title:
Holographic thermalization in N=4 Super Yang-Mills theory at finite
  coupling

abstract:
  We investigate the behavior of energy momentum tensor correlators in
holographic $\mathcal{N}=4$ super Yang-Mills plasma, taking finite coupling
corrections into account. In the thermal limit we determine the flow of
quasinormal modes as a function of the 't Hooft coupling. Then we use a
specific model of holographic thermalization to study the deviation of the
spectral densities from their thermal limit in an out-of-equilibrium situation.
The main focus lies on the thermalization pattern with which the plasma
constituents approach their thermal distribution as the coupling constant
decreases from the infinite coupling limit. All obtained results point towards
the weakening of the usual top-down thermalization pattern.


title:
Solvent Sensitivity of Protein Unfolding: Study of Chicken Villin
  Headpiece Subdomain in Water-Ethanol and Water-DMSO Mixtures

abstract:
  In the present work we study and compare unfolding of a small protein,
chicken villin headpiece (HP-36) in two different aqueous binary mixtures,
namely water-ethanol (EtOH) and water-dimethyl sulphoxide (DMSO). In both the
binary mixtures, HP-36 is found to unfold (fully or partially, depending on the
mixture) under ambient conditions, that otherwise requires temperature as high
as ~600 K to denature in pure aqueous solvent. In all the cases, first step of
unfolding is found to be similar, i.e. separation of the cluster formed by
three hydrophobic (phenylalanine) residues, namely Phe-7, Phe-11 and Phe-18,
which constitute the hydrophobic core, thereby initiating melting of helix-2 of
the protein. Subsequent unfolding steps follow different paths in different
chemical environments. As both water-DMSO and water-ethanol show composition
dependent anomalies, so do the details of unfolding dynamics. With an increase
of co-solvent concentration different partially unfolded intermediates are
found to be formed in both the cases. This is reflected in a remarkable
non-monotonic composition dependence of several order parameters, including
fraction of native contacts and protein-solvent interaction energy. The
emergence of such partially unfolded states is particularly attributed to the
preferential solvation of the hydrophobic residues by the ethyl groups of
ethanol and methyl groups of DMSO. While in DMSO the protein gradually attains
a completely unfolded state at xDMSO=0.30, unfolding in water-ethanol appears
to be more complex and sensitive to solvent composition.


title: On the KNS Conjecture in type $E$

abstract:
  For the exceptional types $E_6$, $E_7$, and $E_8$, we prove that the
specializations at roots of unity of the quantum dimensions of the
Kirillov-Reshetikhin modules give real solutions of $\ell$-restricted
$Q$-systems, as conjectured by Kuniba, Nakanishi, and Suzuki. We also show that
these solutions are positive in type $E_6$. In type $E_7$ and $E_8$, we only
prove positivity for a subset of the nodes of the Dynkin diagram.


title:
An in-depth study of HD 174966 with CoRoT photometry and HARPS
  spectroscopy. Large separation as a new observable for \delta Sct stars

abstract:
  The aim of this work was to use a multi-approach technique to derive the most
accurate values possible of the physical parameters of the \delta Sct star
HD174966. In addition, we searched for a periodic pattern in the frequency
spectra with the goal of using it to determine the mean density of the star.
First, we extracted the frequency content from the CoRoT light curve. Then, we
derived the physical parameters of HD174966 and carried a mode identification
out from the spectroscopic and photometric observations. We used this
information to look for the models fulfilling all the conditions and discussed
the inaccuracies of the method because of the rotation effects. In a final
step, we searched for patterns in the frequency set using a Fourier transform,
discussed its origin and studied the possibility of using the periodicity to
obtain information about the physical parameters of the star. A total of 185
peaks were obtained from the Fourier analysis of the CoRoT light curve, being
almost all reliable pulsating frequencies. From the spectroscopic observations,
18 oscillation modes were detected and identified, and the inclination angle
($62.5^{\circ}$$^{+7.5}_{-17.5}$) and the rotational velocity of the star (142
km/s) were estimated. From the multi-colour photometric observations, 3
frequencies were detected, which correspond to the main ones in the CoRoT light
curve. We looked for periodicities within the 185 frequencies and found a
periodic pattern ~64 \mu Hz. Using the inclination angle, the rotational
velocity and an Echelle diagram, showing a double comb outside the asymptotic
regime, we concluded that the periodicity corresponds to a large separation
structure. The periodic pattern allowed us to discriminate models from a grid,
finding that the value of the mean density is achieved with a 6% uncertainty.
So, the pattern could be used as a new observable for A-F type stars.


title: Continuous boundary values of conformal maps

abstract:
  Let $G$ be a bounded simply connected domain in the complex plane. A point
$a\in \partial G$ is said to be accessible from inside of $G$ if there is a
Jordan arc $J$ such that $J\subset \bar G$ and $J\cap\partial G=\{a\}$. In this
paper the author shows that a univalent analytic function $\psi$ from the unit
disk $D$ onto $G$ extends continuously to $\bar D$ if and only if every
$a\in\partial G$ is accessible. The main result covers a famous theorem proved
by C. Carathe\"{o}dory, which says that if $G$ is a Jordan domain, then $\psi$
extends to be a homeomorphism from $\bar D$ onto to $\bar G$.


title: On the choice of ingredients for a theory of the Ice Ages

abstract:
  "With five parameters one can fit an elephant". This provocative statement
expresses the fact that when a theory has several adjustable parameters, an
agreement with empirical data can be of modest value. What about a theory which
contains unobserved objects? This is the subject of this paper. It is motivated
by a model of the Ice Ages of the Pleistocene, which postulates a hot planet in
an extremely eccentric orbit. This object has many consequences. It is rather
well defined by the requirements, that it must not be in conflict with laws of
nature, nor with empirical data. It must have sufficient mass to produce a
rapid geographic pole shift on Earth after a close flyby at the end of the
Pleistocene, and also be small enough to disintegrate at this occasion and to
evaporate during the Holocene. These requirements leave hardly any adaptable
parameters. In this situation, the agreement with further data, in particular
the reverse Dansgaard-Oeschger events of the Holocene, represents a significant
support of this theory.


title: Scalar model for frictional precursors dynamics

abstract:
  Recent experiments indicate that frictional sliding occurs by the nucleation
of detachment fronts at the contact interface that may appear well before the
onset of global sliding. This intriguing precursory activity is not accounted
for by traditional friction theories but is extremely important for friction
dominated geophysical phenomena such as earthquakes, landslides or avalanches.
Here we simulate the onset of slip of a three dimensional elastic body resting
on a surface and show that experimentally observed frictional precursors depend
in a complex non-universal way on the sample geometry and the loading
conditions. Our model satisfies Archard's law and Amontons' first and second
laws, reproducing with remarkable precision the real contact area dynamics, the
precursors' envelope dynamics prior to the transition to sliding, and the
normal and shear internal stress distributions close to the slider-substrate
interface. Moreover, it allows to assess which experimental features can be
attributed to the elastic equilibrium, and which are attributed to the
out-of-equilibrium dynamics, suggesting that precursory activity is an
intrinsically quasi-static physical process. A direct calculation of the
evolution of the Coulomb stress before and during precursors nucleation shows
large variations across the sample, which helps to explain why earthquake
forecasting methods based only on accumulated slip and Coulomb stress
monitoring are often ineffective.


title: A case of monoidal uniqueness of algebraic models

abstract:
  We prove that there is at most one algebraic model for modules over the
K(1)-local sphere at odd primes that retains some monoidal information.


title: Spintronic Oscillator Based on Magnetic Field Feedback

abstract:
  We present a circuit design of a spintronic oscillator based on magnetic
tunnel junction. In this design, a dc current is passed through a magnetic
tunnel junction which is connected to a feed-back wire below it. Any
fluctuation in the magnetization direction of the free layer of MTJ, drives a
fluctuating current through the feed-back wire, which exerts a magnetic field
on the free layer. This in turn can amplify the magnetization fluctuations of
the free layer. If the dc current passing through the MTJ is more than a
critical value, continuous precessing states of the magnetization are possible.


title:
RF amplification property of the MgO-based magnetic tunnel junction
  using field-induced ferromagnetic resonance

abstract:
  The radio-frequency (RF) voltage amplification property of a tunnel
magnetoresistance device driven by an RF external-magnetic-field-induced
ferromagnetic resonance was studied. The proposed device consists of a magnetic
tunnel junction (MTJ) and an electrically isolated coplanar waveguide. The
input RF voltage applied to the waveguide can excite the resonant dynamics in
the free layer magnetization, leading to the generation of an output RF voltage
under a DC bias current. The dependences of the RF voltage gain on the static
external magnetic field strength and angle were systematically investigated.
The design principles for the enhancement of the gain factor are also
discussed.


title:
Strong-Coupling Effects and Single-Particle Properties in an Ultracold
  Fermi Gas with Mass Imbalance

abstract:
  We investigate single-particle properties of a strongly interacting ultracold
Fermi gas with mass imbalance. Using an extended $T$-matrix theory, we
calculate the density of states, as well as the single-particle spectral
weight, in the unitarity limit above the superfluid phase transition
temperature $T_{\rm c}$. We show that the momentum regions where pairing
fluctuations strongly affect single-particle excitations are different between
light fermions and heavy fermions, reflecting the difference of the Pauli
blocking effects between them. In addition, we obtain different pseudogap
phenomena associated with pairing fluctuations in between the two components.
Since the realization of a mass-imbalanced superfluid Fermi gas is an important
challenge in this field, our results would contribute to the understanding of
physical properties of the hetero-pairing state.


title: Impossibility of Local State Transformation via Hypercontractivity

abstract:
  Local state transformation is the problem of transforming an arbitrary number
of copies of a bipartite resource state to a bipartite target state under local
operations. That is, given two bipartite states, is it possible to transform an
arbitrary number of copies of one of them to one copy of the other state under
local operations only? This problem is a hard one in general since we assume
that the number of copies of the resource state is arbitrarily large. In this
paper we prove some bounds on this problem using the hypercontractivity
properties of some super-operators corresponding to bipartite states. We
measure hypercontractivity in terms of both the usual super-operator norms as
well as completely bounded norms.


title:
Self-Organized Synchronization and Voltage Stability in Networks of
  Synchronous Machines

abstract:
  The integration of renewable energy sources in the course of the energy
transition is accompanied by grid decentralization and fluctuating power
feed-in characteristics. This raises new challenges for power system stability
and design. We intend to investigate power system stability from the viewpoint
of self-organized synchronization aspects. In this approach, the power grid is
represented by a network of synchronous machines. We supplement the classical
Kuramoto-like network model, which assumes constant voltages, with dynamical
voltage equations, and thus obtain an extended version, that incorporates the
coupled categories voltage stability and rotor angle synchronization. We
compare disturbance scenarios in small systems simulated on the basis of both
classical and extended model and we discuss resultant implications and possible
applications to complex modern power grids.


title: On the Problem of Vacuum Energy in FLRW Universes and Dark Energy

abstract:
  We present a (hopefully) novel calculation of the vacuum energy in expanding
FLRW spacetimes based on the renormalization of quantum field theory in
non-zero backgrounds. We compute the renormalized effective action up to the
$2-$point function and then apply the formalism to the cosmological backgrounds
of interest. As an example we calculate for quasi de Sitter spacetimes the
leading correction to the vacuum energy given by the tadpole diagram and show
that it behaves as $\sim H_0^2 \Lambda_{\rm pl}$ where $H_0$ is the Hubble
constant and $\Lambda_{\rm pl}$ is the Planck constant. This is of the same
order of magnitude as the observed dark energy density in the universe.

categories: hep-th astro-ph.CO gr-qc math-ph math.MP


title:
Field-concentration phase diagram of a quantum spin liquid with bond
  defects

abstract:
  The magnetic susceptibility of the gapped quantum spin liquid compound
(C$_4$H$_{12}$N$_2$)Cu$_2$Cl$_6$ and its chemically disordered derivatives
(C$_4$H$_{12}$N$_2$)Cu$_2$(Cl$_{1-x}$Br$_{x}$)$_6$ are systematically studied
in magnetic fields of up to 45 T, as a function of Br concentration. The
corresponding field-temperature and field-concentration phase diagrams are
determined. Measurements on the disorder-free parent compound are not fully
consistent with previously published results by other authors [PRL{\bf 96},
257203 (2006)]. The effect of Br/Cl substitution on the magnetic properties is
superficially similar to that of finite temperature. However, important
differences are identified and discussed with reference to the previously
studied magnetic excitation spectra.


title: Arens algebras of measurable operators for Maharam traces

abstract:
  We study order and topological properties of the non-commutative Arens
algebra associated with arbitrary Maharam trace.


title: Type-I integrable quantum impurities in the Heisenberg model

abstract:
  Type-I quantum impurities are investigated in the context of the integrable
Heisenberg model. This type of defects is associated to the (q)-harmonic
oscillator algebra. The transmission matrices associated to this particular
type of defects are computed via the Bethe ansatz methodology for the XXX
model, as well as for the critical and non-critical XXZ spin chain. In the
attractive regime of the critical XXZ spin chain the transmission amplitudes
for the breathers are also identified.


title:
Measuring the correlation length of intergalactic magnetic fields from
  observations of gamma-ray induced cascades

abstract:
  Context. The imaging and timing properties of {\gamma}-ray emission from
electromagnetic cascades initiated by very-high-energy (VHE) {\gamma}-rays in
the intergalactic medium depend on the strength B and correlation length
{\lambda}B of intergalactic magnetic fields (IGMF). Aims. We study the
possibility of measuring both B and {\lambda}B via observations of the cascade
emission with {\gamma}-ray telescopes. Methods. For each measurement method, we
find two characteristics of the cascade signal, which are sensitive to the IGMF
B and {\lambda}B values in different combinations. For the case of IGMF
measurement using the observation of extended emission around extragalactic VHE
{\gamma}-ray sources, the two characteristics are the slope of the surface
brightness profile and the overall size of the cascade source. For the case of
IGMF measurement from the time delayed emission, these two characteristics are
the initial slope of the cascade emission light curve and the overall duration
of the cascade signal. Results. We show that measurement of the slope of the
cascade induced extended emission and/or light curve can both potentially
provide measure of the IGMF correlation length, provided it lies within the
range 10 kpc< {\lambda}B <1 Mpc. For correlation lengths outside this range,
gamma-ray observations can provide upper or lower bound on {\lambda}B. The
latter of the two methods holds great promise in the near future for providing
a measurement/constraint using measurements from present/next-generation
{\gamma}-ray-telescopes. Conclusions. Measurement of the IGMF correlation
length will provide an important constraint on its origin. In particular, it
will enable to distinguish between an IGMF of galactic wind origin from an IGMF
of cosmological origin.


title: On the kappa ring of $\overline{M}_{g,n}$

abstract:
  Let $\kappa_e(\overline{M}_{g,n})$ denote the kappa ring of
$\overline{M}_{g,n}$ in codimension $e$. For $g,e\geq 0$ fixed, as the number
$n$ of the markings grows large we show that the rank of
$\kappa_e(\overline{M}_{g,n})$ is asymptotic to $$\frac{{n+e\choose
e}{g+e\choose e}}{(e+1)!}\simeq \frac{{g+e\choose e}n^e}{e!(e+1)!}.$$ When
$g\leq 2$ we show that a kappa class $\kappa$ is trivial if and only if the
integral of $\kappa$ against all boundary strata is trivial. For $g=1$ we
further show that the rank of $\kappa_{n-d}(\overline{M}_{1,n})$ is equal to
$|P_1(d,n-d)|$, where $P_i(d,k)$ denotes the set of partitions
$p=(p_1,...,p_\ell)$ of $d$ such that at most $k$ of the numbers
$p_1,...,p_\ell$ are greater than $i$.


title:
Confidence intervals for the critical value in the divide and color
  model

abstract:
  We obtain confidence intervals for the location of the percolation phase
transition in H\"aggstr\"om's divide and color model on the square lattice
$\mathbb{Z}^2$ and the hexagonal lattice $\mathbb{H}$. The resulting
probabilistic bounds are much tighter than the best deterministic bounds up to
date; they give a clear picture of the behavior of the DaC models on
$\mathbb{Z}^2$ and $\mathbb{H}$ and enable a comparison with the triangular
lattice $\mathbb{T}$. In particular, our numerical results suggest similarities
between DaC model on these three lattices that are in line with universality
considerations, but with a remarkable difference: while the critical value
function $r_c(p)$ is known to be constant in the parameter $p$ for $p<p_c$ on
$\mathbb{T}$ and appears to be linear on $\mathbb{Z}^2$, it is almost certainly
non-linear on $\mathbb{H}$.


title: Secure and Policy-Private Resource Sharing in an Online Social Network

abstract:
  Providing functionalities that allow online social network users to manage in
a secure and private way the publication of their information and/or resources
is a relevant and far from trivial topic that has been under scrutiny from
various research communities. In this work, we provide a framework that allows
users to define highly expressive access policies to their resources in a way
that the enforcement does not require the intervention of a (trusted or not)
third party. This is made possible by the deployment of a newly defined
cryptographic primitives that provides - among other things - efficient access
revocation and access policy privacy. Finally, we provide an implementation of
our framework as a Facebook application, proving the feasibility of our
approach.


title: Semilinear elliptic equations admitting similarity transformations

abstract:
  In this paper we study the equation $-\Delta
u+\rho^{-(\alpha+2)}h(\rho^{\alpha}u)=0$ in a smooth bounded domain $\Omega$
where $\rho(x)=\textrm{dist}\,(x,\partial \Omega)$, $\alpha>0$ and $h$ is a
non-decreasing function which satisfies Keller-Osserman condition. We introduce
a condition on $h$ which implies that the equation is subcritical, i.e. the
corresponding boundary value problem is well posed with respect to data given
by finite measures. Under additional assumptions on $h$ we show that this
condition is necessary as well as sufficient. We also discuss b.v. problems
with data given by positive unbounded measures. Our results extend results of
\cite{MV1} treating equations of the form $-\Delta u+\rho^\beta u^q=0$ with
$q>1$, $\beta>-2$.


title: Light Higgs and Dark Photon Searches at BABAR

abstract:
  Several new-physics (NP) models predict the existence of low-mass Higgs
states and light dark matter candidates. Previous BABAR searches have given
null results for these new states and have excluded large regions of the NP
models parameter space. We report on new searches on light Higgs and light dark
matter at BABAR using the 516 1/fb of data collected with the BABAR detector at
the PEP-II asymmetric-energy e+e- collider at the SLAC National Accelerator
Laboratory.


title: Recent Results on T and CP Violation at BABAR

abstract:
  CP-violation (CPV) and Time-reversal violation (TRV) are intimately related
through the CPT theorem: if one of these discrete symmetries is violated the
other one has to be violated in such a way to conserve CPT. Although CPV in the
B0-B0 system has been established by the B-factories, implying indirectly TRV,
there is still no direct evidence of TRV. We report on the observation of TRV
in the B-meson system performed with a dataset of 468 million BB pairs produced
in Y(4S) decays collected by the BABAR detector at the PEP-II asymmetric-energy
e+e- collider at the SLAC National Accelerator Laboratory. We also report on
other CPV measurements recently performed on the B-meson system.


title: Shear localization in 3-Dimensional Amorphous Solids

abstract:
  In this paper we extend the recent theory of shear-localization in
2-dimensional amorphous solids to 3-D. In 2-D the fundamental instability of
shear-localization is related to the appearance of a line of displacement
quadrupoles, that makes an angle of 45 degrees with the principal stress axis.
In 3-D the fundamental plastic instability is also explained by the formation
of a lattice of anisotropic elastic inclusions. In the case of pure external
shear stress, we demonstrate that this is a 2-dimensional triangular lattice of
similar elementary events. It is shown that this lattice is arranged on a
plane, that, similarly to the 2-D case, makes an angle of 45 degrees with
respect to the principal stress axis. This solution is energetically favorable
only if the external strain exceeds a yield-strain value, which is determined
by the strain parameters of the elementary events and the Poisson ratio. The
predictions of the theory are compared to numerical simulations and very good
agreement is observed.


title:
Identification of Four X-ray Sources from the INTEGRAL and Swift
  Catalogs

abstract:
  Four hard X-ray sources from the INTEGRAL and Swift catalogs have been
identified. X-ray and optical spectra have been obtained for each of the
objects being studied by using data from the INTEGRAL, Swift, ROSAT, and
Chandra X-ray observatories as well as observations with the RTT-150 and
AZT-33IK optical telescopes. Two sources (SWIFT J1553.6+2606 and SWIFT
J1852.2+8424) are shown to be extragalactic in nature: the first is a quasar,
while the registered X-ray flux from the second is the total emission from two
Seyfert 1 galaxies at redshifts 0.1828 and 0.2249. The source IGR J22534+6243
resides in our Galaxy and is an X-ray pulsar with a period of ~46.674 s that is
a member of a high-mass X-ray binary, probably with a Be star. The nature of
yet another Galactic source, SWIFT J1852.8+3002, is not completely clear and
infrared spectroscopy is needed to establish it.


title: Adiabatic Tracking of a State: a New Route to Nonequilibrium Physics

abstract:
  We present a novel numerical approach to track the response of a quantum
system to an external perturbation that is progressively switched-on. The
method is applied, within the framework of the density matrix renormalization
group technique, to track current-carrying states of interacting fermions in
one dimension and in presence of an Aharonov-Bohm magnetic flux. This protocol
allows us to access highly excited states. We also discuss the connection with
the entanglement entropy of these excited states.


title:
Matching with Externalities for Context-Aware User-Cell Association in
  Small Cell Networks

abstract:
  In this paper, we propose a novel user-cell association approach for wireless
small cell networks that exploits previously unexplored context information
extracted from users' devices, i.e., user equipments (UEs). Beyond
characterizing precise quality of service (QoS) requirements that accurately
reflect the UEs' application usage, our proposed cell association approach
accounts for the devices' hardware type (e.g., smartphone, tablet, laptop).
This approach has the practical benefit of enabling the small cells to make
better informed cell association decisions that handle practical
device-specific QoS characteristics. We formulate the problem as a matching
game between small cell base stations (SBSs) and UEs. In this game, the SBSs
and UEs rank one another based on well-designed utility functions that capture
composite QoS requirements, extracted from the context features (i.e.,
application in use, hardware type). We show that the preferences used by the
nodes to rank one another are interdependent and influenced by the existing
network-wide matching. Due to this unique feature of the preferences, we show
that the proposed game can be classified as a many-to-one matching game with
externalities. To solve this game, we propose a distributed algorithm that
enables the players (i.e., UEs and SBSs) to self-organize into a stable
matching that guarantees the required applications' QoS. Simulation results
show that the proposed context-aware cell association scheme yields significant
gains, reaching up to 52% improvement compared to baseline context-unaware
approaches.


title:
Correlated spin currents generated by resonant crossed Andreev
  reflections in topological superconductors

abstract:
  Topological superconductors, which support Majorana fermion excitations, have
been the subject of intense studies due to their novel transport properties and
their potential applications in fault-tolerant quantum computations. Here we
propose a new type of topological superconductors which can be used as a novel
source of correlated spin currents. We show that inducing superconductivity on
a AIII class topological insulator wire, which respects a chiral symmetry and
supports protected fermionic end states, will result in a topological
superconductor. This topological superconductor supports two topological phases
with one or two Majorana fermion end states respectively. In the phase with two
Majorana fermions, the superconductor can split Cooper pairs efficiently into
electrons in two spatially separated leads due to Majorana induced resonant
crossed Andreev reflections. The resulting currents in the leads are correlated
and spin-polarized. Importantly, the proposed topological superconductors can
be realized using quantum anomalous Hall insulators in proximity to
superconductors.


title: W-types in Homotopy Type Theory

abstract:
  We will give a detailed account of why the simplicial sets model of the
univalence axiom due to Voevodsky also models W-types. In addition, we will
discuss W-types in categories of simplicial presheaves and an application to
models of set theory.


title: Autowaves in a dc complex plasma confined behind a de Laval nozzle

abstract:
  Experiments to explore stability conditions and topology of a dense
microparticle cloud supported against gravity by a gas flow were carried out.
By using a nozzle shaped glass insert within the glass tube of a dc discharge
plasma chamber a weakly ionized gas flow through a de Laval nozzle was
produced. The experiments were performed using neon gas at a pressure of 100 Pa
and melamine-formaldehyde particles with a diameter of 3.43 {\mu}m. The
capturing and stable global confining of the particles behind the nozzle in the
plasma were demonstrated. The particles inside the cloud behaved as a single
convection cell inhomogeneously structured along the nozzle axis in a tube-like
manner. The pulsed acceleration localized in the very head of the cloud
mediated by collective plasma-particle interactions and the resulting wave
pattern were studied in detail.


title: Subsequences and Divisibility by Powers of the Fibonacci Numbers

abstract:
  Let $F_n$ be the $n$th Fibonacci number. Let $m, n$ be positive integers.
Define a sequence $(G(k,n,m))_{k\geq 1}$ by $G(1,n,m) = F^m_n$, and $G(k+1,n,m)
= F_{nG(k,n,m)}$ for all $k\geq 1$. We show that $F_n^{k+m-1}\mid G(k,n,m)$ for
all $k, m, n\in\mathbb N$. Then we calculate
$\frac{G(k,n,m)}{F_n^{k+m-1}}\pmod{F_n}$.


title:
Competition and Coexistence of Order Parameters in Holographic
  Multi-Band Superconductors

abstract:
  We construct a holographic multi-band superconductor model with each complex
scalar field in the bulk minimally coupled to a same gauge field. Taking into
account the back reaction of matter fields on the background geometry and
focusing on the two band case with two scalar order parameters, we find that
depending on the strength of the back reaction and the charge ratio of the two
bulk scalars, five different superconducting phases exist, and three of five
phases exhibit some region where both orders coexist and are thermodynamically
favored. The other two superconducting phases have only one scalar order. The
model exhibits rich phase structure and we construct the full diagram for the
five superconducting phases. Our analysis indicates that the equivalent
attractive interaction mediated by gravity between the two order parameters
tends to make the coexistence of two orders much more easy rather than more
difficult.


title:
Study of characteristics for heavy water photoneutron source in boron
  neutron capture therapy

abstract:
  Bremsstrahlung photon beams produced by medical linear accelerators are
currently the most commonly used method of radiation therapy for cancerous
tumors. Photons with energies greater than 8-10 MeV potentially generate
neutrons through photonuclear interactions in the accelerator's treatment head,
patient's body, and treatment room ambient. Electrons impinging on a heavy
target generate a cascade shower of bremsstrahlung photons, the energy spectrum
of which shows an end point equal to the electron beam energy. By varying the
target thickness, an optimum thickness exists for which, at the given electron
energy, maximum photon flux is achievable. If a source of high-energy photons
i.e. bremsstrahlung, is conveniently directed to a suitable D2O target, a novel
approach for production of an acceptable flux of filterable photoneturons for
boron neutron capture therapy (BNCT) application is possible. This study
consists of two parts. 1. Comparison and assessment of deuterium photonuclear
cross section data. 2. Evaluation of the heavy water photonuclear source.


title: On a KK-theoretic counterpart of relative index theorems

abstract:
  Relative index theorems, which deal with what happens with the index of
elliptic operators when cutting and pasting, are abundant in the literature. It
is desirable to obtain similar theorems for other stable homotopy invariants,
not the index alone. In the spirit of noncommutative geometry, we prove a
full-fledged "relative index" type theorem that compares certain elements of
the Kasparov KK-group KK(A,B).


title: Dissipationless kinetics of one dimensional interacting fermions

abstract:
  We study the problem of evolution of a density pulse of one-dimensional
interacting fermions with a non-linear single-particle spectrum.
  We show that, despite non-Fermi-liquid nature of the problem, non-equilibrium
phenomena can be described in terms of a kinetic equation for certain
quasiparticles related to the original fermions by a non-linear transformation
which decouples the left- and right-moving excitations. Employing this
approach, we investigate the kinetics of the phase space distribution of the
quasiparticles and thus determine the time evolution of the density pulse. This
allows us to explore a crossover from the essentially free-fermion evolution
for weak or short-range interaction to hydrodynamics emerging in the case of
sufficiently strong, long-range interaction.


title: Spectral Properties of Quantum Walks on Rooted Binary Trees

abstract:
  We define coined Quantum Walks on the infinite rooted binary tree given by
unitary operators $U(C)$ on an associated infinite dimensional Hilbert space,
depending on a unitary coin matrix $C\in U(3)$, and study their spectral
properties. For circulant unitary coin matrices $C$, we derive an equation for
the Carath\'eodory function associated to the spectral measure of a cyclic
vector for $U(C)$. This allows us to show that for all circulant unitary coin
matrices, the spectrum of the Quantum Walk has no singular continuous
component. Furthermore, for coin matrices $C$ which are orthogonal circulant
matrices, we show that the spectrum of the Quantum Walk is absolutely
continuous, except for four coin matrices for which the spectrum of $U(C)$ is
pure point.


title:
Progress in Monte Carlo design and optimization of the Cherenkov
  Telescope Array

abstract:
  The Cherenkov Telescope Array (CTA) will be an instrument covering a wide
energy range in very-high-energy (VHE) gamma rays. CTA will include several
types of telescopes, in order to optimize the performance over the whole energy
range. Both large-scale Monte Carlo (MC) simulations of CTA super-sets
(including many different possible CTA layouts as sub-sets) and smaller-scale
simulations dedicated to individual aspects were carried out and are on-going.
We summarize results of the prior round of large-scale simulations, show where
the design has now evolved beyond the conservative assumptions of the prior
round and present first results from the on-going new round of MC simulations.


title: Zwei-Dreibein Gravity

abstract:
  We present a generally-covariant and parity-invariant "zwei-dreibein" action
for gravity in three space-time dimensions that propagates two massive spin-2
modes, unitarily, and we use Hamiltonian methods to confirm the absence of
unphysical degrees of freedom. We show how zwei-dreibein gravity unifies
previous "3D massive gravity" models, and extends them, in the context of the
AdS/CFT correspondence, to allow for a positive central charge consistent with
bulk unitarity.


title: Interference of Majorana fermions in NS junctions

abstract:
  We investigate interference of Majorana fermions (MFs) in NS junctions. A
general formula of charge conductance G for NS junctions with two MFs is
derived based on the low energy effective model. It is found that G for two MFs
takes various values 0 \leq G \leq 4e^2/h owing to interference of the MFs,
while G is quantized as G = 2e^2/h for a single MF. The value of G is
determined by symmetry of the system. As an example, we investigate the
complete destructive interference of two degenerate MFs reported by Ii et al.
[A. Ii, A. Yamakage, K. Yada, M. Sato, and Y. Tanaka, Phys. Rev. B 86, 174512
(2012)], and identify the symmetry responsible for the destructive
interference.


title: Cyclic cohomology and Baaj-Skandalis duality

abstract:
  We construct a duality isomorphism in equivariant periodic cyclic homology
analogous to Baaj-Skandalis duality in equivariant Kasparov theory. As a
consequence we obtain general versions of the Green-Julg theorem and the dual
Green-Julg theorem in periodic cyclic theory. Throughout we work within the
framework of bornological quantum groups, thus in particular incorporating at
the same time actions of arbitrary classical Lie groups as well as actions of
compact or discrete quantum groups. An important ingredient in the construction
of our duality isomorphism is the notion of a modular pair for a bornological
quantum group, closely related to the concept introduced by Connes and
Moscovici in their work on cyclic cohomology for Hopf algebras.


title: Cherenkov sound on a surface of a topological insulator

abstract:
  Topological insulators are currently of considerable interest due to peculiar
electronic properties originating from helical states on their surfaces. Here
we demonstrate that the sound excited by helical particles on surfaces of
topological insulators has several exotic properties fundamentally different
from sound propagating in non-helical or even isotropic helical systems.
Specifically, the sound may have strictly forward propagation absent for
isotropic helical states. Its dependence on the anisotropy of the realistic
surface-states is of distinguished behavior which may be used as an alternative
experimental tool to measure the anisotropy strength. Fascinating from the
fundamental point of view backward, or anomalous, Cherenkov sound is excited
above the critical angle $\pi/2$ when the anisotropy exceeds a critical value.
Strikingly, at strong anisotropy the sound localizes into a few forward and
backward beams propagating along specific directions.


title: Reconstruction and quantization of Riemannian structures

abstract:
  We study how the Riemannian structure on a manifold can be usefully
reconstructed from its codifferential $\delta$, including a formula
$\nabla_\omega\eta={1\over 2}(
\delta(\omega\eta)-(\delta\omega)\eta+\omega(\delta\eta) +L_\omega(\eta)+i_\eta
d \omega)$ for the Levi-Civita covariant derivative in terms of 1-forms, where
$L, i$ are respectively the Lie derivative and interior product along the
corresponding vector fields. The covariant derivative extends naturally along
forms of any degree and to possibly degenerate $(\ ,\ )$. In the nondegenerate
case, $\delta$ makes the exterior algebra into a BV algebra. In the invertible
case we show that ${\rm Ricci}=-{1\over 2}\Delta g$ where the Hodge Laplacian
$\Delta$ extends in a natural way to act on the metric.
  Our results come from a new way of thinking about metrics and connections as
a kind of cocycle data for central extensions of differential graded algebras
(DGAs), a theory which we introduce. We show that any cleft extension of the
exterior algebra $\Omega(M)$ on a manifold is associated to a
possibly-degenerate metric and covariant derivative. Those for which $d$ is not
deformed up to isomorphism correspond to the Levi-Civita case. We provide a
construction for such extensions both of classical DGAs and of already
non-graded-commutative DGAs, thereby constructing a class of bimodule covariant
derivatives via a kind of quantum analogue of the Koszul formula.
  We also provide a semidirect product of any differential graded algebra by
the quantum differential algebra $\Omega(t,d t)$ in one variable, to introduce
a noncommutative `time'. Composing these two constructions recovers a previous
differential quantisation of $M\times R$.


title: Positivity Problems for Low-Order Linear Recurrence Sequences

abstract:
  We consider two decision problems for linear recurrence sequences (LRS) over
the integers, namely the Positivity Problem (are all terms of a given LRS
positive?) and the Ultimate Positivity Problem} (are all but finitely many
terms of a given LRS positive?). We show decidability of both problems for LRS
of order 5 or less, with complexity in the Counting Hierarchy for Positivity,
and in polynomial time for Ultimate Positivity. Moreover, we show by way of
hardness that extending the decidability of either problem to LRS of order 6
would entail major breakthroughs in analytic number theory, more precisely in
the field of Diophantine approximation of transcendental numbers.


title: Heavy quark impact factor and single bottom quark production at the LHC

abstract:
  We calculate the finite part of the heavy quark impact factor at
next-to-leading logarithmic accuracy in a form suitable for phenomenological
studies such as the calculation of the cross-section for single bottom quark
production at the LHC.


title: A two-sided estimate for the Gaussian noise stability deficit

abstract:
  The Gaussian noise-stability of a set A in R^n is defined by S_rho(A) = P (X
in A and Y in A) where X and Y are standard Gaussian vectors whose correlation
is rho. Borell's inequality states that for all 0 < rho < 1, among all sets A
with a given Gaussian measure, the quantity S_rho(A) is maximized when A is a
half-space.
  We give a novel short proof of this fact, based on stochastic calculus.
Moreover, we prove an almost tight, two-sided, dimension-free robustness
estimate for this inequality: by introducing a new metric to measure the
distance between the set A and its corresponding half-space H (namely the
distance between the two centroids), we show that the deficit S_rho(H) -
S_rho(A) can be controlled from both below and above by essentially the same
function of the distance, up to logarithmic factors.
  As a consequence, we also establish the conjectured exponent in the
robustness estimate proven by Mossel-Neeman, which uses the total-variation
distance as a metric. In the limit rho->1, we get an improved dimension free
robustness bound for the Gaussian isoperimetric inequality. Our estimates are
also valid for a the more general version of stability where more than two
correlated vectors are considered.


title:
Measurement of the polarisation amplitudes in B0 -> J/psi K*(892)0
  decays

abstract:
  An analysis of the decay B0 -> J/psi K*(892)0 is presented using data,
corresponding to an integrated luminosity of 1.0fb^-1, collected in pp
collisions at a centre-of-mass energy of 7TeV with the LHCb detector. The
polarisation amplitudes and the corresponding phases are measured to be
  |A_{\parallel}|^2 = 0.227 +- 0.004 (stat.) +- 0.011 (syst.),
  |A_{\perp}|^2 = 0.201 +- 0.004 (stat.) +- 0.008 (syst.),
  \delta_{\parallel} [rad] = -2.94 +- 0.02 (stat.) +- 0.03 (syst.),
  \delta_{\perp} [rad] = 2.94 +- 0.02 (stat.) +- 0.02 (syst.).
  Comparing B0 -> J/psi K*(892)0 and \bar{B}0 -> J/psi \bar{K}*(892)0 decays,
no evidence for direct CP violation is found.


title:
Coping with Unreliable Workers in Internet-based Computing: An
  Evaluation of Reputation Mechanisms

abstract:
  We present reputation-based mechanisms for building reliable task computing
systems over the Internet. The most characteristic examples of such systems are
the volunteer computing and the crowdsourcing platforms. In both examples end
users are offering over the Internet their computing power or their human
intelligence to solve tasks either voluntarily or under payment. While the main
advantage of these systems is the inexpensive computational power provided, the
main drawback is the untrustworthy nature of the end users. Generally, this
type of systems are modeled under the "master-worker" setting. A "master" has a
set of tasks to compute and instead of computing them locally she sends these
tasks to available "workers" that compute and report back the task results. We
categorize these workers in three generic types: altruistic, malicious and
rational. Altruistic workers that always return the correct result, malicious
workers that always return an incorrect result, and rational workers that
decide to reply or not truthfully depending on what increases their benefit. We
design a reinforcement learning mechanism to induce a correct behavior to
rational workers, while the mechanism is complemented by four reputation
schemes that cope with malice. The goal of the mechanism is to reach a state of
eventual correctness, that is, a stable state of the system in which the master
always obtains the correct task results. Analysis of the system gives provable
guarantees under which truthful behavior can be ensured. Finally, we observe
the behavior of the mechanism through simulations that use realistic system
parameters values. Simulations not only agree with the analysis but also reveal
interesting trade-offs between various metrics and parameters. Finally, the
four reputation schemes are assessed against the tolerance to cheaters.


title: Magnetocrystalline Anisotropy and the Magnetocaloric Effect in Fe2P

abstract:
  Magnetic and magnetocaloric properties of high-purity, giant magnetocaloric
polycrystalline and single-crystalline Fe2P are investigated. Fe2P displays a
moderate magnetic entropy change which spans over 70 K and the presence of
strong magnetization anisotropy proves this system is not fully itinerant but
displays a mix of itinerant and localized magnetism. The properties of pure
Fe2P are compared to those of giant magnetocaloric (Fe,Mn)2(P,A) compounds
helping understand the exceptional characteristics shown by the latter which
are so promising for heat pump and energy conversion applications.


title:
Rising tides or rising stars?: Dynamics of shared attention on Twitter
  during media events

abstract:
  "Media events" such as political debates generate conditions of shared
attention as many users simultaneously tune in with the dual screens of
broadcast and social media to view and participate. Are collective patterns of
user behavior under conditions of shared attention distinct from other "bursts"
of activity like breaking news events? Using data from a population of
approximately 200,000 politically-active Twitter users, we compare features of
their behavior during eight major events during the 2012 U.S. presidential
election to examine (1) the impact of "media events" have on patterns of social
media use compared to "typical" time and (2) whether changes during media
events are attributable to changes in behavior across the entire population or
an artifact of changes in elite users' behavior. Our findings suggest that
while this population became more active during media events, this additional
activity reflects concentrated attention to a handful of users, hashtags, and
tweets. Our work is the first study on distinguishing patterns of large-scale
social behavior under condition of uncertainty and shared attention, suggesting
new ways of mining information from social media to support collective
sensemaking following major events.


title:
On the Efficient Gerschgorin Inclusion Usage in the Global Optimization
  {\alpha}BB Method

abstract:
  In this paper, we revisit the {\alpha}BB method for solving global
optimization problems. We investigate optimality of the scaling vector used in
Gerschgorin's inclusion theorem to calculate bounds on the eigenvalues of the
Hessian matrix. We propose two heuristics to compute good scaling vector d, and
state three necessary optimality conditions for optimal d. Since the scaling
vector calculated by the second presented method satisfies all three optimality
conditions, it serves as a cheap but efficient solution.


title: Forward clusters for degenerate random environments

abstract:
  We consider connectivity properties and asymptotic slopes for certain random
directed graphs on $Z^2$ in which the set of points $C_o$ that the origin
connects to is always infinite. We obtain conditions under which the complement
of $C_o$ has no infinite connected component. Applying these results to one of
the most interesting such models leads to an improved lower bound for the
critical occupation probability for oriented site percolation on the triangular
lattice in 2 dimensions.


title: On the integrability of PT-symmetric dimers

abstract:
  The coupled discrete linear and Kerr nonlinear Schrodinger equations with
gain and loss describing transport on dimers with parity-time PT symmetric
potentials are considered. The model is relevant among others to experiments in
optical couplers and proposals on Bose-Einstein condensates in PT symmetric
double-well potentials. It is known that the models are integrable. Here, the
integrability is exploited further to construct the phase-portraits of the
system. A pendulum equation with a linear potential and a constant force for
the phase-difference between the fields is obtained, which explains the
presence of unbounded solutions above a critical threshold parameter. The
behaviour of all solutions of the system, including changes in the topological
structure of the phase-plane, is then discussed.


title:
Computer Simulation of 3-D Finite-Volume Liquid Transport in Fibrous
  Materials: a Physical Model for Ink Seepage into Paper

abstract:
  A physical model for the simulation ink/paper interaction at the mesoscopic
scale is developed. It is based on the modified Ising model, and is generalized
to consider the restriction of the finite-volume of ink and also its dynamic
seepage. This allows the model to obtain the ink distribution within the paper
volume. At the mesoscopic scale, the paper is modeled using a discretized fiber
structure. The ink distribution is obtained by solving its equivalent
optimization problem, which is solved using a modified genetic algorithm, along
with a new boundary condition and the quasi-linear technique. The model is able
to simulate the finite-volume distribution of ink.


title:
On the performance analysis of resilient networked control systems under
  replay attacks

abstract:
  This paper studies a resilient control problem for discrete-time, linear
time-invariant systems subject to state and input constraints. State
measurements and control commands are transmitted over a communication network
and could be corrupted by adversaries. In particular, we consider the replay
attackers who maliciously repeat the messages sent from the operator to the
actuator. We propose a variation of the receding-horizon control law to deal
with the replay attacks and analyze the resulting system performance
degradation. A class of competitive (resp. cooperative) resource allocation
problems for resilient networked control systems is also investigated.


title:
The Effect of Hessian Evaluations in the Global Optimization {\alpha}BB
  Method

abstract:
  We consider convex underestimators that are used in the global optimization
{\alpha}BB method and its variants. The method is based by augmenting the
original nonconvex function by a relaxation term that is derived from an
interval enclosure of the Hessian matrix. In this paper, we discuss the
advantages of symbolic computation of the Hessian matrix. Symbolic computation
often allows simplifications of the resulting expressions, which in turn means
less conservative underestimators. We show by examples that even a small
manipulation with the symbolic expressions, which can be processed
automatically by computers, can have a large effect on the quality of
underestimators.


title:
Long-distance radiative excitation transfer between quantum dots in
  disordered photonic crystal waveguides

abstract:
  We theoretically investigate the magnitude and range of the photon-mediated
interaction between two quantum dots embedded in a photonic crystal waveguide,
including fabrication disorder both in the crystal and in the dot positioning.
We find that disorder-induced light localization has a drastic effect on the
excitation transfer rate - as compared to an ideal structure - and that this
rate varies widely among different disorder configurations. Nevertheless, we
also find that significant rates of 50 micro-eV at a range of 10 micro-meters
can be achieved in realistic systems.


title: Photohadronic Origin of the TeV-PeV Neutrinos Observed in IceCube

abstract:
  We perform an unbiased search of the origin of the recently observed 28
events above ~30 TeV in the IceCube neutrino observatory, assuming that these
are (apart from the atmospheric background) of astrophysical origin produced by
photohadronic interactions. Instead of relying on the normalization of the
neutrino flux, we demonstrate that spectral shape and flavor composition can be
used to constrain or identify the source class. In order to quantify our
observations, we use a model where the target photons are produced by the
synchrotron emission of co-accelerated electrons, and we include magnetic field
effects on the secondary muons, pions, and kaons. We find that the lack of
observed events with energies much larger than PeV points towards sources with
strong magnetic fields, which do not exhibit a direct correlation between
highest cosmic ray and neutrino energies. While the simplest AGN models with
efficient proton acceleration plausibly describe the current data at about the
3sigma confidence level, we show that IceCube can rule out that the observed
neutrinos stem from the sources of the ultra-high energy cosmic rays with a
factor of ten increased statistics at more than 5sigma if the current
observations are confirmed. A possible caveat are sources with strong magnetic
fields and high Lorentz factors, such as magnetic energy dominated GRBs.


title:
Subdifferential calculus and doubly nonlinear evolution equations in L^p
  spaces with variable exponents

abstract:
  This paper is concerned with the Cauchy-Dirichlet problem for a doubly
nonlinear parabolic equation involving variable exponents and provides some
theorems on existence and regularity of strong solutions. In the proof of these
results, we also analyze the relations occurring between Lebesgue spaces of
space-time variables and Lebesgue-Bochner spaces of vector-valued functions,
with a special emphasis on measurability issues and particularly referring to
the case of space-dependent variable exponents. Moreover, we establish a chain
rule for (possibly nonsmooth) convex functionals defined on variable exponent
spaces. Actually, in such a peculiar functional setting the proof of this
integration formula is nontrivial and requires a proper reformulation of some
basic concepts of convex analysis, like those of resolvent, of Yosida
approximation, and of Moreau-Yosida regularization.


title: Realising the cup-product of local Tate duality

abstract:
  We present an explicit description, in terms of central simple algebras, of a
cup-product map which occurs in the statement of local Tate duality for Galois
modules of prime order p. Given cocycles f and g, we construct a central simple
algebra of dimension p^2 whose class in the Brauer group gives the cup-product
of f with g. This algebra is as small as possible.


title: Longest common subsequences in binary sequences

abstract:
  Given two {0,1}-sequences X and Y of lengths m and n, respectively, we write
L(X,Y) to denote the length of the longest common subsequence (LCS) of X and Y,
and write L(m,n) to denote the expected value of L(X,Y) when X and Y are random
sequences. We study the value of the function z -> lim L(nz,n)/n (as n ->
infinity) and the relation of this function to the outstanding problem of
computing the Chvatal-Sankoff constant lim L(n,n)/n.


title:
Light-Cone Sum Rules for the $D_{(s)}\rightarrow \eta^{(\prime)} l
  \nu_l$ Form Factor

abstract:
  We present an improved light-cone sum rule analysis of the decay form factors
of $D$ and $D_s$ into $\eta$ and $\eta^{\prime}$ and argue that these decays
offer a very promissing possibility to determine the leading Fock-state gluonic
contribution of the $\eta'$ at future experimental facilities as FAIR or
Super-KEKB. We also give the corresponding branching ratios for B decays.


title:
Correlation structure of stochastic neural networks with generic
  connectivity matrices

abstract:
  Using a perturbative expansion for weak synaptic weights and weak sources of
randomness, we calculate the correlation structure of neural networks with
generic connectivity matrices. In detail, the perturbative parameters are the
mean and the standard deviation of the synaptic weights, together with the
standard deviations of the background noise of the membrane potentials and of
their initial conditions. We also show how to determine the correlation
structure of the system when the synaptic connections have a random topology.
This analysis is performed on rate neurons described by Wilson and Cowan
equations, since this allows us to find analytic results. Moreover, the
perturbative expansion can be developed at any order and for a generic
connectivity matrix. We finally show an example of application of this
technique for a particular case of biologically relevant topology of the
synaptic connections.


title: Polar Coded Modulation with Optimal Constellation Labeling

abstract:
  A practical $2^m$-ary polar coded modulation (PCM) scheme with optimal
constellation labeling is proposed. To efficiently find the optimal labeling
rule, the search space is reduced by exploiting the symmetry properties of the
channels. Simulation results show that the proposed PCM scheme can outperform
the bit-interleaved turbo coded modulation scheme used in the WCDMA (Wideband
Code Division Multiple Access) mobile communication systems by up to 1.5dB.


title: A Hybrid ARQ Scheme Based on Polar Codes

abstract:
  A hybrid automatic repeat request (HARQ) scheme based on a novel class of
rate-compatible polar (\mbox{RCP}) codes are proposed. The RCP codes are
constructed by performing punctures and repetitions on the conventional polar
codes. Simulation results over binary-input additive white Gaussian noise
channels (BAWGNCs) show that, using a low-complexity successive cancellation
(SC) decoder, the proposed HARQ scheme performs as well as the existing schemes
based on turbo codes and low-density parity-check (LDPC) codes. The proposed
transmission scheme is only about 1.0-1.5dB away from the channel capacity with
the information block length of 1024 bits.


title: Oriented Attachment of ZnO Nanocrystals

abstract:
  Self-organization of nanoparticles is a major issue to synthesize mesoscopic
structures. Among the possible mechanisms leading to self-organization, the
oriented attachment is efficient yet not completely understood. We investigate
here the oriented attachment process of ZnO nanocrystals preformed in the gas
phase. During the deposition in high vacuum, about 60% of the particles, which
are uncapped, form larger crystals through oriented attachment. In the present
conditions of deposition, no selective direction for the oriented attachment is
noticed. To probe the driving force of the oriented attachment, and more
specifically the possible influence of the dipolar interaction between
particles, we have deposited the same nanocrystals in the presence of a
constant electric field. The expected effect was to enhance the fraction of
domains resulting from the oriented attachment due to the increased interaction
of the particle dipoles with the electric field. The multiscale analytical and
statistical analysis (TEM coupled to XRD) shows no significant influence of the
electric field on the organization of the particles. We therefore conclude that
the dipolar interaction between nanocrystals is not the prominent driving force
in the process. Consequently, we argue, in accordance with recent theoretical
and experimental investigations, that the surface reduction, possibly driven by
Coulombic interaction, may be the major mechanism for the oriented attachment
process.


title: Power-Free Values of Polynomials

abstract:
  Let f be an irreducible polynomial of degree d>=3 with no fixed prime
divisor. We derive an asymptotic formula for the number of primes p<x such that
f(p) is (d-1)-free.


title: Potts Models with Invisible States on General Bethe Lattices

abstract:
  The number of so-called invisible states which need to be added to the
q-state Potts model to transmute its phase transition from continuous to first
order has attracted recent attention. In the q=2 case, a Bragg-Williams,
mean-field approach necessitates four such invisible states while a 3-regular,
random-graph formalism requires seventeen. In both of these cases, the
changeover from second- to first-order behaviour induced by the invisible
states is identified through the tricritical point of an equivalent
Blume-Emery-Griffiths model.
  Here we investigate the generalised Potts model on a Bethe lattice with z
neighbours. We show that, in the q=2 case, r_c(z)=[4 z / 3(z-1)]
[(z-1)/(z-2)]^z invisible states are required to manifest the equivalent
Blume-Emery-Griffiths tricriticality. When z=3, the 3-regular, random-graph
result is recovered, while the infinite z limit delivers the Bragg-Williams,
mean-field result.


title: Krypton-85 in the atmosphere

abstract:
  Measurement results are presented on 85Kr content in the atmosphere over the
European part of Russia in 1971-1995 based on the analysis of the commercial
krypton, which is separated from air by industrial plants. Our results are by
15 per cent lower then 85Kr activites observed over West Europe. According our
prediction by 2030 85Kr content in the atmosphere over Europe will amount to
1,5-3 Bq in m3 air. Average 85Kr release to the atmosphere from regeneration of
spent nuclear fuel (SNF) is estimated, some 180 TBq per a ton SNF. It is
advisable to recommence monitoring of 85Kr content within Russia.


title: Higher Dimensional Coulomb Gases and Renormalized Energy Functionals

abstract:
  We consider a classical system of n charged particles in an external
confining potential, in any dimension d larger than 2. The particles interact
via pairwise repulsive Coulomb forces and the coupling parameter scales like
the inverse of n (mean-field scaling). By a suitable splitting of the
Hamiltonian, we extract the next to leading order term in the ground state
energy, beyond the mean-field limit. We show that this next order term, which
characterizes the fluctuations of the system, is governed by a new
"renormalized energy" functional providing a way to compute the total Coulomb
energy of a jellium (i.e. an infinite set of point charges screened by a
uniform neutralizing background), in any dimension. The renormalization that
cuts out the infinite part of the energy is achieved by smearing out the point
charges at a small scale, as in Onsager's lemma. We obtain consequences for the
statistical mechanics of the Coulomb gas: next to leading order asymptotic
expansion of the free energy or partition function, characterizations of the
Gibbs measures, estimates on the local charge fluctuations and factorization
estimates for reduced densities. This extends results of Sandier and Serfaty to
dimension higher than two by an alternative approach.

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


title: Packing a Knapsack of Unknown Capacity

abstract:
  We study the problem of packing a knapsack without knowing its capacity.
Whenever we attempt to pack an item that does not fit, the item is discarded;
if the item fits, we have to include it in the packing. We show that there is
always a policy that packs a value within factor 2 of the optimum packing,
irrespective of the actual capacity. If all items have unit density, we achieve
a factor equal to the golden ratio. Both factors are shown to be best possible.
In fact, we obtain the above factors using packing policies that are universal
in the sense that they fix a particular order of the items and try to pack the
items in this order, independent of the observations made while packing. We
give efficient algorithms computing these policies. On the other hand, we show
that, for any alpha>1, the problem of deciding whether a given universal policy
achieves a factor of alpha is coNP-complete. If alpha is part of the input, the
same problem is shown to be coNP-complete for items with unit densities.
Finally, we show that it is coNP-hard to decide, for given alpha, whether a set
of items admits a universal policy with factor alpha, even if all items have
unit densities.


title: A Compact High Energy Camera for the Cherenkov Telescope Array

abstract:
  The Compact High Energy Camera (CHEC) is a camera-development project
involving UK, US, Japanese and Dutch institutes for the dual-mirror Small-Sized
Telescopes (SST-2M) of the Cherenkov Telescope Array (CTA). Two CHEC
prototypes, based on different photosensors are funded and will be assembled
and tested in the UK over the next ~18 months. CHEC is designed to record
flashes of Cherenkov light lasting from a few to a hundred nanoseconds, with
typical RMS image width and length of ~0.2 x 1.0 degrees, and has a 9 degree
field of view. The physical camera geometry is dictated by the telescope
optics: a curved focal surface with radius of curvature 1m and diameter ~35cm
is required. CHEC is designed to work with both the ASTRI and GATE SST-2M
telescope structures and will include an internal LED flasher system for
calibration. The first CHEC prototype will be based on multi-anode
photomultipliers (MAPMs) and the second on silicon photomultipliers (SiPMs or
MPPCs). The first prototype will soon be installed on the ASTRI SST-2M
prototype structure on Mt. Etna.


title: A Constant Factor Approximation Algorithm for Fault-Tolerant k-Median

abstract:
  In this paper, we consider the fault-tolerant $k$-median problem and give the
\emph{first} constant factor approximation algorithm for it. In the
fault-tolerant generalization of classical $k$-median problem, each client $j$
needs to be assigned to at least $r_j \ge 1$ distinct open facilities. The
service cost of $j$ is the sum of its distances to the $r_j$ facilities, and
the $k$-median constraint restricts the number of open facilities to at most
$k$. Previously, a constant factor was known only for the special case when all
$r_j$s are the same, and a logarithmic approximation ratio for the general
case. In addition, we present the first polynomial time algorithm for the
fault-tolerant $k$-median problem on a path or a HST by showing that the
corresponding LP always has an integral optimal solution.
  We also consider the fault-tolerant facility location problem, where the
service cost of $j$ can be a weighted sum of its distance to the $r_j$
facilities. We give a simple constant factor approximation algorithm,
generalizing several previous results which only work for nonincreasing weight
vectors.


title:
A Muscle Model Based on Feldman's Lambda Model: 3D Finite Element
  Implementation

abstract:
  This paper presents the introduction of Feldman's muscle model in a three
dimensional continuum finite element model of the human face. This model is
compared to the classical Hill-type muscle model


title:
Granulation properties of giants, dwarfs, and white dwarfs from the
  CIFIST 3D model atmosphere grid

abstract:
  3D model atmospheres for giants, dwarfs, and white dwarfs, computed with the
CO5BOLD code and part of the CIFIST grid, have been used for spectroscopic and
asteroseismic studies. Unlike existing plane-parallel 1D structures, these
simulations predict the spatially and temporally resolved emergent intensity so
that granulation can be analysed, which provides insights on how convective
energy transfer operates in stars. The wide range of atmospheric parameters of
the CIFIST 3D simulations (3600 < Teff (K) < 13,000 and 1 < log g < 9) allows
the comparison of convective processes in significantly different environments.
We show that the relative intensity contrast is correlated with both the Mach
and Peclet numbers in the photosphere. The horizontal size of granules varies
between 3 and 10 times the local pressure scale height, with a tight
correlation between the factor and the Mach number of the flow. Given that
convective giants, dwarfs, and white dwarfs cover the same range of Mach and
Peclet numbers, we conclude that photospheric convection operates in a very
similar way in those objects.


title: GROTESQUE: Noisy Group Testing (Quick and Efficient)

abstract:
  Group-testing refers to the problem of identifying (with high probability) a
(small) subset of $D$ defectives from a (large) set of $N$ items via a "small"
number of "pooled" tests. For ease of presentation in this work we focus on the
regime when $D = \cO{N^{1-\gap}}$ for some $\gap > 0$. The tests may be
noiseless or noisy, and the testing procedure may be adaptive (the pool
defining a test may depend on the outcome of a previous test), or non-adaptive
(each test is performed independent of the outcome of other tests). A rich body
of literature demonstrates that $\Theta(D\log(N))$ tests are
information-theoretically necessary and sufficient for the group-testing
problem, and provides algorithms that achieve this performance. However, it is
only recently that reconstruction algorithms with computational complexity that
is sub-linear in $N$ have started being investigated (recent work by
\cite{GurI:04,IndN:10, NgoP:11} gave some of the first such algorithms). In the
scenario with adaptive tests with noisy outcomes, we present the first scheme
that is simultaneously order-optimal (up to small constant factors) in both the
number of tests and the decoding complexity ($\cO{D\log(N)}$ in both the
performance metrics). The total number of stages of our adaptive algorithm is
"small" ($\cO{\log(D)}$). Similarly, in the scenario with non-adaptive tests
with noisy outcomes, we present the first scheme that is simultaneously
near-optimal in both the number of tests and the decoding complexity (via an
algorithm that requires $\cO{D\log(D)\log(N)}$ tests and has a decoding
complexity of {${\cal O}(D(\log N+\log^{2}D))$}. Finally, we present an
adaptive algorithm that only requires 2 stages, and for which both the number
of tests and the decoding complexity scale as {${\cal O}(D(\log
N+\log^{2}D))$}. For all three settings the probability of error of our
algorithms scales as $\cO{1/(poly(D)}$.


title: Granular discharge rate for submerged hoppers

abstract:
  The discharge of spherical grains from a hole in the bottom of a right
circular cylinder is measured with the entire system underwater. We find that
the discharge rate depends on filling height, in contrast to the well-known
case of dry non-cohesive grains. It is further surprising that the rate
increases up to about twenty five percent, as the hopper empties and the
granular pressure head decreases. For deep filling, where the discharge rate is
constant, we measure the behavior as a function of both grain and hole
diameters. The discharge rate scale is set by the product of hole area and the
terminal falling speed of isolated grains. But there is a small-hole cutoff of
about two and half grain diameters, which is larger than the analogous cutoff
in the Beverloo equation for dry grains.


title:
Kondo-like mass enhancement of Dirac fermion in iron pnictides
  Ba(Fe$_{1-x}$Mn$_x$As)$_2$

abstract:
  The effect of Mn substitution, acting as a magnetic impurity for Fe, on the
Dirac cone was investigated in Ba(Fe$_{1-x}$Mn$_x$As)$_2$. Both
magnetoresistance and Hall resistivity studies clearly indicate that the
cyclotron effective mass ($m^{\ast}$) of the Dirac cone is anomalously enhanced
at low temperatures by the impurity, although its evolution as a function of
carrier number proceeds in a conventional manner at higher temperatures.
Kondo-like band renormalization induced by the magnetic impurity scattering is
suggested as an explanation for this, and the anomalous mass enhancement of the
Dirac fermions is discussed.


title:
Impact of strong disorder on the static magnetic properties of the
  spin-chain compound BaCu2SiGeO7

abstract:
  The disordered quasi-1D magnet BaCu2SiGeO7 is considered as one of the best
physical realizations of the random Heisenberg chain model, which features an
irregular distribution of the exchange parameters and whose ground state is
predicted to be the scarcely investigated random-singlet state (RSS). Based on
extensive 29Si NMR and magnetization studies of BaCu2SiGeO7, combined with
numerical Quantum Monte Carlo simulations, we obtain remarkable quantitative
agreement with theoretical predictions of the random Heisenberg chain model and
strong indications for the formation of a random-singlet state at low
temperatures in this compound. As a local probe, NMR is a well-adapted
technique for studying the magnetism of disordered systems. In this case it
also reveals an additional local transverse staggered field (LTSF), which
affects the low-temperature properties of the RSS. The proposed model
Hamiltonian satisfactorily accounts for the temperature dependence of the NMR
line shapes.


title:
On the microscopic origin of the magneto-electronic phase separation in
  Sr doped LaCoO3

abstract:
  The nanoscopic magneto-electronic phase separation in doped La1-xSrxCoO3
perovskites was studied with local probes. The phase separation is directly
observed by M\"ossbauer spectroscopy in the studied doping range of 0.05 <= x
<= 0.25 both at room-temperature as well as in the low temperature magnetic
phase. Extended with current synchrotron based X-ray spectroscopies, these data
help to characterize the volume as well as the local electric and magnetic
properties of the distinct phases. A simple model based on a random
distribution of the doping Sr ions describes well both the evolution of the
separated phases as well as the variation of the Co spin state. The experiments
suggest that Sr doping initiates small droplets and a high degree of doping
driven cobalt spin-state transition, while the Sr-free second phase vanishes
rapidly with increasing Sr content.


title: The K\"ahler metric of a blow-up

abstract:
  After a review of the general properties of holomorphic spheres in complex
surfaces we describe the local geometry in the vicinity of a CP^1 embedded with
a negative normal bundle. As a by-product, we build (asymptotically locally
hyperbolic) Kahler-Einstein metrics on the total spaces of the line bundles
O(-m), m >= 3 over CP^1. We check that the behavior of the Kahler potential is
compatible with the Chern-Weil formulas for the Euler characteristic and
signature. We also describe two supersymmetric setups where relevant
constructions arise.


title:
Design of One-Dimensional Linear Phase Digital IIR Filters Using
  Orthogonal Polynomials

abstract:
  In the present paper, we discuss a method to design a linear phase
1-dimensional Infinite Impulse Response (IIR) filter using orthogonal
polynomials. The filter is designed using a set of object functions. These
object functions are realized using a set of orthogonal polynomials. The method
includes placement of zeros and poles in such a way that the amplitude
characteristics are not changed while we change the phase characteristics of
the resulting IIR filter.


title:
Anisotropic Diffusion for Details Enhancement in Multi-Exposure Image
  Fusion

abstract:
  We develop a multiexposure image fusion method based on texture features,
which exploits the edge preserving and intraregion smoothing property of
nonlinear diffusion filters based on partial differential equations (PDE). With
the captured multiexposure image series, we first decompose images into base
layers and detail layers to extract sharp details and fine details,
respectively. The magnitude of the gradient of the image intensity is utilized
to encourage smoothness at homogeneous regions in preference to inhomogeneous
regions. Then, we have considered texture features of the base layer to
generate a mask (i.e., decision mask) that guides the fusion of base layers in
multiresolution fashion. Finally, well-exposed fused image is obtained that
combines fused base layer and the detail layers at each scale across all the
input exposures. Proposed algorithm skipping complex High Dynamic Range Image
(HDRI) generation and tone mapping steps to produce detail preserving image for
display on standard dynamic range display devices. Moreover, our technique is
effective for blending flash/no-flash image pair and multifocus images, that
is, images focused on different targets.


title: A note on the hitting probabilities of random covering sets

abstract:
  Let $E=\limsup\limits_{n\to\infty}(g_n+\xi_n)$ be the random covering set on
the torus $\mathbb{T}^d$, where $\{g_n\}$ is a sequence of ball-like sets and
$\xi_n$ is a sequence of independent random variables uniformly distributed on
$\T^d$. We prove that $E\cap F\neq\emptyset$ almost surely whenever
$F\subset\mathbb{T}^d$ is an analytic set with Hausdorff dimension,
$\dim_H(F)>d-\alpha$, where $\alpha$ is the almost sure Hausdorff dimension of
$E$. Moreover, examples are given to show that the condition on $\dim_H(F)$
cannot be replaced by the packing dimension of $F$.


title:
Simultaneous Unbalanced Shared Local Oscillator Heterodyne
  Interferometry (SUSHI) for high SNR, minimally destructive dispersive
  detection of time-dependent atomic spins

abstract:
  We demonstrate "Simultaneous Unbalanced Shared Local Oscillator Heterodyne
Interferometry (SUSHI)," a new method for minimally destructive, high SNR
dispersive detection of atomic spins. In SUSHI a dual-frequency probe laser
interacts with atoms in one arm of a Mach-Zehnder interferometer, then beats
against a bright local oscillator beam traversing the other arm, resulting in
two simultaneous, independent heterodyne measurements of the atom-induced phase
shift. Measurement noise due to mechanical disturbances of beam paths is
strongly rejected by the technique of \emph{active subtraction} in which
anti-noise is actively written onto the local oscillator beam via an optical
phase-locked-loop. In SUSHI, technical noise due to phase, amplitude, and
frequency fluctuations of the various laser fields is strongly rejected (i) for
any mean phase bias between the interferometer arms, (ii) without the use of
piezo actuated mirrors, and (iii) without signal balancing. We experimentally
demonstrate an ultra-low technical noise limited sensitivity of 51
nrad$/\sqrt{\R{Hz}}$ over a measurement bandwidth of 60 Hz to 8 kHz using a 230
$\mu$W probe, and stay within $\sim$3 dB of the standard quantum limit as probe
power is reduced by more than 5 orders of magnitude to as low as 650 pW. SUSHI
is therefore well suited to performing QND measurements for preparing spin
squeezed states and for high SNR, truly continuous observations of ground-state
Rabi flopping in cold atom ensembles.


title:
Orientational dynamics of weakly inertial axisymmetric particles in
  steady viscous flows

abstract:
  The orientational dynamics of weakly inertial axisymmetric particles in a
steady flow is investigated. We derive an asymptotic equation of motion for the
unit axial vector along the particle symmetry axis, valid for small Stokes
number St, and for any axisymmetric particle in any steady linear viscous flow.
This reduced dynamics is analysed in two ways, both pertain to the case of a
simple shear flow. In this case inertia induces a coupling between precession
and nutation. This coupling affects the dynamics of the particle, breaks the
degeneracy of the Jeffery orbits, and creates two limiting periodic orbits. We
calculate the leading-order Floquet exponents of the limiting periodic orbits
and show analytically that prolate objects tend to a tumbling orbit, while
oblate objects tend to a log-rolling orbit, in agreement with previous
analytical and numerical results. Second, we analyse the role of the limiting
orbits when rotational noise is present. We formulate the Fokker-Planck
equation describing the orientational distribution of an axisymmetric particle,
valid for small St and general Peclet number Pe. Numerical solutions of the
Fokker-Planck equation, obtained by means of expansion in spherical harmonics,
show that stationary orientational distributions are close to the inertia-free
case when Pe St << 1, whereas they are determined by inertial effects, though
small, when Pe >> 1/St >> 1.


title: Nonparametric Bayes modeling of count processes

abstract:
  Data on count processes arise in a variety of applications, including
longitudinal, spatial and imaging studies measuring count responses. The
literature on statistical models for dependent count data is dominated by
models built from hierarchical Poisson components. The Poisson assumption is
not warranted in many applications, and hierarchical Poisson models make
restrictive assumptions about over-dispersion in marginal distributions. This
article proposes a class of nonparametric Bayes count process models, which are
constructed through rounding real-valued underlying processes. The proposed
class of models accommodates applications in which one observes separate
count-valued functional data for each subject under study. Theoretical results
on large support and posterior consistency are established, and computational
algorithms are developed using Markov chain Monte Carlo. The methods are
evaluated via simulation studies and illustrated through application to
longitudinal tumor counts and asthma inhaler usage.


title:
Right-handed sneutrinos as asymmetric DM and neutrino masses from
  neutrinophilic Higgs bosons

abstract:
  We consider an extension of the Next-to-Minimal Supersymmetric Standard Model
by three right-handed neutrinos and a pair of neutrinophilic Higgs superfields.
The small neutrino masses arise naturally from a small vacuum expectation value
of the additional Higgs fields (hence without lepton number violation), while
the lightest right-handed sneutrinos can constitute asymmetric Dark Matter. The
right-handed sneutrino and baryon asymmetries are connected through equilibrium
processes in the early universe, explaining the coincidence of the DM and
baryon abundances. We show that particle physics and astrophysical constraints
are satisfied.


title:
Optimal Retirement Tontines for the 21st Century: With Reference to
  Mortality Derivatives in 1693

abstract:
  Historical tontines promised enormous rewards to the last survivors at the
expense of those who died early. While this design appealed to the gambling
instinct, it is a suboptimal way to manage longevity risk during retirement.
This is why fair life annuities making constant payments -- where the insurance
company is exposed to the longevity risk -- induces greater lifetime utility.
However, tontines do not have to be designed using a winner-take-all approach
and insurance companies do not actually sell fair life annuities, partially due
to aggregate longevity risk.
  In this paper we derive the tontine structure that maximizes lifetime
utility, but doesn't expose the sponsor to any longevity risk. We examine its
sensitivity to the size of the tontine pool; individual longevity risk
aversion; and subjective health status. The optimal tontine varies with the
individual's longevity risk aversion $\gamma$ and the number of participants
$n$, which is problematic for product design. That said, we introduce a
structure called a natural tontine whose payout declines in exact proportion to
the (expected) survival probabilities, which is near-optimal for all $\gamma$
and $n$. We compare the utility of optimal tontines to the utility of loaded
life annuities under reasonable demographic and economic conditions and find
that the life annuity's advantage over tontines, is minimal.
  We also review and analyze the first-ever mortality-derivative issued by the
British government, known as King Williams's tontine of 1693. We shed light on
the preferences and beliefs of those who invested in the tontines vs. the
annuities and argue that tontines should be re-introduced and allowed to
co-exist with life annuities. Individuals would likely select a portfolio of
tontines and annuities that suit their personal preferences for consumption and
longevity risk, as they did over 320 years ago.


title: Unintegrated parton distributions in nuclei

abstract:
  We study how unintegrated parton distributions in nuclei can be calculated
from the corresponding integrated partons using the EPS09 parametrization. The
role of nuclear effects is presented in terms of the ratio
$R^A=\text{uPDF}^A/A\cdot \text{PDF}^N$ for both large and small $x$ domains.


title:
Image Denoising Using Tensor Product Complex Tight Framelets with
  Increasing Directionality

abstract:
  Tensor product real-valued wavelets have been employed in many applications
such as image processing with impressive performance. Though edge singularities
are ubiquitous and play a fundamental role in two-dimensional problems, tensor
product real-valued wavelets are known to be only sub-optimal since they can
only capture edges well along the coordinate axis directions. The dual tree
complex wavelet transform (DTCWT), proposed by Kingsbury [16] and further
developed by Selesnick et al. [24], is one of the most popular and successful
enhancements of the classical tensor product real-valued wavelets. The
two-dimensional DTCWT is obtained via tensor product and offers improved
directionality with 6 directions. In this paper we shall further enhance the
performance of DTCWT for the problem of image denoising. Using framelet-based
approach and the notion of discrete affine systems, we shall propose a family
of tensor product complex tight framelets TPCTF_n for all integers n>2 with
increasing directionality, where n refers to the number of filters in the
underlying one-dimensional complex tight framelet filter bank. For dimension
two, such tensor product complex tight framelet TPCTF_n offers (n-1)(n-3)/2+4
directions when n is odd, and (n-4)(n+2)/2+6 directions when n is even. In
particular, TPCTF_4, which is different to DTCWT in both nature and design,
provides an alternative to DTCWT. Indeed, TPCTF_4 behaves quite similar to
DTCWT by offering 6 directions in dimension two, employing the tensor product
structure, and enjoying slightly less redundancy than DTCWT. When TPCTF_4 is
applied to image denoising, its performance is comparable to DTCWT. Moreover,
better results on image denoising can be obtained by using TPCTF_6. Moreover,
TPCTF_n allows us to further improve DTCWT by using TPCTF_n as the first stage
filter bank in DTCWT.


title: Site Percolation on Multi-dimensional Lattice

abstract:
  Sites in an infinite d-dimensional lattice, open with probability greater or
equal to 1/d, form an infinite open path.


title: A Coloring Problem for Infinite Words

abstract:
  In this paper we consider the following question in the spirit of Ramsey
theory: Given $x\in A^\omega,$ where $A$ is a finite non-empty set, does there
exist a finite coloring of the non-empty factors of $x$ with the property that
no factorization of $x$ is monochromatic? We prove that this question has a
positive answer using two colors for almost all words relative to the standard
Bernoulli measure on $A^\omega.$ We also show that it has a positive answer for
various classes of uniformly recurrent words, including all aperiodic balanced
words, and all words $x\in A^\omega$ satisfying $\lambda_x(n+1)-\lambda_x(n)=1$
for all $n$ sufficiently large, where $ \lambda_x(n)$ denotes the number of
distinct factors of $x$ of length $n.$


title:
Photospheric Injection of Magnetic Helicity: Connectivity--based Flux
  Density Method

abstract:
  Magnetic helicity quantifies how globally sheared and/or twisted is the
magnetic field in a volume. This quantity is believed to play a key role in
solar activity due to its conservation property. Helicity is continuously
injected into the corona during the evolution of active regions (ARs). To
better understand and quantify the role of magnetic helicity in solar activity,
the distribution of magnetic helicity flux in ARs needs to be studied. The
helicity distribution can be computed from the temporal evolution of
photospheric magnetograms of ARs such as the ones provided by SDO/HMI and
Hinode/SOT. Most recent analyses of photospheric helicity flux derive an
helicity flux density proxy based on the relative rotation rate of photospheric
magnetic footpoints. Although this proxy allows a good estimate of the
photospheric helicity flux, it is still not a true helicity flux density
because it does not take into account the connectivity of the magnetic field
lines. For the first time, we implement a helicity density which takes into
account such connectivity. In order to use it for future observational studies,
we test the method and its precision on several types of models involving
different patterns of helicity injection. We also test it on more complex
configurations - from magnetohydrodynamics (MHD) simulations - containing
quasi-separatrix layers. We demonstrate that this connectivity-based helicity
flux density proxy is the best to map the true distribution of photospheric
helicity injection.


title: Photon in a cavity -- a Gedankenexperiment

abstract:
  The inertial and gravitational mass of electromagnetic radiation (i.e., a
photon distribution) in a cavity with reflecting walls has been treated by many
authors for over a century. After many contending discussions, a consensus has
emerged that the mass of such a photon distribution is equal to its total
energy divided by the square of the speed of light. Nevertheless, questions
remain unsettled on the interaction of the photons with the walls of the box.
In order to understand some of the details of this interaction, a simple case
of a single photon with an energy $E_\nu = h\,\nu$ bouncing up and down in a
static cavity with perfectly reflecting walls in a constant gravitational field
$\vec{g}$, constant in space and time, is studied and its contribution to the
weight of the box is determined as a temporal average.


title: Integrable theories and generalized graded Maillet algebras

abstract:
  We present a general formalism to investigate the integrable properties of a
large class of non-ultralocal models which in principle allows the construction
of the corresponding lattice versions. Our main motivation comes from the
su(1|1) subsector of the string theory on AdS_5 x S^5 in the uniform gauge,
where such type of non-ultralocality appears in the resulting
Alday-Arutyunov-Frolov (AAF) model. We first show how to account for the second
derivative of the delta function in the Lax algebra of the AAF model by
modifying Maillet's r- and s-matrices formalism, and derive a well-defined
algebra of transition matrices, which allows for the lattice formulation of the
theory. We illustrate our formalism on the examples of the bosonic
Wadati-Konno-Ichikawa-Shimizu (WKIS) model and the two-dimensional free massive
Dirac fermion model, which can be obtained by a consistent reduction of the
full AAF model, and give the explicit forms of their corresponding r-matrices.


title:
Theoretical Antineutrino Detection, Direction and Ranging at Long
  Distances

abstract:
  In this paper we introduce the concept of what we call "NUDAR" (NeUtrino
Direction and Ranging), making the point that measurements of the observed
energy and direction vectors can be employed to passively deduce the exact
three-dimensional location and thermal power of geophysical and anthropogenic
neutrino sources from even a single detector. We present the most precise
background estimates to date, all handled in full three dimensions, as
functions of depth and geographical location. For the present calculations, we
consider a hypothetical 138 kiloton detector which can be transported to an
ocean site and deployed to an operational depth. We present a Bayesian
estimation framework to incorporate any a priori knowledge of the reactor that
we are trying to detect, as well as the estimated uncertainty in the background
and the oscillation parameters. Most importantly, we fully employ the knowledge
of the reactor spectrum and the distance-dependent effects of neutrino
oscillations on such spectra. The latter, in particular, makes possible
determination of range from one location, given adequate signal statistics.
Further, we explore the rich potential of improving detection with even modest
improvements in individual neutrino direction determination. We conclude that a
300 MWth reactor can indeed be geolocated, and its operating power estimated
with one or two detectors in the hundred kiloton class at ranges out to a few
hundred kilometers. We note that such detectors would have natural and
non-interfering utility for scientific studies of geo-neutrinos, neutrino
oscillations, and astrophysical neutrinos. This motivates the development of
cost effective methods of constructing and deploying such next generation
detectors.


title: Relative index theorem in K-homology

abstract:
  We prove an analog of Gromov--Lawson type relative index theorems for
K-homology classes.


title: "Magic" numbers in Smale's 7th problem

abstract:
  Smale's 7-th problem concerns N-point configurations on the 2-dim sphere
which minimize the logarithmic pair-energy V_0(r) = -ln r averaged over the
pairs in a configuration; here, r is the chordal distance between the points
forming a pair. More generally, V_0(r) may be replaced by the standardized
Riesz pair-energy V_s(r)= (r^{-s} -1)/s, which becomes - ln r in the limit s to
0, and the sphere may be replaced by other compact manifolds. This paper
inquires into the concavity of the map from the integers N>1 into the minimal
average standardized Riesz pair-energies v_s(N) of the N-point configurations
on the 2-sphere for various real s. It is known that v_s(N) is strictly
increasing for each real s, and for s<2 also bounded above, hence "overall
concave." It is (easily) proved that v_{-2}(N) is even locally strictly
concave, and that so is v_s(2n) for s<-2. By analyzing computer-experimental
data of putatively minimal average Riesz pair-energies v_s^x(N) for s in
{-1,0,1,2,3} and N in {2,...,200}, it is found that {v}_{-1}^x(N) is locally
strictly concave, while v_s^x(N) is not always locally strictly concave for s
in {0,1,2,3}: concavity defects occur whenever N in C^{x}_+(s) (an s-specific
empirical set of integers). It is found that the empirical map C^{x}_+(s), with
s in {-2,-1,0,1,2,3}, is set-theoretically increasing; moreover, the percentage
of odd numbers in C^{x}_+(s), s in {0,1,2,3}, is found to increase with s. The
integers in C^{x}_+(0) are few and far between, forming a curious sequence of
numbers, reminiscent of the "magic numbers" in nuclear physics. It is
conjectured that the "magic numbers" in Smale's 7-th problem are associated
with optimally symmetric optimal-energy configurations.


title: Quantum-classical comparison: arrival times and statistics

abstract:
  Classical and quantum scattering of a non-Gaussian wave packet by a
rectangular barrier is studied in terms of arrival times to a given detector
location. A classical wave equation, proposed by N. Rosen [{\it{Am. J. Phys.}}
{\bf 32} (1964) 377], is used to study the corresponding classical dynamics.
Mean arrival times are then computed and compared for different values of
initial wave packet parameters and barrier width. The agreement is improved in
the large mass limit as one expects. A short comment on the possibility of
generalization of Rosen's proposal to a two-body system is given. Differences
in distributions of particles obeying different statistics are studied by
considering a system composed of two free particles.


title:
Uniformly rotating neutron stars in the global and local charge
  neutrality cases

abstract:
  In our previous treatment of neutron stars, we have developed the model
fulfilling global and not local charge neutrality. In order to implement such a
model, we have shown the essential role by the Thomas-Fermi equations, duly
generalized to the case of electromagnetic field equations in a general
relativistic framework, forming a coupled system of equations that we have
denominated Einstein-Maxwell-Thomas-Fermi (EMTF) equations. From the
microphysical point of view, the weak interactions are accounted for by
requesting the \beta\ stability of the system, and the strong interactions by
using the \sigma-\omega-\rho\ nuclear model, where \sigma, \omega\ and \rho\
are the mediator massive vector mesons. Here we examine the equilibrium
configurations of slowly rotating neutron stars by using the Hartle formalism
in the case of the EMTF equations indicated above. We integrate these equations
of equilibrium for different central densities and circular angular velocities
and compute the mass, polar and equatorial radii, angular momentum,
eccentricity, moment of inertia, as well as quadrupole moment of the
configurations. Both the Keplerian mass-shedding limit and the axisymmetric
secular instability are used to construct the new mass-radius relation. We
compute the maximum and minimum masses and rotation frequencies of neutron
stars. We compare and contrast all the results for the global and local charge
neutrality cases.


title:
Impact of Fano and Breit-Wigner resonances in the thermoelectric
  properties of nanoscale junctions

abstract:
  We show that the thermoelectric properties of nanoscale junctions featuring
states near the Fermi level strongly depend on the type of resonance generated
by such states, which can be either Fano or Breit-Wigner-like. We give general
expressions for the thermoelectric coefficients generated by the two types of
resonances and calculate the thermoelectric properties of these systems, which
encompass most nanoelectronics junctions. We include simulations of real
junctions where metalloporphyrin molecules bridge gold electrodes and prove
that for some metallic elements the thermoelectric properties show a large
variability. We find that the thermopower and figure of merit are largely
enhanced when the resonance gets close to the Fermi level and reach values much
higher than typical values found in other nanoscale junctions. The specific
value and temperature dependence are determined by a series of factors such as
the strength of the coupling between the state and other molecular states, the
symmetry of the state, the strength of the coupling between the molecule and
the leads and the spin filtering behavior of the junction.