title: The Integrated Sachs-Wolfe effect in $f(R)$ gravity

abstract:
  We study the late-time Integrated Sachs-Wolfe (ISW) effect in $f(R)$ gravity
using N-body simulations. In the $f(R)$ model under study, the linear growth
rate is larger than that in general relativity (GR). This slows down the decay
of the cosmic potential and induces a smaller ISW effect on large scales.
Therefore, the $\dot\Phi$ (time derivative of the potential) power spectrum at
$k<0.1h$/Mpc is suppressed relative to that in GR. In the non-linear regime,
relatively rapid structure formation in $f(R)$ gravity boosts the non-linear
ISW effect relative to GR, and the $\dot\Phi$ power spectrum at $k>0.1h$/Mpc is
increased (100$\%$ greater on small scales at $z=0$). We explore the
detectability of the ISW signal via stacking supercluster and supervoids. The
differences in the corresponding ISW cold or hot spots are $\sim 20\%$ for
structures of $\sim 100$Mpc/$h$. Such differences are greater for smaller
structures, but the amplitude of the signal is lower. The high amplitude of ISW
signal detected by Granett et al. can not explained in the $f(R)$ model. We
find relatively big differences between $f(R)$ and GR in the transverse bulk
motion of matter, and discuss its detectability via the relative frequency
shifts of photons from multiple lensed images.


title: Projections in the curve complex arising from covering maps

abstract:
  Let $P : \Sigma \rightarrow S$ be a finite degree covering map between
surfaces. Rafi and Schleimer show that there is an induced quasi-isometric
embedding $\Pi : \mathcal{C}(S) \rightarrow \mathcal{C}(\Sigma)$ between the
associated curve complexes. We define an operation on curves in
$\mathcal{C}(\Sigma)$ using minimal intersection number conditions and prove
that it approximates a nearest point projection to $\Pi(\mathcal{C}(S))$. We
also approximate hulls of finite sets of vertices in the curve complex,
together with their corresponding nearest point projections, using intersection
numbers.


title: The Master T-Operator for Inhomogeneous XXX Spin Chain and mKP Hierarchy

abstract:
  Following the approach of [Alexandrov A., Kazakov V., Leurent S., Tsuboi Z.,
Zabrodin A., J. High Energy Phys. 2013 (2013), no. 9, 064, 65 pages,
arXiv:1112.3310], we show how to construct the master T-operator for the
quantum inhomogeneous GL(N) XXX spin chain with twisted boundary conditions. It
satisfies the bilinear identity and Hirota equations for the classical mKP
hierarchy. We also characterize the class of solutions to the mKP hierarchy
that correspond to eigenvalues of the master T-operator and study dynamics of
their zeros as functions of the spectral parameter. This implies a remarkable
connection between the quantum spin chain and the classical
Ruijsenaars-Schneider system of particles.


title:
Goldstone-mode Instability leading to Fragmentation in a Spinor
  Bose-Einstein Condensate

abstract:
  We apply the number-conserving Bogoliubov theory to spinor Bose-Einstein
condensates and show that the Goldstone magnon leads instability leading to
fragmentation. Unlike the dynamical instability, where modes with complex
eigenfrequencies grow exponentially, here the zero-energy mode exhibits
algebraic growth. We also point out that a small fraction of thermally excited
atoms enhances the fragmentation dynamics.


title: On Rota's Conjecture and nested separations in matroids

abstract:
  We prove that for each finite field $\mathbb F$ and integer $k\in \mathbb Z$
there exists $n\in \mathbb Z$ such that no excluded minor for the class of
$\mathbb F$-representable matroids has $n$ nested $k$-separations.


abstract:
  In this article we give an analogue of Hecke and Sturm bounds for Hilbert
modular forms over real quadratic fields. Let $K$ be a real quadratic field and
$\Om_K$ its ring of integers. Let $\Gamma$ be a congruence subgroup of
$\SL_2(\Om_K)$ and $M_{(k_1,k_2)}(\Gamma)$ the space of Hilbert modular forms
of weight $(k_1,k_2)$ for $\Gamma$. The first main result is an algorithm to
construct a finite set $S$, depending on $K$, $\Gamma$ and $(k_1,k_2)$, such
that if the Fourier expansion coefficients of a form $G \in
M_{(k_1,k_2)}(\Gamma)$ vanish on the set $S$, then $G$ is the zero form. The
second result corresponds to the same statement in the Sturm case, i.e. suppose
that all the Fourier coefficients of the form $G$ lie in a finite extension of
$\Q$, and let $\id{p}$ be a prime ideal in such extension, whose norm is
unramified in $K$; suppose furthermore that the Fourier expansion coefficients
of $G$ lie in the ideal $\id{p}$ for all the elements in $S$, then they all lie
in the ideal $\id{p}$.


title: DNACloud: A Potential Tool for storing Big Data on DNA

abstract:
  The term Big Data is usually used to describe huge amount of data that is
generated by humans from digital media such as cameras, internet, phones,
sensors etc. By building advanced analytics on the top of big data, one can
predict many things about the user such as behavior, interest etc. However
before one can use the data, one has to address many issues for big data
storage. Two main issues are the need of large storage devices and the cost
associated with it. Synthetic DNA storage seems to be an appropriate solution
to address these issues of the big data. Recently in 2013, Goldman and his
collegues from European Bioinformatics Institute demonstrated the use of the
DNA as storage medium with capacity of storing 2.2 peta bytes of information on
one gram of DNA and retrived the data successfully with low error rate. This
significant step shows a promise for synthetic DNA storage as a useful
technology for the future data storage. Motivated by this, we have developed a
software called DNACloud which makes it easy to store the data on the DNA. In
this work, we present detailed description of the software.


title:
Long time stability of a classical efficient scheme for an
  incompressible two-phase flow model

abstract:
  In this article we consider the implicit Euler scheme for a homogeneous
two-phase flow model in a two-dimensional domain and with the aid of the
discrete Gronwall lemma and of the discrete uniform Gronwall lemma we prove
that the global attractors generated by the numerical scheme converge to the
global attractor of the continuous system as the time-step approaches zero.


title:
Non-minimal Universal Extra Dimensions with Brane Local Terms: The Top
  Quark Sector

abstract:
  We study the physics of Kaluza-Klein (KK) top quarks in the framework of a
non-minimal Universal Extra Dimension (nmUED) with an orbifolded (S1/Z2) flat
extra spatial dimension in the presence of brane-localized terms (BLTs). In
general, BLTs affect the masses and the couplings of the KK excitations in a
non-trivial way including those for the KK top quarks. On top of that, BLTs
also influence the mixing of the top quark chiral states at each KK level and
trigger mixings among excitations from different levels with identical KK
parity (even or odd). The latter phenomenon of mixing of KK levels is not
present in the popular UED scenario known as the minimal UED (mUED) at the tree
level. Of particular interest are the mixings among the KK top quarks from
level `0' and level `2' (driven by the mass of the Standard Model (SM) top
quark). These open up new production modes in the form of single production of
a KK top quark and the possibility of its direct decays to Standard Model (SM)
particles leading to rather characteristic signals at the colliders.
Experimental constraints and the restrictions they impose on the nmUED
parameter space are discussed. The scenario is implemented in MadGraph 5 by
including the quark, lepton, the gauge-boson and the Higgs sectors up to the
second KK level. A few benchmark scenarios are chosen for preliminary studies
of the decay patterns of the KK top quarks and their production rates at the
LHC in various different modes. Recast of existing experimental analyzes in
scenarios having similar states is found to be not so straightforward for the
KK top quarks of the nmUED scenario under consideration.


title: Edge magnetoplasmons in graphene

abstract:
  We have observed propagation of Edge Magneto-Plasmon (EMP) modes in graphene
in the Quantum Hall regime by performing picosecond time of flight measurements
between narrow contacts on the perimeter of micrometric exfoliated graphene. We
find the propagation to be chiral with low attenuation and to have a velocity
which is quantized on Hall plateaus. The velocity has two contributions, one
arising from the Hall conductivity and the other from carrier drift along the
edge, which we were able to separate by their different filling factor
dependence. The drift component is found to be slightly less than the Fermi
velocity as expected for graphene dynamics in an abrupt edge potential. The
Hall conduction contribution is slower than expected and indicates a
characteristic length in the Coulomb potential from the Hall charge of about
500 nm. The experiment illustrates how EMP can be coupled to the
electromagnetic field, opening the perspective of GHz to THz chiral plasmonics
applications to devices such as voltage controlled phase shifters, circulators,
switches and compact, tunable ring resonators.


title: Single Quasiparticle Trapping in Aluminum Nanobridge Josephson Junctions

abstract:
  We present microwave measurements of a high quality factor superconducting
resonator incorporating two aluminum nanobridge Josephson junctions in a loop
shunted by an on-chip capacitor. Trapped quasiparticles (QPs) shift the
resonant frequency, allowing us to probe the trapped QP number and energy
distribution and to quantify their lifetimes. We find that the trapped QP
population obeys a Gibbs distribution above 75 mK, with non-Poissonian trapping
statistics. Our results are in quantitative agreement with the Andreev bound
state model of transport, and demonstrate a practical means to quantify on-chip
QP populations and validate mitigation strategies in a cryogenic environment.


title: The Complexity of Online Manipulation of Sequential Elections

abstract:
  Most work on manipulation assumes that all preferences are known to the
manipulators. However, in many settings elections are open and sequential, and
manipulators may know the already cast votes but may not know the future votes.
We introduce a framework, in which manipulators can see the past votes but not
the future ones, to model online coalitional manipulation of sequential
elections, and we show that in this setting manipulation can be extremely
complex even for election systems with simple winner problems. Yet we also show
that for some of the most important election systems such manipulation is
simple in certain settings. This suggests that when using sequential voting,
one should pay great attention to the details of the setting in choosing one's
voting rule.
  Among the highlights of our classifications are: We show that, depending on
the size of the manipulative coalition, the online manipulation problem can be
complete for each level of the polynomial hierarchy or even for PSPACE. We
obtain the most dramatic contrast to date between the nonunique-winner and
unique-winner models: Online weighted manipulation for plurality is in P in the
nonunique-winner model, yet is coNP-hard (constructive case) and NP-hard
(destructive case) in the unique-winner model. And we obtain what to the best
of our knowledge are the first PNP[1]-completeness and PNP-completeness results
in the field of computational social choice, in particular proving such
completeness for, respectively, the complexity of 3-candidate and 4-candidate
(and unlimited-candidate) online weighted coalition manipulation of veto
elections.


title: Predicting the NFL using Twitter

abstract:
  We study the relationship between social media output and National Football
League (NFL) games, using a dataset containing messages from Twitter and NFL
game statistics. Specifically, we consider tweets pertaining to specific teams
and games in the NFL season and use them alongside statistical game data to
build predictive models for future game outcomes (which team will win?) and
sports betting outcomes (which team will win with the point spread? will the
total points be over/under the line?). We experiment with several feature sets
and find that simple features using large volumes of tweets can match or exceed
the performance of more traditional features that use game statistics.


title:
Power law and exponential ejecta size distributions from the dynamic
  fragmentation of shock-loaded Cu and Sn metals under melt conditions

abstract:
  Large scale molecular dynamics (MD) simulations are performed to study and to
model the ejecta production from the dynamic fragmentation of shock-loaded
metals under melt conditions. A generic 3D crystal in contact with vacuum
containing about 10^8 atoms and with a sinusoidal free surface roughness is
shock loaded so as to undergo a solid-liquid phase change on shock. The
reflection of the shock wave at the interface metal/vacuum gives rise to the
ejection of 2D jets/sheets of atoms (Richtmyer-Meshkov instabilities in the
continuum limit) which develop and break up, forming ejecta (fragments) of
different volumes (or mass). The fragmentation process is investigated by
analyzing the evolution of the resulting volume distribution of the ejecta as a
function of time. Two metals are studied (Cu and Sn) and the amplitude of the
roughness is varied. The simulations show that the associated distributions
exhibit a generic behavior with the sum of two distinct terms of varying
weight, following the expansion rate of the jets: in the small size limit, the
distribution obeys a power law dependence with an exponent equal to 1.15 plus
or minus 0.08 and in the large size limit, it obeys an exponential form. These
two components are interpreted, with the help of additional simple simulations,
as the signature of two different basic mechanisms of fragmentation. The power
law dependence results from the fragmentation of a 2D network of ligaments
arranged following a fractal (scale free) geometry and generated when the
sheets of liquid metal expand and tear. The exponential distribution results
from a 1D Poisson fragmentation process of the largest ligaments previously
generated. Unlike the power law distribution, it is governed by a
characteristic length scale which may be provided by energy balance principle.


title: Regularity for Maxwell eigenproblems in photonic crystal fibre modelling

abstract:
  The convergence behaviour and the design of numerical methods for modelling
the flow of light in photonic crystal fibres depend critically on an
understanding of the regularity of solutions to time-harmonic Maxwell equations
in a three-dimensional, periodic, translationally invariant, heterogeneous
medium. In this paper we determine the strength of the dominant singularities
that occur at the interface between materials. By modifying earlier regularity
theory for polygonal interfaces we find that on each subdomain, where the
material in the fibre is constant, the regularity of in-plane components of the
magnetic field are $H^{2-\eta}$ for all $\eta > 0$. This estimate is sharp in
the sense that these components do not belong to $H^2$, in general. However,
global regularity is restricted by the presence of an interface between these
subdomains and the interface conditions imply only $H^{3/2-\eta}$ regularity
across the interface. The results are useful to anyone applying a numerical
method such as a finite element method or a planewave expansion method to model
photonic crystal fibres or similar materials.


title:
Scalable Synchronization and Reciprocity Calibration for Distributed
  Multiuser MIMO

abstract:
  Large-scale distributed Multiuser MIMO (MU-MIMO) is a promising wireless
network architecture that combines the advantages of "massive MIMO" and "small
cells." It consists of several Access Points (APs) connected to a central
server via a wired backhaul network and acting as a large distributed antenna
system. We focus on the downlink, which is both more demanding in terms of
traffic and more challenging in terms of implementation than the uplink. In
order to enable multiuser joint precoding of the downlink signals, channel
state information at the transmitter side is required. We consider Time
Division Duplex (TDD), where the {\em downlink} channels can be learned from
the user uplink pilot signals, thanks to channel reciprocity. Furthermore,
coherent multiuser joint precoding is possible only if the APs maintain a
sufficiently accurate relative timing and phase synchronization. AP
synchronization and TDD reciprocity calibration are two key problems to be
solved in order to enable distributed MU-MIMO downlink. In this paper, we
propose novel over-the-air synchronization and calibration protocols that scale
well with the network size. The proposed schemes can be applied to networks
formed by a large number of APs, each of which is driven by an inexpensive
802.11-grade clock and has a standard RF front-end, not explicitly designed to
be reciprocal. Our protocols can incorporate, as a building block, any suitable
timing and frequency estimator. Here we revisit the problem of joint ML timing
and frequency estimation and use the corresponding Cramer-Rao bound to evaluate
the performance of the synchronization protocol. Overall, the proposed
synchronization and calibration schemes are shown to achieve sufficient
accuracy for satisfactory distributed MU-MIMO performance.


title: Dimension of Fractional Brownian motion with variable drift

abstract:
  Let $X$ be a fractional Brownian motion in $\mathbb{R}^d$. For any Borel
function $f:[0,1] \to \mathbb{R}^d$, we express the Hausdorff dimension of the
image and the graph of $X+f$ in terms of $f$. This is new even for the case of
Brownian motion and continuous $f$, where it was known that this dimension is
almost surely constant. The expression involves an adaptation of the parabolic
dimension previously used by Taylor and Watson to characterize polarity for the
heat equation. In the case when the graph of $f$ is a self-affine
McMullen-Bedford carpet, we obtain an explicit formula for the dimension of the
graph of $X+f$ in terms of the generating pattern. In particular, we show that
it can be strictly bigger than the maximum of the Hausdorff dimension of the
graph of $f$ and that of $X$. Despite the random perturbation, the Minkowski
and Hausdorff dimension of the graph of $X+f$ can disagree.


title: Pattern-Avoiding Involutions: Exact and Asymptotic Enumeration

abstract:
  We consider the enumeration of pattern-avoiding involutions, focusing in
particular on sets defined by avoiding a single pattern of length 4. As we
demonstrate, the numerical data for these problems demonstrates some surprising
behavior. This strange behavior even provides some very unexpected data related
to the number of 1324-avoiding permutations.


title: On the Geometric Ramsey Number of Outerplanar Graphs

abstract:
  We prove polynomial upper bounds of geometric Ramsey numbers of pathwidth-2
outerplanar triangulations in both convex and general cases. We also prove that
the geometric Ramsey numbers of the ladder graph on $2n$ vertices are bounded
by $O(n^{3})$ and $O(n^{10})$, in the convex and general case, respectively. We
then apply similar methods to prove an $n^{O(\log(n))}$ upper bound on the
Ramsey number of a path with $n$ ordered vertices.


title: Neutrino Physics at DPF 2013

abstract:
  The field of neutrino physics was covered at DPF 2013 in 32 talks, including
three on theoretical advances and the remainder on experiments that spanned at
least 17 different detectors. This summary of those talks cannot do justice to
the wealth of information presented, but will provide links to other material
where possible. There were allso two plenary session contributions on neutrino
physics at this meeting: the current status of what we know about neutrino
(oscillation) physics was outlined by Huber, and the next steps in long
baseline oscillation expeirments were described by Fleming. This article covers
a subset of the topics discussed at the meeting, with emphasis given to those
talks that showed data or new results.


title: Eight light flavors on large lattice volumes

abstract:
  I present first results from large-scale lattice investigations of SU(3)
gauge theory with eight light flavors in the fundamental representation. Using
leadership computing resources at Argonne, we are generating gauge
configurations with lattice volumes up to $64^3\times128$ at relatively strong
coupling, in an attempt to access the chiral regime. We use nHYP-improved
staggered fermions, carefully monitoring finite-volume effects and other
systematics. Here I focus on analyses of the light hadron spectrum and chiral
condensate, measured on lattice volumes up to $48^3\times96$ with fermion
masses as light as m=0.004 in lattice units. We find no clear indication of
spontaneous chiral symmetry breaking in these observables. I discuss the
implications of these initial results, and prospects for further physics
projects employing these ensembles of gauge configurations.


title: Code Optimization in FORM

abstract:
  We describe the implementation of output code optimization in the open source
computer algebra system FORM. This implementation is based on recently
discovered techniques of Monte Carlo tree search to find efficient multivariate
Horner schemes, in combination with other optimization algorithms, such as
common subexpression elimination. For systems for which no specific knowledge
is provided it performs significantly better than other methods we could
compare with. Because the method has a number of free parameters, we also show
some methods by which to tune them to different types of problems.


title: Attosecond pulse shaping around a Cooper minimum

abstract:
  High harmonic generation (HHG) is used to measure the spectral phase of the
recombination dipole matrix element (RDM) in argon over a broad frequency range
that includes the 3p Cooper minimum (CM). The measured RDM phase agrees well
with predictions based on the scattering phases and amplitudes of the
interfering s- and d-channel contributions to the complementary photoionization
process. The reconstructed attosecond bursts that underlie the HHG process show
that the derivative of the RDM spectral phase, the group delay, does not have a
straight-forward interpretation as an emission time, in contrast to the usual
attochirp group delay. Instead, the rapid RDM phase variation caused by the CM
reshapes the attosecond bursts.


title:
The Effect of the Low Energy Constants on the Spectral Properties of the
  Wilson Dirac Operator

abstract:
  We summarize recent analytical results obtained for lattice artifacts of the
non-Hermitian Wilson Dirac operator. Hereby we discuss the effect of all three
low energy constants. In particular we study the limit of small lattice spacing
and also consider the regime of large lattice spacing which is closely related
to the mean field limit. Thereby we extract simple relations between measurable
quantities like the average number of additional real modes and the low energy
constants. These relations may improve the fitting for the low energy
constants.


title:
Hermite-Pad\'e approximation for certain systems of meromorphic
  functions

abstract:
  We study the convergence of sequences of type I and type II Hermite-Pad\'e
approximants for certain systems of meromorphic functions made up of rational
modifications of Nikishin systems of functions.


title:
Interference effects for H --> WW/ZZ --> l anti-nu_l anti-l nu_l
  searches in gluon fusion at the LHC

abstract:
  WW/ZZ interference for Higgs signal and continuum background as well as
signal-background interference is studied for same-flavour l anti-nu_l anti-l
nu_l final states produced in gluon-gluon scattering at the LHC for light and
heavy Higgs masses with minimal and realistic experimental selection cuts. For
the signal cross section, we find WW/ZZ interference effects of O(5%) at M_H =
126 GeV. For M_H >= 200 GeV, we find that WW/ZZ interference is negligible. For
the gg continuum background, we also find that WW/ZZ interference is
negligible. As general rule, we conclude that non-negligible WW/ZZ interference
effects occur only if at least one weak boson of the pair is dominantly
off-shell due to kinematic constraints. The subdominant weak boson pair
contribution induces a correction to the signal-background interference, which
is at the few percentage point level before search selection cuts. Optimised
selection cuts for M_H >~ 600 GeV are suggested.


title:
Magnetic field structure and torque in accretion discs around
  millisecond pulsars

abstract:
  Millisecond pulsars are rather weakly-magnetized neutron stars which are
thought to have been spun up by disc accretion, with magnetic linkage between
the star and the disc playing a key role. Their spin history depends
sensitively on details of the magnetic field structure, but idealized models
from the 1980s and 1990s are still commonly used for calculating the magnetic
field components. This paper is the third in a series presenting results from a
step-by-step analysis which we are making of the problem, starting with very
simple models and then progressively including additional features one at a
time, with the aim of gaining new insights into the mechanisms involved. In our
first two papers, the magnetic field structure in the disc was calculated for a
standard Shakura and Sunyaev model, by solving the magnetic induction equation
numerically in the stationary limit within the kinematic approximation; here we
consider a more general velocity field in the disc, including backflow. We find
that the profiles of the poloidal and toroidal components of the magnetic field
are fairly similar in the two cases but that they can be very different from
those in the models mentioned above, giving important consequences for the
torque exerted on the central object. In particular we find that, contrary to
what is usually thought, some regions of the disc outward of the co-rotation
point (rotating more slowly than the neutron star) may nevertheless contribute
to spinning up the neutron star on account of the detailed structure of the
magnetic field in those parts of disc.


title:
Wellposedness of bounded solutions of the non-homogeneous initial
  boundary value problem for the Ostrovsky-Hunter equation

abstract:
  The Ostrovsky-Hunter equation provides a model for small-amplitude long waves
in a rotating fluid of finite depth. It is a nonlinear evolution equation. In
this paper the welposed- ness of bounded solutions for a non-homogeneous
initial boundary value problem associated to this equation is studied.


title:
Symmetric bifurcation analysis of synchronous states of time-delayed
  coupled Phase-Locked Loop oscillators

abstract:
  In recent years there has been an increasing interest in studying
time-delayed coupled networks of oscillators since these occur in many real
life applications. In many cases symmetry patterns can emerge in these
networks, as a consequence a part of the system might repeat itself, and
properties of this subsystem are representative of the dynamics on the whole
phase space. In this paper an analysis of the second order N-node time-delay
fully connected network is presented which is based on previous work by Correa
and Piqueira \cite{Correa2013} for a 2-node network. This study is carried out
using symmetry groups. We show the existence of multiple eigenvalues forced by
symmetry, as well as the existence of Hopf bifurcations. Three different models
are used to analyze the network dynamics, namely, the full-phase, the phase,
and the phase-difference model. We determine a finite set of frequencies
$\omega$, that might correspond to Hopf bifurcations in each case for critical
values of the delay. The $S_n$ map is used to actually find Hopf bifurcations
along with numerical calculations using the Lambert W function. Numerical
simulations are used in order to confirm the analytical results. Although we
restrict attention to second order nodes, the results could be extended to
higher order networks provided the time-delay in the connections between nodes
remains equal.


title:
Eikonal slant helices and eikonal Darboux helices in 3-dimensional
  pseudo-Riemannian manifolds

abstract:
  In this study, we give definitions and characterizations of eikonal slant
helices, eikonal Darboux helices and non-normed eikonal Darboux helices in
3-dimensional pseudo- Riemannian manifold M . We show that every eikonal slant
helix is also an eikonal Darboux helix for timelike and spacelike curves.
Furthermore, we obtain that if the non-null curve a is a non-normed eikonal
Darboux helix, then a is an eikonal slant helix if and only if 2 2 e 3k +e1t =
constant, where k and t are curvature and torsion of a, respectively. Finally,
we define null-eikonal helices, slant helices and Darboux helices. Also, we
give their characterizations.


title: Rayleigh-Taylor instability in partially ionized prominence plasma

abstract:
  We study Rayleigh-Taylor instability (RTI) at the coronal-prominence boundary
by means of 2.5D numerical simulations in a single-fluid MHD approach including
a generalized Ohm's law. The initial configuration includes a homogeneous
magnetic field forming an angle with the direction in which the plasma is
perturbed. For each field inclination we compare two simulations, one for the
pure MHD case, and one including the ambipolar diffusion in the Ohm's law,
otherwise identical. We find that the configuration containing neutral atoms is
always unstable. The growth rate of the small-scale modes in the non-linear
regime is larger than in the purely MHD case.


title: Dense Gas Towards the RXJ1713.7-3946 Supernova Remnant

abstract:
  We present results from a Mopra 7mm-wavelength survey that targeted the dense
gas-tracing CS(1-0) transition towards the young gamma-ray-bright supernova
remnant, RXJ1713.7-3946 (SNR G347.3-0.5). In a hadronic gamma-ray emission
scenario, where cosmic ray protons interact with gas to produce the observed
gamma-ray emission, the mass of potential cosmic ray target material is an
important factor. We summarise newly-discovered dense gas components, towards
Cores G and L, and Clumps N1, N2, N3 and T1, which have masses of 1-10^4 solar
masses. We argue that these components are not likely to contribute
significantly to gamma-ray emission in a hadronic gamma-ray emission scenario.
This would be the case if RXJ1713.7-3946 were at either the currently favoured
distance of ~1kpc or an alternate distance (as suggested in some previous
studies) of ~6kpc.
  This survey also targeted the shock-tracing SiO molecule. Although no SiO
emission corresponding to the RXJ1713.7-3946 shock was observed,
vibrationally-excited SiO(1-0) maser emission was discovered towards what may
be an evolved star. Observations taken one year apart confirmed a transient
nature, since the intensity, line-width and central velocity of
SiO(J=1-0,v=1,2) emission varied significantly.


title: Stock returns versus trading volume: is the correspondence more general?

abstract:
  This paper presents a quantitative analysis of the relationship between the
stock market returns and corresponding trading volumes using high- frequency
data from the Polish stock market. First, for stocks that were traded for
suffciently long period of time, we study the return and volume distributions
and identify their consistency with the power-law functions. We find that, for
majority of stocks, the scaling exponents of both distri- butions are
systematically related by about a factor of 2 with the ones for the returns
being larger. Second, we study the empirical price impact of trades of a given
volume and find that this impact can be well described by a square-root
dependence: r(V) V^(1/2). We conclude that the prop- erties of data from the
Polish market resemble those reported in literature concerning certain mature
markets.


title:
Simulations of imaging of the local density of states by charged probe
  technique for resonant cavities

abstract:
  We simulate scanning probe imaging of the local density of states related to
scattering Fermi level wave functions inside a resonant cavity. We calculate
potential landscape within the cavity taking into account the Coulomb charge of
the probe and its screening by deformation of the two-dimensional electron gas
using the local density approximation. Approximation of the tip potential by a
Lorentz function is discussed. The electron transfer problem is solved with a
finite difference approach. We look for stable work points for the extraction
of the local density of states from conductance maps. We find that conductance
maps are highly correlated with the local density of states when the Fermi
energy level enters into Fano resonance with states localized within the
cavity. Generally outside resonances the correlation between the local density
of states and conductance maps is low.


title:
Exploring the chemical link between local ellipticals and their
  high-redshift progenitors

abstract:
  We present Keck/MOSFIRE K-band spectroscopy of the first mass-selected sample
of galaxies at $z\sim2.3$. Targets are selected from the 3D-HST Treasury
survey. The six detected galaxies have a mean [NII]$\lambda$6584/H$\alpha$
ratio of $0.27\pm0.01$, with a small standard deviation of 0.05. This mean
value is similar to that of UV-selected galaxies of the same mass. The mean
gas-phase oxygen abundance inferred from the [NII]/H$\alpha$ ratios depends on
the calibration method, and ranges from 12+log(O/H)$_{gas}=8.57$ for the
{Pettini} & {Pagel} (2004) calibration to 12+log(O/H)$_{gas}= 8.87$ for the
{Maiolino} {et~al.} (2008) calibration. Measurements of the stellar oxygen
abundance in nearby quiescent galaxies with the same number density indicate
12+log(O/H)$_{stars}= 8.95$, similar to the gas-phase abundances of the
$z\sim2.3$ galaxies if the {Maiolino} {et~al.} (2008) calibration is used. This
suggests that these high-redshift star forming galaxies may be progenitors of
today's massive early-type galaxies. The main uncertainties are the absolute
calibration of the gas-phase oxygen abundance and the incompleteness of the
$z\sim2.3$ sample: the galaxies with detected H$\alpha$ tend to be larger and
have higher star formation rates than the galaxies without detected H$\alpha$,
and we may still be missing the most dust-obscured progenitors.


title:
Non-Axisymmetric Structure in the Satellite Dwarf Galaxy NGC2976:
  Implications for its Dark/Bright Mass Distribution and Evolution

abstract:
  We present the result of an extensive search for non-axisymmetric structures
in the dwarf satellite galaxy of M81: NGC 2976, using multiwavelength archival
observations. The galaxy is known to present kinematic evidence for a
bysimmetric distortion, anyhow the stellar bar presence is controversial, due
to the possible interpretation of NGC 2976 presenting an elliptical disk
triggered by a prolate dark matter halo. We applied diagnostics in order to
detect stellar bars or spiral arms. The m=2 fourier phase has a jump around 60
arcsecs consistent with a central bar and bisymmetric arms. The CO, 3.6 $\mu$
surface brightness and the dust lanes are consistent with a gas rich central
bar and possibly with gaseous spiral arms. The kinematic jumps related with the
dust lanes suggest that the bar perturbation in the disk kinematics is
non-negligible and the reported non-circular motions, the central gas excess
and the nuclear X-ray source (AGN/Starburst) might be produced by the central
bar. SPH simulations of disks inside triaxial dark halos suggest that the two
symmetric spots at 130 arcsecs and the narrow arms may be produced by gas at
turning points in an elliptical disk, alternatively the potential ellipticity
can be originated by tidally induced strong stellar bar/arms. We conclude that,
the gas rich bar and spiral arms triggered by tidal stirring, and primordial
halo triaxiality, can explain most of the non-circular motions, mass
redistribution and nuclear activity. Distinguishing between them requires
detailed modeling of environmental effects. An analysis similar to this may
reveal such kind of structures in other nearby dwarf satellite galaxies, and if
confirmed, the same evolutionary scenario will be applicable to them. This
implies biases constraining their dark matter distribution and also making
comparison against theoretical predictions for isolated galaxies.


title: The Peculiar Pulsar Population of the Central Parsec

abstract:
  Pulsars orbiting the Galactic center black hole, Sgr A*, would be potential
probes of its mass, distance and spin, and may even be used to test general
relativity. Despite predictions of large populations of both ordinary and
millisecond pulsars in the Galactic center, none have been detected within 25
pc by deep radio surveys. One explanation has been that hyperstrong temporal
scattering prevents pulsar detections, but the recent discovery of radio
pulsations from a highly magnetized neutron star (magnetar) within 0.1 pc shows
that the temporal scattering is much weaker than predicted. We argue that an
intrinsic deficit in the ordinary pulsar population is the most likely reason
for the lack of detections to date: a "missing pulsar problem" in the Galactic
center. In contrast, we show that the discovery of a single magnetar implies
efficient magnetar formation in the region. If the massive stars in the central
parsec form magnetars rather than ordinary pulsars, their short lifetimes could
explain the missing pulsars. Efficient magnetar formation could be caused by
strongly magnetized progenitors, or could be further evidence of a top-heavy
initial mass function. Furthermore, current high-frequency surveys should
already be able to detect bright millisecond pulsars, given the measured degree
of temporal scattering.


title:
CMB Lensing Power Spectrum Biases from Galaxies and Clusters using
  High-angular Resolution Temperature Maps

abstract:
  The lensing power spectrum from cosmic microwave background (CMB) temperature
maps will be measured with unprecedented precision with upcoming experiments,
including upgrades to ACT and SPT. Achieving significant improvements in
cosmological parameter constraints, such as percent level errors on sigma_8 and
an uncertainty on the total neutrino mass of approximately 50 meV, requires
percent level measurements of the CMB lensing power. This necessitates tight
control of systematic biases. We study several types of biases to the
temperature-based lensing reconstruction signal from foreground sources such as
radio and infrared galaxies and the thermal Sunyaev-Zel'dovich effect from
galaxy clusters. These foregrounds bias the CMB lensing signal due to their
non-Gaussian nature. Using simulations as well as some analytical models we
find that these sources can substantially impact the measured signal if left
untreated. However, these biases can be brought to the percent level if one
masks galaxies with fluxes at 150 GHz above 1 mJy and galaxy clusters with
masses above M_vir = 10^14 M_sun. To achieve such percent level bias, we find
that only modes up to a maximum multipole of l_max ~ 2500 should be included in
the lensing reconstruction. We also discuss ways to minimize additional bias
induced by such aggressive foreground masking by, for example, exploring a
two-step masking and in-painting algorithm.


title: Anomaly inflow and thermal equilibrium

abstract:
  Using the anomaly inflow mechanism, we compute the flavor/Lorentz
non-invariant contribution to the partition function in a background with a
U(1) isometry. This contribution is a local functional of the background
fields. By identifying the U(1) isometry with Euclidean time we obtain a
contribution of the anomaly to the thermodynamic partition function from which
hydrostatic correlators can be efficiently computed. Our result is in line
with, and an extension of, previous studies on the role of anomalies in a
hydrodynamic setting. Along the way we find simplified expressions for
Bardeen-Zumino polynomials and various transgression formulae


title: TYC 3159-6-1: a runaway blue supergiant

abstract:
  We report the results of optical spectroscopy of a candidate evolved massive
star in the Cygnus X region, TYC 3159-6-1, revealed via detection of its
curious circumstellar nebula in archival data of the Spitzer Space Telecope. We
classify TYC 3159-6-1 as an O9.5-O9.7 Ib star and derive its fundamental
parameters by using the stellar atmosphere code FASTWIND. The He and CNO
abundances in the photosphere of TYC 3159-6-1 are consistent with the solar
abundances, suggesting that the star only recently evolved off the main
sequence. Proper motion and radial velocity measurements for TYC 3159-6-1 show
that it is a runaway star. We propose that Dolidze 7 is its parent cluster. We
discuss the origin of the nebula around TYC 3159-6-1 and suggest that it might
be produced in several successive episodes of enhanced mass-loss rate
(outbursts) caused by rotation of the star near the critical, \Omega-limit.


title:
Modeling Self-Subtraction in Angular Differential Imaging: Application
  to the HD 32297 Debris Disk

abstract:
  We present a new technique for forward-modeling self-subtraction of spatially
extended emission in observations processed with angular differential imaging
(ADI) algorithms. High-contrast direct imaging of circumstellar disks is
limited by quasi-static speckle noise and ADI is commonly used to suppress
those speckles. However, the application of ADI can result in self-subtraction
of the disk signal due to the disk's finite spatial extent. This signal
attenuation varies with radial separation and biases measurements of the disk's
surface brightness, thereby compromising inferences regarding the physical
processes responsible for the dust distribution. To compensate for this
attenuation, we forward-model the disk structure and compute the form of the
self-subtraction function at each separation. As a proof of concept, we apply
our method to 1.6 and 2.2 micron Keck AO NIRC2 scattered-light observations of
the HD 32297 debris disk reduced using a variant of the "locally optimized
combination of images" (LOCI) algorithm. We are able to recover disk surface
brightness that was otherwise lost to self-subtraction and produce simplified
models of the brightness distribution as it appears with and without
self-subtraction. From the latter models, we extract radial profiles for the
disk's brightness, width, midplane position, and color that are unbiased by
self-subtraction. Our analysis of these measurements indicates a break in the
brightness profile power law at r~110 AU and a disk width that increases with
separation from the star. We also verify disk curvature that displaces the
midplane by up to 30 AU towards the northwest relative to a straight fiducial
midplane.


title: From cosmic ray source to the Galactic pool

abstract:
  The Galactic cosmic ray spectrum is a remarkably straight power law. Our
current understanding is that the dominant sources that accelerate cosmic rays
up to the knee ($3 \times 10^{15}$ eV) or perhaps even the ankle ($3 \times
10^{18}$ eV), are young Galactic supernova remnants. In theory, however, there
are various reasons why the spectrum may be different for different sources,
and may not even be a power law if nonlinear shock acceleration applies during
the most efficient stages of acceleration. We show how the spectrum at the
accelerator translates to the spectrum that make up the escaping cosmic rays
that replenish the Galactic pool of cosmic rays. We assume that cosmic ray
confinement, and thus escape, is linked to the level of magnetic field
amplification, and that the magnetic field is amplified by streaming cosmic
rays according to the non-resonant hybrid or resonant instability. When a fixed
fraction of the energy is transferred to cosmic rays, it turns out that a
source spectrum that is flatter than $E^{-2}$ will result in a $E^{-2}$ escape
spectrum, whereas a steeper source spectrum will result in an escape spectrum
with equal steepening. This alleviates some of the concern that may arise from
expected flat or concave cosmic ray spectra associated with nonlinear shock
modification.


title:
Multiplicativity of completely bounded $p$-norms implies a strong
  converse for entanglement-assisted capacity

abstract:
  The fully quantum reverse Shannon theorem establishes the optimal rate of
noiseless classical communication required for simulating the action of many
instances of a noisy quantum channel on an arbitrary input state, while also
allowing for an arbitrary amount of shared entanglement of an arbitrary form.
Turning this theorem around establishes a strong converse for the
entanglement-assisted classical capacity of any quantum channel. This paper
proves the strong converse for entanglement-assisted capacity by a completely
different approach and identifies a bound on the strong converse exponent for
this task. Namely, we exploit the recent entanglement-assisted "meta-converse"
theorem of Matthews and Wehner, several properties of the recently established
sandwiched Renyi relative entropy (also referred to as the quantum Renyi
divergence), and the multiplicativity of completely bounded $p$-norms due to
Devetak et al. The proof here demonstrates the extent to which the Arimoto
approach can be helpful in proving strong converse theorems, it provides an
operational relevance for the multiplicativity result of Devetak et al., and it
adds to the growing body of evidence that the sandwiched Renyi relative entropy
is the correct quantum generalization of the classical concept for all
$\alpha>1$.


title: Charming the Higgs

abstract:
  We show that current Higgs data permit a significantly enhanced Higgs
coupling to charm pairs, comparable to the Higgs to bottom pairs coupling in
the Standard Model, without resorting to additional new physics sources in
Higgs production. With a mild level of the latter current data even allow for
the Higgs to charm pairs to be the dominant decay channel. An immediate
consequence of such a large charm coupling is a significant reduction of the
Higgs signal strengths into the known final states as in particular into bottom
pairs. This might reduce the visible vector-boson associated Higgs production
rate to a level that could compromise the prospects of ever observing it. We
however demonstrate that a significant fraction of this reduced signal can be
recovered by jet-flavor-tagging targeted towards charm-flavored jets. Finally
we argue that an enhanced Higgs to charm pairs coupling can be obtained in
various new physics scenarios in the presence of only a mild accidental
cancellation between various contributions.


title: An advanced scattered moonlight model for Cerro Paranal

abstract:
  The largest natural source of light at night is the Moon, and it is the major
contributor to the astronomical sky background. Being able to accurately
predict the sky background, including scattered moonlight is important for
scheduling astronomical observations. We have developed an improved scattered
moonlight model, in which the components are computed with a better physical
understanding as opposed to the simple empirical fit in the frequently used
photometric model of Krisciunas & Schaefer (1991). Our spectroscopic model can
better trace the spectral trends of scattered moonlight for any position of the
Moon and target observation. This is the first scattered moonlight model that
we know of which is this physical and versatile. We have incorporated an
observed solar spectrum, accurate lunar albedo fit, and elaborate scattering
and absorption calculations that include scattering off of molecules and
aerosols. It was designed for Cerro Paranal, but can be modified for any
location with known atmospheric properties. Throughout the optical range, the
uncertainty is less than 20%. This advanced scattered moonlight model can
predict the amount of scattered moonlight for any given geometry of the Moon
and target, and lunar phase for the entire optical spectrum.


title:
What Next-Generation 21 cm Power Spectrum Measurements Can Teach Us
  About the Epoch of Reionization

abstract:
  A number of experiments are currently working towards a measurement of the 21
cm signal from the Epoch of Reionization. Whether or not these experiments
deliver a detection of cosmological emission, their limited sensitivity will
prevent them from providing detailed information about the astrophysics of
reionization. In this work, we consider what types of measurements will be
enabled by a next-generation of larger 21 cm EoR telescopes. To calculate the
type of constraints that will be possible with such arrays, we use simple
models for the instrument, foreground emission, and the reionization history.
We focus primarily on an instrument modeled after the $\sim 0.1~\rm{km}^2$
collecting area Hydrogen Epoch of Reionization Array (HERA) concept design, and
parameterize the uncertainties with regard to foreground emission by
considering different limits to the recently described "wedge" footprint in
k-space. Uncertainties in the reionization history are accounted for using a
series of simulations which vary the ionizing efficiency and minimum virial
temperature of the galaxies responsible for reionization, as well as the mean
free path of ionizing photons through the IGM. Given various combinations of
models, we consider the significance of the possible power spectrum detections,
the ability to trace the power spectrum evolution versus redshift, the
detectability of salient power spectrum features, and the achievable level of
quantitative constraints on astrophysical parameters. Ultimately, we find that
$0.1~\rm{km}^2$ of collecting area is enough to ensure a very high significance
($\gtrsim30\sigma$) detection of the reionization power spectrum in even the
most pessimistic scenarios. This sensitivity should allow for meaningful
constraints on the reionization history and astrophysical parameters,
especially if foreground subtraction techniques can be improved and
successfully implemented.


title: V4641 Sgr: a candidate precessing microblazar

abstract:
  The X-ray spectrum of the Galactic X-ray binary V4641 Sgr in outburst has
been found to exhibit a remarkably broad emission feature above 4 keV, with
inferred equivalent widths up to 2 keV. Such a feature was first detected
during the X-ray flaring activity associated with the giant outburst that the
source experienced in 1999 September. The extraordinarily large equivalent
width line was then ascribed to reflection/reprocessing of fluorescent Fe
emission within an extended optically thick outflow enshrouding the binary
system as a result of a short-lived, super-Eddington accretion episode. Making
use of new and archival X-ray observations, we show here that a similar feature
persists over four orders of magnitude in luminosity, down to Eddington ratios
as low as log(L_Edd) = -4.5, where the existence of an optically thick envelope
appears at odds with any viable accretion flow model. Possible interpretations
for this highly unusual X-ray spectrum include a blend of Doppler
shifted/boosted Fe lines from unresolved X-ray jets (a la SS433), or, the first
Galactic analog of a blazar spectrum, where the >4 keV emission would
correspond to the onset of the Inverse Compton hump. Either requires a low
inclination angle of the jet with respect to the line of sight, in agreement
with the estimates for the 1999 superluminal jet (i_jet<10 deg). The fast
variability of the feature, combined with the high orbital axis inclination (60
deg< i_orb<71 deg), argue for a rapidly precessing accretion flow around V4641
Sgr, possibly leading to a transient microblazar behavior.


title:
A feasible roadmap for unsupervised deconvolution of two-source mixed
  gene expressions

abstract:
  Tissue heterogeneity is a major confounding factor in studying individual
populations that cannot be resolved directly by global profiling. Experimental
solutions to mitigate tissue heterogeneity are expensive, time consuming,
inapplicable to existing data, and may alter the original gene expression
patterns. Here we ask whether it is possible to deconvolute two-source mixed
expressions (estimating both proportions and cell-specific profiles) from two
or more heterogeneous samples without requiring any prior knowledge. Supported
by a well-grounded mathematical framework, we argue that both constituent
proportions and cell-specific expressions can be estimated in a completely
unsupervised mode when cell-specific marker genes exist, which do not have to
be known a priori, for each of constituent cell types. We demonstrate the
performance of unsupervised deconvolution on both simulation and real gene
expression data, together with perspective discussions.


title:
Calibration of semi-analytic models of galaxy formation using Particle
  Swarm Optimization

abstract:
  We present a fast and accurate method to select an optimal set of parameters
in semi-analytic models of galaxy formation and evolution (SAMs). Our approach
compares the results of a model against a set of observables applying a
stochastic technique called Particle Swarm Optimization (PSO), a self-learning
algorithm for localizing regions of maximum likelihood in multidimensional
spaces that outperforms traditional sampling methods in terms of computational
cost. We apply the PSO technique to the SAG semi-analytic model combined with
merger trees extracted from a standard $\Lambda$CDM N-body simulation. The
calibration is performed using a combination of observed galaxy properties as
constraints, including the local stellar mass function and the black hole to
bulge mass relation. We test the ability of the PSO algorithm to find the best
set of free parameters of the model by comparing the results with those
obtained using a MCMC exploration. Both methods find the same maximum
likelihood region, however the PSO method requires one order of magnitude less
evaluations. This new approach allows a fast estimation of the best-fitting
parameter set in multidimensional spaces, providing a practical tool to test
the consequences of including other astrophysical processes in SAMs.


title:
Dusty supernovae running the thermodynamics of the matter reinserted
  within young and massive super stellar clusters

abstract:
  Following the observational and theoretical evidence that points at core
collapse supernovae as major producers of dust, here we calculate the
hydrodynamics of the matter reinserted within young and massive super stellar
clusters under the assumption of gas and dust radiative cooling. The large
supernova rate expected in massive clusters allows for a continuous
replenishment of dust immersed in the high temperature thermalized reinserted
matter and warrants a stationary presence of dust within the cluster volume
during the type II supernova era. We first show that such a balance determines
the range of dust to gas mass ratio and this the dust cooling law. We then
search for the critical line that separates stationary cluster winds from the
bimodal cases in the cluster mechanical luminosity (or cluster mass) vs cluster
size parameter space. In the latter, strong radiative cooling reduces
considerably the cluster wind mechanical energy output and affects particularly
the cluster central regions, leading to frequent thermal instabilities that
diminish the pressure and inhibit the exit of the reinserted matter. Instead
matter accumulates there and is expected to eventually lead to gravitational
instabilities and to further stellar formation with the matter reinserted by
former massive stars. The main outcome of the calculations is that the critical
line is almost two orders of magnitude or more, depending on the assumed value
of the adiabatic wind terminal speed, lower than when only gas radiative
cooling is applied. And thus, many massive clusters are predicted to enter the
bimodal regime.


title: Characterization of superconducting RF breakdown by two-mode excitation

abstract:
  We show that thermal and magnetic contributions to the breakdown of
superconductivity in radiofrequency (RF) fields can be separated by applying
two RF modes simultaneously to a superconducting surface. We develop a simple
model that illustrates how mode-mixing RF data can be related to properties of
the superconductor. Within our model the data can be described by a single
parameter, which can be derived either from RF or thermometry data. Our RF and
thermometry data are in good agreement with the model. We propose to use
mode-mixing technique to decouple thermal and magnetic effects on RF breakdown
of superconductors.


title:
Optical/Near-IR Polarization Survey of Sh 2-29: Magnetic Fields, Dense
  Cloud Fragmentations and Anomalous Dust Grain Sizes

abstract:
  Sh 2-29 is a conspicuous star-forming region marked by the presence of
massive embedded stars as well as several notable interstellar structures. In
this research, our goals were to determine the role of magnetic fields and to
study the size distribution of interstellar dust particles within this
turbulent environment. We have used a set of optical and near-infrared
polarimetric data obtained at OPD/LNA (Brazil) and CTIO (Chile), correlated
with extinction maps, 2MASS data and images from DSS and Spitzer. The region's
most striking feature is a swept out interstellar cavity whose polarimetric
maps indicate that magnetic field lines were dragged outwards, pilling up along
its borders. This led to a higher magnetic strength value ($\approx400\,\mu$G)
and an abrupt increase in polarization degree, probably due to an enhancement
in alignment efficiency. Furthermore, dense cloud fragmentations with peak
$A_{V}$ between 20 and 37 mag were probably triggered by its expansion. The
presence of $24\,\mu$m point-like sources indicates possible newborn stars
inside this dense environment. A statistical analysis of the angular dispersion
function revealed areas where field lines are aligned in a well-ordered
pattern, seemingly due to compression effects from the HII region expansion.
Finally, Serkowski function fits were used to study the ratio of the
total-to-selective extinction, reveling a dual population of anomalous grain
particles sizes. This trend suggests that both effects of coagulation and
fragmentation of interstellar grains are present in the region.


title:
Evidence that All States Are Unitarily Equivalent to X States of the
  Same Entanglement

abstract:
  Strong numerical evidence is presented suggesting that all two-qubit mixed
states are equivalent to X states by a single entanglement-preserving unitary
(EPU) transformation, so that the concurrence of such an X state equals that of
the original general state. An X-state parameterization of a general two-qubit
state is given, allowing all states to have their concurrence parametrically
specified. A new kind of entanglement measure is proposed, relating a general
state's entanglement to that of a pure state in the same system. New states
called "H States" are presented, having fully parametric concurrence and
purity, with the intention of using them to construct entanglement-preserving
depolarization channels, which may aid development of the new entanglement
measure. A theory of "true-generalized" X states (TGX states) is proposed for
the general case of $N$-partite systems. While such states do not generally
have the literal "X" shape, evidence is shown that they are the true
generalizations of X states in larger systems, since they appear to always be
EPU-equivalent to general states of all ranks, whereas literal X states
generally are not. An example of this is given for $2\times 3$, including the
proposition of the $2\times 3$ maximally entangled mixed states (MEMS). If the
claim that TGX states are universal is valid, then any entanglement measure may
be computable in a simpler form by using the EPU-equivalence between general
states and TGX states.


title: WIMP physics with ensembles of direct-detection experiments

abstract:
  The search for weakly-interacting massive particle (WIMP) dark matter is
multi-pronged. Ultimately, the WIMP-dark-matter picture will only be confirmed
if different classes of experiments see consistent signals and infer the same
WIMP properties. In this work, we review the ideas, methods, and status of
direct-detection searches. We focus in particular on extracting WIMP physics
(WIMP interactions and phase-space distribution) from direct-detection data in
the early discovery days when multiple experiments see of order dozens to
hundreds of events. To demonstrate the essential complementarity of different
direct-detection experiments in this context, we create mock data intended to
represent the data from the near-future Generation 2 experiments. We consider
both conventional supersymmetry-inspired benchmark points (with
spin-independent and -dependent elastic cross sections just below current
limits), as well as benchmark points for other classes of models (inelastic and
effective-operator paradigms). We also investigate the effect on parameter
estimation of loosening or dropping the assumptions about the local WIMP
phase-space distribution. We arrive at two main conclusions. Firstly, teasing
out WIMP physics with experiments depends critically on having a wide set of
detector target materials, spanning a large range of target nuclear masses and
spin-dependent sensitivity. It is also highly desirable to obtain data from
low-threshold experiments. Secondly, a general reconstruction of the local WIMP
velocity distribution, which will only be achieved if there are multiple
experiments using different target materials, is critical to obtaining a robust
and unbiased estimate of the WIMP mass.


title: Cosmic Frontier Indirect Dark Matter Detection Working Group Summary

abstract:
  As part of the Snowmass process, the Cosmic Frontier Indirect-Detection
subgroup (CF2) has drawn on input from the Cosmic Frontier and the broader
Particle Physics community to produce this document. The purposes of this
report are to identify opportunities for dark matter science through indirect
detection, to give an overview of the primary scientific drivers for indirect
searches for dark matter, and to survey current and planned experiments that
have, as a large part of their scientific program, the goal of searching for
indirect (or astrophysical) signatures of dark matter. We primarily address
existing experiments with a large U.S. role, or future experiments where a U.S.
contribution is sought. We also address the limitations of this technique, and
answer the tough questions relevant to this subgroup posed by the HEP community
through the Snowmass process.


title:
A complete classification of equational classes of threshold functions
  included in clones

abstract:
  The class of threshold functions is known to be characterizable by functional
equations or, equivalently, by pairs of relations, which are called relational
constraints. It was shown by Hellerstein that this class cannot be
characterized by a finite number of such objects. In this paper, we investigate
classes of threshold functions which arise as intersections of the class of all
threshold functions with clones of Boolean functions, and provide a complete
classification of such intersections in respect to whether they have finite
characterizations. Moreover, we provide a characterizing set of relational
constraints for each class of threshold functions arising in this way.


title:
On Convexification of Range Measurement Based Sensor and Source
  Localization Problems

abstract:
  This manuscript is a preliminary pre-print version of a journal submission by
the authors, revisiting the problem of range measurement based localization of
a signal source or a sensor. The major geometric difficulty of the problem
comes from the non-convex structure of optimization tasks associated with range
measurements, noting that the set of source locations corresponding to a
certain distance measurement by a fixed point sensor is non-convex both in two
and three dimensions. Differently from various recent approaches to this
localization problem, all starting with a non-convex geometric minimization
problem and attempting to devise methods to compensate the non-convexity
effects, we suggest a geometric strategy to compose a convex minimization
problem first, that is equivalent to the initial non-convex problem, at least
in noise-free measurement cases. Once the convex equivalent problem is formed,
a wide variety of convex minimization algorithms can be applied. The paper also
suggests a gradient based localization algorithm utilizing the introduced
convex cost function for localization. Furthermore, the effects of measurement
noises are briefly discussed. The design, analysis, and discussions are
supported by a set of numerical simulations.


title: Nucleon form factors with light Wilson quarks

abstract:
  We present nucleon observables - primarily isovector vector form factors -
from calculations using 2+1 flavors of Wilson quarks. One ensemble is used for
a dedicated high-precision study of excited-state effects using five
source-sink separations between 0.7 and 1.6 fm. We also present results from a
larger set of calculations that include an ensemble with pion mass 149 MeV and
box size 5.6 fm, which nearly eliminates the uncertainty associated with
extrapolation to the physical pion mass. The results show agreement with
experiment for the vector form factors, which occurs only when excited-state
contributions are reduced. Finally, we show results from a subset of ensembles
that have pion mass 254 MeV with varying temporal and spatial box sizes, which
we use for a controlled study of finite-volume effects and a test of the
"$m_\pi L=4$" rule of thumb.


title: Latest RHIC Results on Ultra-Peripheral Collisions

abstract:
  With RHIC running in its second phase at higher luminosities the new data
sets collected so far by PHENIX and STAR are allowing improvements in the study
of vector meson photo-production in Ultra peripheral Collision events in Au+Au
at the highest energy. This is a brief summary of what has been accomplished so
far by both collaborations.


title:
Twisted relative Cuntz-Krieger algebras associated to finitely aligned
  higher-rank graphs

abstract:
  To each finitely aligned higher-rank graph $\Lambda$ and each
$\mathbb{T}$-valued 2-cocycle on $\Lambda$, we associate a family of twisted
relative Cuntz-Krieger algebras. We show that each of these algebras carries a
gauge action, and prove a gauge-invariant uniqueness theorem. We describe an
isomorphism between the fixed point algebras for the gauge actions on the
twisted and untwisted relative Cuntz-Krieger algebras. We show that the
quotient of a twisted relative Cuntz-Krieger algebra by a gauge-invariant ideal
is canonically isomorphic to a twisted relative Cuntz-Krieger algebra
associated to a subgraph. We use this to provide a complete graph-theoretic
description of the gauge-invariant ideal structure of each twisted relative
Cuntz-Krieger algebra.


title:
Broadband and efficient plasmonic control in the near-infrared and
  visible via strong interference of surface plasmon polaritons

abstract:
  Broadband and tunable control of surface plasmon polaritons in the
near-infrared and visible spectrum is demonstrated theoretically and
numerically with a pair of phased nanoslits. We establish with simulations
supported by a coupled wave model that by dividing the incident power equally
between two input channels, the maximum plasmon intensity deliverable to either
side of the nanoslit pair is twice that for an isolated slit. For a broadband
source, a compact device with nanoslit separation of the order of a tenth of
the wavelength is shown to steer nearly all the generated plasmons to one side
for the same phase delay, thereby achieving a broadband unidirectional plasmon
launcher. The reported effect can be applied to the design of ultra-broadband
and efficient tunable plasmonic devices.


title: Summary of the EDS Blois 2013 Workshop

abstract:
  I give a personal overview of some highlights of the EDS Blois 2013
Conference on elastic and diffractive scattering in Saariselka, Finland.


title: Scaling SVM and Least Absolute Deviations via Exact Data Reduction

abstract:
  The support vector machine (SVM) is a widely used method for classification.
Although many efforts have been devoted to develop efficient solvers, it
remains challenging to apply SVM to large-scale problems. A nice property of
SVM is that the non-support vectors have no effect on the resulting classifier.
Motivated by this observation, we present fast and efficient screening rules to
discard non-support vectors by analyzing the dual problem of SVM via
variational inequalities (DVI). As a result, the number of data instances to be
entered into the optimization can be substantially reduced. Some appealing
features of our screening method are: (1) DVI is safe in the sense that the
vectors discarded by DVI are guaranteed to be non-support vectors; (2) the data
set needs to be scanned only once to run the screening, whose computational
cost is negligible compared to that of solving the SVM problem; (3) DVI is
independent of the solvers and can be integrated with any existing efficient
solvers. We also show that the DVI technique can be extended to detect
non-support vectors in the least absolute deviations regression (LAD). To the
best of our knowledge, there are currently no screening methods for LAD. We
have evaluated DVI on both synthetic and real data sets. Experiments indicate
that DVI significantly outperforms the existing state-of-the-art screening
rules for SVM, and is very effective in discarding non-support vectors for LAD.
The speedup gained by DVI rules can be up to two orders of magnitude.


title: The Small Numbers of Large Kuiper Belt Objects

abstract:
  We explore the brightness distribution of the largest and brightest (m(R)<22)
Kuiper belt objects (KBOs). We construct a luminosity function of the
dynamically excited or hot Kuiper belt (orbits with inclinations > 5 degrees)
from the very brightest to m(R)=23. We find for m(R)< 23, a single slope
appears to describe the luminosity function. We estimate ~12 KBOs brighter than
m(R)~19.5 are present in the Kuiper belt today. With 9 bodies already
discovered this suggests that the inventory of bright KBOs is nearly complete.


title: Rank-finiteness for modular categories

abstract:
  We prove a rank-finiteness conjecture for modular categories: up to
equivalence, there are only finitely many modular categories of any fixed rank.
Our technical advance is a generalization of the Cauchy theorem in group theory
to the context of spherical fusion categories. For a modular category
$\mathcal{C}$ with $N=ord(T)$, the order of the modular $T$-matrix, the Cauchy
theorem says that the set of primes dividing the global quantum dimension $D^2$
in the Dedekind domain $\mathbb{Z}[e^{\frac{2\pi i}{N}}]$ is identical to that
of $N$.


title:
Nonlinear Fourier analysis for discontinuous conductivities:
  computational results

abstract:
  Two reconstruction methods of Electrical Impedance Tomography (EIT) are
numerically compared for nonsmooth conductivities in the plane based on the use
of complex geometrical optics (CGO) solutions to D-bar equations involving the
global uniqueness proofs for Calder\'on problem exposed in [Nachman; Annals of
Mathematics 143, 1996] and [Astala and P\"aiv\"arinta; Annals of Mathematics
163, 2006]: the Astala-P\"aiv\"arinta theory-based "low-pass transport matrix
method" implemented in [Astala et al.; Inverse Problems and Imaging 5, 2011]
and the "shortcut method" which considers ingredients of both theories. The
latter method is formally similar to the Nachman theory-based regularized EIT
reconstruction algorithm studied in [Knudsen, Lassas, Mueller and Siltanen;
Inverse Problems and Imaging 3, 2009] and several references from there.
  New numerical results are presented using parallel computation with size
parameters larger than ever, leading mainly to two conclusions as follows.
First, both methods can approximate piecewise constant conductivities better
and better as the cutoff frequency increases, and there seems to be a
Gibbs-like phenomenon producing ringing artifacts. Second, the transport matrix
method loses accuracy away from a (freely chosen) pivot point located outside
of the object to be studied, whereas the shortcut method produces
reconstructions with more uniform quality.


title: B and L at the SUSY Scale, Dark Matter and R-parity Violation

abstract:
  We present a simple theory where baryon and lepton numbers are spontaneously
broken at the supersymmetry scale. In this context R-parity must be
spontaneously broken but the theory still contains a stable field which can
play the role of the cold dark matter of the Universe. We discuss the spectrum
of the theory, the properties of the dark matter candidate and the predictions
for direct detection experiments. This theory provides a concrete example of
exotic supersymmetric signatures associated with having the simultaneous
presence of R-parity violating and missing energy signals at the Large Hadron
Collider.


title: Multiplicative Arithmetic Functions of Several Variables: A Survey

abstract:
  We survey general properties of multiplicative arithmetic functions of
several variables and related convolutions, including the Dirichlet convolution
and the unitary convolution. We introduce and investigate a new convolution,
called gcd convolution. We define and study the convolutes of arithmetic
functions of several variables, according to the different types of
convolutions. We discuss the multiple Dirichlet series and Bell series and
present certain arithmetic and asymptotic results of some special
multiplicative functions arising from problems in number theory, group theory
and combinatorics. We give a new proof to obtain the asymptotic density of the
set of ordered $r$-tuples of positive integers with pairwise relatively prime
components and consider a similar question related to unitary divisors.


title: The NEXT experiment. Towards phase I

abstract:
  Phase I of the NEXT-100 $0\nu\beta\beta$ experiment (NEW) is scheduled for
data taking in 2015 at Laboratorio Subterr\'aneo de Canfranc in the Spanish
Pyrenees. Thanks to the light proportional technique, NEW anticipates an
outstanding energy resolution nearing the Fano factor in Xenon
(0.5-1%FWHM@$Q_{\beta\beta,^{136}Xe}$), with a TPC-design that allows tracking
and identification of the double end-blob feature of the $0\nu\beta\beta$
decay. When properly mastered, the combination of these two assets can suppress
the irreducible $2\nu\beta\beta$ and (single-blob) $\gamma$ backgrounds from
natural radioactivity to minute levels, of the order of $5\times{10^{-4}}$
ckky. Given our knowledge of the available phase-space as obtained from
neutrino oscillation experiments, this feat will expectedly allow for a
sensitivity to the effective electron neutrino mass of $m_{\beta\beta}\simeq
30$ meV for exposures at the 20 ton $\times$ year scale. Hence, ultimately, a
full survey of the inverse hierarchy of the neutrino mass ordering appears to
be within reach for a ton-scale experiment based on this technology.
  NEW, with 10 kg of Xenon 90%-enriched in $^{136}$Xe, sets an unprecedented
scale for gaseous Xenon TPCs and will be an important milestone for its
anticipated upgrades (100 kg and 1 ton). I briefly summarize the status of the
NEXT experiment, from the main results obtained with $\sim 1$ kg prototypes
that substantiate the concept, to the ongoing works for deploying its first
phase.


title:
Asymptotic distribution for the birthday problem with multiple
  coincidences, via an embedding of the collision process

abstract:
  We study the random variable B(c,n), which counts the number of balls that
must be thrown into n equally-sized bins in order to obtain c collisions. The
asymptotic expected value of B(1,n) is the well-known $\sqrt{n\pi/2}$ appearing
in the solution to the birthday problem; the limit distribution and asymptotic
moments of B(1,n) are also well known. We calculate the distribution and
moments of B(c,n) asymptotically as n goes to infinity and c = O(n).
  Our main tools are an embedding of the collision process, realizing the
process as a deterministic function of the standard Poisson process, and a
central limit result by Renyi.


title: A note on using Bayes priors for Weibull distribution

abstract:
  In this note, the practical use of priors for Bayes estimators, of the two
parameters of the Weibull reliability model, is discussed in a technological
context. The meaning of the priors as expression of virtual data samples is
analyzed. The implications of physics of failures are also highlighted. The
whole analysis shows a rational way to convert a really available technological
knowledge into prior information, effectively and without a long elicitation
process. A large Monte Carlo study, on both complete and censored samples of
small size, shows the good properties of some estimators, which can exploit
such a new approach.


title: Extremal Eigenvalues and Eigenvectors of Deformed Wigner Matrices

abstract:
  We consider random matrices of the form $H = W + \lambda V$,
$\lambda\in\mathbb{R}^+$, where $W$ is a real symmetric or complex Hermitian
Wigner matrix of size $N$ and $V$ is a real bounded diagonal random matrix of
size $N$ with i.i.d.\ entries that are independent of $W$. We assume
subexponential decay for the matrix entries of $W$ and we choose $\lambda \sim
1$, so that the eigenvalues of $W$ and $\lambda V$ are typically of the same
order. Further, we assume that the density of the entries of $V$ is supported
on a single interval and is convex near the edges of its support. In this paper
we prove that there is $\lambda_+\in\mathbb{R}^+$ such that the largest
eigenvalues of $H$ are in the limit of large $N$ determined by the order
statistics of $V$ for $\lambda>\lambda_+$. In particular, the largest
eigenvalue of $H$ has a Weibull distribution in the limit $N\to\infty$ if
$\lambda>\lambda_+$. Moreover, for $N$ sufficiently large, we show that the
eigenvectors associated to the largest eigenvalues are partially localized for
$\lambda>\lambda_+$, while they are completely delocalized for
$\lambda<\lambda_+$. Similar results hold for the lowest eigenvalues.


title:
Lack of BV Bounds for Approximate Solutions to the p-system with Large
  Data

abstract:
  We consider front tracking approximate solutions to the p-system of
isentropic gas dynamics. At interaction times, the outgoing wave fronts have
the same strength as in the exact solution of the Riemann problem, but some
error is allowed in their speed. For large BV initial data, we construct
examples showing that the total variation of these approximate solutions can
become arbitrarily large, or even blow up in finite time. This happens even if
the density of the gas remains uniformly positive.


title: A Determinantal Formula for Catalan Tableaux and TASEP Probabilities

abstract:
  We present a determinantal formula for the steady state probability of each
state of the TASEP (Totally Asymmetric Simple Exclusion Process) with open
boundaries, a 1D particle model that has been studied extensively and displays
rich combinatorial structure. These steady state probabilities are computed by
the enumeration of Catalan tableaux, which are certain Young diagrams filled
with $\alpha$'s and $\beta$'s that satisfy some conditions on the rows and
columns. We construct a bijection from the Catalan tableaux to weighted lattice
paths on a Young diagram, and from this we enumerate the paths with a
determinantal formula, building upon a formula of Narayana that counts
unweighted lattice paths on a Young diagram. Finally, we provide a formula for
the enumeration of Catalan tableaux that satisfy a given condition on the rows,
which corresponds to the steady state probability that in the TASEP on a
lattice with $n$ sites, precisely $k$ of the sites are occupied by particles.
This formula is an $\alpha\ /\ \beta$ generalization of the Narayana numbers.


title:
On the foreshocks of strong earthquakes in the light of catastrophe
  theory

abstract:
  It is useful to consider the earthquakes in terms of catastrophe theory. In
the paper, we illustrate this statement by analysis foreshocks preceding the
strong earthquakes. We focused on the so-called catastrophe flags, and on the
triggers that cause the critical transitions. The analysis shows a sharp
increase of foreshock activity 3 h before the mainshock. This result is
reminiscent of the well-known activation of the ULF magnetic precursors of
earthquakes. Furthermore, we found that the characteristic frequency of
foreshock sequence decreases a few hours before the mainshock, which is
consistent with a prediction of the catastrophe theory. Finally, the analysis
testifies that the strong foreshocks seems may be triggers of mainshocks. The
idea is that the surface waves propagating outwards from the foreshock return
back to the vicinity of the epicenter after having made a complete revolution
around the Earth and induce there the mainshock.


title: GeV - PeV Neutrino Production and Oscillation in hidden jets from GRBs

abstract:
  Long gamma-ray bursts have been widely associated with collapsing massive
stars in the framework of collapsar model. High-energy neutrinos and photons
can be produced in the internal shocks of middle relativistic jets from
core-collapse supernova. Although photons can hardly escape, high-energy
neutrinos could be the only signature when the jets are hidden. We show that
using suitable parameters, high-energy neutrinos in GeV - PeV range can be
produced in the hidden jet inside the collapsar, thus demonstrating that these
objects are candidates to produce neutrinos with energies between 1 - 10 PeV
which were observed with IceCube. On the other hand, due to matter effects,
high-energy neutrinos may oscillate resonantly from one flavor to another
before leaving the star. Using two (solar, atmospheric and accelerator
parameters) and three neutrino mixing, we study the possibility of resonant
oscillation for these neutrinos created in internal shocks. Also we compute the
probabilities of neutrino oscillations in the matter at different distances
along the jet (before leaving the star) and after in vacuum, on their path to
Earth. Finally, neutrino flavor ratios on Earth are estimated.


title:
Real-Time Planning with Primitives for Dynamic Walking over Uneven
  Terrain

abstract:
  We present an algorithm for receding-horizon motion planning using a finite
family of motion primitives for underactuated dynamic walking over uneven
terrain. The motion primitives are defined as virtual holonomic constraints,
and the special structure of underactuated mechanical systems operating subject
to virtual constraints is used to construct closed-form solutions and a special
binary search tree that dramatically speed up motion planning. We propose a
greedy depth-first search and discuss improvement using energy-based
heuristics. The resulting algorithm can plan several footsteps ahead in a
fraction of a second for both the compass-gait walker and a planar
7-Degree-of-freedom/five-link walker.


title: On the Convergence of Decentralized Gradient Descent

abstract:
  Consider the consensus problem of minimizing $f(x)=\sum_{i=1}^n f_i(x)$ where
each $f_i$ is only known to one individual agent $i$ out of a connected network
of $n$ agents. All the agents shall collaboratively solve this problem and
obtain the solution subject to data exchanges restricted to between neighboring
agents. Such algorithms avoid the need of a fusion center, offer better network
load balance, and improve data privacy. We study the decentralized gradient
descent method in which each agent $i$ updates its variable $x_{(i)}$, which is
a local approximate to the unknown variable $x$, by combining the average of
its neighbors' with the negative gradient step $-\alpha \nabla f_i(x_{(i)})$.
The iteration is $$x_{(i)}(k+1) \gets \sum_{\text{neighbor} j \text{of} i}
w_{ij} x_{(j)}(k) - \alpha \nabla f_i(x_{(i)}(k)),\quad\text{for each agent}
i,$$ where the averaging coefficients form a symmetric doubly stochastic matrix
$W=[w_{ij}] \in \mathbb{R}^{n \times n}$. We analyze the convergence of this
iteration and derive its converge rate, assuming that each $f_i$ is proper
closed convex and lower bounded, $\nabla f_i$ is Lipschitz continuous with
constant $L_{f_i}$, and stepsize $\alpha$ is fixed. Provided that $\alpha <
O(1/L_h)$ where $L_h=\max_i\{L_{f_i}\}$, the objective error at the averaged
solution, $f(\frac{1}{n}\sum_i x_{(i)}(k))-f^*$, reduces at a speed of $O(1/k)$
until it reaches $O(\alpha)$. If $f_i$ are further (restricted) strongly
convex, then both $\frac{1}{n}\sum_i x_{(i)}(k)$ and each $x_{(i)}(k)$ converge
to the global minimizer $x^*$ at a linear rate until reaching an
$O(\alpha)$-neighborhood of $x^*$. We also develop an iteration for
decentralized basis pursuit and establish its linear convergence to an
$O(\alpha)$-neighborhood of the true unknown sparse signal.


title: Decaying Domain Walls in an Extended Gravity Model and Cosmology

abstract:
  We investigate cosmological consequences of an extended gravity model which
belongs to the same class studied by Accetta and Steinhardt in an extended
inflationary scenario. But we do not worry about inflation in our model;
instead, we focus on a topological object formed during cosmological phase
transitions. Although domain walls appear during first-order phase transitions
such as QCD transition, they decay at the end of the phase transition.
Therefore the "domain wall problem" does not exist in the suitable range of
pameters and, on the contrary, the "fragments" of walls may become seeds of
dark matter. A possible connection to "oscillating universe" model offered by
Morikawa et al. is also discussed.


title: On the Contou-Carrere Symbol for Surfaces

abstract:
  This is a preliminary report on the Contou-Carrere symbol for surfaces. It
consists of two parts. In the first part, we recall technical results needed to
define the symbol. The second part is where we compute all components of the
Coutou-Carrere symbol for surfaces, using iterated integrals over membranes.


title: The q=-1 phenomenon via homology concentration

abstract:
  We introduce a homological approach to exhibiting instances of Stembridge's
q=-1 phenomenon. This approach is shown to explain two important instances of
the phenomenon, namely that of partitions whose Ferrers diagrams fit in a
rectangle of fixed size and that of plane partitions fitting in a box of fixed
size. A more general framework of invariant and coinvariant complexes with
coefficients taken mod 2 is developed, and as a part of this story an analogous
homological result for necklaces is conjectured.


title:
Repulsive interactions of a lipid membrane with graphene in composite
  materials

abstract:
  The van der Waals interaction between a lipid membrane and a substrate
covered by a graphene sheet is investigated using the Lifshitz theory. The
reflection coefficients are obtained for a layered planar system submerged in
water. The dielectric response properties of the involved materials are also
specified and discussed. Our calculations show that a graphene covered
substrate can repel the biological membrane in water. This is attributed to the
significant changes in the response properties of the system due to the
monolayer graphene. It is also found that the van der Waals interaction is
mostly dominated by the presence of graphene, while the role of the particular
substrate is secondary.

categories: cond-mat.mes-hall cond-mat.mtrl-sci cond-mat.soft quant-ph


title: Scissors resonance in the quasi-continuum of Th, Pa and U isotopes

abstract:
  The gamma-ray strength function in the quasi-continuum has been measured for
231-233Th, 232,233Pa and 237-239U using the Oslo method. All eight nuclei show
a pronounced increase in gamma strength at omega_SR approx 2.4 MeV, which is
interpreted as the low-energy M1 scissors resonance (SR). The total strength is
found to be B_SR = 9-11 mu_N^2 when integrated over the 1 - 4 MeV gamma-energy
region. The SR displays a double-hump structure that is theoretically not
understood. Our results are compared with data from (gamma, gamma') experiments
and theoretical sum-rule estimates for a nuclear rigid-body moment of inertia.


title:
Survey of Period Variations of Superhumps in SU UMa-Type Dwarf Novae. V:
  The Fifth Year (2012-2013)

abstract:
  Continuing the project described by Kato et al. (2009a, arXiv:0905.1757), we
collected times of superhump maxima for SU UMa-type dwarf novae mainly observed
during the 2012-2013 season. We found three objects (V444 Peg, CSS J203937 and
MASTER J212624) having strongly positive period derivatives despite the long
orbital period (Porb). By using the period of growing stage (stage A)
superhumps, we obtained mass ratios for six objects. We characterized nine new
WZ Sge-type dwarf novae. We made a pilot survey of the decline rate of slowly
fading part of SU UMa-type and WZ Sge-type outbursts. The decline time scale
was found to generally follow the expected Porb^(1/4) dependence and WZ
Sge-type outbursts also generally follow this trend. There are some objects
which show slower decline rates, and we consider these objects good candidates
for period bouncers. We also studied unusual behavior in some objects,
including BK Lyn which made a transition from an ER UMa-type state to the
novalike (standstill) state in 2013 and unusually frequent occurrence of
superoutbursts in NY Ser and CR Boo. We applied least absolute shrinkage and
selection operator (Lasso) power spectral analysis, which has been proven to be
very effective in analyzing the Kepler data, to ground-based photometry of BK
Lyn and detected the dramatic disappearance of the signal of negative
superhumps in 2013. We suggested that the mass-transfer rates did not vary
strongly between the ER UMa-type state and novalike state in BK Lyn, and this
transition was less likely caused by a systematic variation of the
mass-transfer rate.


title:
Evidence for dipole nature of the low-energy $\gamma$ enhancement in
  $^{56}$Fe

abstract:
  The $\gamma$-ray strength function of $^{56}$Fe has been measured from
proton-$\gamma$ coincidences for excitation energies up to $\approx 11$ MeV.
The low-energy enhancement in the $\gamma$-ray strength function, which was
first discovered in the ($^3$He,$\alpha\gamma$)$^{56}$Fe reaction, is confirmed
with the ($p,p^\prime\gamma$)$^{56}$Fe experiment reported here. Angular
distributions of the $\gamma$ rays give for the first time evidence that the
enhancement is dominated by dipole transitions.


title:
Application of optimization method to the $x^4$ model in the Tsallis
  nonextensive statistics

abstract:
  We study the effects of the environment described by the Tsallis nonextensive
statistics on physical quantities using an optimization method in the case of
small deviation from the Boltzmann-Gibbs statistics. The $x^4$ model is used
and the density operator is restricted to be a gaussian form. The variational
parameter is the frequency $\Omega$ of a particle in the optimization method.
We obtain an approximate expression of free energy and of the expectation value
of $\beta m \Omega^2 x^2 /2$, where $\beta$ is the inverse of the temperature
and $m$ is the mass of a particle. Numerically, the optimized frequency is
estimated and the expectation value of $\beta m \Omega^2 x^2 /2$ is calculated.
The effects of the Tsallis nonextensive statistic for small deviation from the
Boltzmann-Gibbs statistics are found: 1) the frequency modulation of a particle
and 2) the variation of the expectation value of $\beta m \Omega^2 x^2 /2$ at
high temperature.


title: Transitional $\gamma$ strength in Cd isotopes

abstract:
  The level densities and $\gamma$-ray strength functions of
$^{105,106,111,112}$Cd have been extracted from particle-$\gamma$ coincidence
data using the Oslo method. The level densities are in very good agreement with
known levels at low excitation energy. The $\gamma$-ray strength functions
display no strong enhancement for low $\gamma$ energies. However, more
low-energy strength is apparent for $^{105,106}$Cd than for $^{111,112}$Cd. For
$\gamma$ energies above $\approx$ 4 MeV, there is evidence for some extra
strength, similar to what has been previously observed for the Sn isotopes. The
origin of this extra strength is unclear; it might be due to $E1$ and $M1$
transitions originating from neutron skin oscillations or the spin-flip
resonance, respectively.


title:
Isomorphism classes of finite dimensional connected Hopf algebras in
  positive characteristic

abstract:
  We classify all finite-dimensional connected Hopf algebras with large abelian
primitive spaces. We show that they are Hopf algebra extensions of restricted
enveloping algebras of certain restricted Lie algebras. For any abelian matched
pair associated with these extensions, we construct a cohomology group, which
classifies all the extensions up to equivalence. Moreover, we present a $1$-$1$
correspondence between the isomorphism classes and a group quotient of the
cohomology group deleting some exceptional points, where the group respects the
automorphisms of the abelian matched pair and the exceptional points represent
those restricted Lie algebra extensions.


title: The $\tau_2$ model and parafermions

abstract:
  Paul Fendley has recently found a "parafermionic" way to diagonalise a simple
solvable hamiltonian associated with the chiral Potts model. Here we indicate
how this method generalizes to the $\tau_2$ model with open boundaries and make
some comments.


title:
Detection of ultra high energy neutrinos by IceCube: Sterile neutrino
  scenario

abstract:
  The short-baseline neutrino oscillation experiments, the excess of radiation
from the measurement of the cosmic microwave background radiation, the
necessity of the nonbaryonic dark matter candidate and the depletion of the
neutrino flux in IceCube all seem to hint at new physics beyond the standard
model. An economical way to address these issues is to invoke the existence of
sterile neutrinos. We present simple extensions of the standard model with
additional three sterile neutrinos and discuss the corresponding PMNS like
neutrino flavor mixing matrix. The noteworthy features of the sterile neutrino
scenario advocated here is that the lightest one is almost degenerate with one
of the active neutrinos, the second sterile has mass of order eV and the
heaviest one is in the keV range. In the present scenario, the short baseline
anomaly is explained through $\Delta m^2\sim 1\, {\rm eV^2}$, the depletion of
muon neutrino flux in IceCube is explained through $\Delta m^2\sim 4.0\times
10^{-16}\, {\rm eV^2}$ and the dark matter problem is addressed through $\Delta
m^2\sim 1\, {\rm keV^2}$. Our proposed mixing matrix is also compatible with
the observed neutrino oscillation data. We show that the high energy muon and
the tau neutrino fluxes from Gamma Ray Bursts can be depleted in IceCube by as
much as 38% and 43% respectively. These substantial depletion in both muon and
tau neutrino fluxes is due to their small but sizable mixing with the sterile
neutrinos.


title:
Modulation of galactic cosmic rays during the unusual solar minimum
  between cycles 23 and 24

abstract:
  During the recent solar minimum between cycles 23 and 24 (solar minimum
$P_{23/24}$) the intensity of Galactic Cosmic Rays (GCRs) measured at the Earth
was the highest ever recorded since space age. It is the purpose of this paper
to resolve the most plausible mechanism for this unusually high intensity. A
GCR transport model in three-dimensional heliosphere based on a simulation of
Markov stochastic process is used to find the relation of cosmic ray modulation
to various transport parameters, including solar wind (SW) speed, distance of
heliospheric boundary, magnitude of interplanetary magnetic field (IMF) at the
Earth, tilt angle of heliospheric current sheet (HCS), values of parallel and
perpendicular diffusion coefficients. We calculate GCR proton energy spectra at
the Earth for the last three solar minima $P_{21/22}$, $P_{22/23}$, and
$P_{23/24}$, with the transport parameters obtained from observations. Besides
weak IMF magnitude and slow SW speed, we find that a possible low magnetic
turbulence, which increases the parallel diffusion and reduces the
perpendicular diffusion in the polar direction, might be an additional possible
mechanism for the high GCR intensity in the solar minimum $P_{23/24}$.


title: Feasibility Study of Real-Time Planning for Stereotactic Radiosurgery

abstract:
  Purpose: 3D rotational setup errors in radiotherapy are often ignored by most
clinics due to inability to correct or simulate them accurately and
efficiently. There are two types of rotation-related problems in a clinical
setting. One is to assess the affected dose distribution in real-time if
correction is not applied and the other one is to correct the rotational setup
errors prior to the initiation of the treatment. Here, we present our
analytical solutions to both problems.