title:
Polarization Enhancement in Perovskite Superlattices by Oxygen
  Octahedral Tilts

abstract:
  Interface engineering in perovskite oxide superlattices has developed into a
flourishing field, enabling not only further tuning of the exceptional
properties, but also giving access to emergent physical phenomena. Here, we
reveal a new mechanism for enhancing the electric polarization by the
interface-induced oxygen octahedral tilts in BaTiO3/CaTiO3 superlattices. By
combining a novel genetic algorithm with density functional theory (DFT), we
predict that the true ground states in 1:1 and 2:2 BaTiO3/CaTiO3 superlattices
grown on SrTiO3 adopt Pc symmetry with a large proper electric polarization
(32.8{\mu}C/cm2 for 1:1 and 35.8 {\mu}C/cm2 for 2:2 superlattices), which is
even larger than that of bulk BaTiO3. The tilt of oxygen octahedron is found to
play a key role for the enhancement of out-of-plane polarization in 1:1
superlattices because it reduces greatly the rotation of oxygen octahedron
(out-of-phase) which significantly suppresses the out-of-plane polarization.


title: An evolution of adiabatic matter: A case for the quasistatic regime

abstract:
  We establish the connection between the standard ADM 3+1 treatment of matter
with its characteristic equivalent, in the context of spherical symmetry. The
flux-conservative rendition of the fluid equations are obtained. Considering
adiabatic distributions of perfect fluid, we evolve the system using the
so-called post-quasi-static approximation in radiation coordinates. We obtain
an adiabatic matter evolution in the quasi-static regime or slow motion, which
is not shear-free nor geodesic.


title:
Controlling magnetic Feshbach resonances in polar open-shell molecules
  with non-resonant light

abstract:
  Magnetically tunable Feshbach resonances for polar paramagnetic ground-state
diatomics are too narrow to allow for magnetoassociation starting from trapped,
ultracold atoms. We show that non-resonant light can be used to engineer the
Feshbach resonances in their position and width. For non-resonant field
strengths of the order of $10^9\,$W/cm$^2$, we find the width to be increased
by three orders of magnitude, reaching a few Gauss. This opens the way for
producing ultracold molecules with sizeable electric and magnetic dipole
moments and thus for many-body quantum simulations with such particles.


title: Sampling Theory with Average Values on the Sierpinski Gasket

abstract:
  In the case of some fractals, sampling with average values on cells is more
natural than sampling on points. In this paper we investigate this method of
sampling on $SG$ and $SG_{3}$. In the former, we show that the cell graph
approximations have the spectral decimation property and prove an analog of the
Shannon sampling theorem.. We also investigate the numerical properties of
these sampling functions and make conjectures which allow us to look at
sampling on infinite blowups of $SG$. In the case of $SG_{3}$, we show that the
cell graphs have the spectral decimation property, but show that it is not
useful for proving an analogous sampling theorem.


title: Search for CP Violation in Charm at $e^+e^-$ colliders

abstract:
  In this proceeding, I discuss results from the BaBar and Belle collaborations
for searches of direct CP violation in the singly Cabibbo-suppressed decay
$\D^\pm\to K^+K^-\pi^\pm$ from $e^+e^-$ annihilation data collected at a
center-of-mass energy at or just below the \Y4S resonance. The Belle
collaboration measures the CP asymmetry as a function of the production angle
of the $D^\pm$ meson in the quasi two-body $\D^\pm\to\phi\pi^\pm$ decay. The
Babar experiment studies the entire phase-space with model-independent and
model-dependent Dalitz plot analysis techniques to search for CP-violating
asymmetries in the various intermediate states, in addition to a phase-space
integrated measurement as a function of the production angle. No evidence for
CP violation is reported from either experiment.


title: Quartic graphs with every edge in a triangle

abstract:
  We characterise the quartic (i.e. 4-regular) multigraphs with the property
that every edge lies in a triangle. The main result is that such graphs are
either squares of cycles, line multigraphs of cubic multigraphs, or are
obtained from these by a number of simple subgraph-replacement operations. A
corollary of this is that a simple quartic graph with every edge in a triangle
is either the square of a cycle, the line graph of a cubic graph or a graph
obtained from the line multigraph of a cubic multigraph by replacing triangles
with copies of K_{1,1,3}.


title:
Large deviation function and fluctuation theorem for classical particle
  transport

abstract:
  We analytically evaluate the large deviation function in a simple model of
classical particle transfer between two reservoirs. We illustrate how the
asymptotic large time regime is reached starting from a special propagating
initial condition. We show that the steady state fluctuation theorem holds
provided that the distribution of the particle number decays faster than an
exponential, implying analyticity of the generating function and a discrete
spectrum for its evolution operator.


title:
Dominant Resource Fairness in Cloud Computing Systems with Heterogeneous
  Servers

abstract:
  We study the multi-resource allocation problem in cloud computing systems
where the resource pool is constructed from a large number of heterogeneous
servers, representing different points in the configuration space of resources
such as processing, memory, and storage. We design a multi-resource allocation
mechanism, called DRFH, that generalizes the notion of Dominant Resource
Fairness (DRF) from a single server to multiple heterogeneous servers. DRFH
provides a number of highly desirable properties. With DRFH, no user prefers
the allocation of another user; no one can improve its allocation without
decreasing that of the others; and more importantly, no user has an incentive
to lie about its resource demand. As a direct application, we design a simple
heuristic that implements DRFH in real-world systems. Large-scale simulations
driven by Google cluster traces show that DRFH significantly outperforms the
traditional slot-based scheduler, leading to much higher resource utilization
with substantially shorter job completion times.


title: Device-independent certification of the teleportation of a qubit

abstract:
  We want to certify in a black box scenario that two parties simulating the
teleportation of a qubit are really using quantum resources. If active
compensation is part of the simulation, perfect teleportation can be faked with
purely classical means. If active compensation is not implemented, a classical
simulation is necessarily imperfect: in this case, we provide bounds for
certification of quantumness using only the observed statistics. The usual
figure of merit, namely the average fidelity of teleportation, turns out to be
too much of a coarse-graining of the available statistical information in the
case of a black-box assessment.


title:
An Improved Parameterized Algorithm for the Independent Feedback Vertex
  Set Problem

abstract:
  In this paper, we develop a new parameterized algorithm for the {\sc
Independent Feedback Vertex Set} (IFVS) problem. Given a graph $G=(V,E)$, the
goal of the problem is to determine whether there exists a vertex subset
$F\subseteq V$ such that $V-F$ induces a forest in $G$ and $F$ is an
independent set. We show that there exists a parameterized algorithm that can
determine whether a graph contains an IFVS of size $k$ or not in time
$O(4^kn^{2})$. To our best knowledge, this result improves the known upper
bound for this problem, which is $O^{*}(5^{k}n^{O(1)})$.


title: Tunable single-photon frequency conversion in a Sagnac interferometer

abstract:
  We study the single-photon frequency conversion of a five-level emitter
coupled to a Sagnac interferometer. We show that the unity conversion
efficiency can be achieved either in resonance or off-resonance case under the
ideal condition. In particular, the frequency of the output photon can be
controlled by the frequencies and Rabi frequencies of the external driving
fields.


title:
Vertex operator algebras associated to the Virasoro algebra over an
  arbitrary field

abstract:
  The vertex operator algebras and modules associated to the highest weight
modules for the Virasoro algebra over an arbitrary field F whose characteristic
is not equal to 2 are studied. The irreducible modules of vertex operator
algebra L(1/2,0)_F are classified. The rationality of L(1/2,0)_F is established
if the characteristic of F is different from 7.


title: Flavor Violating Lepton Family U(1)$_\lambda$

abstract:
  The Standard Model is extended minimally with a new flavor-violating family
symmetry ${\rm U(1)}_\lambda$, which acts only on leptons including the
right-handed neutrinos. The model is anomaly free with family-dependent ${\rm
U(1)}_\lambda$ charges, and consistent with the observed neutrino mixing
angles. It predicts charged lepton flavor-violating processes mediated by a new
gauge boson. Under certain conditions, the smallness of $\theta_{13}$ of
neutrino mixing can be justified in terms of the muon-to-tau mass ratio, at the
same time explaining the electron-to-tau large mass hierarchy.


title: Status of theta13 measurement in reactor experiments

abstract:
  The status of theta13 measurements from Daya Bay, RENO and Double Chooz
experiments is reviewed.


title: Resistive Threshold Logic

abstract:
  We report a resistance based threshold logic family useful for mimicking
brain like large variable logic functions in VLSI. A universal Boolean logic
cell based on an analog resistive divider and threshold logic circuit is
presented. The resistive divider is implemented using memristors and provides
output voltage as a summation of weighted product of input voltages. The output
of resistive divider is converted into a binary value by a threshold operation
implemented by CMOS inverter and/or Opamp. An universal cell structure is
presented to decrease the overall implementation complexity and number of
components. When the number of input variables become very high, the proposed
cell offers advantages of smaller area and design simplicity in comparison with
CMOS based logic circuits.


title: Distortion of genealogical properties when the sample is very large

abstract:
  Study sample sizes in human genetics are growing rapidly, and in due course
it will become routine to analyze samples with hundreds of thousands if not
millions of individuals. In addition to posing computational challenges, such
large sample sizes call for carefully re-examining the theoretical foundation
underlying commonly-used analytical tools. Here, we study the accuracy of the
coalescent, a central model for studying the ancestry of a sample of
individuals. The coalescent arises as a limit of a large class of random mating
models and it is an accurate approximation to the original model provided that
the population size is sufficiently larger than the sample size. We develop a
method for performing exact computation in the discrete-time Wright-Fisher
(DTWF) model and compare several key genealogical quantities of interest with
the coalescent predictions. For realistic demographic scenarios, we find that
there are a significant number of multiple- and simultaneous-merger events
under the DTWF model, which are absent in the coalescent by construction.
Furthermore, for large sample sizes, there are noticeable differences in the
expected number of rare variants between the coalescent and the DTWF model. To
balance the tradeoff between accuracy and computational efficiency, we propose
a hybrid algorithm that utilizes the DTWF model for the recent past and the
coalescent for the more distant past. Our results demonstrate that the hybrid
method with only a handful of generations of the DTWF model leads to a
frequency spectrum that is quite close to the prediction of the full DTWF
model.


title: Subtle leakage of a Majorana mode into a quantum dot

abstract:
  We investigate quantum transport through a quantum dot connected to source
and drain leads and side-coupled to a topological superconducting nanowire
(Kitaev chain) sustaining Majorana end modes. Using a recursive Green's
function approach, we determine the local density of states (LDOS) of the
system and find that the end Majorana mode of the wire leaks into the dot thus
emerging as a unique dot level {\it pinned} to the Fermi energy $\varepsilon_F$
of the leads. Surprisingly, this resonance pinning, resembling in this sense a
"Kondo resonance", occurs even when the gate-controlled dot level
$\varepsilon_\text{dot}(V_g)$ is far above or far below $\varepsilon_F$. The
calculated conductance $G$ of the dot exhibits an unambiguous signature for the
Majorana end mode of the wire: in essence, an off-resonance dot
[$\varepsilon_\text{dot}(V_g)\neq \varepsilon_F$], which should have $G=0$,
shows instead a conductance $e^2/2h$ over a wide range of $V_g$, due to this
pinned dot mode. Interestingly, this pinning effect only occurs when the dot
level is coupled to a Majorana mode; ordinary fermionic modes (e.g., disorder)
in the wire simply split and broaden (if a continuum) the dot level. We discuss
experimental scenarios to probe Majorana modes in wires via these leaked/pinned
dot modes.


title: Quark confinement via magnetic color-flavor locking

abstract:
  The color-flavor locking phenomenon in the magnetic picture can be the
microscopic description of the quark confinement in QCD. We demonstrate it in
an N=2 supersymmetric SU(Nc)xSU(Nc) quiver gauge theory coupled to Nf flavors
of quarks (Nf<Nc). This model reduces to SU(Nc) gauge theory with Nf flavors
when the vacuum expectations value of the link field is much larger than the
dynamical scales, and thus provides a continuous deformation of the N=2
supersymmetric QCD. We study a vacuum which survives upon adding a
superpotential term to reduce to N=1 while preserving the vectorial SU(Nf)
flavor symmetry. We find a region of the parameter space where the confinement
is described by the Higgsing of a weakly coupled magnetic SU(Nf)xU(1) gauge
theory. The Higgsing locks the quantum numbers of SU(Nf) magnetic color to
those of SU(Nf) flavor symmetry, and thus the massive magnetic gauge bosons
become the singlet and adjoint representations of the flavor group, i.e, the
vector mesons. If the qualitative picture remains valid in non-supersymmetric
QCD, one can understand the Hidden Local Symmetry as the magnetic dual
description of QCD, and the confining string is identified as the vortex of
vector meson fields.


title: Improving Physical Layer Secrecy Using Full-Duplex Jamming Receivers

abstract:
  This paper studies secrecy rate optimization in a wireless network with a
single-antenna source, a multi-antenna destination and a multi-antenna
eavesdropper. This is an unfavorable scenario for secrecy performance as the
system is interference-limited. In the literature, assuming that the receiver
operates in half duplex (HD) mode, the aforementioned problem has been
addressed via use of cooperating nodes who act as jammers to confound the
eavesdropper. This paper investigates an alternative solution, which assumes
the availability of a full duplex (FD) receiver. In particular, while receiving
data, the receiver transmits jamming noise to degrade the eavesdropper channel.
The proposed self-protection scheme eliminates the need for external helpers
and provides system robustness. For the case in which global channel state
information is available, we aim to design the optimal jamming covariance
matrix that maximizes the secrecy rate and mitigates loop interference
associated with the FD operation. We consider both fixed and optimal linear
receiver design at the destination, and show that the optimal jamming
covariance matrix is rank-1, and can be found via an efficient 1-D search. For
the case in which only statistical information on the eavesdropper channel is
available, the optimal power allocation is studied in terms of ergodic and
outage secrecy rates. Simulation results verify the analysis and demonstrate
substantial performance gain over conventional HD operation at the destination.


title:
Monte-Carlo-based electromagnetic modeling of nanoscale structures:
  accounting for inhomogeneous broadening in polydisperse ensembles

abstract:
  Many experimental systems consist of large ensembles of uncoupled or weakly
interacting elements operating as a single whole; this is the case in many
experimental systems in nano-optics and plasmonics including colloidal
solutions, plasmonic nanoparticles, dielectric resonators, antenna arrays, and
others. In such experiments, measurements of the optical spectra of ensembles
will differ from measurements of the independent elements even if these
elements are designed to be identical as a result of small variations from
element to element, known as polydispersity. In particular, sharp spectral
features arising from narrow-band resonances will tend to appear broader and
can even be washed out completely. Here, we explore this effect of
inhomogeneous broadening as it occurs in colloidal nano-polymers comprising
self-assembled nanorod chains in solution. Using a technique combining
finite-difference time-domain (FDTD) simulations and Monte-Carlo sampling, we
predict the inhomogeneously-broadened optical spectra of these colloidal
nano-polymers, and observe significant qualitative differences compared to the
unbroadened spectra. The approach combining an electromagnetic simulation
technique with Monte-Carlo sampling is widely applicable for quantifying the
effects of inhomogeneous broadening in a variety of physical systems, including
those with many degrees of freedom which are otherwise computationally
intractable.


title: Vector Fields in Kerr/CFT Correspondence

abstract:
  In this paper, we use the appropriate boundary action for the vector fields
near the horizon of near extremal Kerr black hole to calculate the two-point
function for the vector fields in Kerr/CFT correspondence. We show the
gauge-independent part of the two-point function is in agreement with what is
expected from CFT.


title: On Hurwitz stable polynomials with integer coefficients

abstract:
  Let H(N) denote the set of all polynomials with positive integer coefficients
which have their zeros in the open left half-plane. We are looking for
polynomials in H(N) whose largest coefficients are as small as possible and
also for polynomials in H(N) with minimal sum of the coefficients. Let h(N) and
s(N) denote these minimal values. Using Fekete's subadditive lemma we show that
the N-th square roots of h(N) and s(N) have a limit as N goes to infinity and
that these two limits coincide. We also derive tight bounds for the common
value of the limits.


title:
Probing gluon dynamics by charm and bottom mesons in nuclear medium from
  heavy meson effective theory with 1/M-corrections

abstract:
  We consider heavy mesons with charm and bottom in nuclear medium. We
construct the effective Lagrangian with axial-vector coupling including
1/M-corrections for the heavy meson mass $M$ by following the
velocity-rearrangement invariance. As an application, we consider heavy mesons,
$\bar{\mathrm{D}}$ and $\bar{\mathrm{D}}^{\ast}$ mesons for charm and
$\mathrm{B}$ and $\mathrm{B}^{\ast}$ mesons for bottom, bound in nuclear
matter, and we discuss their in-medium masses modified by the interaction with
nucleons via pion exchanges including the 1/M-corrections. The mass
modifications are affected by the gluon dynamics in nuclear medium. By
comparison with the heavy quark effective theory, we find that the effects of
scale anomaly become suppressed in nuclear medium. We also find that the
contributions from the chromoelectric gluon are enhanced in nuclear medium,
while those from the chromomagnetic gluon are reduced. We propose to use heavy
mesons as probes to research the gluon fields in nuclear medium in experimental
studies.


title:
A new approach in position-based routing protocol using learning
  automata for vanets in city scenario

abstract:
  One of the main issues in Vehicular Ad-hoc NETworks (VANETs) is providing a
reliable and efficient routing in urban scenarios with regard to the high
vehicle mobility and presence of radio obstacle. In this paper, we propose a
Position-Based routing protocol using Learning Automata (PBLA). In addition,
PBLA uses the traffic information for enhancing learning. As we know, a main
characteristic of learning is increasing performance over time. We exploit this
characteristic to decreasing use of traffic information. Initially, PBLA make
effort to finding best and shortest path to mobile destination using traffic
information.


title: Current Algebras from DG Symplectic Pairs in Supergeometry

abstract:
  We propose a new unified formulation of the current algebra theory in terms
of supergeometry. We take a QP-structure, i.e. a differential graded symplectic
structure, on a graded cotangent bundle as a fundamental framework. A Poisson
bracket in a current algebra is constructed by the so called derived bracket of
the graded Poisson structure induced from the above symplectic structure. By
taking a canonical transformation on a QP-manifold, correct anomalous terms in
physical theories are derived. A large class of current algebras with and
without anomalous terms are constructed from this structure. Moreover, a new
class of current algebras related higher structures are obtained
systematically.


title:
From Cellular Characteristics to Disease Diagnosis: Uncovering
  Phenotypes with Supercells

abstract:
  Cell heterogeneity and the inherent complexity due to the interplay of
multiple molecular processes within the cell pose difficult challenges for
current single-cell biology. We introduce an approach that identifies a disease
phenotype from multiparameter single-cell measurements, which is based on the
concept of "supercell statistics", a single-cell-based averaging procedure
followed by a machine learning classification scheme. We are able to assess the
optimal tradeoff between the number of single cells averaged and the number of
measurements needed to capture phenotypic differences between healthy and
diseased patients, as well as between different diseases that are difficult to
diagnose otherwise. We apply our approach to two kinds of single-cell datasets,
addressing the diagnosis of a premature aging disorder using images of cell
nuclei, as well as the phenotypes of two non-infectious uveitides (the ocular
manifestations of Beh\c{c}et's disease and sarcoidosis) based on multicolor
flow cytometry. In the former case, one nuclear shape measurement taken over a
group of 30 cells is sufficient to classify samples as healthy or diseased, in
agreement with usual laboratory practice. In the latter, our method is able to
identify a minimal set of 5 markers that accurately predict Beh\c{c}et's
disease and sarcoidosis. This is the first time that a quantitative phenotypic
distinction between these two diseases has been achieved. To obtain this clear
phenotypic signature, about one hundred CD8+ T cells need to be measured.
Beyond these specific cases, the approach proposed here is applicable to
datasets generated by other kinds of state-of-the-art and forthcoming
single-cell technologies, such as multidimensional mass cytometry, single-cell
gene expression, and single-cell full genome sequencing techniques.


title:
Mutual Information-Based Planning for Informative Windowed Forecasting
  of Continuous-Time Linear Systems

abstract:
  This paper presents expression of mutual information that defines the
information gain in planning of sensing resources, when the goal is to reduce
the forecast uncertainty of some quantities of interest and the system dynamics
is described as a continuous-time linear system. The method extends the
smoother approach in [5] to handle more general notion of verification entity -
continuous sequence of variables over some finite time window in the future.
The expression of mutual information for this windowed forecasting case is
derived and quantified, taking advantage of underlying conditional independence
structure and utilizing the fixed-interval smoothing formula with correlated
noises. Two numerical examples on (a) simplified weather forecasting with
moving verification paths, and (b) sensor network scheduling for tracking of
multiple moving targets are considered for validation of the proposed approach.


title: Origin and properties of strong inter-nucleon interactions

abstract:
  I start with a historical review of the attempts to construct theories for
the origin of nuclear forces, for which I also summaries the most important
properties. The review then shifts to its main focus, which is the chiral
effective field theory approach to nuclear forces. I summarize the current
status of this approach and discuss the most important open issues: the proper
renormalization of the chiral two-nucleon potential and sub-leading
three-nucleon forces.


title:
A Fast Eigen Solution for Homogeneous Quadratic Minimization with at
  most Three Constraints

abstract:
  We propose an eigenvalue based technique to solve the Homogeneous Quadratic
Constrained Quadratic Programming problem (HQCQP) with at most 3 constraints
which arise in many signal processing problems. Semi-Definite Relaxation (SDR)
is the only known approach and is computationally intensive. We study the
performance of the proposed fast eigen approach through simulations in the
context of MIMO relays and show that the solution converges to the solution
obtained using the SDR approach with significant reduction in complexity.


title: On the Frobenius Manifolds for Cusp Singularities

abstract:
  We show that the Frobenius manifold associated to the pair of a cusp
singularity and it's canonical primitive form is isomorphic to the one
constructed from the Gromov--Witten theory for an orbifold projective line with
at most three orbifold points. We also calculate the intersection form of the
Frobenius manifold.


title: Extending the NOvA Physics Program

abstract:
  Following the precise measurement of $\theta_{13}$ by reactor experiments
three main questions remain within the now standard picture of neutrino
oscillations: (1) Is the value of $\theta_{23}$ such that the $\nu_3$ state
contains more muon flavor, more tau flavor, or equal amounts? (2) What is the
neutrino mass hierarchy? (3) Is CP violated in the neutrino sector? The NOvA
experiment will address all three of these questions. In each case the
measurements are statistics limited motivating exploration of what could be
accomplished with additional exposure.


title: Edge States in Silicene Nanodisks

abstract:
  Silicene is a honeycomb-structure silicon atoms, which shares many intriguing
properties with graphene. Silicene is expected to be a quantum spin-Hall
insulator due to its spin-orbit interactions. We investigate the electronic
properties of silicene nanodisks, which are silicene derivatives with closed
edge. In case of the simplest model of graphene nanodisks, the number of the
zero-energy modes is given by the lower bound of the Lieb theorem. They are
standing wave states.When the spin-orbit interaction is introduced and the
system becomes a topological insulator, they begin to propagate around a
nanodisk. Helical edge currents flow around the edge of a nanodisk though the
crystal momentum is ill-defined. We have newly found the counting rule of the
zero-energy states, and constructed the low-energy theory of zigzag triangular
silicene. We also show the validity of the bulk-edge correspondence in
nanodisks with rough edge by calculating the local probability amplitude and
current. Finally, the signatures of the topological phase transition in
silicene nanodisks under an external electric field are revealed.Our results
will be observable by means of STM experiments.


title: Genesis of spiral galaxies

abstract:
  Enigmatic spiral structure of many galaxies and its huge orbital momentum
originated due to the capture of lightweight bare black hole by gravity of
heavy primordial gas cloud at large impact parameter. The rotating of black
hole caused the formation of accretion disc from the cloud and the transfer of
orbital momentum to the disc, while during the fall to the center of mass, the
spiral trace of black hole in the disc did create the spiral front line of
sound waves in the gas, that further evolved into the stellar spiral arms. This
mechanism opens the way to study features of spiral galaxy formation, say, an
influence and a significance of dark matter in this process.


title:
Optimal Receiver Design for Diffusive Molecular Communication With Flow
  and Additive Noise

abstract:
  In this paper, we perform receiver design for a diffusive molecular
communication environment. Our model includes flow in any direction, sources of
information molecules in addition to the transmitter, and enzymes in the
propagation environment to mitigate intersymbol interference. We characterize
the mutual information between receiver observations to show how often
independent observations can be made. We derive the maximum likelihood sequence
detector to provide a lower bound on the bit error probability. We propose the
family of weighted sum detectors for more practical implementation and derive
their expected bit error probability. Under certain conditions, the performance
of the optimal weighted sum detector is shown to be equivalent to a matched
filter. Receiver simulation results show the tradeoff in detector complexity
versus achievable bit error probability, and that a slow flow in any direction
can improve the performance of a weighted sum detector.


title:
A mechanical switch for state transfer in dual cavity optomechanical
  systems

abstract:
  Dual cavity opto-electromechanical systems (OEMS) are those where two
electromagnetic cavities are connected by a common mechanical spring. These
systems have been shown to facilitate high fidelity quantum state transfer from
one cavity to another. In this paper, we explicitly calculate the effect on the
fidelity of state transfer, when an additional spring is attached to only one
of the cavities. Our quantitative estimates of loss of fidelity, highlight the
sensitivity of dual cavity OEMS when it couples to additional mechanical modes.
We show that this sensitivity can be used to design an effective mechanical
switch, for inhibition or high fidelity transmission of quantum states between
the cavities.


title: On a morphism of compactifications of moduli schemes of vector bundes

abstract:
  A morphism of nonreduced Gieseker - Maruyama functor (of semistable coherent
torsion-free sheaves) on a surface to the nonreduced functor of admissible
semistable pairs with the same Hilbert polynomial, is constructed. This leads
to the morphism of moduli schemes with possibly nonreduced scheme structures.
As usually, we consider subfunctors corresponding to main components of moduli
schemes.


title:
SN 2009ip and SN 2010mc: Core-collapse Type IIn supernovae arising from
  blue supergiants

abstract:
  The recent supernova (SN) known as SN 2009ip had dramatic precursor eruptions
followed by an even brighter explosion in 2012. Its pre-2012 observations make
it the best documented SN progenitor in history, but have fueled debate about
the nature of its 2012 explosion --- whether it was a true SN or some type of
violent non-terminal event. Both could power shock interaction with
circumstellar material (CSM), but only a core-collapse SN provides a
self-consistent explanation. The persistent broad emission lines in the
spectrum require a relatively large ejecta mass, and a corresponding kinetic
energy of at least 10^51 erg, while the faint 2012a event is consistent with
published models of core-collapse SNe from compact (~60 R_Sun) blue
supergiants. The light curves of SN 2009ip and another Type IIn, SN 2010mc,
were nearly identical; we demonstrate that their spectra match as well, and
that both are standard SNe IIn. Our observations contradict the recent claim
that the late-time spectrum of SN 2009ip is returning to its progenitor's
LBV-like state, and we show that late-time spectra of SN 2009ip closely
resemble spectra of SN 1987A. Moreover, SN 2009ip's changing H-alpha equivalent
width after explosion matches behavior typically seen in core-collapse SNe IIn.
Several key facts about SN 2009ip and SN 2010mc argue strongly in favor of a
core-collapse interpretation, and make a non-terminal 10^50 erg event
implausible. The most straighforward and self-consistent interpretation is that
SN 2009ip was an initially faint core-collapse explosion of a blue supergiant
that produced about half as much 56-Ni as SN 1987A, with most of the peak
luminosity from CSM interaction.


title:
The dual of the homotopy category of projective modules satisfies Brown
  representability

abstract:
  We show that the dual of the homotopy category of projective modules over an
arbitrary ring satisfies Brown representability.


title:
The low-mass stellar population in the young cluster Tr37: Disk
  evolution, accretion, and environment

abstract:
  We present a study of accretion and protoplanetary disks around M-type stars
in the 4 Myr-old cluster Tr37. With a well-studied solar-type population, Tr37
is a benchmark for disk evolution. We used low-resolution spectroscopy to
identify 141 members (78 new) and 64 probable members, mostly M-type stars.
H\alpha\ emission provides information about accretion. Optical, 2MASS,
Spitzer, and WISE data are used to trace the SEDs. We construct radiative
transfer models to explore the structures of full-disks, pre-transition,
transition, and dust-depleted disks. Including the new and previously known
members, we confirm that a substantial fraction (~2/5) of disks show signs of
evolution, either as radial dust evolution (transition/pre-transition disks) or
as a more global evolution (low small-dust masses, dust settling, and
weak/absent accretion signatures). Accretion is strongly dependent on the SED
type. About half of the transition objects are consistent with no accretion,
and dust-depleted disks have weak (or undetectable) accretion signatures,
especially among M-type stars. The analysis of accretion and disk structure
suggests a parallel evolution of dust and gas. We find several distinct classes
of evolved disks, based on SED type and accretion, pointing to different disk
dispersal mechanisms and probably different evolutionary paths. Dust depletion
and opening of inner holes appear to be independent processes: most transition
disks are not dust-depleted, and most dust-depleted disks do not require inner
holes. The differences in disk structure between M-type and solar-type stars in
Tr37 (4 Myr) are not as remarkable as in the young, sparse, Coronet cluster
(1-2 Myr), suggesting that other factors, like the environment/interactions,
are likely to play a role in the disk evolution and dispersal. Finally, we also
find some evidence of clumpy star formation or mini-clusters within Tr37.


title: Experimental investigation of dynamic pressure loads during dam break

abstract:
  The objectives of this work are to revisit the experimental measurements on
dam break flow over a dry horizontal bed and to provide a detailed insight into
the dynamics of the dam break wave impacting a vertical wall downstream the
dam, with emphasis on the pressure loads. The measured data are statistically
analyzed and critically discussed. As a result, an extensive set of data for
validation of computational tools is provided.


title:
Proceedings of the CAS - CERN Accelerator School: Course on High Power
  Hadron Machines, Bilbao, Spain, 24 May - 2 Jun 2011

abstract:
  These proceedings collate lectures given at the twenty-fifth specialized
course organised by the CERN Accelerator School (CAS). The course was held in
Bilbao, Spain from 24 May to 2 June 2011, in collaboration with ESS Bilbao. The
course covered the background accelerator physics, different types of particle
accelerators and the underlying accelerator systems and technologies, all from
the perspective of high beam power. The participants pursued one of six case
studies in order to get "hands-on" experience of the issues connected with high
power machines.


title: On the amplitudes in N=(1,1) D=6 SYM

abstract:
  We consider the on-shell amplitudes in N=(1,1) SYM in D=6 dimensions within
the spinor helicity and on-shell superspace formalism. This leads to an
effective and straightforward technique reducing the calculation to a set of
scalar master integrals. As an example, the simplest four point amplitude is
calculated in one and two loops in the planar limit. All answers are UV and IR
finite and expressed in terms of logs and Polylogs of transcendentality level 2
at one loop, and 4 and 3 at two loops. The all loop asymptotical limit at high
energy is obtained which exhibits the Regge type behaviour. The intercept is
calculated in the planar limit and is equal to alpha(t)=1+\sqrt{g_{YM}^2
N_c|t|/32pi^3}.


title: Time-Resolved Measurement of Interatomic Coulombic Decay in Ne_2

abstract:
  The lifetime of interatomic Coulombic decay (ICD) [L. S. Cederbaum et al.,
Phys. Rev. Lett. 79, 4778 (1997)] in Ne_2 is determined via an extreme
ultraviolet pump-probe experiment at the Free-Electron Laser in Hamburg. The
pump pulse creates a 2s inner-shell vacancy in one of the two Ne atoms,
whereupon the ionized dimer undergoes ICD resulting in a repulsive
Ne^{+}(2p^{-1}) - Ne^{+}(2p^{-1}) state, which is probed with a second pulse,
removing a further electron. The yield of coincident Ne^{+} - Ne^{2+} pairs is
recorded as a function of the pump-probe delay, allowing us to deduce the ICD
lifetime of the Ne_{2}^{+}(2s^{-1}) state to be (150 +/- 50) fs in agreement
with quantum calculations.


title: Linear Polarization Measurements for High-Spin States in 146Gd

abstract:
  A {\gamma}-ray linear polarization measurement has been performed to directly
determine the parities for the levels in 146Gd nucleus. High-spin states in
this nucleus were populated in a reaction 115In + 34S at 140 MeV incident
energy. Linearly polarized {\gamma} - rays emitted from oriented states were
measured using a Compton polarimeter consisting of an array of 8
Compton-suppressed Clover detectors. Unambiguous assignments of the spin and
parity have been made for most of the observed levels and changes made in the
previously reported spin-parity assignments for a few levels. Shell model
calculations performed with judicious truncation over the {\pi}(gdsh) valence
space interpret the structure of only the low-lying levels up to J{\pi} = 19+
and 9-. N = 82 neutron-core breaking is found to be essential for high spin
states with excitation energies Ex > 7 MeV.


title:
Joint Distributed Source-Channel Decoding for LDPC-Coded Binary Markov
  Sources

abstract:
  We propose a novel joint decoding technique for distributed source-channel
(DSC) coded systems for transmission of correlated binary Markov sources over
additive white Gaussian noise (AWGN) channels. In the proposed scheme,
relatively short-length, low-density parity-check (LDPC) codes are
independently used to encode the bit sequences of each source. To reconstruct
the original bit sequence, a joint source-channel decoding (JSCD) technique is
proposed which exploits the knowledge of both temporal and source correlations.
The JSCD technique is composed of two stages, which are iteratively performed.
First, a sum-product (SP) decoder is serially concatenated with a BCJR decoder,
where the knowledge of source memory is utilized during {\em local (horizontal)
iterations}. Then, the estimate of correlation between the sources is used to
update the concatenated decoder during {\em global (vertical) iterations}.
Therefore, the correlation of the sources is assumed as side information in the
subsequent global iteration of each concatenated decoder. From the simulation
results of frame/bit error rate (FER/BER), we note that significant gains are
achieved by the proposed decoding scheme with respect to the case where the
correlation knowledge is not completely utilized at the decoder.


title:
Intertwining operators for l-conformal Galilei algebras and hierarchy of
  invariant equations

abstract:
  l-Conformal Galilei algebra, denoted by g{l}{d}, is a non-semisimple Lie
algebra specified by a pair of parameters (d,l). The algebra is regarded as a
nonrelativistic analogue of the conformal algebra. We derive hierarchies of
partial differential equations which have invariance of the group generated by
g{l}{d} with central extension as kinematical symmetry. This is done by
developing a representation theory such as Verma modules, singular vectors of
g{l}{d} and vector field representations for d = 1, 2.


title:
A Computational Procedure for solving a Non-Convex Multi-Objective
  Quadratic Programming under Fuzzy Environment

abstract:
  The purpose of this paper is to study a non-convex fuzzy multi-objective
quadratic programming problem, in which both the technological coefficients and
resources are fuzzy with nonlinear membership function. A computational
procedure to find a fuzzy efficient solution of this problem is developed. A
numerical example is given to illustrate the procedure.


title:
Probing of electromagnetic fields on atomic scale by photoelectric
  phenomena in graphene

abstract:
  We report on the observation of the reststrahl band assisted photocurrents in
epitaxial graphene on SiC excited by infrared radiation. The peculiar spectral
dependence for frequencies lying within the reststrahl band of the SiC
substrate provides a direct and noninvasive way to probe the electric field
magnitude at atomic distances from the material's surface. Furthermore our
results reveal that nonlinear optical and optoelectronic phenomena in 2D
crystals and other atomic scale structures can be giantly enhanced by a proper
combination of the spectral range and substrate material.


title:
The Standard Model in a Weak Gravitational Background. Dilatons, Scale
  Anomalies and Conformal Methods

abstract:
  The principal goal of the physics of the fundamental interactions is to
provide a consistent description of the nature of the subnuclear forces, which
manifest in our universe, together with the gravitational force, in a unified
framework. This attempt, which is far from being complete, is characterized by
two milestones, the Standard Model of the elementary particles and the
Einstein's theory of General Relativity. The coupling of a quantum field
theory, such as the Standard Model, to a weak gravitational background provides
significant information concerning the coupling of matter to gravity and allows
to study in a systematic way the origin of the conformal anomaly. For this
reason, the computation of correlation functions in a weak gravitational
background is of remarkable interest and the consequences of this analysis are
also of phenomenological relevance. For instance, they concern the appearance
in the spectrum of the theory of a composite state, the dilaton, which is
identified, in perturbation theory, by an infrared coupled anomaly pole. The
study of some applications of the methods discussed so far is presented in the
second part of this thesis. In particular it is shown that the analysis of the
classical metric perturbations in gravity can be related to some specific field
theories via a holographic mapping. This requires the computation of
correlators of energy-momentum tensors in $d=3$ dimensions and plays a role in
the study of the non-gaussianities of the cosmic background radiation in the
early universe. Finally, we mention an application in momentum space of the
constraints derived from the conformal symmetry in the characterization of some
correlation functions. This relies on the solution of a system of second order
partial differential equations for a certain class of generalized
hypergeometric functions of two variables.


title: Recent RHIC in-situ coating technology developments

abstract:
  To rectify the problems of electron clouds observed in RHIC and unacceptable
ohmic heating for superconducting magnets that can limit future machine
upgrades, we started developing a robotic plasma deposition technique for
$in-situ$ coating of the RHIC 316LN stainless steel cold bore tubes based on
staged magnetrons mounted on a mobile mole for deposition of Cu followed by
amorphous carbon (a-C) coating. The Cu coating reduces wall resistivity, while
a-C has low SEY that suppresses electron cloud formation. Recent RF resistivity
computations indicate that 10 {\mu}m of Cu coating thickness is needed. But, Cu
coatings thicker than 2 {\mu}m can have grain structures that might have lower
SEY like gold black. A 15-cm Cu cathode magnetron was designed and fabricated,
after which, 30 cm long samples of RHIC cold bore tubes were coated with
various OFHC copper thicknesses; room temperature RF resistivity measured.
Rectangular stainless steel and SS discs were Cu coated. SEY of rectangular
samples were measured at room; and, SEY of a disc sample was measured at
cryogenic temperatures.


title: Installation for SEE observation in the presence of magnetic field

abstract:
  The installation provides direct measurements of secondary emission yield and
secondary electron velocity/energy distribution in the presence of magnetic
field. The measurement system is designed to be installed into superconducting
solenoid with maximum field of 10T. At present time the installation under
commissioning at room temperature. The structure and performance capabilities
of the setup are described, first experimental results are presented.


title:
Resurgence in QFT: Unitons, Fractons and Renormalons in the Principal
  Chiral Model

abstract:
  We explain the physical role of non-perturbative saddle points of path
integrals in theories without instantons, using the example of the
asymptotically free two-dimensional principal chiral model (PCM). Standard
topological arguments based on homotopy considerations suggest no role for
non-perturbative saddles in such theories. However, resurgence theory, which
unifies perturbative and non-perturbative physics, predicts the existence of
several types of non-perturbative saddles associated with features of the
large-order structure of perturbation theory. These points are illustrated in
the PCM, where we find new non-perturbative `fracton' saddle point field
configurations, and give a quantum interpretation of previously discovered
`uniton' unstable classical solutions. The fractons lead to a semi-classical
realization of IR renormalons in the circle-compactified theory, and yield the
microscopic mechanism of the mass gap of the PCM.


title:
Resonant X-ray scattering and the $j_{\mathrm{eff}}=1/2$ electronic
  ground state in iridate perovskites

abstract:
  The resonant X-ray scattering (magnetic elastic, RXMS, and inelastic, RIXS)
of Ir$^{4+}$ at the L$_{2,3}$ edges relevant to spin-orbit Mott insulators
A$_{n+1}$Ir$_{n}$O$_{3n+1}$ (A=Sr, Ba, etc.) are calculated using a single-ion
model which treats the spin-orbit and tetragonal crystal-field terms on an
equal footing. Both RXMS and RIXS in the spin-flip channel are found to display
a non-trivial dependence on the direction of the magnetic moment,
$\boldsymbol\mu$. Crucially, we show that for $\boldsymbol\mu$ in the
\emph{ab}-plane, RXMS at the L$_2$ edge is zero \emph{irrespective} of the
tetragonal crystal-field; spin-flip RIXS, relevant to measurements of magnons,
behaves reciprocally being zero at L$_2$ when $\boldsymbol\mu$ is perpendicular
to the \emph{ab}-plane. Our results provide important insights into the
interpretation of X-ray data from the iridates, including that a
$j_{\mathrm{eff}}=1/2$ ground state cannot be assigned on the basis of
L$_2$/L$_3$ intensity ratio alone.


title:
Cooperative Enhancement of Energy Transfer in a High-Density Thermal
  Vapor

abstract:
  We present an experimental study of energy transfer in a thermal vapor of
atomic rubidium. We measure the fluorescence spectrum in the visible and near
infra-red as a function of atomic density using confocal microscopy. At low
density we observe energy transfer consistent with the well-known energy
pooling process. In contrast, above a critical density we observe a dramatic
enhancement of the fluorescence from high-lying states that is not to be
expected from kinetic theory. We show that the density threshold for excitation
on the D1 and D2 resonance line corresponds to the value at which the
dipole-dipole interactions begins to dominate, thereby indicate the key role of
these interactions in the enhanced emission.


title:
Comment on 'Interpretation of the Lempel-Ziv Complexity Measure in the
  context of Biomedical Signal Analysis'

abstract:
  In this Communication, we express our reservations on some aspects of the
interpretation of the Lempel-Ziv Complexity measure (LZ) by Mateo et al. in
"Interpretation of the Lempel-Ziv complexity measure in the context of
biomedical signal analysis," IEEE Trans. Biomed. Eng., vol. 53, no. 11, pp.
2282-2288, Nov. 2006. In particular, we comment on the dependence of the LZ
complexity measure on number of harmonics, frequency content and amplitude
modulation. We disagree with the following statements made by Mateo et al.
  1. "LZ is not sensitive to the number of harmonics in periodic signals."
  2. "LZ increases as the frequency of a sinusoid increases."
  3. "Amplitude modulation of a signal doesnot result in an increase in LZ."
  We show the dependence of LZ complexity measure on harmonics and amplitude
modulation by using a modified version of the synthetic signal that has been
used in the original paper. Also, the second statement is a generic statement
which is not entirely true. This is true only in the low frequency regime and
definitely not true in moderate and high frequency regimes.


title: Violation of Bell inequality in perfect translation invariant systems

abstract:
  Bell inequalities and nonlocality have been widely studied in one-dimensional
quantum systems. As a kind of quantum correlation, it is expected that
bipartite nonlocaity should be present in quantum systems, just as bipartite
entanglement does. Surprisingly, for various models, two-qubit states do not
violate Bell inequalities, i.e., they are local. Recently, it is realized that
the results are related to the monogamy trade-off obeyed by bipartite Bell
correlations, thus it is believed that for general translation invariant
systems, two-qubit states should not violate the Bell inequality(Oliveira, EPL
100, 60004 (2012)). In this report, we will demonstrate that in perfect
translation invariant systems, the Bell inequality can be violated. A
nontrivial model is constructed to confirm the conclusion.


title:
Jacob's ladders and some generalizations of certain Ramachandra's
  inequality

abstract:
  In this paper we obtain some essential generalizations of certain
Ramachandra's inequality, i. e. we obtain new lower estimates for the energies
of some complicated signals generated by the Riemann zeta-function on the
critical line.


title: The cosmic-ray positron energy spectrum measured by PAMELA

abstract:
  Precision measurements of the positron component in the cosmic radiation
provide important information about the propagation of cosmic rays and the
nature of particle sources in our Galaxy. The satellite-borne experiment PAMELA
has been used to make a new measurement of the cosmic-ray positron flux and
fraction that extends previously published measurements up to 300 GeV in
kinetic energy. The combined measurements of the cosmic-ray positron energy
spectrum and fraction provide a unique tool to constrain interpretation models.
During the recent solar minimum activity period from July 2006 to December 2009
approximately 24500 positrons were observed. The results cannot be easily
reconciled with purely secondary production and additional sources of either
astrophysical or exotic origin may be required.


title:
The Red MSX Source Survey: the Massive Young Stellar Population of our
  Galaxy

abstract:
  We present the Red MSX Source (RMS) Survey, the largest statistically
selected catalog of young massive protostars and HII regions to date. We
outline the construction of the catalog using mid and near infrared color
selection, as well as the detailed follow up work at other wavelengths, and at
higher spatial resolution in the infrared. We show that within the adopted
selection bounds we are more than 90% complete for the massive protostellar
population, with a positional accuracy of the exciting source of better than 2
arcseconds. We briefly summarize some of the results that can be obtained from
studying the properties of the objects in the catalog as a whole, and find
evidence that the most massive stars form: (i) preferentially nearer the
Galactic centre than the anti-centre; (ii) in the most heavily reddened
environments, suggestive of high accretion rates; and (iii) from the most
massive cloud cores.


title: Homotopy finiteness of some DG categories from algebraic geometry

abstract:
  In this paper, we prove that the bounded derived category $D^b_{coh}(Y)$ of
coherent sheaves on a separated scheme $Y$ of finite type over a field
$\mathrm{k}$ of characteristic zero is homotopically finitely presented. This
confirms a conjecture of Kontsevich. We actually prove a stronger statement:
$D^b_{coh}(Y)$ is equivalent to a DG quotient $D^b_{coh}(\tilde{Y})/T,$ where
$\tilde{Y}$ is some smooth and proper variety, and the subcategory $T$ is
generated by a single object.
  The proof uses categorical resolution of singularities of Kuznetsov and Lunts
\cite{KL}, and a theorem of Orlov \cite{Or} stating that the class of geometric
smooth and proper DG categories is stable under gluing.
  We also prove the analogous result for $\mathbb{Z}/2$-graded DG categories of
coherent matrix factorizations on such schemes. In this case instead of
$D^b_{coh}(\tilde{Y})$ we have a semi-orthogonal gluing of a finite number of
DG categories of matrix factorizations on smooth varieties, proper over
$\mathbb{A}_{\mathrm{k}}^1$.


title: X- problem of value three

abstract:
  The X-problem of number 3 for one dimension and related observations are
discussed


title:
Galactic and Cosmic Type Ia SN rates: is it possible to impose
  constraints on SNIa progenitors?

abstract:
  We compute the Type Ia supernova rates in typical elliptical galaxies by
varying the progenitor models for Type Ia supernovae. To do that a formalism
which takes into account the delay distribution function (DTD) of the explosion
times and a given star formation history is adopted. Then the chemical
evolution for ellipticals with baryonic initial masses $10^{10}$, $10^{11}$ and
$10^{12} M_{\odot}$ is computed, and the mass of Fe produced by each galaxy is
precisely estimated. We also compute the expected Fe mass ejected by
ellipticals in typical galaxy clusters (e.g. Coma and Virgo), under different
assumptions about Type Ia SN progenitors. As a last step, we compute the cosmic
Type Ia SN rate in an unitary volume of the Universe by adopting several cosmic
star formation rates and compare it with the available and recent observational
data. Unfortunately, no firm conclusions can be derived only from the cosmic
SNIa rate, neither on SNIa progenitors nor on the cosmic star formation rate.
Finally, by analysing all our results together, and by taking into account
previous chemical evolution results, we try to constrain the best Type Ia
progenitor model. We conclude that the best progenitor models for Type Ia SNe
are still the single degenerate model, the double degenerate wide model, and
the empirical bimodal model. All these models require the existence of prompt
Type Ia supernovae, exploding in the first 100 Myr since the beginning of star
formation, although their fraction should not exceed 15-20% in order to fit
chemical abundances in galaxies.


title:
Electron-electron interaction effects on transport through mesoscopic
  superconducting hybrid junctions

abstract:
  Effects due to the proximity of a superconductor has motivated a lot of
research work in the last several decades both from theoretical and
experimental point of view. In this review we are going to describe the physics
of systems containing normal metal-superconductor interface. Mainly we discuss
transport properties through such hybrid structures. In particular, we describe
the effects of electron electron interaction on transport through such
superconducting junction of multiple one-dimensional quantum wires. The latter
can be described in terms of a non-Fermi liquid theory called Luttinger liquid.
In this review, from the application point of view, we also demonstrate the
possible scenarios for production of pure spin current and large tunnelling
magnetoresistance in such hybrid junctions and analyze the influence of
electron-electron interaction on the stability of the production of pure spin
current.


title: Conductance across strain junctions in graphene nanoribbons

abstract:
  To address the robustness of the transport gap induced by locally strained
regions in graphene nanostructures, the effect of disorder and smoothness of
the interface region is investigated within the Landauer-B\"uttiker formalism.
The electronic conductance across strained junctions and barriers in graphene
nanoribbons is calculated numerically, with and without various types of
disorder, and comparing smooth and sharp strain junctions. A smooth strain
barrier in graphene is seen to be generically as efficient in suppressing
transport at low densities as a sharp one, and the critical density (or energy)
for the onset of transmission depends on the strain orientation with respect to
the ribbon. In addition, hopping (or strain) inhomogeneity and work function
mismatch at the interface region do not visibly degrade the transport gap.
These results show that the strain-induced transport gap at a strain junction
is robust to more realistic strain conditions.


title:
The Impact of Orography and Latent Heating on the Location of the
  Tropical Easterly Jet

abstract:
  The Tropical Easterly Jet (TEJ) is a prominent atmospheric circulation
feature observed during the Asian Summer Monsoon. It is generally assumed that
Tibet is an essential ingredient in determining the location of the TEJ.
However studies have also suggested the importance of latent heating in
determining the jet location. The relative importance of Tibetan orography and
latent heating is explored through simulations with a general circulation
model.
  The simulation of TEJ by the Community Atmosphere Model, version 3.1
(CAM-3.1) has been discussed in detail. Although the simulated TEJ replicated
many observed features of the jet, the jet maximum was located too far to the
west when compared to observation. The precipitation in the control simulation
was high to the west of India and this caused the TEJ to shift westwards by
approximately the same amount. Orography was found to have minimal impact on
the simulated TEJ hence indicating that latent heating is the crucial
parameter. The primacy of latent heating in determining the jet location was
confirmed by additional simulations where the simulated precipitation was
brought closer to observations. This made the TEJ to also shift to the correct
position.


title:
Physics performance of the upgraded MAGIC telescopes obtained with Crab
  Nebula data

abstract:
  MAGIC is a system of two Imaging Atmospheric Cherenkov Telescopes located at
the Canary Island of La Palma, designed to observe gamma rays with energies
above 50 GeV. Recently it has undergone an upgrade of the camera, digital
trigger and readout systems. The upgrade has led to an improvement in the
performance of the telescopes, especially in the lower energy range. We
evaluate the performance of the upgraded MAGIC telescopes using Monte Carlo
simulations and a large sample of Crab Nebula data. We study differential and
integral sensitivity of the system, its angular resolution as well as its
energy resolution.


title:
The phase lags of high-frequency quasi-periodic oscillations in four
  black-hole candidates

abstract:
  We measured the phase-lag spectrum of the high-frequency quasi-periodic
oscillations (QPO) in the black hole systems (at QPO frequencies) GRS 1915+105
(35 Hz and 67 Hz), GRO J1655-40 (300 Hz and 450 Hz), XTE J1550-564 (180 Hz and
280 Hz), and IGR J17091-3624 (67 Hz). The lag spectra of the 67-Hz QPO in,
respectively, GRS 1915+105 and IGR J17091-3624, and the 450-Hz QPO in GRO
J1655-40 are hard (hard photons lag the soft ones) and consistent with each
other, with the hard lags increasing with energy. On the contrary, the lags of
the 35-Hz QPO in GRS 1915+105 are soft, with the lags becoming softer as the
energy increases; the lag spectrum of the 35-Hz QPO is inconsistent with that
of the 67-Hz QPO. The lags of the 300-Hz QPO in GRO J1655-40, and the 180-Hz
and the 280-Hz QPO in XTE J1550-564 are independent of energy, consistent with
each other and with being zero or slightly positive (hard lags). For GRO
J1655-40 the lag spectrum of the 300-Hz QPO differs significantly from that of
the 450-Hz QPOs. The similarity of the lag spectra of the 180-Hz and 280-Hz QPO
in XTE J1550-564 suggests that these two are the same QPO seen at a different
frequency in different observations. The lag spectrum of the 67-Hz QPO in GRS
1915+105 is significantly different from that of the $2.7 \times 10^{-4}$ Hz
QPO in the narrow-line Seyfert 1 galaxy RE J1034+396, which disproves the
suggestion that the two QPOs are the same physical phenomenon with their
frequencies scaled only by the black-hole mass. The lag spectrum of the QPO in
RE J1034+396 is similar to that of the 35-Hz QPO in GRS 1915+105, although
identifying these two QPOs as being the same physical feature remains
problematic. We compare our results with those for the lags of the kilohertz
QPOs in neutron-star systems and the broadband noise component in active
galactic nuclei, and discuss possible scenarios for producing the lags in these
systems.


title: Near-optimal phase retrieval of sparse vectors

abstract:
  In many areas of imaging science, it is difficult to measure the phase of
linear measurements. As such, one often wishes to reconstruct a signal from
intensity measurements, that is, perform phase retrieval. In several
applications the signal in question is believed to be sparse. In this paper, we
use ideas from the recently developed polarization method for phase retrieval
and provide an algorithm that is guaranteed to recover a sparse signal from a
number of phaseless linear measurements that scales linearly with the sparsity
of the signal (up to logarithmic factors). This is particularly remarkable
since it is known that a certain popular class of convex methods is not able to
perform recovery unless the number of measurements scales with the square of
the sparsity of the signal. This is a shorter version of a more complete
publication that will appear elsewhere.


title: Phase transitions in 3D loop models and the $CP^{n-1}$ $\sigma$ model

abstract:
  We consider the statistical mechanics of a class of models involving
close-packed loops with fugacity $n$ on three-dimensional lattices. The models
exhibit phases of two types as a coupling constant is varied: in one, all loops
are finite, and in the other, some loops are infinitely extended. We show that
the loop models are discretisations of $CP^{n-1}$ $\sigma$ models. The finite
and infinite loop phases represent, respectively, disordered and ordered phases
of the $\sigma$ model, and we discuss the relationship between loop properties
and $\sigma$ model correlators. On large scales, loops are Brownian in an
ordered phase and have a non-trivial fractal dimension at a critical point. We
simulate the models, finding continuous transitions between the two phases for
$n=1,2,3$ and first order transitions for $n\geq 4$. We also give a
renormalisation group treatment of the $CP^{n-1}$ model that shows how a
continuous transition can survive for values of $n$ larger than (but close to)
two, despite the presence of a cubic invariant in the Landau-Ginzburg
description. The results we obtain are of broader relevance to a variety of
problems, including SU(n) quantum magnets in (2+1) dimensions, Anderson
localisation in symmetry class C, and the statistics of random curves in three
dimensions.


title: Dislocations in magnetohydrodynamic waves in a stellar atmosphere

abstract:
  We describe the presence of wavefront dislocations in magnetohydrodynamic
waves in stratified stellar atmospheres. Scalar dislocations such as edges and
vortices can appear in Alfv\'en waves, as well as in general magneto-acoustic
waves. We detect those dislocations in observations of magnetohydrodynamic
waves in sunspots in the solar chromosphere. Through the measured charge of all
the dislocations observed, we can give for the first time estimates of the
modal contribution in the waves propagating along magnetic fields in solar
sunspots.


title: Cubic diophantine inequalities for split forms

abstract:
  Denote by $s_0^{(r)}$ the least integer such that if $s \ge s_0^{(r)}$, and
$F$ is a cubic form with real coefficients in $s$ variables that splits into
$r$ parts, then $F$ takes arbitrarily small values at nonzero integral points.
We bound $s_0^{(r)}$ for $r \le 6$.


title: Anisotropic Quintessence stars

abstract:
  We propose a relativistic model for quintessence stars with the combination
of an anisotropic pressure corresponding to normal matter and a quintessence
dark energy having a characteristic parameter {\omega}q such that -1 <{\omega}q
< - 1/3. We discuss various physical features of the model and show that the
model satisfies all the regularity conditions and can provide stable
equilibrium configurations.


title: Balancing indivisible real-valued loads in arbitrary networks

abstract:
  In parallel computing, a problem is divided into a set of smaller tasks that
are distributed across multiple processing elements. Balancing the load of the
processing elements is key to achieving good performance and scalability. If
the computational costs of the individual tasks vary over time in an
unpredictable way, dynamic load balancing aims at migrating them between
processing elements so as to maintain load balance. During dynamic load
balancing, the tasks amount to indivisible work packets with a real-valued
cost. For this case of indivisible, real- valued loads, we analyze the
balancing circuit model, a local dynamic load-balancing scheme that does not
require global communication. We extend previous analyses to the present case
and provide a probabilistic bound for the achievable load balance. Based on an
analogy with the offline balls-into-bins problem, we further propose a novel
algorithm for dynamic balancing of indivisible, real-valued loads. We benchmark
the proposed algorithm in numerical experiments and compare it with the
classical greedy algorithm, both in terms of solution quality and communication
cost. We find that the increased communication cost of the proposed algorithm
is compensated by a higher solution quality, leading on average to about an
order of magnitude gain in overall performance.


title: F-injectivity and Buchsbaum singularities

abstract:
  Let (R,m) be a local ring that contains a field. We show that, when R has
equal characteristic p>0 and when H_m^i(R) has finite length for all i<dimR,
then R is F-injective if and only if every ideal generated by a system of
parameters is Frobenius closed. As a corollary, we show that such an R is in
fact a Buchsbaum ring. This answers positively a question of S. Takagi that
F-injective singularities with isolated non-Cohen-Macaulay locus are Buchsbaum.
We also study the characteristic 0 analogue of this question and we show that
Du Bois singularities with isolated non-Cohen-Macaulay locus are Buchsbaum in
the graded case.


title:
Flight demonstration of formation flying capabilities for future
  missions (NEAT Pathfinder)

abstract:
  PRISMA is a demonstration mission for formation-flying and on-orbit-servicing
critical technologies that involves two spacecraft launched in low Earth orbit
in June 2010 and still in operation. Funded by the Swedish National Space
Board, PRISMA mission has been developed by OHB Sweden with important
contributions from the German Aerospace Centre (DLR/GSOC), the French Space
Agency (CNES), and the Technical University of Denmark (DTU). The paper focuses
on the last CNES experiment achieved in September 2012 that was devoted to the
preparation of future astrometry missions illustrated by the NEAT and microNEAT
mission concepts. The experiment consisted in performing the type of formation
maneuvers required to point the two-satellite axis to a celestial target and
maintain it fixed during the observation period. Achieving inertial pointing
for a LEO formation represented a new challenge given the numerous constraints
from propellant usage to star tracker blinding. The paper presents the
experiment objectives in relation with the NEAT/microNEAT mission concept,
describes its main design features along with the guidance and control
algorithms evolutions and discusses the results in terms of performances
achieved during the two rehearsals


title:
Kondo hybridisation and the origin of metallic states at the (001)
  surface of SmB6

abstract:
  SmB6, a well-known Kondo insulator, has been proposed to be an ideal
topological insulator with states of topological character located in a clean,
bulk electronic gap, namely the Kondo hybridisation gap. Seeing as the Kondo
gap arises from many body electronic correlations, this would place SmB6 at the
head of a new material class: topological Kondo insulators. Here, for the first
time, we show that the k-space characteristics of the Kondo hybridisation
process is the key to unravelling the origin of the two types of metallic
states observed directly by ARPES in the electronic band structure of
SmB6(001). One group of these states is essentially of bulk origin, and cuts
the Fermi level due to the position of the chemical potential 20 meV above the
lowest lying 5d-4f hybridisation zone. The other metallic state is more
enigmatic, being weak in intensity, but represents a good candidate for a
topological surface state. However, before this claim can be substantiated by
an unequivocal measurement of its massless dispersion relation, our data raises
the bar in terms of the ARPES resolution required, as we show there to be a
strong renormalisation of the hybridisation gaps by a factor 2-3 compared to
theory, following from the knowledge of the true position of the chemical
potential and a careful comparison with the predictions from recent
LDA+Gutzwiler calculations. All in all, these key pieces of evidence act as
triangulation markers, providing a detailed description of the electronic
landscape in SmB6, pointing the way for future, ultrahigh resolution ARPES
experiments to achieve a direct measurement of the Dirac cones in the first
topological Kondo insulator.


title:
Rashba-induced spin electromagnetic fields in a strong sd coupling
  regime

abstract:
  Spin electromagnetic fields driven by the Rashba spin-orbit interaction, or
Rashba-induced spin Berry's phase, in ferromagnetic metals is theoretically
studied based on the Keldysh Green's function method. Considering a limit of
strong sd coupling without spin relaxation (adiabatic limit), the spin electric
and magnetic fields are determined by calculating transport properties. The
spin electromagnetic fields turn out to be expressed in terms of a
Rashba-induced effective vector potential, and thus they satisfy the Maxwell's
equation. In contrast to the conventional spin Berry's phase, the
Rashba-induced one is linear in the gradient of magnetization profile, and thus
can be extremely large even for slowly varying structures. We show that the
Rashba-induced spin Berry's phase exerts the Lorentz force on spin resulting in
a giant spin Hall effect in magnetic thin films in the presence of
magnetization structures. Rashba-induced spin magnetic field would be useful to
distinguish between topologically equivalent magnetic structures.


title: New solvable sigma models in plane--parallel wave background

abstract:
  We explicitly solve the classical equations of motion for strings in
backgrounds obtained as non-abelian T-duals of a homogeneous isotropic
plane-parallel wave. To construct the dual backgrounds, semi-abelian Drinfeld
doubles are used which contain the isometry group of the homogeneous plane wave
metric. The dual solutions are then found by the Poisson-Lie transformation of
the explicit solution of the original homogeneous plane wave background.
Investigating their Killing vectors, we have found that the dual backgrounds
can be transformed to the form of more general plane-parallel waves.


title: Very good and very bad field generators

abstract:
  Let k be a field. A "field generator" is a polynomial F in k[X,Y] satisfying
k(F,G) = k(X,Y) for some G in k(X,Y). If G can be chosen in k[X,Y], we call F a
"good field generator"; otherwise, F is a "bad field generator". These notions
were first studied by Abhyankar, Jan and Russell in the 1970s. The present
paper introduces and studies the notions of "very good" and "very bad" field
generators. We give theoretical results as well as new examples of bad and very
bad field generators.


title:
Approximate Analytical Solutions to Relativistic and Nonrelativistic
  P\"{o}schl-Teller Potential with its Thermodynamic Properties

abstract:
  We apply the asymptotic iteration method (AIM) to obtain the solutions of
Schrodinger equation in the presence of Poschl-Teller (PT) potential. We also
obtain the solutions of Dirac equation for the same potential under the
condition of spin and pseudospin (p-spin) symmetries. We show that in the
nonrelativistic limits, the solution of Dirac system converges to that of
Schrodinger system. Rotational-Vibrational energy eigenvalues of some diatomic
molecules are calculated. Some special cases of interest are studied such as
s-wave case, reflectionless-type potential and symmetric hyperbolic PT
potential. Furthermore, we present a high temperature partition function in
order to study the behavior of the thermodynamic functions such as the
vibrational mean energy U, specific heat C, free energy F and entropy S.


title: Positional strategies in long Ehrenfeucht-Fraiss\'e games

abstract:
  We prove that it is relatively consistent with ZF + CH that there exist two
models of cardinality \aleph_2 such that the second player has a winning
strategy in the Ehrenfeucht-Fra\"iss\'e-game of length \omega_1 but there is no
\sigma-closed back-and-forth set for the two models. If CH fails, no such pairs
of models exist.


title: Continuity in time of solutions of a phase-field model

abstract:
  A phase field model proposed by G. Caginalp for the description of phase
changes in materials is under consideration. It is assumed that the medium is
located in a container with heat conductive walls that are not subjected to
phase changes. Therefore, the temperature variable is defined both in the
medium and wall regions, whereas the phase variable is only considered in the
medium part. The case of Lipschitz domains in two and three dimensions is
studied. We show that the temperature and phase variables are continuous in
time functions with values in $L^2$ and $H^1$, respectively, provided that the
initial values of them are from $L^2$ and $H^1$, respectively. Moreover,
continuous dependence of solutions on the initial data and boundary conditions
is proved.


title: First-Class Functions for First-Order Database Engines

abstract:
  We describe Query Defunctionalization which enables off-the-shelf first-order
database engines to process queries over first-class functions. Support for
first-class functions is characterized by the ability to treat functions like
regular data items that can be constructed at query runtime, passed to or
returned from other (higher-order) functions, assigned to variables, and stored
in persistent data structures. Query defunctionalization is a non-invasive
approach that transforms such function-centric queries into the data-centric
operations implemented by common query processors. Experiments with XQuery and
PL/SQL database systems demonstrate that first-order database engines can
faithfully and efficiently support the expressive "functions as data" paradigm.


title: Weak mixing properties for nonsingular actions

abstract:
  For a general group G we consider various weak mixing properties of
nonsingular actions. In the case where the action is actually measure
preserving all these properties coincide, and our purpose here is to check
which implications persist in the nonsingular case.


title:
Bright light emission and waveguiding in conjugated polymer nanofibers
  electrospun from organic-salt added solutions

abstract:
  Light emitting electrospun nanofibers of
poly-[(9,9-dioctylfluorenyl-2,7-diyl)-co-(N,N'-diphenyl)-N,N'-di(p-butyl-oxy-phenyl)-1,4-diaminobenzene)]
(PFO-PBAB) are produced by electrospinning under different experimental
conditions. In particular, uniform fibers with average diameter of 180 nm are
obtained by adding an organic salt to the electrospinning solution. The
spectroscopic investigation assesses that the presence of the organic salt does
not alter the optical properties of the active material, therefore providing an
alternative approach for the fabrication of highly emissive conjugated polymer
nanofibers. The produced nanofibers display self-waveguiding of light, and
polarized photoluminescence, which is especially promising for embedding active
electrospun fibers in sensing and nanophotonic devices.


title: Diffuse TeV Gamma-Ray Emission in the H.E.S.S. Galactic Plane Survey

abstract:
  Diffuse gamma-ray emission has long been established as the most prominent
feature in the GeV sky. Although the imaging atmospheric Cherenkov technique
has been successful in revealing a large population of discrete TeV gamma-ray
sources, a thorough investigation of diffuse emission at TeV energies is still
pending. Data from the Galactic Plane Survey (GPS) obtained by the High Energy
Stereoscopic System (H.E.S.S.) have now achieved a sensitivity and coverage
adequate for probing signatures of diffuse emission in the energy range of ~100
GeV to a few TeV. Gamma-rays are produced in cosmic-ray interactions with the
interstellar medium (aka "sea of cosmic rays") and in inverse Compton
scattering on cosmic photon fields. This inevitably leads to guaranteed
gamma-ray emission related to the gas content along the line-of-sight. Further
contributions relate to those gamma-ray sources that fall below the current
detection threshold and the aforementioned inverse Compton emission. Based on
the H.E.S.S. GPS, we present the first observational assessment of diffuse TeV
gamma-ray emission. The observation is compared with corresponding flux
predictions based on the HI (LAB data) and CO (as a tracer of H2, NANTEN data)
gas distributions. Consequences for unresolved source contributions and the
anticipated level of inverse Compton emission are discussed.


title:
High-spin structures of 88Kr and 89Rb: Evolution from collective to
  single-particle behaviors

abstract:
  The high-spin states of the two neutron-rich nuclei, 88Kr and 89R have been
studied from the 18O + 208Pb fusion-fission reaction. Their level schemes were
built from triple gamma-ray coincidence data and gamma-gamma angular
correlations were analyzed in order to assign spin and parity values to most of
the observed states. The two levels schemes evolve from collective structures
to single-particle excitations as a function of the excitation energy.
Comparison with results of shell-model calculations gives the specific proton
and neutron configurations which are involved to generate the angular momentum
along the yrast lines.


title:
Theoretical study of the parity and time reversal violating interaction
  in solids

abstract:
  A new theoretical approach to study the properties in solids, which are
sensitive to a change of densities of the valence electrons in atomic cores
(hyperfine structure constants, parameters of space parity (P) and time
reversal (T) violation interaction, etc.) is proposed and implemented. It uses
the two-step concept of calculation of such properties which was implemented
earlier for the case of molecules [Progr.\ Theor.\ Chem.\ Phys. B 15, 253
(2006)]. The approach is applied to evaluate the parameter $X$ describing
electronic density gradient on the Pb nucleus that is required to interpret the
proposed experiment on PbTiO$_3$ crystal [PRA, 72, 034501 (2005)] to search for
the Schiff moment of the $^{207}$Pb nucleus because of its high sensitivity to
the corresponding P,T-violating interactions. For comparison the $X$ parameter
has also been calculated on the Pb nucleus for the $^1\Sigma^+$ state of
$^{207}$PbO molecule using the same density functionals as those utilized in
PbTiO$_3$ studies. The relativistic coupled-clusters approach with single,
double and perturbative triple cluster amplitudes, applicable to a few atom
systems and providing high accuracy for $X$, is also applied to the PbO case to
estimate the accuracy of density functional studies.


title: The Effect of Fluctuations on the QCD Critical Point in a Finite Volume

abstract:
  We investigate the effect of a finite volume on the critical behavior of the
theory of the strong interaction (QCD) by means of a quark-meson model for two
quark flavors. In particular, we analyze the effect of a finite volume on the
location of the critical point in the phase diagram existing in our model. In
our analysis, we take into account the effect of long-range fluctuations with
the aid of renormalization group techniques. We find that these quantum and
thermal fluctuations, absent in mean-field studies, play an import role for the
dynamics in a finite volume. We show that the critical point is shifted towards
smaller temperatures and larger values of the quark chemical potential if the
volume size is decreased. This behavior persists for antiperiodic as well as
periodic boundary conditions for the quark fields as used in many lattice QCD
simulations.


title: De Rahm Cohomology of Local Cohomology modules II

abstract:
  Let $K$ be an algebraically closed field of characteristic zero and let $R =
K[X_1,\ldots,X_n]$. Let $I$ be an ideal in $R$. Let $A_n(K)$ be the $n^{th}$
Weyl algebra over $K$. By a result of Lyubeznik, the local cohomology modules
$H^i_I(R)$ are holonomic $A_n(K)$-modules for each $i \geq 0$. In this paper we
compute the Euler characteristic of De-Rahm cohomology of $H^{\htt P}_P(R)$ for
certain classes of prime ideals $P$ in $R$.


title: Axigluon Phenomenology using ATLAS dijet data

abstract:
  In recent years, there has been a renewed interest on axigluons as part of a
possible extension of strong interactions at high energies. In this work, we
use recent ATLAS measurements of the dijet spectrum in order to set limits on
the axigluon mass and coupling to quarks. We pay special attention to the
methodology used to extract the resonant contribution from theoretical
simulations. Finally, we present some predictions for the next LHC run at
$\sqrt{s}=14$ TeV.


title:
Zeros in Bosonic Wave-Function Result in Local Anti-Bunching: Refining
  Feynman's argument

abstract:
  The effect of boson bunching is frequently mentioned and discussed in the
literature. This effect is the manifestation of bosons tendency to "travel" in
clusters. One of the core arguments for boson bunching was formulated by
Feynman in his well-known lecture series and has been frequently used ever
since. By comparing the scattering probabilities of two bosons and of two
non-identical particles, Feynman concluded: "We have the result that it is
twice as likely to find two identical Bose particles scattered into the same
state as you would calculate assuming the particles were different." [1].
Indeed, in most scenarios, this reasoning is valid, however, as it is shown in
this paper, there are cases, even in the most ordinary scattering scenarios,
where this reasoning is invalid, and in fact the opposite occurs: boson
anti-bunching appears. Similarly, it is shown that at exactly the same
scenarios, fermions bunch together.


title: Conservativity for theories of compositional truth via cut elimination

abstract:
  We present a cut elimination argument that witnesses the conservativity of
the compositional axioms for truth (without the extended induction axiom) over
any theory interpreting a weak subsystem of arithmetic. In doing so we also fix
a critical error in Halbach's original presentation. Our methods show that the
admission of these axioms determines a hyper-exponential reduction in the size
of derivations of truth-free statements.


title: Normal ordering problem and the extensions of the Stirling grammar

abstract:
  The purpose of this paper is to investigate the connection between
context-free grammars and normal ordering problem, and then to explore various
extensions of the Stirling grammar. We present grammatical characterizations of
several well known combinatorial sequences, including the generalized Stirling
numbers of the second kind related to the normal ordering problem and the
$r$-Dowling polynomials. Also, possible avenues for future research are
described.


title:
PCR-based isolation of multigene families: Lessons from the avian MHC
  class IIB

abstract:
  The amount of sequence data available today highly facilitates the access to
genes from many gene families. Universal primers amplifying the desired genes
over a range of species are readily obtained by aligning conserved gene
regions, and laborious gene isolation procedures can often be replaced by
quicker PCR-based approaches. However, in case of multigene families, PCR-based
approaches bear the risk of incomplete isolation of family members. This
problem is most prominent in gene families with highly variable and thus
unpredictable number of gene copies among species, such as in the major
histocompatibility complex (MHC). In the present study we (i) report new
primers for the isolation of the MHC class IIB (MHCIIB) gene family in birds,
and (ii) share our experience with isolating MHCIIB genes from an unprecedented
number of avian species from all over the avian phylogeny. We report important
and usually underappreciated problems encountered during PCR-based multigene
family isolation, and provide a collection of measures that may help to
significantly improve the chance of successfully isolating complete multigene
families using PCR-based approaches.


title:
Control of magnetization reversal in oriented Strontium Ferrite thin
  films

abstract:
  Oriented Strontium Ferrite films with the c axis orientation were deposited
with varying oxygen partial pressure on Al2O3(0001) substrate using PLD
technique. The angle dependent magnetic hysteresis, remanent coercivity and
temperature dependent coercivity had been employed to understand the
magnetization reversal of these films. It was found that the Strontium Ferrite
thin film grown at lower (higher) oxygen partial pressure shows
Stoner-Wohlfarth type (Kondorsky like) reversal. The relative importance of
pinning and nucleation processes during magnetization reversal is used to
explain the type of the magnetization reversal with different oxygen partial
pressure during growth.


title:
Purified SASE undulator configuration to enhance the performance of the
  soft x-ray beamline at the European XFEL

abstract:
  The purified SASE (pSASE) undulator configuration recently proposed at SLAC
promises an increase in the output spectral density of XFELs. In this article
we study a straightforward implementation of this configuration for the soft
x-ray beamline at the European XFEL. A few undulator cells, resonant at a
subharmonic of the FEL radiation, are used in the middle of the exponential
regime to amplify the radiation, while simultaneously reducing the FEL
bandwidth. Based on start-to-end simulations, we show that with the proposed
configuration the spectral density in the photon energy range between 1.3 keV
and 3 keV can be enhanced of an order of magnitude compared to the baseline
mode of operation. This option can be implemented into the tunable-gap SASE3
baseline undulator without additional hardware, and it is complementary to the
self-seeding option with grating monochromator proposed for the same undulator
line, which can cover the photon energy range between about 0.26 keV and 1 keV.


title: Braess's Paradox in Wireless Networks: The Danger of Improved Technology

abstract:
  When comparing new wireless technologies, it is common to consider the effect
that they have on the capacity of the network (defined as the maximum number of
simultaneously satisfiable links). For example, it has been shown that giving
receivers the ability to do interference cancellation, or allowing transmitters
to use power control, never decreases the capacity and can in certain cases
increase it by $\Omega(\log (\Delta \cdot P_{\max}))$, where $\Delta$ is the
ratio of the longest link length to the smallest transmitter-receiver distance
and $P_{\max}$ is the maximum transmission power. But there is no reason to
expect the optimal capacity to be realized in practice, particularly since
maximizing the capacity is known to be NP-hard. In reality, we would expect
links to behave as self-interested agents, and thus when introducing a new
technology it makes more sense to compare the values reached at game-theoretic
equilibria than the optimum values.
  In this paper we initiate this line of work by comparing various notions of
equilibria (particularly Nash equilibria and no-regret behavior) when using a
supposedly "better" technology. We show a version of Braess's Paradox for all
of them: in certain networks, upgrading technology can actually make the
equilibria \emph{worse}, despite an increase in the capacity. We construct
instances where this decrease is a constant factor for power control,
interference cancellation, and improvements in the SINR threshold ($\beta$),
and is $\Omega(\log \Delta)$ when power control is combined with interference
cancellation. However, we show that these examples are basically tight: the
decrease is at most O(1) for power control, interference cancellation, and
improved $\beta$, and is at most $O(\log \Delta)$ when power control is
combined with interference cancellation.


title: MATCASC: A tool to analyse cascading line outages in power grids

abstract:
  Blackouts in power grids typically result from cascading failures. The key
importance of the electric power grid to society encourages further research
into sustaining power system reliability and developing new methods to manage
the risks of cascading blackouts. Adequate software tools are required to
better analyze, understand, and assess the consequences of the cascading
failures. This paper presents MATCASC, an open source MATLAB based tool to
analyse cascading failures in power grids. Cascading effects due to line
overload outages are considered. The applicability of the MATCASC tool is
demonstrated by assessing the robustness of IEEE test systems and real-world
power grids with respect to cascading failures.


title:
Novel Localized Waves in a Two-mode Nonlinear Fiber with High-order
  Effects

abstract:
  We study on rational solutions on nonzero background of coupled Sasa-Satsuma
equations through Darboux transformation method, which take into account third
order dispersion, the term with self-frequency shift, and the term describing
self-steepening corrections to the cubic nonlinearity. We find there are some
new types of localized waves in the coupled system, such as dark-antidark
soliton pair, W-shaped soliton, dark W-shaped soliton, and the combined
localized waves of them. The results indicate that there are abundant novel
localized waves in the two-mode fiber with these high-order effects, which
would inspire experimental realization in the related physical systems.


title:
Temporal evolution and scaling of mixing in two-dimensional
  Rayleigh-Taylor turbulence

abstract:
  We report a high-resolution numerical study of two-dimensional (2D) miscible
Rayleigh-Taylor (RT) incompressible turbulence with the Boussinesq
approximation. An ensemble of 100 independent realizations were performed at
small Atwood number and unit Prandtl number with a spatial resolution of
$2048\times8193$ grid points. Our main focus is on the temporal evolution and
the scaling behavior of global quantities and of small-scale turbulence
properties. Our results show that the buoyancy force balances the inertial
force at all scales below the integral length scale and thus validate the basic
force-balance assumption of the Bolgiano-Obukhov scenario in 2D RT turbulence.
It is further found that the Kolmogorov dissipation scale $\eta(t)\sim
t^{1/8}$, the kinetic-energy dissipation rate $\varepsilon_u(t)\sim t^{-1/2}$,
and the thermal dissipation rate $\varepsilon_{\theta}(t)\sim t^{-1}$. All of
these scaling properties are in excellent agreement with the theoretical
predictions of the Chertkov model [Phys. Rev. Lett. \textbf{91}, 115001
(2003)]. We further discuss the emergence of intermittency and anomalous
scaling for high order moments of velocity and temperature differences. The
scaling exponents $\xi^r_p$ of the $p$th-order temperature structure functions
are shown to saturate to $\xi^r_{\infty}\simeq0.78\pm0.15$ for the highest
orders, $p\sim10$. The value of $\xi^r_{\infty}$ and the order at which
saturation occurs are compatible with those of turbulent Rayleigh-B\'{e}nard
(RB) convection [Phys. Rev. Lett. \textbf{88}, 054503 (2002)], supporting the
scenario of universality of buoyancy-driven turbulence with respect to the
different boundary conditions characterizing the RT and RB systems.


title: Distinct distances on algebraic curves in the plane

abstract:
  Let $P$ be a set of $n$ points in the real plane contained in an algebraic
curve $C$ of degree $d$. We prove that the number of distinct distances
determined by $P$ is at least $c_d n^{4/3}$, unless $C$ contains a line or a
circle. We also prove the lower bound $c_d' \min(m^{2/3}n^{2/3}, m^2, n^2)$ for
the number of distinct distances between $m$ points on one irreducible plane
algebraic curve and $n$ points on another, unless the two curves are parallel
lines, orthogonal lines, or concentric circles. This generalizes a result on
distances between lines of Sharir, Sheffer, and Solymosi in arXiv:1302.3081.


title: Coded Caching with Nonuniform Demands

abstract:
  We consider a network consisting of a file server connected through a shared
link to a number of users, each equipped with a cache. Knowing the popularity
distribution of the files, the goal is to optimally populate the caches such as
to minimize the expected load of the shared link. For a single cache, it is
well known that storing the most popular files is optimal in this setting.
However, we show here that this is no longer the case for multiple caches.
Indeed, caching only the most popular files can be highly suboptimal. Instead,
a fundamentally different approach is needed, in which the cache contents are
used as side information for coded communication over the shared link. We
propose such a coded caching scheme and prove that it is close to optimal.


title: Infinite Free Resolutions over Monomial Rings in Two Variables

abstract:
  Let M in k[x,y] be a monomial ideal M=(m_1,m_2,...,m_r), where the m_i are a
minimal generating set of M. We construct an explicit free resolution of k over
S=k[x,y]/M for all monomial ideals M, and provide recursive formulas for the
Betti numbers. In particular, if M is any monomial ideal (excepting five
degenerate cases,) the total Betti numbers \beta_i^S(k) are given by
\beta_0^S(k)=1, \beta_1^S(k)=2, and
\beta_i^S(k)=\beta_{i-1}(k)+(r-1)\beta_{i-2}^S(k), where r is the number of
minimal generators of M.
  This specializes to the classic example S=k[x,y]/(x^2,xy), which has
\beta_i^S(k)=F_{i+1}, where F_{i+1} is the (i+1)st Fibonacci number.
  Macaulay2 code producing these resolutions is available at:
http://cs.hood.edu/~whieldon/pages/research.html


title: Space complexity of list H-colouring: a dichotomy

abstract:
  The Dichotomy Conjecture for constraint satisfaction problems (CSPs) states
that every CSP is in P or is NP-complete (Feder-Vardi, 1993). It has been
verified for conservative problems (also known as list homomorphism problems)
by A. Bulatov (2003). We augment this result by showing that for digraph
templates H, every conservative CSP, denoted LHOM(H), is solvable in logspace
or is hard for NL. More precisely, we introduce a digraph structure we call a
circular N, and prove the following dichotomy: if H contains no circular N then
LHOM(H) admits a logspace algorithm, and otherwise LHOM(H) is hard for NL. Our
algorithm operates by reducing the lists in a complex manner based on a novel
decomposition of an auxiliary digraph, combined with repeated applications of
Reingold's algorithm for undirected reachability (2005). We also prove an
algebraic version of this dichotomy: the digraphs without a circular N are
precisely those that admit a finite chain of polymorphisms satisfying the
Hagemann-Mitschke identities. This confirms a conjecture of Larose and Tesson
(2007) for LHOM(H). Moreover, we show that the presence of a circular N can be
decided in time polynomial in the size of H.


title:
On Separation by Locally Testable and Locally Threshold Testable
  Languages

abstract:
  A separator for two languages is a third language containing the first one
and disjoint from the second one. We investigate the following decision
problem: given two regular input languages, decide whether there exists a
locally testable (resp. a locally threshold testable) separator. In both cases,
we design a decision procedure based on the occurrence of special patterns in
automata accepting the input languages. We prove that the problem is
computationally harder than deciding membership. The correctness proof of the
algorithm yields a stronger result, namely a description of a possible
separator. Finally, we discuss the same problem for context-free input
languages.


title:
New formulas for Maslov's canonical operator in a neighborhood of focal
  points and caustics in 2D semiclassical asymptotics

abstract:
  We suggest a new representation of Maslov's canonical operator in a
neighborhood of the caustics using a special class of coordinate systems
("eikonal coordinates") on Lagrangian manifolds. The specific features of the
two-dimensional case are considered. The general case is treated in
arXiv:1307.2292 [math-ph].