title: Nonlinear Randomized Urn Models: a Stochastic Approximation Viewpoint

abstract:
  This paper extends the link between stochastic approximation (SA) theory and
randomized urn models developed in Laruelle, Pag{\`e}s (2013), and their
applications to clinical trials introduced in Bai, HU (1999,2005) and Bai, Hu,
Shen (2002). We no longer assume that the drawing rule is uniform among the
balls of the urn (which contains d colors), but can be reinforced by a function
f. This is a way to model risk aversion. Firstly, by considering that f is
concave or convex and by reformulating the dynamics of the urn composition as
an SA algorithm with remainder, we derive the a.s. convergence and the
asymptotic normality (Central Limit Theorem, CLT) of the normalized procedure
by calling upon the so-called ODE and SDE methods. An in-depth analysis of the
case d=2 exhibits two different behaviors: A single equilibrium point when f is
concave, and when f is convex, a transition phase from a single attracting
equilibrium to a system with two attracting and one repulsive equilibrium
points. The last setting is solved using results on non-convergence toward
noisy and noiseless "traps" in order to deduce the a.s. convergence toward one
of the attracting points. Secondly, the special case of a Polya urn (when the
addition rule is the identity matrix) is analyzed, still using result from SA
theory about "traps". Finally, these results are applied to a function with
regular variation and to an optimal asset allocation in Finance.


title:
Observation of Bloch-point domain walls in cylindrical magnetic
  nanowires

abstract:
  Topological protection is an elegant way of warranting the integrity of
quantum and nanosized systems. In magnetism one example is the Bloch-point, a
peculiar object implying the local vanishing of magnetization within a
ferromagnet. Its existence had been postulated and described theoretically
since several decades, however it has never been observed. We con rm
experimentally the existence of Bloch points, imaged within domain walls in
cylindrical magnetic nanowires, combining surface and transmission XMCD-PEEM
magnetic microscopy. This opens the way to the experimental search for peculiar
phenomena predicted during the motion of Bloch-point-based domain walls.


title: Worst-Case Analysis of Weber's Algorithm

abstract:
  Recently, Ken Weber introduced an algorithm for finding the $(a,b)$-pairs
satisfying $au+bv\equiv 0\pmod{k}$, with $0<|a|,|b|<\sqrt{k}$, where $(u,k)$
and $(v,k)$ are coprime. It is based on Sorenson's and Jebelean's "$k$-ary
reduction" algorithms. We provide a formula for $N(k)$, the maximal number of
iterations in the loop of Weber's GCD algorithm.


title:
Exact Large Deviations of the Current in the Asymmetric Simple Exclusion
  Process with Open Boundaries

abstract:
  In this thesis, we consider one of the most popular models of non-equilibrium
statistical physics: the Asymmetric Simple Exclusion Process, in which
particles jump stochastically on a one-dimensional lattice, between two
reservoirs at fixed densities, with the constraint that each site can hold at
most one particle at a given time. This model has the mathematical property of
being integrable, which makes it a good candidate for exact calculations. What
interests us in particular is the current of particles that flows through the
system (which is a sign of it being out of equilibrium), and how it fluctuates
with time. We present a method, based on the "matrix Ansatz" devised by
Derrida, Evans, Hakim and Pasquier, that allows to access the exact cumulants
of that current, for any finite size of the system and any value of its
parameters. We also analyse the large size asymptotics of our result, and make
a conjecture for the phase diagram of the system in the so-called "s-ensemble".
Finally, we show how our method relates to the algebraic Bethe Ansatz, which
was thought not to be applicable to this situation.


title: Starbugs: all-singing, all-dancing fibre positioning robots

abstract:
  Starbugs are miniature piezoelectric 'walking' robots with the ability to
simultaneously position many optical fibres across a telescope's focal plane.
Their simple design incorporates two piezoceramic tubes to form a pair of
concentric 'legs' capable of taking individual steps of a few microns, yet with
the capacity to move a payload several millimetres per second. The Australian
Astronomical Observatory has developed this technology to enable fast and
accurate field reconfigurations without the inherent limitations of more
traditional positioning techniques, such as the 'pick and place' robotic arm.
We report on our recent successes in demonstrating Starbug technology, driven
principally by R&D efforts for the planned MANIFEST (many instrument
fibre-system) facility for the Giant Magellan Telescope. Significant
performance gains have resulted from improvements to the Starbug system,
including i) the use of a vacuum to attach Starbugs to the underside of a
transparent field plate, ii) optimisation of the control electronics, iii) a
simplified mechanical design with high sensitivity piezo actuators, and iv) the
construction of a dedicated laboratory 'test rig'. A method of reliably
rotating Starbugs in steps of several arcminutes has also been devised, which
integrates with the pre-existing x-y movement directions and offers greater
flexibility while positioning. We present measured performance data from a
prototype system of 10 Starbugs under full (closed-loop control), at field
plate angles of 0-90 degrees.


title:
Comments on $AdS_2$ solutions from M2-branes on complex curves and the
  backreacted K\"ahler geometry

abstract:
  We consider $AdS_2$ solutions of M-theory which are obtained by twisted
compactifications of M2-branes on a complex curve. They are of a generalized
class, in the sense that the non-abelian part of the connection for the
holomorphic bundle over the supersymmetric cycle is nontrivial. They are
solutions of $U(1)^4$ gauged supergravity in $D=4$, with magnetic flux over the
curve, and then uplifted to $D=11$. We discuss the behavior of conformal fixed
points as a function of the non-abelian connection. We also describe how they
fit into the general description of wrapped M2-brane $AdS_2$ solutions and
their higher-order generalizations, by showing that they satisfy the master
equation for the eight-dimensional K\"ahler base space.


title:
Limited-Feedback-Based Channel-Aware Power Allocation for Linear
  Distributed Estimation

abstract:
  This paper investigates the problem of distributed best linear unbiased
estimation (BLUE) of a random parameter at the fusion center (FC) of a wireless
sensor network (WSN). In particular, the application of limited-feedback
strategies for the optimal power allocation in distributed estimation is
studied. In order to find the BLUE estimator of the unknown parameter, the FC
combines spatially distributed, linearly processed, noisy observations of local
sensors received through orthogonal channels corrupted by fading and additive
Gaussian noise. Most optimal power-allocation schemes proposed in the
literature require the feedback of the exact instantaneous channel state
information from the FC to local sensors. This paper proposes a
limited-feedback strategy in which the FC designs an optimal codebook
containing the optimal power-allocation vectors, in an iterative offline
process, based on the generalized Lloyd algorithm with modified distortion
functions. Upon observing a realization of the channel vector, the FC finds the
closest codeword to its corresponding optimal power-allocation vector and
broadcasts the index of the codeword. Each sensor will then transmit its analog
observations using its optimal quantized amplification gain. This approach
eliminates the requirement for infinite-rate digital feedback links and is
scalable, especially in large WSNs.


title:
A Tentative Description of Z_c,b States in Terms of Metastable Feshbach
  Resonances

abstract:
  We attempt a description of the recently discovered Z_{c,b} states in terms
of Feshbach resonances arising from the interaction between the `closed'
subspace of hadrocharmonium levels and the `open' one of open-charm/beauty
thresholds. We show how the neutrality of the X(3872) might be understood in
this scheme and provide a preliminary explanation of the pattern of the
measured total widths of X,Z_{c,b}.


title: On the Leray-Schauder degree of the Toda system on compact surfaces

abstract:
  In this paper we consider the so-called Toda system of equations on a compact
surface. In particular, we discuss the parity of the Leray-Schauder degree of
that problem. Our main tool is a theorem of Krasnoselskii and Zabreiko on the
degree of maps symmetric with respect to a subspace. This result yields new
existence results as well as a new proof of previous results in literature.


title:
Numerical study of the Dyson-Schwinger equations for the Wess-Zumino
  model

abstract:
  Supersymmetric models, in most cases, suffer from the lack of
non-perturbative techniques. Recently, an approach based on Dyson-Schwinger
equations has been proposed for the massless Wess-Zumino model. In this case,
the equations for the self-energies of the fields were solved with the strong
ansatz to take them all equal. We show, by numerically solving the equations,
that this is a too strong choice as also solutions with all different
self-energies are acceptable and more generic. This could have interesting
implications for supersymmetry breaking.


title:
The Numerically Optimized Regulator and the Functional Renormalization
  Group

abstract:
  We aim to optimize the functional form of the compactly supported smooth
(CSS) regulator within the functional renormalization group (RG), in the
framework of bosonized two-dimensional Quantum Electrodynamics (QED_2) and of
the three-dimensional O(N=1) scalar field theory in the local potential
approximation (LPA). The principle of minimal sensitivity (PMS) is used for the
optimization of the CSS regulator, recovering all the major types of regulators
in appropriate limits. Within the investigated class of functional forms, a
thorough investigation of the CSS regulator, optimized with two different
normalizations within the PMS method, confirms that the functional form of a
regulator first proposed by Litim is optimal within the LPA. However, Litim's
exact form leads to a kink in the regulator function. A form of the CSS
regulator, numerically close to Litim's limit while maintaining infinite
differentiability, remains compatible with the gradient expansion to all
orders. A smooth analytic behaviour of the regulator is ensured by a small, but
finite value of the exponential fall-off parameter in the CSS regulator.
Consequently, a compactly supported regulator, in a parameter regime close to
Litim's optimized form, but regularized with an exponential factor, appears to
have favorable properties and could be used to address the scheme dependence of
the functional renormalization group, at least within the the approximations
employed in the studies reported here.


title: The commuting local Hamiltonian on locally-expanding graphs is in NP

abstract:
  The local Hamiltonian problem is famously complete for the class QMA, the
quantum analogue of NP. The complexity of its semi-classical version, in which
the terms of the Hamiltonian are required to commute (the CLH problem), has
attracted considerable attention recently due to its intriguing nature, as well
as in relation to growing interest in the qPCP conjecture. We show here that if
the underlying bipartite interaction graph of the CLH instance is a good
locally-expanding graph, namely, the expansion of any constant-size set is
e-close to optimal, then approximating its ground energy to within additive
factor O(e) lies in NP. The proof holds for k- local Hamiltonians for any
constant k and any constant dimensionality of particles d. We also show that
the approximation problem of CLH on such good local expanders is NP-hard. This
implies that too good local expansion of the interaction graph constitutes an
obstacle against quantum hardness of the approximation problem, though it
retains its classical hardness. The result highlights new difficulties in
trying to mimic classical proofs (in particular Dinur's PCP proof) in an
attempt to prove the quantum PCP conjecture. A related result was discovered
recently independently by Brandao and Harrow, for 2-local general Hamiltonians,
bounding the quantum hardness of the approximation problem on good expanders,
though no NP-hardness is known in that case.


title: Butterflies on the Stretched Horizon

abstract:
  In this paper I return to the question of what kind of perturbations on
Alice's side of an Einstein-Rosen bridge can send messages to Bob as he enters
the horizon at the other end. By definition "easy" operators do not activate
messages and "hard" operators do, but there are no clear criteria to identify
the difference between easy and hard. In this paper I argue that the difference
is related to the time evolution of a certain measure of computational
complexity, associated with the stretched horizon of Alice's black hole. The
arguments suggest that the AMPSS commutator argument is more connected with
butterflies than with firewalls.


title:
Testing the Interaction between Dark Energy and Dark Matter with Planck
  Data

abstract:
  Interacting Dark Energy and Dark Matter is used to go beyond the standard
cosmology. We base our arguments on Planck data and conclude that an
interaction is compatible with the observations and can provide a strong
argument towards consistency of different values of cosmological parameters.


title:
Perturbative corrections to power suppressed effects in semileptonic B
  decays

abstract:
  We compute the $O(\alpha_s)$ corrections to the Wilson coefficient of the
chromomagnetic operator in inclusive semileptonic B decays. The results are
employed to evaluate the complete $O(\alpha_s \Lambda^2/m_b^2)$ correction to
the semileptonic width and to the first moments of the lepton energy
distribution.


title:
Gaussian and Non-Gaussian operations on non-Gaussian state: engineering
  non-Gaussianity

abstract:
  Multiple photon subtraction applied to a displaced phase-averaged coherent
state, which is a non-Gaussian classical state, produces conditional states
with a non trivial (positive) Glauber-Sudarshan $P$-representation. We
theoretically and experimentally demonstrate that, despite its simplicity, this
class of conditional states cannot be fully characterized by direct detection
of photon numbers. In particular, the non-Gaussianity of the state is a
characteristics that must be assessed by phase-sensitive measurements. We also
show that the non-Gaussianity of conditional states can be manipulated by
choosing suitable conditioning values and composition of phase-averaged states.


title: Least-squares deconvolution based analysis of stellar spectra

abstract:
  In recent years, astronomical photometry has been revolutionised by space
missions such as MOST, CoRoT and Kepler. However, despite this progress,
high-quality spectroscopy is still required as well. Unfortunately,
high-resolution spectra can only be obtained using ground-based telescopes, and
since many interesting targets are rather faint, the spectra often have a
relatively low S/N. Consequently, we have developed an algorithm based on the
least-squares deconvolution profile, which allows to reconstruct an observed
spectrum, but with a higher S/N. We have successfully tested the method using
both synthetic and observed data, and in combination with several common
spectroscopic applications, such as e.g. the determination of atmospheric
parameter values, and frequency analysis and mode identification of stellar
pulsations.


title: Green-Kubo formula for weakly coupled system with dynamical noise

abstract:
  We study the Green-Kubo (GK) formula $\kappa (\varepsilon, \xi)$ for the heat
conductivity of an infinite chain of $d$-dimensional finite systems (cells)
coupled by a smooth nearest neighbour potential $\varepsilon V$. The uncoupled
systems evolve according to Hamiltonian dynamics perturbed stochastically by an
energy conserving noise of strength $\xi$. Noting that $\kappa (\varepsilon,
\xi)$ exists and is finite whenever $\xi> 0$, we are interested in what happens
when the strength of the noise $\xi \to 0$. For this, we start in this work by
formally expanding $\kappa (\varepsilon, \xi)$ in a power series in
$\varepsilon$, $\kappa (\varepsilon, \xi) = \varepsilon^2 \sum_{n\ge 2}
\varepsilon^{n-2} \kappa_n (\xi)$ and investigating the (formal) equations
satisfied by $\kappa_n (\xi$. We show in particular that $\kappa_2 (\xi)$ is
well defined when no pinning potential is present, and coincides formally with
the heat conductivity obtained in the weak coupling (van Hove) limit, where
time is rescaled as $\varepsilon^{-2}t$, for the cases where the latter has
been established \cite{LO, DL}. For one-dimensional systems, we investigate
$\kappa_2 (\xi)$ as $\xi\to 0$ in three cases: the disordered harmonic chain,
the rotor chain and a chain of strongly anharmonic oscillators. Moreover, we
formally identify $\kappa_2 (\xi)$ with the conductivity obtained by having the
chain between two reservoirs at temperature $T$ and $T+\delta T$, in the limit
$\delta T\to 0$, $N \to \infty$, $\varepsilon \to 0$.

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


title: Algorithmic Identification of Probabilities

abstract:
  TThe problem is to identify a probability associated with a set of natural
numbers, given an infinite data sequence of elements from the set. If the given
sequence is drawn i.i.d. and the probability mass function involved (the
target) belongs to a computably enumerable (c.e.) or co-computably enumerable
(co-c.e.) set of computable probability mass functions, then there is an
algorithm to almost surely identify the target in the limit. The technical tool
is the strong law of large numbers. If the set is finite and the elements of
the sequence are dependent while the sequence is typical in the sense of
Martin-L\"of for at least one measure belonging to a c.e. or co-c.e. set of
computable measures, then there is an algorithm to identify in the limit a
computable measure for which the sequence is typical (there may be more than
one such measure). The technical tool is the theory of Kolmogorov complexity.
We give the algorithms and consider the associated predictions.


title:
Multifractal analysis of some inhomogeneous multinomial measures with
  distinct analytic Olsen's $b$ and $B$ functions

abstract:
  Inhomogeneous multinomial measures on the mixed symbolic spaces and the real
line are given. By counting the zeros of the corresponding generalized
Dirichlet polynomials, one obtains a probability measure whose Olsen's
functions $b$ and $B$ are analytic and their graphs differ except at two points
where they are tangent. Also, interpretations of the Legendre transform of $b$
and $B$ are given in terms of dimensions.


title:
Solar Modulation of Cosmic Rays during the Declining and Minimum Phases
  of Solar Cycle 23: Comparison with Past Three Solar Cycles

abstract:
  We study solar modulation of galactic cosmic rays (GCRs) during the deep
solar minimum, including the declining phase, of solar cycle 23 and compare the
results of this unusual period with the results obtained during similar phases
of the previous solar cycles 20, 21, and 22. These periods consist of two
epochs each of negative and positive polarities of the heliospheric magnetic
field from the north polar region of the Sun. In addition to cosmic ray data,
we utilize simultaneous solar and interplanetary plasma/field data including
the tilt angle of the heliospheric current sheet. We study the relation between
simultaneous variations in cosmic ray intensity and solar/interplanetary
parameters during the declining and the minimum phases of cycle 23. We compare
these relations with those obtained for the same phases in the three previous
solar cycles. We observe certain peculiar features in cosmic ray modulation
during the minimum of solar cycle 23 including the record high GCR intensity.
We find, during this unusual minimum, that the correlation of GCR intensity is
poor with sunspot number (R = -0.41), better with interplanetary magnetic field
(R = -0.66), still better with solar wind velocity (R = -0.80) and much better
with the tilt angle of the heliospheric current sheet (R = -0.92). In our view,
it is not the diffusion or the drift alone, but the solar wind convection is
the most likely additional effect responsible for the record high GCR intensity
observed during the deep minimum of solar cycle 23.


title: Web Mining Techniques in E-Commerce Applications

abstract:
  Today web is the best medium of communication in modern business. Many
companies are redefining their business strategies to improve the business
output. Business over internet provides the opportunity to customers and
partners where their products and specific business can be found. Nowadays
online business breaks the barrier of time and space as compared to the
physical office. Big companies around the world are realizing that e-commerce
is not just buying and selling over Internet, rather it improves the efficiency
to compete with other giants in the market. For this purpose data mining
sometimes called as knowledge discovery is used. Web mining is data mining
technique that is applied to the WWW. There are vast quantities of information
available over the Internet.


title:
Partial preservation of chiral symmetry and colossal magnetoresistance
  in adatom doped graphene

abstract:
  We analyze the electronic properties of adatom doped graphene in the low
impurity concentration regime. We focus on the Anderson localized regime and
calculate the localization length ($\xi$) as a function of the electron doping
and an external magnetic field. The impurity states hybridize with carbon's
$p_z$ states and form a partially filled band close to the Dirac point. Near
the impurity band center, the chiral symmetry of the system's effective
Hamiltonian is partially preserved which leads to a large enhancement of $\xi$.
The sensitivity of transport properties, namely Mott's variable range hopping
scale $T_0$, to an external magnetic field perpendicular to the graphene sheet
leads to a colossal magnetoresistance effect, as observed in recent
experiments.


title: Quantified 'shock sensitivity' above the Maxwell load

abstract:
  Using the static-dynamic analogy, work at Bath and Bristol has uncovered the
vital organizing role of the Maxwell 'energy criterion' load in the advanced
post-buckling of long-thin structures which exhibit severe shell-like
imperfection sensitivity. It has become clear that above the Maxwell load,
$P_M$, there are localized solutions offering an order-of-magnitude increase in
sensitivity to lateral side-loads, whether static or dynamic. We propose to
call this 'shock-sensitivity', and notice that so far only the seminal paper by
Horak, Lord and Peletier in 2006 has quantified this in terms of an $E(P)$
energy-barrier versus load graph. In this paper we present three graphs of this
nature for archetypal problems: the free twisted rod, the cylindrically
constrained rod, and the strut on a softening elastic foundation. We find in
all cases that the energy barrier of the localizing solution above $P_M$ is
quite close to the energy of a single periodic wave. Now a single such wave is
not kinematically admissible, and the corresponding periodic barrier must be
for all the waves in the long structure, $N$, say. So in practice $N$ will be
large, and does indeed tend to infinity with the length of the structure. Thus
the sensitivity increases by a factor of a large $N$ as the Maxwell load is
exceeded. This is important in its own right, and we do not seek to explain or
fit curves to the scattered experimental buckling loads of shell structures.


title:
The Emergence of Supersymmetry in $\gamma_i$-deformed ${\cal N}=4$
  super-Yang-Mills theory

abstract:
  The $\gamma_i$-deformed $\mathcal{N}=4$ super-Yang-Mills theory is a
non-supersymmetric deformation of the maximally-supersymmetric gauge theory in
four dimensions which is conformally-invariant at the planar level. At the
non-planar level non-trivial renormalization of marginal double-trace operators
appears to break conformal invariance. At non-planar level, however, the
behavior of this theory is less well understood. We study the one loop
renormalization of the theory and the resulting flow of Yukawa and scalar
coupling at the order ${\cal O}(\frac{\lambda}{N^2})$, and find $\gamma_i$
parameters receive nontrivial quantum corrections. We show that, at low
energies, the $\gamma_i$ parameters flow to a common value and
$\gamma_i$-deformed theory reaches an $\mathcal{N}=1$-supersymmetric fixed
point described by the $\beta$-deformed $\mathcal{N}=4$ super Yang-Mills
theory.


title: Initial conditions for evolution of double parton distributions

abstract:
  Double parton distribution functions (DPDFs) are used in the QCD description
of double parton scattering. The DPDFs evolve with hard scales through
relatively new QCD evolution equations which obey nontrivial momentum and
valence quark number sum rules. Based on the constructed numerical program, we
present results on the QCD evolution of the DPDFs. In particular, we discuss
the problem how to specify initial conditions for the evolution equations which
exactly fulfill the sum rules.


title:
Lattice calculation of $D_s$ to $\eta^{(\prime)}$ semi-leptonic decay
  form factors

abstract:
  We report lattice results of $D_s$ meson semi-leptonic decay form factors to
$\eta$ and $\eta'$ mesons. This decay process contains disconnected fermion
loops, which are challenging in lattice calculations. Our result shows that the
disconnected loops give significant contributions to the form factors.


title: A generic map from non-Lindblad to Lindblad master equations

abstract:
  Many current problems of interest in quantum non-equilibrium are described by
time-local master equations (TLMEs) for the density matrix that are not of the
Lindblad form, that is, that are not strictly probability conserving and/or
Markovian. Here we describe an generic approach by which the system of interest
that obeys the TLME is coupled to an ancilla, such that the dynamics of the
combined system-plus-ancilla is Markovian and thus described by a Lindblad
equation. This in turn allows us to recover the properties of the original TLME
dynamics from a physical unravelling of this associated Lindblad dynamics. We
discuss applications of this generic mapping in two areas of current interest.
The first one is that of "thermodynamics of trajectories", where non-Lindblad
master equations encode the large-deviation properties of the dynamics, and we
show that the relevant large-deviation functions (i.e. dynamical free-energies)
can be recovered from appropriate observables of the ancilla. The second one is
that of quantum filters, where we show tracking a quantum system undergoing a
continuous homodyne measurement with another quantum system of the same size
will inherently be inefficient in our framework.


title: Predictive Scaling Laws for Spherical Rotating Dynamos

abstract:
  State of the art numerical models of the Geodynamo are still performed in a
parameter regime extremely remote from the values relevant to the physics of
the Earth's core. In order to establish a connection between dynamo modeling
and the geophysical motivation, {it is necessary to use} scaling laws. Such
scaling laws establish the dependence of essential quantities (such as the
magnetic field strength) on measured or controlled quantities. They allow for a
direct confrontation of advanced models with geophysical {constraints}.
  (...)
  We show that previous empirical scaling laws for the magnetic field strength
essentially reflect the statistical balance between energy production and
dissipation for saturated dynamos. Such power based scaling laws are thus
necessarily valid for any dynamo in statistical equilibrium and applicable to
any numerical model, irrespectively of the dynamo mechanism.
  We show that direct numerical fits can provide contradictory results owing to
biases in the parameters space covered in the numerics and to the role of a
priori hypothesis on the fraction of ohmic dissipation.
  We introduce predictive scaling laws, i.e. relations involving input
parameters of the governing equations only. We guide our reasoning on physical
considerations. We show that our predictive scaling laws can properly describe
the numerical database and reflect the dominant forces balance at work in these
numerical simulations. We highlight the dependence of the magnetic field
strength on the rotation rate. Finally, our results stress that available
numerical models operate in a viscous dynamical regime, which is not relevant
to the Earth's core.


title: Varieties fibred over abelian varieties with fibres of log general type

abstract:
  Let $(X,B)$ be a complex projective klt pair, and let $f\colon X\to Z$ be a
surjective morphism onto a normal projective variety with maximal albanese
dimension such that $K_X+B$ is relatively big over $Z$. We show that such pairs
have good log minimal models.


title: Freeze-out parameters from continuum extrapolated lattice data

abstract:
  We present continuum extrapolated lattice results for the higher order
fluctuations of conserved charges in high temperature Quantum Chromodynamics.
Through the matching of the grand canonical ensemble on the lattice to the net
charge and net baryon distribution realized in heavy ion experiments the
temperature and the chemical potential may be estimated at the time of chemical
freeze-out


title: Integrability and Reduction of Hamiltonian Actions on Dirac Manifolds

abstract:
  For a Hamiltonian, proper and free action of a Lie group $G$ on a Dirac
manifold $(M,L)$, with a regular moment map $\mu:M\to \mathfrak{g}^*$, the
manifolds $M/G$, $\mu^{-1}(0)$ and $\mu^{-1}(0)/G$ all have natural induced
Dirac structures. If $(M,L)$ is an integrable Dirac structure, we show that
$M/G$ is always integrable, but $\mu^{-1}(0)$ and $\mu^{-1}(0)/G$ may fail to
be integrable, and we describe the obstructions to their integrability.


title:
A brief review of the theory of charmonium suppression in heavy ion
  collisions

abstract:
  A brief overview of the theory of charmonium suppression in heavy ion
collisions is presented. In particular I will concentrate on the effects caused
by the hot, deconfined medium and on the effort to treat them using
field-theoretical, QCD-based techniques, such as lattice QCD and Effective
Field Theories.


title: Stop_times based Routing Protocol for VANET

abstract:
  Vehicular Ad hoc Network (VANET) is a special class of Mobile Ad hoc Network
(MANET) where vehicles are considered as MANET nodes with wireless links. The
key difference of VANET and MANET is the special mobility pattern and rapidly
changeable topology. There has been significant interest in improving safety
and traffic efficiency using VANET. The design of routing protocols in VANET is
important and necessary issue for support the smart ITS. Existing routing
protocols of MANET are not suitable for VANET. AOMDV is the most important on
demand multipath routing protocol. This paper proposes SSD-AOMDV as VANET
routing protocol. SSD-AOMDV improves AOMDV to suit VANET characteristics.
SSD-AOMDV adds the mobility parameters: Stop_times, Speed and Direction to hop
count as new AOMDV routing metric to select next hop during the route discovery
phase. Stop_times metric is added to simulate buses mobility pattern and
traffic lights at intersections. Simulation results show that SSD-AOMDV
achieves better performance compared to AOMDV.


title: Shape from Texture using Locally Scaled Point Processes

abstract:
  Shape from texture refers to the extraction of 3D information from 2D images
with irregular texture. This paper introduces a statistical framework to learn
shape from texture where convex texture elements in a 2D image are represented
through a point process. In a first step, the 2D image is preprocessed to
generate a probability map corresponding to an estimate of the unnormalized
intensity of the latent point process underlying the texture elements. The
latent point process is subsequently inferred from the probability map in a
non-parametric, model free manner. Finally, the 3D information is extracted
from the point pattern by applying a locally scaled point process model where
the local scaling function represents the deformation caused by the projection
of a 3D surface onto a 2D image.


title: Detection Techniques for Trapped Ions

abstract:
  Various techniques are used to detect the presence of charged particles
stored in electromagnetic traps, their energy, their mass, or their internal
states. Detection methods can rely on the variation of the number of trapped
particles (destructive methods) or the use of the ion's interaction with
electromagnetic radiation as a non-destructive tool to probe the trapped
particles. This review gives an introduction into various methods, discussing
the basic mode of operation completed by the description of recent
realizations.


title: Remarks on Privileged Words

abstract:
  We discuss the notion of privileged word, recently introduced by Peltomaki. A
word w is privileged if it is of length <=1, or has a privileged border that
occurs exactly twice in w. We prove the following results: (1) if w^k is
privileged for some k >=1, then w^j is privileged for all j >= 0; (2) the
language of privileged words is neither regular nor context-free; (3) there is
a linear-time algorithm to check if a given word is privileged; and (4) there
are at least 2^{n-5}/n^2 privileged binary words of length n.


title:
Pointwise multiplication on vector-valued function spaces with power
  weights

abstract:
  We investigate pointwise multipliers on vector-valued function spaces over
$\mathbb{R}^d$, equipped with Muckenhoupt weights. The main result is that in
the natural parameter range, the characteristic function of the half-space is a
pointwise multiplier on Bessel-potential spaces with values in a UMD Banach
space. This is proved for a class of power weights, including the unweighted
case, and extends the classical result of Shamir and Strichartz. The
multiplication estimate is based on the paraproduct technique and a randomized
Littlewood-Paley decomposition. An analogous result is obtained for Besov and
Triebel-Lizorkin spaces.


title:
Klein-Gordon Equation with Coulomb Potential in the Presence of a
  Minimal Length

abstract:
  We study the Klein-Gordon equation for Coulomb potential, V(r)=(-Ze^{2})/r,
in quantum mechanics with a minimal length. The zero energy solution is
obtained analytically in momentum space in terms of Heun's functions. The
asymptotic behavior of the solution shows that the presence of a minimal length
regularize the potential in the strong attractive regime, Z>68. The equation
with nonzero energy is established in a particular case in the first order of
the deformation parameter; it is a generalized Heun's equation.


title: Quarks and gluons in a magnetic field

abstract:
  The quark gap equation under the rainbow truncation, with two versions of a
phenomenological one-gluon exchange interaction and in the presence of a
uniform magnetic field is considered. It is argued that in order to describe
the quark condensate in the limit of vanishing magnetic fields, one must sum
over the Landau levels. The resulting chiral quark condensate rises
quadratically for small magnetic fields and linearly for large fields, in
qualitative agreement with various recent lattice results. It is observed that
when discussing quarks, the magnitude of the magnetic field must be considered
relative to the scale of the strong interaction.


title:
Super-polylogarithmic hypergraph coloring hardness via low-degree long
  codes

abstract:
  We prove improved inapproximability results for hypergraph coloring using the
low-degree polynomial code (aka, the 'short code' of Barak et. al. [FOCS 2012])
and the techniques proposed by Dinur and Guruswami [FOCS 2013] to incorporate
this code for inapproximability results. In particular, we prove
quasi-NP-hardness of the following problems on $n$-vertex hyper-graphs:
  * Coloring a 2-colorable 8-uniform hypergraph with
$2^{2^{\Omega(\sqrt{\log\log n})}}$ colors.
  * Coloring a 4-colorable 4-uniform hypergraph with
$2^{2^{\Omega(\sqrt{\log\log n})}}$ colors.
  * Coloring a 3-colorable 3-uniform hypergraph with $(\log
n)^{\Omega(1/\log\log\log n)}$ colors.
  In each of these cases, the hardness results obtained are (at least)
exponentially stronger than what was previously known for the respective cases.
In fact, prior to this result, polylog n colors was the strongest quantitative
bound on the number of colors ruled out by inapproximability results for
O(1)-colorable hypergraphs.
  The fundamental bottleneck in obtaining coloring inapproximability results
using the low- degree long code was a multipartite structural restriction in
the PCP construction of Dinur-Guruswami. We are able to get around this
restriction by simulating the multipartite structure implicitly by querying
just one partition (albeit requiring 8 queries), which yields our result for
2-colorable 8-uniform hypergraphs. The result for 4-colorable 4-uniform
hypergraphs is obtained via a 'query doubling' method. For 3-colorable
3-uniform hypergraphs, we exploit the ternary domain to design a test with an
additive (as opposed to multiplicative) noise function, and analyze its
efficacy in killing high weight Fourier coefficients via the pseudorandom
properties of an associated quadratic form.


title:
Exact asymptotics of the optimal Lp-error of asymmetric linear spline
  approximation

abstract:
  In this paper we study the best asymmetric (sometimes also called penalized
or sign-sensitive) approximation in the metrics of the space $L_p$, $1\leqslant
p\leqslant\infty$, of functions $f\in C^2\left([0,1]^2\right)$ with nonnegative
Hessian by piecewise linear splines $s\in S(\triangle_N)$, generated by given
triangulations $\triangle_N$ with $N$ elements. We find the exact asymptotic
behavior of optimal (over triangulations $\triangle_N$ and splines $s\in
S(\triangle_N)$ error of such approximation as $N\to \infty$.


title: Three-dimensional gravity and instability of $\text{AdS}_{3}$

abstract:
  This is an extended version of my lecture at the LIII Cracow School of
Theoretical Physics in Zakopane in which I presented the results of joint work
with Piotr Bizo\'n concerning (in)stability of the three-dimensional anti-de
Sitter spacetime.


title: Correction of dephasing oscillations in matter wave interferometry

abstract:
  Vibrations, electromagnetic oscillations and temperature drifts are among the
main reasons for dephasing in matter-wave interferometry. Sophisticated
interferometry experiments, e.g. with ions or heavy molecules, often require
integration times of several minutes due to the low source intensity or the
high velocity selection. Here we present a scheme to suppress the influence of
such dephasing mechanisms - especially in the low-frequency regime - by
analyzing temporal and spatial particle correlations available in modern
detectors. Such correlations can reveal interference properties that would
otherwise be washed out due to dephasing by external oscillating signals. The
method is shown experimentally in a biprism electron interferometer where a
perturbing oscillation is artificially introduced by a periodically varying
magnetic field. We provide a full theoretical description of the particle
correlations where the perturbing frequency and amplitude can be revealed from
the disturbed interferogram. The original spatial fringe pattern without the
perturbation can thereby be restored. The technique can be applied to lower the
general noise requirements in matter-wave interferometers. It allows for the
optimization of electromagnetic shielding and decreases the efforts for
vibrational or temperature stabilization.


title:
Dynamic Spin Fluctuations at $T\rightarrow 0$ in a Spin-1/2
  Ferromagnetic Kagome Lattice

abstract:
  We report magnetization, electron spin resonance (ESR), and muon spin
relaxation ($\mu $SR) measurements on single crystals of the $S=1/2$ (Cu$%
^{+2}$) kagom\'{e} compound Cu(1,3-benzendicarboxylate). The $\mu $SR is
carried to temperatures as low as 45 mK. The spin Hamiltonian parameters are
determined from the analysis of the magnetization and ESR data. We find that
this compound has anisotropic ferromagnetic interactions. Nevertheless, no spin
freezing is observed even at temperatures two orders of magnitude lower than
the coupling constants. In light of this finding, the relation between
persistent spin dynamics and spin liquid are reexamined.


title:
Chromospheric and Coronal Observations of Solar Flares with the
  Helioseismic and Magnetic Imager

abstract:
  We report observations of white-light ejecta in the low corona, for two
X-class flares on the 2013 May 13, using data from the Helioseismic and
Magnetic Imager (HMI) of the Solar Dynamics Observatory. At least two distinct
kinds of sources appeared (chromospheric and coronal), in the early and later
phases of flare development, in addition to the white-light footpoint sources
commonly observed in the lower atmosphere. The gradual emissions have a clear
identification with the classical loop-prominence system, but are brighter than
expected and possibly seen here in the continuum rather than line emission. We
find the HMI flux exceeds the radio/X-ray interpolation of the bremsstrahlung
produced in the flare soft X-ray sources by at least one order of magnitude.
This implies the participation of cooler sources that can produce free-bound
continua and possibly line emission detectable by HMI. One of the early sources
dynamically resembles "coronal rain", appearing at a maximum apparent height
and moving toward the photosphere at an apparent constant projected speed of
134 $\pm$ 8 $\mathrm{km s^{-1}}$. Not much literature exists on the detection
of optical continuum sources above the limb of the Sun by non-coronagraphic
instruments, and these observations have potential implications for our basic
understanding of flare development, since visible observations can in principle
provide high spatial and temporal resolution.


title:
Anti-de Sitter holography for gravity and higher spin theories in two
  dimensions

abstract:
  We provide a holographic description of two-dimensional dilaton gravity with
Anti-de Sitter boundary conditions. We find that the asymptotic symmetry
algebra consists of a single copy of the Virasoro algebra with non-vanishing
central charge and point out difficulties with the standard canonical
treatment. We generalize our results to higher spin theories and thus provide
the first examples of two-dimensional higher spin gravity with holographic
description. For spin-3 gravity we find that the asymptotic symmetry algebra is
a single copy of the W_3-algebra.


title: Local magnetism and structural properties of Heusler Ni$_2$MnGa alloys

abstract:
  We present a detailed experimental study of bulk and powder samples of the
Heusler shape memory alloy Ni$_2$MnGa, including zero-field static and dynamic
$^{55}$Mn NMR experiments, X-ray powder diffraction and magnetization
experiments. The NMR spectra give direct access to the sequence of structural
phase transitions in this compound, from the high-T austenitic phase down to
the low-T martensitic phase. In addition, a detailed investigation of the
so-called rf-enhancement factor provides local information for the magnetic
stiffness and restoring fields for each separate coordination, structural,
crystallographic environment, thus differentiating signals coming from
austenitic and martensitic components. The temperature evolution of the NMR
spectra and the rf-enhancement factors shows strong dependence on sample
preparation. In particular, we find that sample powderization gives rise to a
significant portion of martensitic traces inside the high-T austenitic region,
and that these traces can be subsequently removed by annealing.


abstract:
  Electron-impact direct double ionization (DDI) process is studied as a
sequence of two and three step processes. Contribution from
ionization-ionization, ionization-excitation-ionization, and
excitation-ionization-ionization processes is taken into account. The present
results help to resolve the long-standing discrepancies; in particular, a good
agreement with experimental measurements is obtained for double ionization
cross-sections of $O^{1+}$, $O^{2+}$, $O^{3+}$, $C^{1+}$, and $Ar^{2+}$ ions.
We show that distribution of the energy of scattered and ejected electrons,
which participate in the next step of ionization, strongly affects DDI
cross-sections.


title: Bihermitian Geometry and the Holomorphic Sections of Twistor Space

abstract:
  In this paper, we construct tools from the holomorphic twistor spaces that we
introduced in \cite{Gindi1} to derive results about the complex geometries of
their base manifolds. In particular, we develop a new approach to studying
generalized Kahler manifolds that leads to insights into their real and
holomorphic Poisson structures.


title:
Competing thermodynamic and dynamic factors select molecular assemblies
  on a gold surface

abstract:
  Controlling the self-assembly of surface-adsorbed molecules into
nanostructures requires understanding physical mechanisms that act across
multiple length and time scales. By combining scanning tunneling microscopy
with hierarchical ab initio and statistical mechanical modeling of
1,4-substituted benzenediamine (BDA) molecules adsorbed on a gold (111)
surface, we demonstrate that apparently simple nanostructures are selected by a
subtle competition of thermodynamics and dynamics. Of the collection of
possible BDA nanostructures mechanically stabilized by hydrogen bonding, the
interplay of intermolecular forces, surface modulation, and assembly dynamics
select at low temperature a particular subset: low free energy oriented linear
chains of monomers, and high free energy branched chains.


title: Inertio-elastic instability of non shear-banding wormlike micelles

abstract:
  Homogeneous polymer solutions are well-known to exhibit viscoelastic flow
instabilities: purely elastic when inertia is negligible, inertio-elastic
otherwise. Recently, shear-banding wormlike micelles solutions were also
discovered to follow a similar phenomenology. In the shear-banding regime,
inertia is usually negligible so only purely elastic flows have been reported.
Here, we investigate a non-shear-banding solution where inertia becomes
significant, leading to flow patterns akin to the inertio-elastic regime of
dilute polymer solutions. We show that the instability follows a supercritical
bifurcation and we investigate the structure of the inertio-elastic vortices
that develop above onset.


title:
Risk- and ambiguity-averse portfolio optimization with quasiconcave
  utility functionals

abstract:
  Motivated by recent axiomatic developments, we study the risk- and
ambiguity-averse investment problem where trading takes place over a fixed
finite horizon and terminal payoffs are evaluated according to a criterion
defined in terms of a quasiconcave utility functional. We extend to the present
setting certain existence and duality results established for the so-called
variational preferences by Schied (2007). The results are proven by building on
existing results for the classical utility maximization problem.


title: A generalization of Toeplitz operators on the Bergman space

abstract:
  If $\mu$ is a finite measure on the unit disc and $k\ge 0$ is an integer, we
study a generalization derived from Englis's work, $T_\mu^{(k)}$, of the
traditional Toeplitz operators on the Bergman space $A^2$, which are the case
$k=0$. Among other things, we prove that when $\mu\ge 0$, these operators are
bounded if and only if $\mu$ is a Carleson measure, and we obtain some
estimates for their norms.


title: In-Network Caching vs. Redundancy Elimination

abstract:
  Network-level Redundancy Elimination (RE) techniques have been proposed to
reduce the amount of traffic in the Internet. and the costs of the WAN access
in the Internet. RE middleboxes are usually placed in the network access
gateways and strip off the repeated data from the packets. More recently,
generic network-level caching architectures have been proposed as alternative
to reduce the redundant data traffic in the network, presenting benefits and
drawbacks compared to RE. In this paper, we compare a generic in-network
caching architecture against state-of-the-art redundancy elimination (RE)
solutions on real network topologies, presenting the advantages of each
technique. Our results show that in-network caching architectures outperform
state-of-the-art RE solutions across a wide range of traffic characteristics
and parameters.


title: LiteLab: Efficient Large-scale Network Experiments

abstract:
  Large-scale network experiments is a challenging problem. Simulations,
emulations, and real-world testbeds all have their advantages and
disadvantages. In this paper we present LiteLab, a light-weight platform
specialized for large-scale networking experiments. We cover in detail its
design, key features, and architecture. We also perform an extensive evaluation
of LiteLab's performance and accuracy and show that it is able to both simulate
network parameters with high accuracy, and also able to scale up to very large
networks. LiteLab is flexible, easy to deploy, and allows researchers to
perform large-scale network experiments with a short development cycle. We have
used LiteLab for many different kinds of network experiments and are planning
to make it available for others to use as well.


title: Extended Void Merging Tree Algorithm for Self-Similar Models

abstract:
  In hierarchical evolution, voids exhibit two different behaviors related with
their surroundings and environments, they can merge or collapse. These two
different types of void processes can be described by the two-barrier excursion
set formalism based on Brownian random walks. In this study, the analytical
approximate description of the growing void merging algorithm is extended by
taking into account the contributions of voids that are embedded into overdense
region(s) which are destined to vanish due to gravitational collapse. Following
this, to construct a realistic void merging model that consists of both
collapse and merging processes, the two-barrier excursion set formalism of the
void population is used. Assuming spherical voids in the Einstein de Sitter
Universe, the void merging algorithm which allows us to consider the two main
processes of void hierarchy in one formalism is constructed. In addition to
this, the merger rates, void survival probabilities, void size distributions in
terms of the collapse barrier and finally, the void merging tree algorithm in
the self-similar models are defined and derived.


title:
Multimode propagation in phononic crystals with overlapping Bragg and
  hybridization effects

abstract:
  Unusual dispersion properties are observed in a phononic crystal of nylon
rods in water when the lattice constant is adjusted so that Bragg and
hybridization gaps overlap in frequency. On the basis of experimental and
numerical analyses of time-dependent transmission and spatial field maps, the
presence of two coexisting propagation modes of similar amplitude is
demonstrated near the resonance frequency. This phenomenon is attributed to the
coupling of the rod resonances arranged in a triangular lattice, with phase
shifts driven by the Bragg condition.


title: Higgs boson pair production at the LHC: top-quark mass effects at NLO

abstract:
  Higgs boson pair production is considered at next-to-leading order with
special emphasis on the effect of a finite top quark mass. It is shown that,
unlike for single-Higgs boson production, power-suppressed corrections are
numerically important.


title: Rigidity of lattices and syndetic hulls in solvable Lie groups

abstract:
  First let $G$ be a completely solvable Lie group. We recall the proof of the
following result: Any closed subgroup of $G$ possesses a unique syndetic hull
in $G$. As a consequence we conclude that any uniform subgroup $\Gamma$ of $G$
is strongly rigid in the sense of G. D. Mostow: If $\alpha:\Gamma\to G$ is a
homomorphism of Lie groups such that $\alpha(\Gamma)$ is uniform in $G$, then
there is an automorphism $\varphi$ of $G$ such that
$\varphi\,|\,\Gamma=\alpha$. Now let $G$ be an arbitrary (exponential) solvable
Lie group. We discuss certain conditions on closed subgroups of $G$ which are
sufficient for the existence of a syndetic hull.


title:
Classical solutions and higher regularity for nonlinear fractional
  diffusion equations

abstract:
  We study the regularity properties of the solutions to the nonlinear equation
with fractional diffusion $$ \partial_tu+(-\Delta)^{\sigma/2}\varphi(u)=0, $$
posed for $x\in \mathbb{R}^N$, $t>0$, with $0<\sigma<2$, $N\ge1$. If the
nonlinearity satisfies some not very restrictive conditions: $\varphi\in
C^{1,\gamma}(\mathbb{R})$, $1+\gamma>\sigma$, and $\varphi'(u)>0$ for every
$u\in\mathbb{R}$, we prove that bounded weak solutions are classical solutions
for all positive times. We also explore sufficient conditions on the
non-linearity to obtain higher regularity for the solutions, even $C^\infty$
regularity. Degenerate and singular cases, including the power nonlinearity
$\varphi(u)=|u|^{m-1}u$, $m>0$, are also considered, and the existence of
classical solutions in the power case is proved.


title:
Potential of a longitudinally focusing insertion for a storage ring
  X-ray FEL

abstract:
  In present work we investigate the potential of a longitudinally focusing
device to compress bunches passing an undulator for a synchrotron storage ring.
If integrated into a storage ring similar to PETRAIII such device could
potentially produce continuous $\sim$1ps pulses of photons in the $nm$ range
with peak pulse powers of tens of GW. Even without operating in FEL saturation
mode the longitudinal focusing can provide means to increase the brightness and
shorten the photon pulse length.


title:
The Hybrid Detailed / Statistical Opacity Code SCO-RCG: New Developments
  and Applications

abstract:
  We present the hybrid opacity code SCO-RCG which combines statistical
approaches with fine-structure calculations. Radial integrals needed for the
computation of detailed transition arrays are calculated by the code SCO
(Super-configuration Code for Opacity), which calculates atomic structure at
finite temperature and density, taking into account plasma effects on the
wave-functions. Levels and spectral lines are then computed by an adapted RCG
routine of R. D. Cowan. SCO-RCG now includes the Partially Resolved Transition
Array model, which allows one to replace a complex transition array by a
small-scale detailed calculation preserving energy and variance of the genuine
transition array and yielding improved high-order moments. An approximate
method for studying the impact of strong magnetic field on opacity and
emissivity was also recently implemented.


title:
A local Gaussian filter and adaptive morphology as tools for completing
  partially discontinuous curves

abstract:
  This paper presents a method for extraction and analysis of curve--type
structures which consist of disconnected components. Such structures are found
in electron--microscopy (EM) images of metal nanograins, which are widely used
in the field of nanosensor technology.
  The topography of metal nanograins in compound nanomaterials is crucial to
nanosensor characteristics. The method of completing such templates consists of
three steps. In the first step, a local Gaussian filter is used with different
weights for each neighborhood. In the second step, an adaptive morphology
operation is applied to detect the endpoints of curve segments and connect
them. In the last step, pruning is employed to extract a curve which optimally
fits the template.


title:
Coherent Frequency Combs produced by Self Frequency Modulation in
  Quantum Cascade Lasers

abstract:
  One salient characteristic of Quantum Cascade Laser (QCL) is its very shor
gain recovery time that so far thwarted the attempts to achieve self-mode
locking of the device into a train of single pulses. We show theoretically that
four wave mixing, combined with the short gain recovery time causes QCL to
operate in the self-frequency-modulated regime characterized by a constant
power in time domain and stable coherent comb in the frequency domain.Coherent
frequency comb may enable many potential applications of QCL in sensing and
measurement.


title: Induced Gravitational Collapse in the BATSE era: the case of GRB 970828

abstract:
  Following the recently established "Binary-driven HyperNova" (BdHN) paradigm,
we here interpret GRB 970828 in terms of the four episodes typical of such a
model. The "Episode 1", up to 40 s after the trigger time t_0, with a time
varying thermal emission and a total energy of E_{iso,1st} = 2.60 x 10^{53}
erg, is interpreted as due to the onset of an hyper-critical accretion process
onto a companion neutron star, triggered by the companion star, an FeCO core
approaching a SN explosion. The "Episode 2", observed up t_0+90 s, is
interpreted as a canonical gamma ray burst, with an energy of E^{e^+e^-}_{tot}
= 1.60 x 10^{53} erg, a baryon load of B = 7 x 10^{-3} and a bulk Lorentz
factor at transparency of \Gamma = 142.5. From this Episode 2, we infer that
the GRB exploded in an environment with a large average particle density <n>
\approx 10^3 particles/cm^3 and dense clouds characterized by typical
dimensions of (4 \div 8) x 10^{14} cm and \delta n / n ~ 10. The "Episode 3" is
identified from t_0+90 s all the way up to 10^{5-6} s: despite the paucity of
the early X-ray data, typical in the BATSE, pre-Swift era, we find extremely
significant data points in the late X-ray afterglow emission of GRB 970828,
which corresponds to the ones observed in all BdHNe sources. The "Episode 4",
related to the Supernova emission, does not appear to be observable in this
source, due to the presence of darkening from the large density of the GRB
environment, also inferred from the analysis of the Episode 2.


title: Single molecule enzymology a la Michaelis-Menten

abstract:
  In the past one hundred years, deterministic rate equations have been
successfully used to infer enzyme-catalysed reaction mechanisms and to estimate
rate constants from reaction kinetics experiments conducted in vitro. In recent
years, sophisticated experimental techniques have been developed that allow the
measurement of enzyme- catalysed and other biopolymer-mediated reactions inside
single cells at the single molecule level. Time course data obtained by these
methods are considerably noisy because molecule numbers within cells are
typically quite small. As a consequence, the interpretation and analysis of
single cell data requires stochastic methods, rather than deterministic rate
equations. Here we concisely review both experimental and theoretical
techniques which enable single molecule analysis with particular emphasis on
the major developments in the field of theoretical stochastic enzyme kinetics,
from its inception in the mid-twentieth century to its modern day status. We
discuss the differences between stochastic and deterministic rate equation
models, how these depend on enzyme molecule numbers and substrate inflow into
the reaction compartment and how estimation of rate constants from single cell
data is possible using recently developed stochastic approaches.


title:
Observability, Identifiability and Sensitivity of Vision-Aided
  Navigation

abstract:
  We analyze the observability of motion estimates from the fusion of visual
and inertial sensors. Because the model contains unknown parameters, such as
sensor biases, the problem is usually cast as a mixed identification/filtering,
and the resulting observability analysis provides a necessary condition for any
algorithm to converge to a unique point estimate. Unfortunately, most models
treat sensor bias rates as noise, independent of other states including biases
themselves, an assumption that is patently violated in practice. When this
assumption is lifted, the resulting model is not observable, and therefore past
analyses cannot be used to conclude that the set of states that are
indistinguishable from the measurements is a singleton. In other words, the
resulting model is not observable. We therefore re-cast the analysis as one of
sensitivity: Rather than attempting to prove that the indistinguishable set is
a singleton, which is not the case, we derive bounds on its volume, as a
function of characteristics of the input and its sufficient excitation. This
provides an explicit characterization of the indistinguishable set that can be
used for analysis and validation purposes.


title: Experimenting with BitTorrent on a Cluster: A Good or a Bad Idea?

abstract:
  Evaluation of large-scale network systems and applications is usually done in
one of three ways: simulations, real deployment on Internet, or on an emulated
network testbed such as a cluster. Simulations can study very large systems but
often abstract out many practical details, whereas real world tests are often
quite small, on the order of a few hundred nodes at most, but have very
realistic conditions. Clusters and other dedicated testbeds offer a middle
ground between the two: large systems with real application code. They also
typically allow configuring the testbed to enable repeatable experiments. In
this paper we explore how to run large BitTorrent experiments in a cluster
setup. We have chosen BitTorrent because the source code is available and it
has been a popular target for research. Our contribution is twofold. First, we
show how to tweak and configure the BitTorrent client to allow for a maximum
number of clients to be run on a single machine, without running into any
physical limits of the machine. Second, our results show that the behavior of
BitTorrent can be very sensitive to the configuration and we revisit some
existing BitTorrent research and consider the implications of our findings on
previously published results. As we show in this paper, BitTorrent can change
its behavior in subtle ways which are sometimes ignored in published works.


title: A test of Taylor- and modified Taylor-expansion

abstract:
  We compare Taylor expansion and a modified variant of Taylor expansion, which
incorporates features of the fugacity series, for expansions in the chemical
potential around a zero-density lattice field theory. As a first test we apply
both series to the cases of free fermions and free bosons. Convergence and
other properties are analyzed.


title:
Lower bound for the escape probability in the Lorentz Mirror Model on
  the lattice

abstract:
  We show that in the Lorentz mirror model, at any density of mirrors, the
probability of a particle starting at the origin to reach distance n is at
least 1/(2n+1).


title: Enhanced Probing of Fermion Interaction Using Weak Value Amplification

abstract:
  We propose a scheme for enhanced probing of an interaction between two single
fermions based on weak-value amplification. The scheme is applied to measuring
the anisotropic electron-hole exchange interaction strength in semiconductor
quantum dots, where both spin and energy are mapped onto emitted photons. We
study the effect of dephasing of the probe on the weak-value-enhanced
measurement. We find that in the limit of slow noise, weak-value amplification
provides a unique tool for enhanced-precision measurement of few-fermion
systems.


title: Excited random walk with periodic cookies

abstract:
  In this paper we consider an excited random walk on $\mathbb{Z}$ in
identically piled periodic environment. This is a discrete time process on
$\mathbb{Z}$ defined by parameters $(p_1,\dots p_M) \in [0,1]^M$ for some
positive integer $M$, where the walker upon the $i$-th visit to $z \in
\mathbb{Z}$ moves to $z+1$ with probability $p_{i\pmod M}$, and moves to $z-1$
with probability $1-p_{i \pmod M}$. We give an explicit formula in terms of the
parameters $(p_1,\dots,p_M)$ which determines whether the walk is recurrent,
transient to the left, or transient to the right. In particular, in the case
that $\frac{1}{M}\sum_{i=1}^{M}p_{i}=\frac {1}{2}$ all behaviors are possible,
and may depend on the order of the $p_i$. Our framework allows us to reprove
some known results on ERW with no additional effort.


title: B decays to radially excited D

abstract:
  We discuss the possibility to measure in present experiments, especially
LHCb, the non leptonic decay branching ratio $B \to D' \pi$, and emphasize
phenomenological implications on $B \to D' l \nu$ semileptonic decay. We have
estimated by lattice QCD the $D'$ decay constant $f_{D'}$ that parameterizes
the $D'$ emission contribution to the Class-III non leptonic decay $B^- \to D^0
\pi^-$. In addition, we provide a new estimate of the decay constants
$f_{D_{s,q}}$ which read $f_{D_{s}}=252(3)$ MeV and
$f_{D_{s}}/f_{D}=1.23(1)(1)$.


title: Almost involutive Hopf algebras

abstract:
  We define the concept of \emph{companion automorphism} of a Hopf algebra $H$
as an automorphism $\sigma:H \rightarrow H$: $\sigma^2=S^2$ --where $S$ denotes
the antipode--. A Hopf algebra is said to be \emph{almost involutive} (AI) if
it admits a companion automorphism that can be viewed as a special additional
symmetry. We present examples and study some of the basic properties and
constructions of AI-Hopf algebras centering the attention in the finite
dimensional case. In particular we show that within the family of Hopf algebras
of dimension smaller or equal than 15, only in dimension eight and twelve,
there are non almost involutive Hopf algebras.


title: Irreducibility is Minimum Synergy Among Parts

abstract:
  For readers already familiar with Partial Information Decomposition (PID), we
show that PID's definition of synergy enables quantifying at least four
different notions of irreducibility. First, we show four common notions of
"parts" give rise to a spectrum of four distinct measures of irreducibility.
Second, we introduce a nonnegative expression based on PID for each notion of
irreducibility. Third, we delineate these four notions of irreducibility with
exemplary binary circuits. This work will become more useful once the
complexity community has converged on a palatable $\operatorname{I}_{\cap}$ or
$\operatorname{I}_{\cup}$ measure.


title: NiS - An unusual self-doped, nearly compensated antiferromagnetic metal

abstract:
  NiS, exhibiting a text-book example of a first-order transition with many
unusual properties at low temperatures, has been variously described in terms
of conflicting descriptions of its ground state during the past several
decades. We calculate these physical properties within first-principle
approaches based on the density functional theory and conclusively establish
that all experimental data can be understood in terms of a rather unusual
ground state of NiS that is best described as a self-doped, nearly compensated,
antiferromagnetic metal, resolving the age-old controversy. We trace the origin
of this novel ground state to the specific details of the crystal structure,
band dispersions and a sizable Coulomb interaction strength that is still
sub-critical to drive the system in to an insulating state. We also show how
the specific antiferromagnetic structure is a consequence of the less-discussed
90 degree and less than 90 degree superexchange interactions built in to such
crystal structures.


title:
Nonequilibrium dynamics and transport near the chiral phase transition
  of a quark-meson model

abstract:
  Based on the 2PI quantum effective action of the linear sigma model with
constituent quarks, we develop a transport approach to study systems out of
equilibrium. In particular, we focus on the chiral phase transition as well as
the critical point, where nonequilibrium effects near the phase transition give
rise to critical behavior such as the fluctuation of the baryon number density.
Predictions for long-range correlations and fluctuations of observables in our
model could be used to study fundamental properties of the QCD phase
transition. In the previous version of our transport model the chiral fields
are implemented as mean fields, whereas quarks are treated as on-shell
particles in the Vlasov equation with a dynamical force term. The current
update includes also the distribution functions of sigma mesons and pions in a
self-consistent way. On this basis a dissipation kernel between the mean fields
and particle modes can be implemented.


title:
Homotopy fixed points for profinite groups emulate homotopy fixed points
  for discrete groups

abstract:
  If K is a discrete group and Z is a K-spectrum, then the homotopy fixed point
spectrum Z^{hK} is Map_*(EK_+, Z)^K, the fixed points of a familiar expression.
Similarly, if G is a profinite group and X is a discrete G-spectrum, then
X^{hG} is often given by (H_{G,X})^G, where H_{G,X} is a certain explicit
construction given by a homotopy limit in the category of discrete G-spectra.
Thus, in each of two common equivariant settings, the homotopy fixed point
spectrum is equal to the fixed points of an explicit object in the ambient
equivariant category. We enrich this pattern by proving in a precise sense that
the discrete G-spectrum H_{G,X} is just "a profinite version" of Map_*(EK_+,
Z): at each stage of its construction, H_{G,X} replicates in the setting of
discrete G-spectra the corresponding stage in the formation of Map_*(EK_+, Z)
(up to a certain natural identification).


title: Finite translation surfaces with maximal number of translations

abstract:
  The natural automorphism group of a translation surface is its group of
translations. For finite translation surfaces of genus g > 1 the order of this
group is naturally bounded in terms of g due to a Riemann-Hurwitz formula
argument. In analogy with classical Hurwitz surfaces, we call surfaces which
achieve the maximal bound Hurwitz translation surfaces. We study for which g
there exist Hurwitz translation surfaces of genus g.


title:
Normal forms for Lie symmetric cotangent bundle systems with free and
  proper actions

abstract:
  We consider free and proper cotangent-lifted symmetries of Hamiltonian
systems. For the special case of G = SO(3), we construct symplectic slice
coordinates around an arbitrary point. We thus obtain a parametrisation of the
phase space suitable for the study of dynamics near relative equilibria, in
particular for the Birkhoff-Poincare normal form method. For a general symmetry
group, we observe that for the calculation of the truncated normal forms, one
does not need an explicit coordinate transformation but only its higher
derivatives at the relative equilibrium. We outline an iterative scheme using
these derivatives for the computation of truncated Birkhoff-Poincare normal
forms.


title:
Asymptotic Behavior of Critical Infection Rates for Threshold-one
  Contact Processes on Lattices and Regular Trees

abstract:
  In this paper we study threshold-one contact processes on lattices and
regular trees. The asymptotic behavior of the critical infection rates as the
degrees of the graphs growing to infinity are obtained. Defining \lambda_c as
the supremum of infection rates which causes extinction of the process at
equilibrium, we prove that n\lambda_c^{T^n}\rightarrow1 and
2d\lambda_c^{Z^d}\rightarrow1 as n,d\rightarrow+\infty. Our result is a
development of the conclusion that \lambda_c^{Z^d}\leq\frac{2.18}{d} shown in
\cite{Dur1991}. To prove our main result, a crucial lemma about the probability
of a simple random walk on a lattice returning to zero is obtained. In details,
the lemma is that \lim_{d\rightarrow+\infty}2dP\big(\exists n\geq1,
S_n^{(d)}=0\big)=1, where S_n^{(d)} is a simple random walk on Z^d with
S_0^{(d)}=0.


title: Bootstrap Percolation on Periodic Trees

abstract:
  We study bootstrap percolation with the threshold parameter $\theta \geq 2$
and the initial probability $p$ on infinite periodic trees that are defined as
follows. Each node of a tree has degree selected from a finite predefined set
of non-negative integers and starting from any node, all nodes at the same
graph distance from it have the same degree. We show the existence of the
critical threshold $p_f(\theta) \in (0,1)$ such that with high probability, (i)
if $p > p_f(\theta)$ then the periodic tree becomes fully active, while (ii) if
$p < p_f(\theta)$ then a periodic tree does not become fully active. We also
derive a system of recurrence equations for the critical threshold
$p_f(\theta)$ and compute these numerically for a collection of periodic trees
and various values of $\theta$, thus extending previous results for regular
(homogeneous) trees.


title:
Data-driven modeling of the olfactory neural codes and their dynamics in
  the insect antennal lobe

abstract:
  Recordings from neurons in the insects' olfactory primary processing center,
the antennal lobe (AL), reveal that the AL is able to process the input from
chemical receptors into distinct neural activity patterns, called olfactory
neural codes. These exciting results show the importance of neural codes and
their relation to perception. The next challenge is to \emph{model the
dynamics} of neural codes. In our study, we perform multichannel recordings
from the projection neurons in the AL driven by different odorants. We then
derive a neural network from the electrophysiological data. The network
consists of lateral-inhibitory neurons and excitatory neurons, and is capable
of producing unique olfactory neural codes for the tested odorants.
Specifically, we (i) design a projection, an odor space, for the neural
recording from the AL, which discriminates between distinct odorants
trajectories (ii) characterize scent recognition, i.e., decision-making based
on olfactory signals and (iii) infer the wiring of the neural circuit, the
connectome of the AL. We show that the constructed model is consistent with
biological observations, such as contrast enhancement and robustness to noise.
The study answers a key biological question in identifying how lateral
inhibitory neurons can be wired to excitatory neurons to permit robust activity
patterns.


title: Deep 3 GHz Number Counts from a P(D) Fluctuation Analysis

abstract:
  Radio source counts constrain galaxy populations and evolution, as well as
the global star formation history. However, there is considerable disagreement
among the published 1.4-GHz source counts below 100 microJy. Here we present a
statistical method for estimating the microJy and even sub-microJy source count
using new deep wide-band 3-GHz data in the Lockman Hole from the Karl G. Jansky
Very Large Array (VLA). We analyzed the confusion amplitude distribution P(D),
which provides a fresh approach in the form of a more robust model, with a
comprehensive error analysis. We tested this method on a large-scale
simulation, incorporating clustering and finite source sizes. We discuss in
detail our statistical methods for fitting using Monte Carlo Markov chains,
handling correlations, and systematic errors from the use of wide-band radio
interferometric data. We demonstrated that the source count can be constrained
down to 50 nJy, a factor of 20 below the rms confusion. We found the
differential source count near 10 microJy to have a slope of -1.7, decreasing
to about -1.4 at fainter flux densities. At 3GHz the rms confusion in an
8arcsec FWHM beam is ~ 1.2 microJy/beam, and a radio background temperature ~
14mK. Our counts are broadly consistent with published evolutionary models.
With these results we were also able to constrain the peak of the Euclidean
normalized differential source count of any possible new radio populations that
would contribute to the cosmic radio background down to 50 nJy.


title:
Spin relaxation in a zinc-blende (110) symmetric quantum well with
  delta-doping

abstract:
  The spin relaxation of a two-dimensional electron system (2DES) formed in a
symmetric quantum well is studied theoretically when the quantum well is
parallel to the (110) plane of the zinc-blende structure, the spin polarization
is perpendicular to the well, and electrons occupy only the ground subband. The
spin relaxation rate is calculated as a function of the distribution of donor
impurities which are placed in the well layer. Considered processes of the spin
relaxation are (1) intrasubband process by impurity-potential-induced
spin-orbit interaction (SOI), which is the Elliott-Yafet mechanism in the 2DES,
and (2) virtual intersubband processes consisting of a spin flip by (2a)
well-potential-induced SOI or (2b) the Dresselhaus SOI, and a scattering from
an impurity. It is shown that all of the above processes disappear, when all
impurities are located on the center plane of the well. Even if impurities are
distributed over three (110) atomic layers, the spin relaxation rate is two
orders of magnitude lower than that for the uniform distribution over the well
width of 7.5\ nm. In GaAs/AlGaAs type-I quantum wells the processes (1) and
(2a) interfere constructively, being dominant over (2b) for the well width of
$\sim$10\ nm, while in some type-II quantum wells they can interfere
destructively.


title: Multi-hump solitary waves of nonlinear Dirac equation

abstract:
  This paper concentrates on a (1+1)-dimensional nonlinear Dirac (NLD) equation
with a general self-interaction, being a linear combination of the scalar,
pseudoscalar, vector and axial vector self-interactions to the power of the
integer $k+1$. The solitary wave solutions to the NLD equation are analytically
derived, and the upper bounds of the hump number in the charge, energy and
momentum densities for the solitary waves are proved in theory. The results
show that: (1) for a given integer $k$, the hump number in the charge density
is not bigger than $4$, while that in the energy density is not bigger than
$3$; (2) those upper bounds can only be achieved in the situation of higher
nonlinearity, namely, $k\in\{5,6,7,\cdots \}$ for the charge density and
$k\in\{3,5,7,\cdots\}$ for the energy density; (3) the momentum density has the
same multi-hump structure as the energy density; (4) more than two humps (resp.
one hump) in the charge (resp. energy) density can only happen under the linear
combination of the pseudoscalar self-interaction and at least one of the scalar
and vector (or axial vector) self-interactions. Our results on the multi-hump
structure will be interesting in the interaction dynamics for the NLD solitary
waves.


title:
Theoretical investigation of thermostability of incompressible channels
  in quantum Hall states

abstract:
  In this work we use self-consistent method considering a two dimensional
electron gas system in the integer quantum Hall regime, to calculate the
temperature induced decay of incompressible stripes. There are two types of
incompressible strips which can form in a Hall bar system by varying the
electron density or magnetic field. We observe that the way of collapse of
incompressible strips strongly depends on the type of them. With increasing
temperature a bulk incompressible strip will decay from the middle and separate
into two edge channels by a density ramp, while an incompressible edge channel
reduces its size from both sides until vanishes.


title:
Semi-Penalized Inference with Direct False Discovery Rate Control in
  High-Dimensions

abstract:
  We propose a new method, semi-penalized inference with direct false discovery
rate control (SPIDR), for variable selection and confidence interval
construction in high-dimensional linear regression. SPIDR first uses a
semi-penalized approach to constructing estimators of the regression
coefficients. We show that the SPIDR estimator is ideal in the sense that it
equals an ideal least squares estimator with high probability under a sparsity
and other suitable conditions. Consequently, the SPIDR estimator is
asymptotically normal. Based on this distributional result, SPIDR determines
the selection rule by directly controlling false discovery rate. This provides
an explicit assessment of the selection error. This also naturally leads to
confidence intervals for the selected coefficients with a proper confidence
statement. We conduct simulation studies to evaluate its finite sample
performance and demonstrate its application on a breast cancer gene expression
data set. Our simulation studies and data example suggest that SPIDR is a
useful method for high-dimensional statistical inference in practice.


title: Constructing local L-packets for tame unitary groups

abstract:
  We generalize the work of DeBacker and Reeder to the case of unitary groups
split by a tame extension. The approach is broadly similar and the restrictions
on the parameter the same, but many of the details of the arguments differ.
  Let $G$ be a unitary group defined over a local field $K$ and splitting over
a tame extension $E/K$. Given a Langlands parameter $\varphi : \mathcal{W}_K
\rightarrow {^L G}$ that is tame, discrete and regular, we give a natural
construction of an $L$-packet $\Pi_\varphi$ associated to $\varphi$, consisting
of representations of pure inner forms of $G(K)$ and parametrized by the
characters of the finite abelian group $A_\varphi =
\operatorname{Z}_{\hat{G}}(\varphi)$.


title:
The Star of Bethlehem is Not the Nova DO Aquilae (Nor Any Other Nova,
  Supernova, or Comet)

abstract:
  The Star of Bethlehem is only known from a few verses in the Gospel of
Matthew, with the Star inspiring and leading the Magi (i.e., Persian
astrologers) to Jerusalem and ultimately worshipping the young Jesus Christ in
Bethlehem. In the last four centuries, astronomers have put forth over a dozen
greatly different naturalistic explanations, all involving astronomical events,
often a bright nova, supernova, or comet. This paper will evaluate one
prominent recent proposal, that the Star was a 'recurrent nova' now catalogued
as DO Aquilae, and provide three refutations. In particular, (1) DO Aql is
certainly not a recurrent nova, but rather an ordinary nova with a recurrence
time scale of over a million years, (2) in its 1925 eruption, DO Aql certainly
never got brighter than 8.5 mag, and the physics of the system proves that it
could never get to the required luminosity of a supernova, and (3) the Magi
were astrologers who had no recognition or interpretation for novae (or
supernovae or comets) so any such event is completely irrelevant and
meaningless to them.


title:
Optimum Tag Reading Efficiency of Multi-Packet Reception Capable RFID
  Readers

abstract:
  Maximizing the tag reading rate of a reader is one of the most important
design objectives in RFID systems as the tag reading rate is inversely
proportional to the time required to completely read all the tags within the
reader's radio field. To this end, numerous techniques have been independently
suggested so far and they can be broadly categorized into pure advancements in
the link-layer tag anti-collision protocols and pure advancements in the
physical-layer RF transmission/reception model. In this paper, we show by
rigorous mathematical analysis and Monte Carlo simulations that how such two
independent approaches can be coupled to attain the optimum tag reading
efficiency in a RFID system considering a Dynamic Frame Slotted Aloha based
link layer anti-collision protocol at tags and a Multi-Packet Reception capable
RF reception model at the reader.


title: Black holes in $\omega$-defomed gauged $N=8$ supergravity

abstract:
  Motivated by the recently found 4-dimensional omega-deformed gauge
supergravity, we investigate the black hole solutions within all the single
scalar field consistent truncations of this theory. We construct black hole
solutions that have spherical, toroidal, and hyperbolic horizon topology. The
scalar field is regular everywhere outside the curvature singularity and the
stress-energy tensor satisfies the null energy condition. When the parameter
omega does not vanish, there is a degeneracy in the spectrum of black hole
solutions for boundary conditions that preserve the asymptotic Anti-de Sitter
symmetries. These boundary conditions correspond to multi-trace deformations in
the dual field theory.


title:
Structure, strain, and control of ground state property in
  LaTiO$_3$/LaAlO$_3$ superlattice

abstract:
  Using first-principles density functional theory calculations, we examined
the ground state property of LaTiO$_3$/LaAlO$_3$ superlattice. Total energy
calculations, taking account of the structural distortions, $U$ dependence, and
exchange correlation functional dependence, show that the spin and orbital
ground state can be controlled systematically by the epitaxial strain. In the
wide range of strains, ferromagnetic spin and antiferro orbital ordering are
stabilized, which is notably different from the previously reported ground
state in titanate systems. By applying large tensile strains, the system can be
transformed into an antiferromagnetic spin and ferro-orbital-ordered phase.


title: Computing Three-Point Functions for Short Operators

abstract:
  We compute the three-point structure constants for short primary operators of
N=4 super Yang-Mills theory to leading order in the inverse coupling by mapping
the problem to a flat-space string theory calculation. We check the validity of
our procedure by comparing to known results for three chiral primaries. We then
compute the three-point functions for any combination of chiral and non-chiral
primaries, with the non-chiral primaries all dual to string states at the first
massive level. Along the way we find many cancellations that leave us with
simple expressions, suggesting that integrability is playing an important role.


title: Continuous Collision Detection for Composite Quadric Models

abstract:
  A composite quadric model (CQM) is an object modeled by piecewise linear or
quadric patches. We study the continuous detection problem of a special type of
CQM objects which are commonly used in CAD/CAM, that is, the boundary surfaces
of such a CQM intersect only in straight line segments or conic curve segments.
We present a framework for continuous collision detection (CCD) of this special
type of CQM (which we also call CQM for brevity) in motion. We derive algebraic
formulations and compute numerically the first contact time instants and the
contact points of two moving CQMs in $\mathbb R^3$. Since it is difficult to
process CCD of two CQMs in a direct manner because they are composed of
semi-algebraic varieties, we break down the problem into subproblems of solving
CCD of pairs of boundary elements of the CQMs. We present procedures to solve
CCD of different types of boundary element pairs in different dimensions. Some
CCD problems are reduced to their equivalents in a lower dimensional setting,
where they can be solved more efficiently.


title:
Study of depth profile of hydrogen in hydrogenated diamond like carbon
  thin film using ion beam analysis techniques

abstract:
  The Hydrogenated Diamond Like Carbon (HDLC) thin films are deposited on
Silicon substrate at room temperature using asymmetric capacitively coupled RF
plasma with varying flow rates of methane. These films are undergone annealing
at high vacuum and high temperature furnace. The as-prepared and annealed HDLC
films have been depth profiled for hydrogen using the resonance at 6.44 MeV in
nuclear reaction between fluoride ion beam and HDLC. The as prepared films
exhibit non-uniform depth distribution of hydrogen: it decreases with depth.
Annealing in vacuum brings about a significant desorption of hydrogen from the
films. Loss of hydrogen, albeit in much lower proportions, is also induced by
the bombarding beam. The films also experience a mild loss of carbon, as shown
by proton backscattering spectrometry, during high vacuum annealing. The depth
profiles of hydrogen in the annealed films are indicative of the prevalence of
graphitic carbon near interface between film and substrate.


title:
Nonequilibrium Langevin equation and effective temperature for particle
  interacting with spatially extended environment

abstract:
  We investigate a novel type of Langevin model that describes the
nonequilibrium dynamics of a classical particle interacting with a spatially
extended environment. In this model, a particle, which interacts with the
environment through the nonlinear interaction Hamiltonian, is driven by a
constant external force, and subsequently, it reaches a nontrivial
nonequilibrium steady state. We derive an effective Langevin equation for the
particle in the nonequilibrium steady states. Using this equation, we calculate
the effective temperature defined as the ratio of the correlation function of
the velocity fluctuation to the linear response function with respect to a
small perturbation. As a result, it is shown that the effective temperature
associated with the time scale of the particle is identical to the kinetic
temperature if the time scale of the environment and that of the particle are
well separated. Furthermore, a noteworthy expression, which relates the kinetic
temperature with the curvature of the driving force-mean velocity curve, is
derived.


title:
Properties of semi-convection and convective overshooting for massive
  stars

abstract:
  Properties of semi-convection and core convective overshooting of stars with
15 $M_{\odot}$ and 30 $M_{\odot}$ are calculated in the present paper. New
methods are used to deal with semi-convection. Different entropy gradient is
used when adopting the Schwarzschild method and the Ledoux method which are
used to confine the convective boundary and to calculate the turbulent
quantities: $\frac{\partial \overline{s}}{\partial
r}=-\frac{c_{p}}{H_P}(\nabla-\nabla_{\rm ad})$ when the Schwarzschild method is
adopted and $\frac{\partial \overline{s}}{\partial
r}=-\frac{c_{p}}{H_P}(\nabla-\nabla_{\rm ad}-\nabla_{\mu})$ when the Ledoux
method is adopted. Core convective overshooting and semi-convection are treated
as a whole part and the development of them are found to present nearly
opposite tendency, more intensive core convective overshooting lead to weaker
semi-convection. The influences of different parameters and the convection
processing methods on the turbulent quantities are analyzed in this paper.
Increasing the mixing-length parameter $\alpha$ leads to more turbulent dynamic
energy in the convective core and prolonging the overshooting distance but
depressing the development of semi-convection. The Ledoux method adopted leads
to overshooting extending further and semi-convection developing suppressed.


title:
Linear Network Error Correction Multicast/Broadcast/Dispersion/Generic
  Codes

abstract:
  In the practical network communications, many internal nodes in the network
are required to not only transmit messages but decode source messages. For
different applications, four important classes of linear network codes in
network coding theory, i.e., linear multicast, linear broadcast, linear
dispersion, and generic network codes, have been studied extensively. More
generally, when channels of communication networks are noisy, information
transmission and error correction have to be under consideration
simultaneously, and thus these four classes of linear network codes are
generalized to linear network error correction (LNEC) coding, and we say them
LNEC multicast, broadcast, dispersion, and generic codes, respectively.
Furthermore, in order to characterize their efficiency of information
transmission and error correction, we propose the (weakly, strongly) extended
Singleton bounds for them, and define the corresponding optimal codes, i.e.,
LNEC multicast/broadcast/dispersion/generic MDS codes, which satisfy the
corresponding Singleton bounds with equality. The existences of such MDS codes
are discussed in detail by algebraic methods and the constructive algorithms
are also proposed.


title: CHARM 2013: X(4260) as a Mixed Charmonium-Tetraquark State

abstract:
  Using the QCD sum rule approach we study the X(4260) state assuming that it
can be described by a mixed charmonium-tetraquark current with $J^{PC}=1^{--}$
quantum numbers. For the mixing angle around $\theta=(53.0 \pm 0.5)^0$, we
obtain a value for the mass which is in good agreement with the experimental
mass of the X(4260). For the decay width into the channel $X \to J/\psi \pi
\pi$, we find the value $\Gamma_{X \to J/\psi\pi\pi}=(4.1 \pm 0.6)$ MeV, which
is much smaller than the total experimental width $\Gamma = (108\pm 12)$ MeV.
However, considering the experimental upper limits for the decay of the X(4260)
into open charm, we conclude that we cannot rule out the possibility of
describing this state as a mixed charmonium-tetraquark state.


title: Frobenius modules over multivariate Robba rings

abstract:
  We describe a class of multivariate series rings generalizing the usual Robba
ring over a p-adic field, and give a basic development of phi-modules over such
rings. This makes it possible to give a unified survey of a number of recent
developments in p-adic Hodge theory.


title: Estimation of the release time of solar energetic particles near the Sun

abstract:
  This paper investigates the onset time of Solar Energetic Particle (SEP)
events with numerical simulations, and analyses the accuracy of the Velocity
Dispersion Analysis (VDA) method. Using a 3-dimensional focused transport
model, we calculate the fluxes of protons observed in the ecliptic at 1 AU in
the energy range between 10 MeV and 80 MeV. In particular, three models are
used to describe different SEP sources produced by flare or coronal shock, and
the effects of particle perpendicular diffusion in the interplanetary space are
also studied. We have the following findings: When the observer is disconnected
from the source, the effects of perpendicular diffusion in the interplanetary
space and particles propagating in the solar atmosphere have significant
influence on the VDA results. As a result, although the VDA method is valid
with impulsive source duration, low background, and weak scattering in the
interplanetary space or fast diffusion in the solar atmosphere, the method is
not valid with gradual source duration, high background, or strong scattering.


title: Conceptual aspects of geometric quantum computation

abstract:
  Geometric quantum computation is the idea that geometric phases can be used
to implement quantum gates, i.e., the basic elements of the Boolean network
that forms a quantum computer. Although originally thought to be limited to
adiabatic evolution, controlled by slowly changing parameters, this form of
quantum computation can as well be realized at high speed by using nonadiabatic
schemes. Recent advances in quantum gate technology have allowed for
experimental demonstrations of different types of geometric gates in adiabatic
and nonadiabatic evolution. Here, we address some conceptual issues that arise
in the realizations of geometric gates. We examine the appearance of dynamical
phases in quantum evolution and point out that not all dynamical phases need to
be compensated for in geometric quantum computation. We delineate the relation
between Abelian and non-Abelian geometric gates and find an explicit physical
example where the two types of gates coincide. We identify differences and
similarities between adiabatic and nonadiabatic realizations of quantum
computation based on non-Abelian geometric phases.


title: Kelvin-Helmholtz Instabilities in Multi-Sized Dust Layers

abstract:
  We examine the effect of the dust size distribution on Kelvin-Helmholtz
instabilities in the protoplanetary disk with dust sedimentation. With newly
taking into account the dust size distribution, the growth rate of the
Kelvin-Helmholtz instability is calculated using the linear stability analysis
with the dust density distribution consistent with sedimentation. Dust
abundance required for gravitational instabilities before the Kelvin-Helmholtz
instability is derived from the linear stability analysis, and it is found that
the required dust abundance significantly coincides with that estimated from
the Richardson number. It is also found that when the dust size distribution is
taken into account, the critical Richardson number for the onset of the
Kelvin-Helmholtz instability tends to increase with dust abundance. This result
is different from that in the case without the dust size distribution.


title:
Interpolation of nonstationary high frequency spatial-temporal
  temperature data

abstract:
  The Atmospheric Radiation Measurement program is a U.S. Department of Energy
project that collects meteorological observations at several locations around
the world in order to study how weather processes affect global climate change.
As one of its initiatives, it operates a set of fixed but irregularly-spaced
monitoring facilities in the Southern Great Plains region of the U.S. We
describe methods for interpolating temperature records from these fixed
facilities to locations at which no observations were made, which can be useful
when values are required on a spatial grid. We interpolate by conditionally
simulating from a fitted nonstationary Gaussian process model that accounts for
the time-varying statistical characteristics of the temperatures, as well as
the dependence on solar radiation. The model is fit by maximizing an
approximate likelihood, and the conditional simulations result in
well-calibrated confidence intervals for the predicted temperatures. We also
describe methods for handling spatial-temporal jumps in the data to interpolate
a slow-moving cold front.


title: Multi-state asymmetric simple exclusion processes

abstract:
  It is known that the Markov matrix of the asymmetric simple exclusion process
(ASEP) is invariant under the Uq(sl2) algebra. This is the result of the fact
that the Markov matrix of the ASEP coincides with the generator of the
Temperley-Lieb (TL) algebra, the dual algebra of the Uq(sl2) algebra. Various
types of algebraic extensions have been considered for the ASEP. In this paper,
we considered the multi-state extension of the ASEP, by allowing more than two
particles to occupy the same box. We constructed the Markov matrix by
dimensionally extending the TL generators and derived explicit forms of the
particle densities and the currents on the steady states. Then we showed how
decay lengths differ from the original two-state ASEP under the closed boundary
conditions.

categories: cond-mat.stat-mech math-ph math.MP nlin.SI