribution, with the best fit occurring for a
binary distribution that favors low mass ratios (and higher binary fractions).
We also represent the method for radial analysis of the binary fraction in the
representative case of NGC 6981, which shows a decreasing trend for the binary
fraction towards the outside, consistent with theoretical predictions for the
dynamical effect on the binary fraction.


title:
Ultra Low Power Associative Computing with Spin Neurons and Resistive
  Crossbar Memory

abstract:
  Emerging resistive-crossbar memory (RCM) technology can be promising for
computationally-expensive analog pattern-matching tasks. However, the use of
CMOS analog-circuits with RCM would result in large power-consumption and poor
scalability, thereby eschewing the benefits of RCM-based computation. We
propose the use of low-voltage, fast-switching, magneto-metallic spin-neurons
for ultra low-power non-Boolean computing with RCM. We present the design of
analog associative memory for face recognition using RCM, where, substituting
conventional analog circuits with spin-neurons can achieve ~100x lower power.
This makes the proposed design ~1000x more energy-efficient than a 45nm-CMOS
digital ASIC, thereby significantly enhancing the prospects of RCM based
computational hardware.


title:
In search of superluminal quantum communications: recent experiments and
  possible improvements

abstract:
  As shown in the famous \emph{EPR} paper (Einstein, Podolsky e Rosen,1935),
Quantum Mechanics is non-local. The Bell theorem and the experiments by Aspect
and many others, ruled out the possibility of explaining quantum correlations
between entangled particles using local hidden variables models (except for
implausible combinations of loopholes). Some authors (Bell, Eberhard, Bohm and
Hiley) suggested that quantum correlations could be due to superluminal
communications (tachyons) that propagate isotropically with velocity
\emph{$v_{t}>c$} in a preferred reference frame. For finite values of
\emph{$v_{t}$}, Quantum Mechanics and superluminal models lead to different
predictions. Some years ago a Geneva group and our group did experiments on
entangled photons to evidence possible discrepancies between experimental
results and quantum predictions. Since no discrepancy was found, these
experiments established only lower bounds for the possible tachyon velocities
\emph{$v_{t}$}. Here we propose an improved experiment that should lead us to
explore a much larger range of possible tachyon velocities \emph{$v_{t}$} for
any possible direction of velocity $\vec{V}$ of the tachyons preferred frame.


title: The temperature evolution of the shear viscosity in a unitary Fermi gas

abstract:
  We present an ab initio determination of the shear viscosity for the unitary
Fermi gas based on finite temperature quantum Monte Carlo (QMC) calculations
and the Kubo linear-response formalism. The results are confronted with the
bound for the shear viscosity originating from hydrodynamic fluctuations.
Assuming smoothness of the frequency dependent shear viscosity eta(omega), we
show that the bound is violated in the low temperature regime and the violation
occurs simultaneously with the onset of the Cooper paring in the system. In
order to preserve the hydrodynamic bound in QMC eta(omega) has to possess a
sharp structure located in the vicinity of zero frequency which is not resolved
by an analytic continuation procedure.


title: Ordered $*$-Semigroups and a $C^*$-Correspondence for a Partial Isometry

abstract:
  Certain $*$-semigroups are associated with the universal $C^*$-algebra
generated by a partial isometry, which is itself the universal $C^*$-algebra of
a $*$-semigroup. A fundamental role for a $*$-structure on a semigroup is
emphasized, and ordered and matricially ordered $*$-semigroups are introduced,
along with their universal $C^*$-algebras. The universal $C^*$-algebra
generated by a partial isometry is isomorphic to a relative Cuntz-Pimsner
$C^*$-algebra of a $C^*$-correspondence over the $C^*$-algebra of a matricially
ordered $*$-semigroup. One may view the $C^*$-algebra of a partial isometry as
the crossed product algebra associated with a dynamical system defined by a
complete order map modelled by a partial isometry acting on a matricially
ordered $*$-semigroup.


title: Cumulative Probability of Blast Fragmentation Effect

abstract:
  This paper presents formulae for calculation of cumulative probability of
effect made by blast fragments. Analysis with Mott distribution, discrete
fragment enumeration, spatial non-uniformity, numerical issues, and a
generalisation for a set of effects are also discussed.


title: Wave-particle duality: an information-based approach

abstract:
  Recently, Bohr's complementarity principle was assessed in setups involving
delayed choices. These works argued in favor of a reformulation of the
aforementioned principle so as to account for situations in which a quantum
system would simultaneously behave as wave and particle. Here we defend a
framework that, supported by well-known experimental results and consistent
with the decoherence paradigm, allows us to interpret complementarity in terms
of correlations between the system and an {\em informer}. Our proposal offers
formal definition and operational interpretation for the dual behavior in terms
of both nonlocal resources and the couple work-information. Most importantly,
our results provide a generalized information-based trade-off for the
wave-particle duality and a causal interpretation for delayed-choice
experiments.


title: Trapping Electromagnetic Solitons in Cylinders

abstract:
  Electromagnetic waves, in vacuum or dielectrics, can be confined in unbounded
cylinders in such a way that they turn around the main axis. For particular
choices of the cylinder's section, interesting stationary configurations may be
assumed. By refining some results obtained in previous papers, additional more
complex situations are examined here. For such peculiar guided waves an
explicit expression is given in terms of Bessel's functions. Possible
applications are in the development of whispering gallery resonators.


title: Near Heisenberg limited atomic clocks in the presence of decoherence

abstract:
  The ultimate stability of atomic clocks is limited by the quantum noise of
the atoms. To reduce this noise it has been suggested to use entangled atomic
ensembles with reduced atomic noise. Potentially this can push the stability
all the way to the limit allowed by the Heisenberg uncertainty relation, which
is denoted the Heisenberg limit. In practice, however, entangled states are
often more prone to decoherence, which may prevent reaching this performance.
Here we present an adaptive measurement protocol that in the presence of a
realistic source of decoherence enables us to get near Heisenberg limited
stability of atomic clocks using entangled atoms. The protocol may thus realize
the full potential of entanglement for quantum metrology despite the
detrimental influence of decoherence.


title: The effect of phenotypic selection on stochastic gene expression

abstract:
  Genetically identical cells in the same population can take on phenotypically
variable states, leading to differentiated responses to external signals, such
as nutrients and drug-induced stress. Many models and experiments have focused
on a description based on discrete phenotypic states. Here we consider the
effects of selection acting on a single trait, which we explicitly link to the
variable number of proteins expressed by a gene. Considering different
regulatory models for the gene under selection, we calculate the steady-state
distribution of expression levels and show how the population adapts its
expression to enhance its fitness. We quantitatively relate the overall fitness
of the population to the heritability of expression levels, and their diversity
within the population. We show how selection can increase or decrease the
variability in the population, alter the stability of bimodal states, and
impact the switching rates between metastable attractors.


title: Macro Lambda Calculus

abstract:
  The goal of our Macro Lambda Calculus project (MLC) is to encode lambda terms
into interaction nets. Its software implementation will accept input in the
notation similar to lambda calculus allowing macro definitions. Output is
similar to interaction calculus and is suitable for our Interaction Nets
Compiler program (INC). In this paper, we describe the interaction system for
call-by-need evaluation and the mechanism of encoding lambda terms into this
system which MLC is based on.


title: Gauge invariant backreaction in general single field models of inflation

abstract:
  In a general single field inflationary model we consider the effects of long
wavelength scalar fluctuations on the effective expansion rate and equation of
state seen by a class of free falling observers, using a physical gauge
invariant formulation. In a previous work we showed that for a free massive
inflaton no backreaction is observed within some constraints. In this paper we
extend the validity of our previous results to the case of an arbitrary
self-interacting inflation potential, working to second order in cosmological
perturbation theory and to all order in slow-roll approximation. For these
general inflationary models, we also show the equivalence of the free falling
observers to the ones comoving with the inflaton field.


title: Phantom Instability of Viscous Dark Energy in Anisotropic Space-Time

abstract:
  Phantom dark energy is a proposal that explains the current observations that
mildly favor the equation of state of dark energy $\omega^{de}$ crossing -1 at
68% confidence level. However, phantom fields are generally ruled out by
ultraviolet quantum instabilities. To overcome this discrepancy, in this paper
we propose a mechanism to show that how the presence of bulk viscosity in the
cosmic fluid can temporarily drive the fluid into the phantom region
($\omega<-1$). As time is going on, phantom decays and ultimately $\omega^{de}$
approaches to -1. Then we show these quintessence and phantom descriptions of
non-viscous and viscous dark energy and reconstruct the potential of these two
scalar fields. Also a diagnostic for these models are performed by using the
statefinder pairs $\{s,r\}$. All results are obtained in an anisotropic
space-time which is a generalization of FLRW universe.


title:
A competing risks approach for nonparametric estimation of transition
  probabilities in a non-Markov illness-death model

abstract:
  Competing risks model time to first event and type of first event. An example
from hospital epidemiology is the incidence of hospital-acquired infection,
which has to account for hospital discharge of non-infected patients as a
competing risk. An illness-death model would allow to further study hospital
outcomes of infected patients. Such a model typically relies on a Markov
assumption. However, it is conceivable that the future course of an infected
patient does not only depend on the time since hospital admission and current
infection status but also on the time since infection. We demonstrate how a
modified competing risks model can be used for nonparametric estimation of
transition probabilities when the Markov assumption is violated.


title:
Prediction of the dynamic oscillation threshold in a clarinet model with
  a linearly increasing blowing pressure : influence of noise

abstract:
  This paper presents an analysis of the effects of noise and precision on a
simplified model of the clarinet driven by a variable control parameter. When
the control parameter is varied the clarinet model undergoes a dynamic
bifurcation. A consequence of this is the phenomenon of bifurcation delay: the
bifurcation point is shifted from the static oscillation threshold to an higher
value called dynamic oscillation threshold. In a previous work [8], the dynamic
oscillation threshold is obtained analytically. In the present article, the
sensitivity of the dynamic threshold on precision is analyzed as a stochastic
variable introduced in the model. A new theoretical expression is given for the
dynamic thresholds in presence of the stochastic variable, providing a fair
prediction of the thresholds found in finite-precision simulations. These
dynamic thresholds are found to depend on the increase rate and are independent
on the initial value of the parameter, both in simulations and in theory.


title: The finiteness problem for automaton semigroups is undecidable

abstract:
  The finiteness problem for automaton groups and semigroups has been widely
studied, several partial positive results are known. However we prove that, in
the most general case, the problem is undecidable. We study the case of
automaton semigroups. Given a NW-deterministic Wang tile set, we construct an
Mealy automaton, such that the plane admit a valid Wang tiling if and only if
the Mealy automaton generates a finite semigroup. The construction is similar
to a construction by Kari for proving that the nilpotency problem for cellular
automata is unsolvable. Moreover Kari proves that the tiling of the plane is
undecidable for NW-deterministic Wang tile set. It follows that the finiteness
problem for automaton semigroup is undecidable.


title: A fourth-order model for MEMS with clamped boundary conditions

abstract:
  The dynamical and stationary behaviors of a fourth-order equation in the unit
ball with clamped boundary conditions and a singular reaction term are
investigated. The equation arises in the modeling of microelectromechanical
systems (MEMS) and includes a positive voltage parameter $\lambda$. It is shown
that there is a threshold value $\lambda_*>0$ of the voltage parameter such
that no radially symmetric stationary solution exists for $\lambda>\lambda_*$,
while at least two such solutions exist for $\lambda\in (0,\lambda_*)$. Local
and global well-posedness results are obtained for the corresponding hyperbolic
and parabolic evolution problems as well as the occurrence of finite time
singularities when $\lambda>\lambda_*$.


title: A solution to the Pompeiu problem

abstract:
  Let $f \in L_{loc}^1 (\R^n)\cap \mathcal{S}$, where $\mathcal{S}$ is the
Schwartz class of distributions, and $$\int_{\sigma (D)} f(x) dx = 0 \quad
\forall \sigma \in G, \qquad (*)$$ where $D\subset \R^n$ is a bounded domain,
the closure $\bar{D}$ of which is diffeomorphic to a closed ball, and $S$ is
its boundary. Then the comp$ is connected and path connected. By $G$ the group
of all rigid motions of $\R^n$ is denoted. This group consists of all
translations and rotations. A proof of the following theorem is given.
  Theorem 1. {\it Assume that $n=2$, $f\not\equiv 0$, and (*) holds. Then $D$
is a ball.}
  Corollary. {\it If the problem $(\nabla^2+k^2)u=0$ in $D$, $u_N|_S=0$,
$u|_S=const\neq 0$ has a solution, then $D$ is a ball.}
  Here $N$ is the outer unit normal to $S$.


title: A discreteness criterion for groups containing parabolic isometries

abstract:
  This note will prove a discreteness criterion for groups of
orientation-preserving isometries of the hyperbolic space which contain a
parabolic element. It can be viewed as a generalization of the well-known
results of Shimizu-Leutbecher and Jorgensen in dimensions 2 and 3, and is
closely related to Waterman's inequality in higher dimensions. Unlike his
algebraic method, the argument presented here is geometric and yields an
improved asymptotic bound.


title: Fossil Evidence for the Two-phase Formation of Elliptical Galaxies

abstract:
  Massive early-type galaxies have undergone dramatic structural evolution over
the last 10 Gyr. A companion paper shows that nearby elliptical galaxies with
M*>1.3x10^{11} M_sun generically contain three photometric subcomponents: a
compact inner component with effective radius Re<1 kpc, an intermediate-scale
middle component with Re~2.5 kpc, and an extended outer envelope with $R_e
\approx 10$ kpc. Here we attempt to relate these substructures with the
properties of early-type galaxies observed at higher redshifts. We find that a
hypothetical structure formed from combining the inner plus the middle
components of local ellipticals follows a strikingly tight stellar mass-size
relation, one that resembles the distribution of early-type galaxies at z~1.5.
Outside of the central kpc, the median stellar mass surface density profiles of
this composite structure agree closest with those of massive galaxies that have
similar cumulative number density at 1.5<z<2.0 within the uncertainty. We
propose that the central substructures in nearby ellipticals are the
evolutionary descendants of the "red nuggets" formed under highly dissipative
("wet") conditions at high redshifts, as envisioned in the initial stages of
the two-phase formation scenario recently advocated for massive galaxies.
Subsequent accretion, plausibly through dissipationless ("dry") minor mergers,
builds the outer regions of the galaxy identified as the outer envelope in our
decomposition. The large scatter exhibited by this component on the stellar
mass-size plane testifies to the stochastic nature of the accretion events.


title:
Incremental Computation of Pseudo-Inverse of Laplacian: Theory and
  Applications

abstract:
  A divide-and-conquer based approach for computing the Moore-Penrose
pseudo-inverse of the combinatorial Laplacian matrix $(\bb L^+)$ of a simple,
undirected graph is proposed. % The nature of the underlying sub-problems is
studied in detail by means of an elegant interplay between $\bb L^+$ and the
effective resistance distance $(\Omega)$. Closed forms are provided for a novel
{\em two-stage} process that helps compute the pseudo-inverse incrementally.
Analogous scalar forms are obtained for the converse case, that of structural
regress, which entails the breaking up of a graph into disjoint components
through successive edge deletions. The scalar forms in both cases, show
absolute element-wise independence at all stages, thus suggesting potential
parallelizability. Analytical and experimental results are presented for
dynamic (time-evolving) graphs as well as large graphs in general (representing
real-world networks). An order of magnitude reduction in computational time is
achieved for dynamic graphs; while in the general case, our approach performs
better in practice than the standard methods, even though the worst case
theoretical complexities may remain the same: an important contribution with
consequences to the study of online social networks.