title: PyPLN: a Distributed Platform for Natural Language Processing

abstract:
  This paper presents a distributed platform for Natural Language Processing
called PyPLN. PyPLN leverages a vast array of NLP and text processing open
source tools, managing the distribution of the workload on a variety of
configurations: from a single server to a cluster of linux servers. PyPLN is
developed using Python 2.7.3 but makes it very easy to incorporate other
softwares for specific tasks as long as a linux version is available. PyPLN
facilitates analyses both at document and corpus level, simplifying management
and publication of corpora and analytical results through an easy to use web
interface. In the current (beta) release, it supports English and Portuguese
languages with support to other languages planned for future releases. To
support the Portuguese language PyPLN uses the PALAVRAS parser\citep{Bick2000}.
Currently PyPLN offers the following features: Text extraction with encoding
normalization (to UTF-8), part-of-speech tagging, token frequency, semantic
annotation, n-gram extraction, word and sentence repertoire, and full-text
search across corpora. The platform is licensed as GPL-v3.


title: Dynamics on free-by-cyclic groups

abstract:
  Given a free-by-cyclic group $G = F_N \rtimes_\varphi \mathbb{Z}$ determined
by any outer automorphism $\varphi \in \mathrm{Out}(F_N)$ which is represented
by an expanding irreducible train-track map $f$, we construct a $K(G,1)$
$2$-complex $X$ called the folded mapping torus of $f$, and equip it with a
semiflow. We show that $X$ enjoys many similar properties to those proven by
Thurston and Fried for the mapping torus of a pseudo-Anosov homeomorphism. In
particular, we construct an open, convex cone $\mathcal{A} \subset
H^1(X;\mathbb{R}) = \mathrm{Hom}(G;\mathbb{R})$ containing the homomorphism
$u_0 \colon G \to \mathbb{Z}$ having $\mathrm{ker}(u_0) = F_N$, a homology
class $\epsilon \in H_1(X;\mathbb{R})$, and a continuous, convex, homogeneous
of degree $-1$ function $\mathfrak H\colon\mathcal{A} \to \mathbb{R}$ with the
following properties. Given any primitive integral class $u \in \mathcal{A}$
there is a graph $\Theta_u \subset X$ such that: (1) the inclusion $\Theta_u
\to X$ is $\pi_1$-injective and $\pi_1(\Theta_u) = \mathrm{ker}(u)$, (2)
$u(\epsilon) = \chi(\Theta_u)$, (3) $\Theta_u \subset X$ is a section of the
semiflow and the first return map to $\Theta_u$ is an expanding irreducible
train track map representing $\varphi_u \in \mathrm{Out}(\mathrm{ker}(u))$ such
that $G = \mathrm{ker}(u) \rtimes_{\varphi_u} \mathbb{Z}$, (4) the logarithm of
the stretch factor of $\varphi_u$ is precisely $\mathfrak H(u)$, (5) if
$\varphi$ was further assumed to be hyperbolic and fully irreducible then for
every primitive integral $u\in \mathcal{A}$ the automorphism $\varphi_u$ of
$\mathrm{ker}(u)$ is also hyperbolic and fully irreducible.


title:
Transport-entropy inequalities and deviation estimates for stochastic
  approximation schemes

abstract:
  We obtain new transport-entropy inequalities and, as a by-product, new
deviation estimates for the laws of two kinds of discrete stochastic
approximation schemes. The first one refers to the law of an Euler like
discretization scheme of a diffusion process at a fixed deterministic date and
the second one concerns the law of a stochastic approximation algorithm at a
given time-step. Our results notably improve and complete those obtained in
[Frikha, Menozzi,2012]. The key point is to properly quantify the contribution
of the diffusion term to the concentration regime. We also derive a general
non-asymptotic deviation bound for the difference between a function of the
trajectory of a continuous Euler scheme associated to a diffusion process and
its mean. Finally, we obtain non-asymptotic bound for stochastic approximation
with averaging of trajectories, in particular we prove that averaging a
stochastic approximation algorithm with a slow decreasing step sequence gives
rise to optimal concentration rate.


title: Design of Marx generators as a structured eigenvalue assignment

abstract:
  We consider the design problem for a Marx generator electrical network, a
pulsed power generator. The engineering specification of the design is that a
suitable resonance condition is satisfied by the circuit so that the energy
initially stored in a number of storage capacitors is transferred in finite
time to a single load capacitor which can then store the total energy and
deliver the pulse. We show that the components design can be conveniently cast
as a structured real eigenvalue assignment with significantly lower dimension
than the state size of the Marx circuit. Then we comment on the nontrivial
nature of this structured real eigenvalue assignment problem and present two
possible approaches to determine its solutions. A first symbolic approach
consists in the use of Gr\"obner basis representations, which allows us to
compute all the (finitely many) solutions. A second approach is based on
convexification of a nonconvex optimization problem with polynomial
constraints. We show that the symbolic method easily provides solutions for
networks up to six stages while the numerical method can reach up to seven and
eight stages. We also comment on the conjecture that for any number of stages
the problem has finitely many solutions, which is a necessary assumption for
the proposed methods to converge. We regard the proof of this conjecture as an
interesting challenge of general interest in the real algebraic geometry field.


title:
Borel summation of the small time expansion of the heat kernel. The
  scalar potential case

abstract:
  We study the Borel summability of the small time expansion of the heat kernel
for the Schr\"odinger operator in several dimensions. On the torus, we prove a
Poisson formula.


title: Circular Modes for Flat Beams in LHC

abstract:
  Typically x/y optical coupling is considered as unwanted and thus
suppressed--particular exclusions are electron and ionization coolers. Could
some special coupled modes be effectively applied for the LHC complex?
Apparently, the answer is positive: use of the circular modes in the injectors
with their transformation into planar modes in the LHC allows both the space
charge and beam-beam luminosity limitations to be significantly reduced, if not
practically eliminated.


title:
Exploiting Symmetry in Tensors for High Performance: Multiplication with
  Symmetric Tensors

abstract:
  Symmetric tensor operations arise in a wide variety of computations. However,
the benefits of exploiting symmetry in order to reduce storage and computation
is in conflict with a desire to simplify memory access patterns. In this paper,
we propose a blocked data structure (Blocked Compact Symmetric Storage) wherein
we consider the tensor by blocks and store only the unique blocks of a
symmetric tensor. We propose an algorithm-by-blocks, already shown of benefit
for matrix computations, that exploits this storage format by utilizing a
series of temporary tensors to avoid redundant computation. Further, partial
symmetry within temporaries is exploited to further avoid redundant storage and
redundant computation. A detailed analysis shows that, relative to storing and
computing with tensors without taking advantage of symmetry and partial
symmetry, storage requirements are reduced by a factor of $ O\left( m! \right)$
and computational requirements by a factor of $O\left( (m+1)!/2^m \right)$,
where $ m $ is the order of the tensor. However, as the analysis shows, care
must be taken in choosing the correct block size to ensure these storage and
computational benefits are achieved (particularly for low-order tensors). An
implementation demonstrates that storage is greatly reduced and the complexity
introduced by storing and computing with tensors by blocks is manageable.
Preliminary results demonstrate that computational time is also reduced. The
paper concludes with a discussion of how insights in this paper point to
opportunities for generalizing recent advances in the domain of linear algebra
libraries to the field of multi-linear computation.


title:
Equitability, mutual information, and the maximal information
  coefficient

abstract:
  Reshef et al. recently proposed a new statistical measure, the "maximal
information coefficient" (MIC), for quantifying arbitrary dependencies between
pairs of stochastic quantities. MIC is based on mutual information, a
fundamental quantity in information theory that is widely understood to serve
this need. MIC, however, is not an estimate of mutual information. Indeed, it
was claimed that MIC possesses a desirable mathematical property called
"equitability" that mutual information lacks. This was not proven; instead it
was argued solely through the analysis of simulated data. Here we show that
this claim, in fact, is incorrect. First we offer mathematical proof that no
(non-trivial) dependence measure satisfies the definition of equitability
proposed by Reshef et al.. We then propose a self-consistent and more general
definition of equitability that follows naturally from the Data Processing
Inequality. Mutual information satisfies this new definition of equitability
while MIC does not. Finally, we show that the simulation evidence offered by
Reshef et al. was artifactual. We conclude that estimating mutual information
is not only practical for many real-world applications, but also provides a
natural solution to the problem of quantifying associations in large data sets.

categories: q-bio.QM math.ST stat.ME stat.ML stat.TH


title: Phases and phase transitions in disordered quantum systems

abstract:
  These lecture notes give a pedagogical introduction to phase transitions in
disordered quantum systems and to the exotic Griffiths phases induced in their
vicinity. We first review some fundamental concepts in the physics of phase
transitions. We then derive criteria governing under what conditions spatial
disorder or randomness can change the properties of a phase transition. After
introducing the strong-disorder renormalization group method, we discuss in
detail some of the exotic phenomena arising at phase transitions in disordered
quantum systems. These include infinite-randomness criticality, rare regions
and quantum Griffiths singularities, as well as the smearing of phase
transitions. We also present a number of experimental examples.


title:
Entrainment of the intrinsic dynamics of single isolated neurons by
  natural-like input

abstract:
  Neuronal dynamics is intrinsically unstable, producing activity fluctuations
that are essentially scale-free. Here we show that while these scale-free
fluctuations are independent of temporal input statistics, they can be
entrained by input variation. Joint input output statistics and spike train
reproducibility in synaptically isolated cortical neurons were measured in
response to various input regimes over extended time scales (many minutes).
Response entrainment was found to be maximal when the input itself possesses
natural-like, scale-free statistics. We conclude that preference for natural
stimuli, often observed at the system level, exists already at the elementary,
single neuron level.


title:
A coordinated optical and X-ray spectroscopic campaign on HD179949:
  searching for planet-induced chromospheric and coronal activity

abstract:
  HD179949 is an F8V star, orbited by a close-in giant planet with a period of
~3 days. Previous studies suggested that the planet enhances the magnetic
activity of the parent star, producing a chromospheric hot spot which rotates
in phase with the planet orbit. However, this phenomenon is intermittent since
it was observed in several but not all seasons. A long-term monitoring of the
magnetic activity of HD179949 is required to study the amplitude and time
scales of star-planet interactions. In 2009 we performed a simultaneous optical
and X-ray spectroscopic campaign to monitor the magnetic activity of HD179949
during ~5 orbital periods and ~2 stellar rotations. We analyzed the CaII H&K
lines as a proxy for chromospheric activity, and we studied the X-ray emission
in search of flux modulations and to determine basic properties of the coronal
plasma. A detailed analysis of the flux in the cores of the CaII H&K lines and
a similar study of the X-ray photometry shows evidence of source variability,
including one flare. The analysis of the the time series of chromospheric data
indicates a modulation with a ~11 days period, compatible with the stellar
rotation period at high latitudes. Instead, the X-ray light curve suggests a
signal with a period of ~4 days, consistent with the presence of two active
regions on opposite hemispheres. The observed variability can be explained,
most likely, as due to rotational modulation and to intrinsic evolution of
chromospheric and coronal activity. There is no clear signature related to the
orbital motion of the planet, but the possibility that just a fraction of the
chromospheric and coronal variability is modulated with the orbital period of
the planet, or the stellar-planet beat period, cannot be excluded. We conclude
that any effect due to the presence of the planet is difficult to disentangle.


title: Longitudinal thermalization via the chromo-Weibel instability

abstract:
  Non-Abelian plasma instabilities play an important role in the
non-equilibrium dynamics of a weakly coupled quark-gluon plasma. Using the
discretized hard loop framework we calculate the time evolution of soft gluonic
fields in a longitudinally free streaming background. Extrapolating our results
to energies probed in relativistic heavy-ion collisions we find a pressure
anisotropy that persists for a few fm/c. However, the chromofields quickly
develop a Boltzmann longitudi- nal energy spectrum, suggesting fast
longitudinal thermalization of the quark gluon plasma even though it remains
momentum-space anisotropic. In this proceedings contribution we review our
recent numerical results, present new results for the scaling of the
isotropization time with the initial current fluctuation amplitude, and present
tests of the gauge invariance of the extracted longitudinal spectra.


title:
Quantization maps, algebra representation and non-commutative Fourier
  transform for Lie groups

abstract:
  The phase space given by the cotangent bundle of a Lie group appears in the
context of several models for physical systems. A representation for the
quantum system in terms of non-commutative functions on the (dual) Lie algebra,
and a generalized notion of (non-commutative) Fourier transform, different from
standard harmonic analysis, has been recently developed, and found several
applications, especially in the quantum gravity literature. We show that this
algebra representation can be defined on the sole basis of a quantization map
of the classical Poisson algebra, and identify the conditions for its
existence. In particular, the corresponding non-commutative star-product
carried by this representation is obtained directly from the quantization map
via deformation quantization. We then clarify under which conditions a unitary
intertwiner between such algebra representation and the usual group
representation can be constructed giving rise to the non-commutative plane
waves and consequently, the non-commutative Fourier transform. The compact
groups U(1) and SU(2) are considered for different choices of quantization
maps, such as the symmetric and the Duflo map, and we exhibit the corresponding
star-products, algebra representations and non-commutative plane waves.


title:
On Operator Theoretical Interpretations for some Classical Problems in
  Geometry and Differential Equatioins

abstract:
  A consequence of the Gauss Bonnet theorem is interpreted in term of operator
theory by Alain Connes in his book, Non Commutative geometry. In this note we
explain in details about his method. We also introduce an operator theoretical
nature for limit cycle theory.


title:
Possible latitude effects of Chern-Simons gravity on quantum
  interference

abstract:
  It has been recently suggested that possible effects of Chern-Simons gravity
on a quantum interferometer are dependent on the latitude and direction of the
interferometer on Earth in orbital motion around Sun. Continuing work initiated
in the earlier publication [Okawara, Yamada and Asada, Phys. Rev. Lett. 109,
231101 (2012)], we perform numerical calculations of time variation in the
induced phase shifts for nonequatorial cases. We show that the maximum phase
shift at any latitude might occur at 6, 0 (and 12), and 18 hours (in local
time) of each day, when the normal vector to the interferometer is vertical,
eastbound and northbound, respectively. If two identical interferometers were
located at different latitudes, the difference between two phase shifts that
are measured at the same local time would be $O(\sin \delta\varphi)$ for a
small latitude difference $\delta\varphi$. It might thus become maximally $\sim
20$ percents for $\delta\varphi \sim 10$ degrees, for instance.


title:
Density Profiles of CDM Microhalos and their Implications for
  Annihilation Boost Factors

abstract:
  In a standard cold dark matter (CDM) cosmology, microhalos at the CDM cutoff
scale are the first and smallest objects expected to form in the universe. Here
we present results of high resolution simulations of three representative
roughly Earth-mass microhalos in order to determine their inner density
profile. We find that CDM microhalos in simulations without a cutoff in the
power spectrum roughly follow the NFW density profile, just like the much
larger CDM halos on galaxy and galaxy cluster scales. But having a cutoff in
the initial power spectrum at a typical neutralino free streaming scale of
$10^{-7} M_{\odot}$ makes their inner density profiles considerably steeper,
i.e. $\rho \propto r^{-(1.3-1.4)}$, in good agreement with the results from
Ishiyama et al. (2010). An extrapolation of the halo and subhalo mass functions
down to the cutoff scale indicates that microhalos are extremely abundant
throughout the present day dark matter distribution and might contribute
significantly to indirect dark matter detection signals. Assuming a transition
from a NFW to a steeper inner profile ($\rho \propto r^{-1.4}$) two orders of
magnitude above the cutoff scale, the total boost factor for a Milky Way sized
dark matter halo increases from about 3.5 to 4. We further find that CDM
microhalo concentrations are consistent with the Bullock et al. (2001) model
and clearly rule out simplistic power law models for the mass dependence of
concentrations and subhalo annihilation, which would erroneously lead to very
large boost factors (a few hundred for galaxy halos and over 1000 for
clusters).


title: A Complete Model for R-parity Violation

abstract:
  We present a complete model whose low energy effective theory is the R-parity
violating NMSSM with a baryon number violating udd vertex of the MFV SUSY form,
leading to prompt LSP decay and evading the ever stronger LHC bounds on
low-scale R-parity conserving supersymmetry. MFV flavor structure is enforced
by gauging an SU(3) flavor symmetry at high energies. After the flavor group is
spontaneously broken, mass mixing between the standard model fields and heavy
vector-like quarks and leptons induces hierarchical Yukawa couplings which
depend on the mixing angles. The same mechanism generates the udd coupling,
explaining its shared structure. A discrete R-symmetry is imposed which forbids
all other dangerous lepton and baryon-number violating operators (including
Planck-suppressed operators) and simultaneously solves the mu problem. While
flavor constraints require the flavor gauge bosons to be outside of the reach
of the LHC, the vector-like top partners could lie below 1 TeV.


title:
The Galaxy-Halo/Subhalo connection: Mass relations and implications for
  some satellite occupational distributions

abstract:
  We infer the local stellar-to-halo/subhalo mass relations (MRs) for central
and satellite galaxies separately. We constraint this relations by using
several combinations of observational data, consisting of the total galaxy
stellar mass function, its decomposition into centrals and satellites, and the
projected two-point correlation functions measured in different stellar mass
bins. The differences among the resulting MRs are within the model-fit
uncertainties (which are very small, smaller than the intrinsic scatter between
galaxy and halo mass), no matter what combination of data are used. We also
constrain the values of the intrinsic scatter around the central-halo (CH) and
satellite-subhalo (SS) MRs assuming them to be constant: sigma_c= 0.168+-0.051
dex and sigma_s = 0.172+-0.057 dex, respectively. The CH and SS MRs are
actually different, in particular when we take the subhalo mass at the
present-day epoch instead of at their accretion time. We calculate several
population statistics. We find that the central galaxy is not on average within
the mass distribution of the most-massive satellite, even for cluster-sized
halos, i.e., centrals are not a mere realization of the high-end of the
satellite mass function; however for > 3x10^13 msun halos, ~15% of centrals
could be. We also find that the probabilities of MW-sized halos of having N
Magellanic-Clouds (MCs)-sized satellites agree well with observational
measures; for a halo mass of 2x10^12 msun, the probability to have 2 MCs is
5.4%, but if we exclude those systems with satellites larger than the MCs, then
the probability decreases to <2.2%.


title: Determining Reflectance Spectra of Surfaces and Clouds on Exoplanets

abstract:
  Planned missions will spatially resolve temperate terrestrial planets from
their host star. Although reflected light from such a planet encodes
information about its surface, it has not been shown how to establish surface
characteristics of a planet without assuming known surfaces to begin with. We
present a re-analysis of disk-integrated, time-resolved, multiband photometry
of Earth obtained by the Deep Impact spacecraft as part of the EPOXI Mission of
Opportunity. We extract reflectance spectra of clouds, ocean and land without a
priori knowledge of the numbers or colors of these surfaces. We show that the
inverse problem of extracting surface spectra from such data is a novel and
extreme instance of spectral unmixing, a well-studied problem in remote
sensing. Principal component analysis is used to determine an appropriate
number of model surfaces with which to interpret the data. Shrink-wrapping a
simplex to the color excursions of the planet yields a conservative estimate of
the planet's endmember spectra. The resulting surface maps are unphysical,
however, requiring negative or larger-than-unity surface coverage at certain
locations. Our "rotational unmixing" supersedes the endmember analysis by
simultaneously solving for the surface spectra and their geographical
distributions on the planet, under the assumption of diffuse reflection and
known viewing geometry. We use a Markov Chain Monte Carlo to determine best-fit
parameters and their uncertainties. The resulting albedo spectra are similar to
clouds, ocean and land seen through a Rayleigh-scattering atmosphere. This
study suggests that future direct-imaging efforts could identify and map
unknown surfaces and clouds on exoplanets.


title: Discovering young stars in the Gum 31 region with infrared observations

abstract:
  Context. The Gum 31 bubble containing the stellar cluster NGC 3324 is a
poorly-studied young region close to the Carina Nebula.
  Aims. We are aiming to characterise the young stellar and protostellar
population in and around Gum 31 and to investigate the star-formation process
in this region.
  Methods. We identify candidate young stellar objects from Spitzer, WISE, and
Herschel data. Combining these, we analyse the spectral energy distributions of
the candidate young stellar objects. With density and temperature maps obtained
from Herschel data and comparisons to a 'collect and collapse' scenario for the
region we are able to further constrain the characteristics of the region as a
whole.
  Results. 661 candidate young stellar objects are found from WISE data, 91
protostar candidates are detected through Herschel observations in a 1.0 deg x
1.1 deg area. Most of these objects are found in small clusters or are well
aligned with the H II bubble. We also identify the sources of Herbig-Haro jets.
The infrared morphology of the region suggests that it is part of the larger
Carina Nebula complex.
  Conclusions. The location of the candidate young stellar objects in the rim
of the H II bubble is suggestive of their being triggered by a 'collect and
collapse' scenario, which agrees well with the observed parameters of the
region. Some candidate young stellar objects are found in the heads of pillars,
which points towards radiative triggering of star formation. Thus, we find
evidence that in the region different mechanisms of triggered star formation
are at work. Correcting the number of candidate young stellar objects for
contamination we find ~ 600 young stellar objects in Gum 31 above our
completeness limit of about 1 M_sol. Extrapolating the intital mass function
down to 0.1 M_sol, we estimate a total population of ~ 5000 young stars for the
region.


title:
Tidal Stirring of Disky Dwarfs with Shallow Dark Matter Density
  Profiles: Enhanced Transformation into Dwarf Spheroidals

abstract:
  (Abridged) The origin of dSphs in the Local Group (LG) remains an enigma. The
tidal stirring model posits that late-type, rotationally-supported dwarfs
resembling present-day dwarf irregular (dIrr) galaxies can transform into dSphs
via interactions with Milky Way-sized hosts. Using collisionless N-body
simulations, we investigate for the first time how tidal stirring depends on
the dark matter (DM) density distribution in the central stellar region of the
progenitor disky dwarf. Specifically, we explore various asymptotic inner
slopes gamma of the dwarf DM density profiles (rho \propto r^{-gamma} as r ->
0). For a given orbit inside the primary, rotationally-supported dwarfs
embedded in DM halos with core-like density distributions (gamma = 0.2) and
mild density cusps (gamma = 0.6) demonstrate a substantially enhanced
likelihood and efficiency of transformation into dSphs compared to their
counterparts with steeper DM density profiles (gamma = 1). Such shallow DM
distributions are akin to those of observed dIrrs, highlighting tidal stirring
as a plausible model for the LG morphology-density relation. When gamma <1, a
single pericentric passage can induce dSph formation and disky dwarfs on
low-eccentricity or large-pericenter orbits are able to transform into dSphs;
these new results allow the tidal stirring model to explain the existence of
virtually all known dSphs across a wide range of distances from their hosts. A
subset of rotationally-supported dwarfs with gamma <1 are eventually disrupted
by the primary; those that survive as dSphs are generally on orbits that are
biased towards lower eccentricities and/or larger pericenters relative to those
of typical CDM satellites. The latter could explain the rather peculiar orbits
of several classic LG dSphs such as Fornax, Leo I, Tucana, and Cetus.


title:
PS1-10afx at z=1.388: Pan-STARRS1 Discovery of a New Type of
  Superluminous Supernova

abstract:
  We present the Pan-STARRS1 discovery of PS1-10afx, a unique
hydrogen-deficient superluminous supernova (SLSN) at z=1.388. The light curve
peaked at z_P1=21.7 mag, making PS1-10afx comparable to the most luminous known
SNe, with M_u = -22.3 mag. Our extensive optical and NIR observations indicate
that the bolometric light curve of PS1-10afx rose on the unusually fast
timescale of ~12 d to the extraordinary peak luminosity of 4.1e44 erg/s (M_bol
= -22.8 mag) and subsequently faded rapidly. Equally important, the SED is
unusually red for a SLSN, with a color temperature of 6800 K near maximum
light, in contrast to previous H-poor SLSNe, which are bright in the UV. The
spectra more closely resemble those of a normal SN Ic than any known SLSN, with
a photospheric velocity of 11,000 km/s and evidence for line blanketing in the
rest-frame UV. Despite the fast rise, these parameters imply a very large
emitting radius (>5e15 cm). We demonstrate that no existing theoretical model
can satisfactorily explain this combination of properties: (i) a nickel-powered
light curve cannot match the combination of high peak luminosity with the fast
timescale; (ii) models powered by the spindown energy of a rapidly-rotating
magnetar predict significantly hotter and faster ejecta; and (iii) models
invoking shock breakout through a dense circumstellar medium cannot explain the
observed spectra or color evolution. The host galaxy is well detected in
pre-explosion imaging with a luminosity near L*, a star formation rate of 15
M_sun/yr, and is fairly massive (2e10 M_sun), with a stellar population age of
1e8 yr, also in contrast to the dwarf hosts of known H-poor SLSNe. PS1-10afx is
distinct from known examples of SLSNe in its spectra, colors, light-curve
shape, and host galaxy properties, suggesting that it resulted from a different
channel than other hydrogen-poor SLSNe.


title: Completeness of Imaging Surveys for Eccentric Exoplanets

abstract:
  The detection of exoplanets through direct imaging has produced numerous new
positive identifications in recent years. The technique is biased towards
planets at wide separations due to the difficulty in removing the stellar
signature at small angular separations. Planets in eccentric orbits will thus
move in and out of the detectable region around a star as a function of time.
Here we use the known diversity of orbital eccentricities to determine the
range of orbits which may lie beneath the detection threshold of current
surveys. We quantify the percentage of the orbit which yields a detectable
signature as a function of semi-major axis, eccentricity, and orbital
inclination and estimate the fraction of planets which likely remain hidden by
the flux of the host star.


title: High redshift blazars

abstract:
  Blazars are sources whose jet is pointing to us. Since their jets are
relativistic, the flux is greatly amplified in the direction of motion, making
blazars the most powerful persistent objects in the Universe. This is true at
all frequencies, but especially where their spectrum peaks. Although the
spectrum of moderate powerful sources peaks in the ~GeV range, extremely
powerful sources at high redshifts peak in the ~MeV band. This implies that the
hard X-ray band is the optimal one to find powerful blazars beyond a redshift
of ~4. First indications strongly suggest that powerful high-z blazars harbor
the most massive and active early black holes, exceeding a billion solar
masses. Since for each detected blazars there must exist hundreds of similar,
but misaligned, sources, the search for high-z blazars is becoming competitive
with the search of early massive black holes using radio-quiet quasars. Finding
how the two populations of black holes (one in jetted sources, the other in
radio-quiet objects) evolve in redshift will shed light on the growth of the
most massive black holes and possibly on the feedback between the central
engine and the rest of the host galaxy.


title: Baryogenesis from dark matter

abstract:
  We consider the possibility that some primordial fields decay purely into the
dark sector creating asymmetric dark matter. This asymmetry is subsequently
transmuted into leptons and baryons. Within this paradigm we compute the amount
of asymmetric dark matter created from the out of equilibrium decays of the
primordial fields with CP violating Yukawa couplings. The dark matter asymmetry
is then transferred to the visible sector by the asymmetry transfer equation
and generates an excess of $B-L$. Baryogenesis occurs via sphaleron processes
which conserve $B-L$ but violate $B+L$. A mechanism for the annihilation of the
symmetric component of dark matter is also discussed. The model leads to
multi-component dark matter consisting of both bosonic and fermionic
components.


title: Ground-state Energies of Spinless Free Fermions and Hard-core Bosons

abstract:
  We compare the groundstate energies of bosons and fermions with the same form
of the Hamiltonian. If both are noninteracting, the groundstate energy of
bosons is always lower, owing to Bose-Einstein Condensation. However, the
comparison is nontrivial when bosons do interact. We first prove that, when the
hopping is unfrustrated (all the hopping amplitudes are non-negative),
hard-core bosons still must have a lower groundstate energy than the fermions.
When the hopping is frustrated, bosons can have higher groundstate energy than
fermions. We prove rigorously that this inversion indeed occurs in several
examples, using various techniques.


title: Is there evidence for additional neutrino species from cosmology?

abstract:
  It has been suggested that recent cosmological and flavor-oscillation data
favor the existence of additional neutrino species beyond the three predicted
by the Standard Model of particle physics. We apply Bayesian model selection to
determine whether there is indeed any evidence from current cosmological
datasets for the standard cosmological model to be extended to include
additional neutrino flavors. The datasets employed include cosmic microwave
background temperature, polarization and lensing power spectra, and
measurements of the baryon acoustic oscillation scale and the Hubble constant.
We also consider other extensions to the standard neutrino model, such as
massive neutrinos, and possible degeneracies with other cosmological
parameters. The Bayesian evidence indicates that current cosmological data do
not require any non-standard neutrino properties.


title: Walls, Lines, and Spectral Dualities in 3d Gauge Theories

abstract:
  In this paper we analyze various half-BPS defects in a general three
dimensional N=2 supersymmetric gauge theory T. They correspond to closed paths
in SUSY parameter space and their tension is computed by evaluating period
integrals along these paths. In addition to such defects, we also study wall
defects that interpolate between T and its SL(2,Z) transform by coupling the 3d
theory to a 4d theory with S-duality wall. We propose a novel spectral duality
between 3d gauge theories and integrable systems. This duality complements a
similar duality discovered by Nekrasov and Shatashvili. As another application,
for 3d N=2 theories associated with knots and 3-manifolds we compute periods of
(super) A-polynomial curves and relate the results with the spectrum of domain
walls and line operators.


title: New insights on hadron acceleration at supernova remnant shocks

abstract:
  We outline the main features of nuclei acceleration at supernova remnant
forward shocks, stressing the crucial role played by self-amplified magnetic
fields in determining the energy spectrum observed in this class of sources. In
particular, we show how the standard predictions of the non-linear theory of
diffusive shock acceleration has to be completed with an additional ingredient,
which we propose to be the enhanced velocity of the magnetic irregularities
particles scatter against, to reconcile the theory of efficient particle
acceleration with recent observations of gamma-ray bright supernova remnants.


title: Adaptive Control of Scalar Plants in the Presence of Unmodeled Dynamics

abstract:
  Robust adaptive control of scalar plants in the presence of unmodeled
dynamics is established in this paper. It is shown that implementation of a
projection algorithm with standard adaptive control of a scalar plant ensures
global boundedness of the overall adaptive system for a class of unmodeled
dynamics.


title:
Precise High-Cadence Time Series of Five Variable Young Stars in Auriga
  with MOST

abstract:
  To explore young star variability on a large range of timescales, we have
used the MOST satellite to obtain 24 days of continuous, sub-minute cadence,
high-precision optical photometry on a field of classical and weak-lined T
Tauri stars (TTS) in the Taurus-Auriga star formation complex. Observations of
AB Aurigae, SU Aurigae, V396 Aurigae, V397 Aurigae, and HD 31305 reveal
brightness fluctuations at the 1-10% level on timescales of hours to weeks. We
have further assessed the variability properties with Fourier, wavelet, and
autocorrelation techniques, identifying one significant period per star. We
present spot models in an attempt to fit the periodicities, but find that we
cannot fully account for the observed variability. Rather, all stars exhibit a
mixture of periodic and aperiodic behavior, with the latter dominating
stochastically on timescales less than several days. After removal of the main
periodicity, periodograms for each light curve display power law trends
consistent with those seen for other young accreting stars. Several of our
targets exhibited unusual variability patterns not anticipated by prior
studies, and we propose that this behavior originates with the circumstellar
disks. The MOST observations underscore the need for investigation of TTS light
variations on a wide range of timescales in order to elucidate the physical
processes responsible; we provide guidelines for future time series
observations.


title: Fixed-to-Variable Length Distribution Matching

abstract:
  Fixed-to-variable length (f2v) matchers are used to reversibly transform an
input sequence of independent and uniformly distributed bits into an output
sequence of bits that are (approximately) independent and distributed according
to a target distribution. The degree of approximation is measured by the
informational divergence between the output distribution and the target
distribution. An algorithm is developed that efficiently finds optimal f2v
codes. It is shown that by encoding the input bits blockwise, the informational
divergence per bit approaches zero as the block length approaches infinity. A
relation to data compression by Tunstall coding is established.


title:
Defect states and excitations in a Mott insulator with orbital degrees
  of freedom: Mott-Hubbard gap versus optical and transport gaps in doped
  systems

abstract:
  We address the role played by charged defects in doped Mott insulators with
active orbital degrees of freedom. It is observed that defects feature a rather
complex and rich physics, which is well captured by a degenerate Hubbard model
extended by terms that describe crystal-field splittings and orbital-lattice
coupling, as well as by terms generated by defects such as the Coulomb
potential terms that act both on doped holes and on electrons within occupied
orbitals at undoped sites. We show that the multiplet structure of the excited
states generated in such systems by strong electron interactions is well
described within the unrestricted Hartree-Fock approximation, once the symmetry
breaking caused by the onset of magnetic and orbital order is taken into
account. Furthermore, we uncover new spectral features that arise within the
Mott-Hubbard gap and in the multiplet spectrum at high energies due to the
presence of defect states and strong correlations. These features reflect the
action on electrons/holes of the generalized defect potential that affects
charge and orbital degrees of freedom, and indirectly also spin ones. The
present study elucidates the mechanism behind the Coulomb gap appearing in the
band of defect states and investigates the dependence on the electron-electron
interactions and the screening by the orbital polarization field. As an
illustrative example of our general approach, we present explicit calculations
for the model describing three t_2g orbital flavors in the perovskite vanadates
doped by divalent Sr or Ca ions, such as in La_(1-x)Sr_xVO_3 and
Y_(1-x)Ca_xVO_3 systems. We analyze the orbital densities at vanadium ions in
the vicinity of defects, and the excited defect states which determine the
optical and transport gaps in doped systems.


title: Multiple ionization of neon by soft X-rays at ultrahigh intensity

abstract:
  At the free-electron laser FLASH, multiple ionization of neon atoms was
quantitatively investigated at 93.0 eV and 90.5 eV photon energy. For ion
charge states up to 6+, we compare the respective absolute photoionization
yields with results from a minimal model and an elaborate description. Both
approaches are based on rate equations and take into acccout a Gaussian spatial
intensity distribution of the laser beam. From the comparison we conclude, that
photoionization up to a charge of 5+ can be described by the minimal model. For
higher charges, the experimental ionization yields systematically exceed the
elaborate rate based prediction.


title: A multiwavelength view of star-disk interaction in NGC 2264

abstract:
  Variability is a signature property of cool young stars, particularly for
those surrounded by disks. Traditional single-band time series display complex
features associated with accretion, disk structure, and accompanying stellar
activity, but these processes are challenging to model. To make progress in
connecting observed time domain properties with the underlying physics of young
stars and their disks, we have embarked on an unprecedented multiwavelength
monitoring campaign: the Coordinated Synoptic Investigation of NGC 2264 ("CSI
2264"). Beginning in December 2011, CSI 2264 has acquired 30 continuous days of
mid-infrared time series from Spitzer, simultaneous optical monitoring from
CoRoT and MOST, X-ray observations with Chandra, as well as complementary data
from a number of ground-based telescopes. The extraordinary photometric
precision, cadence, and time baseline of these observations enable detailed
correlation of variability properties at different wavelengths, corresponding
to locations from the stellar surface to the inner AU of the disk. We present
the early results of the program, and discuss the need for further modeling
efforts into young stars and their disks.


title:
Measurement of the Radius of Neutron Stars with High S/N Quiescent
  Low-mass X-ray Binaries in Globular Clusters

abstract:
  This paper presents the measurement of the neutron star (NS) radius using the
thermal spectra from quiescent low-mass X-ray binaries (qLMXBs) inside globular
clusters (GCs). Recent observations of NSs have presented evidence that cold
ultra dense matter -- present in the core of NSs -- is best described by
"normal matter" equations of state (EoSs). Such EoSs predict that the radii of
NSs, Rns, are quasi-constant (within measurement errors, of ~10%) for
astrophysically relevant masses (Mns > 0.5 Msun). The present work adopts this
theoretical prediction as an assumption, and uses it to constrain a single Rns
value from five qLMXB targets with available high signal-to-noise X-ray
spectroscopic data. Employing a Markov-Chain Monte-Carlo approach, we produce
the marginalized posterior distribution for Rns, constrained to be the same
value for all five NSs in the sample. An effort was made to include all
quantifiable sources of uncertainty into the uncertainty of the quoted radius
measurement. These include the uncertainties in the distances to the GCs, the
uncertainties due to the Galactic absorption in the direction of the GCs, and
the possibility of a hard power-law spectral component for count excesses at
high photon energy, which are observed in some qLMXBs in the Galactic plane.
Using conservative assumptions,we found that the radius, common to the five
qLMXBs and constant for a wide range of masses, lies in the low range of
possible NS radii, Rns=9.1(+1.3)(-1.5) km (90%-confidence). Such a value is
consistent with low-res equations of state. We compare this result with
previous radius measurements of NSs from various analyses of different types of
systems. In addition, we compare the spectral analyses of individual qLMXBs to
previous works.


title:
Asymptotic theory of magnetic island saturation in equilibria with a
  finite current gradient

abstract:
  A novel asymptotic matching procedure is developed to revisit the problem of
magnetic island saturation in case of a finite current gradient at the rational
surface. Nonlinear dispersion relation is derived for saturated magnetic
island. It is shown that arbitrary normalization factors that were present in
previous theories are fully specified with the asymptotic matching.


title: Evidence for and Obstructions to Non-Linear Partially Massless Gravity

abstract:
  Non-linear partially massless (PM) gravity, if it exists, is a theory of
massive gravity in which the graviton has four propagating degrees of freedom.
In PM gravity, a scalar gauge symmetry removes one of the five modes of the
massive graviton. This symmetry ties the value of the cosmological constant to
the mass of the graviton, which in turn can be kept small in a technically
natural way. Thus PM gravity could offer a compelling solution to the old
cosmological constant problem. In this work we look for such a theory among the
known ghost-free massive gravity models with a de Sitter reference metric. We
find that despite the existence of strong supporting evidence for the existence
of a PM theory of gravity, technical obstructions arise which preclude its
formulation using the standard massive gravity framework.


title:
Efficient classical density-functional theories of rigid-molecular
  fluids and a simplified free energy functional for liquid water

abstract:
  Classical density-functional theory provides an efficient alternative to
molecular dynamics simulations for understanding the equilibrium properties of
inhomogeneous fluids. However, application of density-functional theory to
multi-site molecular fluids has so far been limited by complications due to the
implicit molecular geometry constraints on the site densities, whose resolution
typically requires expensive Monte Carlo methods. Here, we present a general
scheme of circumventing this so-called inversion problem: compressed
representations of the orientation density. This approach allows us to combine
the superior iterative convergence properties of multipole representations of
the fluid configuration with the improved accuracy of site-density functionals.
Next, from a computational perspective, we show how to extend the DFT++
algebraic formulation of electronic density-functional theory to the classical
fluid case and present a basis-independent discretization of our formulation
for molecular classical density-functional theory. Finally, armed with the
above general framework, we construct a simplified free-energy functional for
water which captures the radial distributions, cavitation energies, and the
linear and non-linear dielectric response of liquid water. The resulting
approach will enable efficient and reliable first-principles studies of
atomic-scale processes in contact with solution or other liquid environments.


title:
Strain-induced transitions to quantum chaos and effective time-reversal
  symmetry breaking in triangular graphene nanoflakes

abstract:
  We investigate the effect of strain-induced gauge fields on statistical
distribution of energy levels of triangular graphene nanoflakes with zigzag
edges. In the absence of strain fields but in the presence of weak potential
disorder such systems were found in Ref. [1] to display the spectral statistics
of the Gaussian unitary ensemble (GUE) due to the effective time-reversal
(symplectic) symmetry breaking. Here show that, in the absence of disorder,
strain fields may solely lead to spectral fluctuations of GUE providing a
nanoflake is deformed such that all its geometric symmetries are broken. In a
particular case when a single mirror symmetry is preserved the spectral
statistics follow the Gaussian orthogonal ensemble (GOE) rather then GUE. The
corresponding transitions to quantum chaos are rationalized by means of
additive random-matrix models and the analogy between strain-induced gauge
fields and real magnetic fields is discussed.


title: Kinetics of the disordered Bose gas with collisions

abstract:
  We discuss the kinetics of the disordered interacting Bose gas using the
Boltzmann transport equation. The theory may serve as a unifying framework for
studying questions of dynamics of the expanding Bose gas at different stages of
the expansion. We show that the transport theory allows us to straightforwardly
reproduce and generalize a number of results previously obtained from
microscopic models in different formalisms. Based on estimates for the
interparticle scattering rates, we discuss the relevance of interaction effects
for the localization problem in the interacting disordered Bose gas. We argue
that, if the number of particles is large enough, the size of the expanding
cloud may exceed the localization length. We describe the spreading of the wave
packet in this regime as collision-induced diffusion and compare the obtained
rate of expansion to known results on subdiffusive spreading in nonlinear
disordered lattices.


title:
Serverification of Molecular Modeling Applications: the Rosetta Online
  Server that Includes Everyone (ROSIE)

abstract:
  The Rosetta molecular modeling software package provides experimentally
tested and rapidly evolving tools for the 3D structure prediction and
high-resolution design of proteins, nucleic acids, and a growing number of
non-natural polymers. Despite its free availability to academic users and
improving documentation, use of Rosetta has largely remained confined to
developers and their immediate collaborators due to the code's difficulty of
use, the requirement for large computational resources, and the unavailability
of servers for most of the Rosetta applications. Here, we present a unified web
framework for Rosetta applications called ROSIE (Rosetta Online Server that
Includes Everyone). ROSIE provides (a) a common user interface for Rosetta
protocols, (b) a stable application programming interface for developers to add
additional protocols, (c) a flexible back-end to allow leveraging of computer
cluster resources shared by RosettaCommons member institutions, and (d)
centralized administration by the RosettaCommons to ensure continuous
maintenance. This paper describes the ROSIE server infrastructure, a
step-by-step 'serverification' protocol for use by Rosetta developers, and the
deployment of the first nine ROSIE applications by six separate developer
teams: Docking, RNA de novo, ERRASER, Antibody, Sequence Tolerance,
Supercharge, Beta peptide design, NCBB design, and VIP redesign. As illustrated
by the number and diversity of these applications, ROSIE offers a general and
speedy paradigm for serverification of Rosetta applications that incurs
negligible cost to developers and lowers barriers to Rosetta use for the
broader biological community. ROSIE is available at
http://rosie.rosettacommons.org.


title: The holographic Ricci dark energy and its possible doomsdays

abstract:
  It is well known that the holographic Ricci dark energy can induce some
future doomsdays in the evolution of the universe. Here we analyse the possible
avoidance of those doomsdays by invoking a modification to general relativity
on the form of curvature effects.


title: What We've Learned from Heavy Flavour Experiments Since CKM2010

abstract:
  A summary of the latest experimental results in heavy flavour physics is
presented.


title:
Isostables, isochrons, and Koopman spectrum for the action-angle
  representation of stable fixed point dynamics

abstract:
  For asymptotically periodic systems, a powerful (phase) reduction of the
dynamics is obtained by computing the so-called isochrons, i.e. the sets of
points that converge toward the same trajectory on the limit cycle. Motivated
by the analysis of excitable systems, a similar reduction has been attempted
for non-periodic systems admitting a stable fixed point. In this case, the
isochrons can still be defined but they do not capture the asymptotic behavior
of the trajectories. Instead, the sets of interest-that we call isostables-are
defined in literature as the sets of points that converge toward the same
trajectory on the stable slow manifold of the fixed point. However, it turns
out that this definition of the isostables holds only for systems with
slow-fast dynamics. Also, efficient methods for computing the isostables are
missing.
  The present paper provides a general framework for the definition and the
computation of the isostables of stable fixed points, which is based on the
spectral properties of the so-called Koopman operator. More precisely, the
isostables are defined as the level sets of a particular eigenfunction of the
Koopman operator. Through this approach, the isostables are unique and
well-defined objects related to the asymptotic properties of the system. Also,
the framework reveals that the isostables and the isochrons are two different
but complementary notions which define a set of action-angle coordinates for
the dynamics. In addition, an efficient algorithm for computing the isostables
is obtained, which relies on the evaluation of Laplace averages along the
trajectories. The method is illustrated with the excitable FitzHugh-Nagumo
model and with the Lorenz model. Finally, we discuss how these methods based on
the Koopman operator framework relate to the global linearization of the system
and to the derivation of special Lyapunov functions.


title: On extremal self-dual codes of length 120

abstract:
  We prove that the only primes which may divide the order of the automorphism
group of a putative binary self-dual doubly-even [120, 60, 24] code are 2, 3,
5, 7, 19, 23 and 29. Furthermore we prove that automorphisms of prime order $p
\geq 5$ have a unique cycle structure.


title:
Remarks on the Fundamental Lemma for stable twisted Endoscopy of
  Classical Groups

abstract:
  The twisted fundamental lemmas for three series of stable twisted endoscopy
(Sp_{2n} to PGL_{2n+1}, GSpin_{2n+1} to GL_{2n}\times GL_1, Sp_{2n} to
SO_{2n+2}) will be reduced to a fundamental-lemma-like statement for ordinary
(i.e. untwisted) stable orbital integrals on the groups $\SO_{2n+1}$ of type
$B_n$ resp. $\SP_{2n}$ of type $C_n$. This manusript, written around 2001,
anticipates similar results of Waldspurger (2008), and may be used to reduce
the twisted fundamental lemma to the work of Ngo. The original aim was to
reduce the fundumantal lemma for the lift from Sp_4 to PGL_5 to the twisted
fundamental lemma for the lift from GSp_4=GSpin_5 to Gl_4 \times GL_1.


title: On the energy dependence of the D^+/D^- production asymmetry

abstract:
  In this paper we discuss the origin of the asymmetry present in D meson
production and its energy dependence. In particular, we have applied the meson
cloud model to calculate the asymmetries in D^-/D^+ meson production in high
energy p-p collisions and find a good agreement with recent LHCb data. Although
small, this non-vanishing asymmetry may shed light on the role played by the
charm meson cloud of the proton.


title: Monge equation of arbitrary degree in 1 + 1 space

abstract:
  Solution of Monge equation of arbitrary degree (non linear differential
equation n-orden) is connected with solution of functional equation for 4
functions with 4 different arguments. Some number solutions of this equation is
represented in explicit form.


title: Unavoidable decoherence in the quantum control of an unknown state

abstract:
  A common objective for quantum control is to force a quantum system,
initially in an unknown state, into a particular target subspace. We show that
if the subspace is required to be a decoherence-free subspace of dimension
greater than 1, then such control must be decoherent. That is, it will take
almost any pure state to a mixed state. We make no assumptions about the
control mechanism, but our result implies that for this purpose coherent
control offers no advantage, in principle, over the obvious measurement-based
feedback protocol.


title:
Variance reduction using antithetic variables for a nonlinear convex
  stochastic homogenization problem

abstract:
  We consider a nonlinear convex stochastic homogenization problem, in a
stationary setting. In practice, the deterministic homogenized energy density
can only be approximated by a random apparent energy density, obtained by
solving the corrector problem on a truncated domain.
  We show that the technique of antithetic variables can be used to reduce the
variance of the computed quantities, and thereby decrease the computational
cost at equal accuracy. This leads to an efficient approach for approximating
expectations of the apparent homogenized energy density and of related
quantities.
  The efficiency of the approach is numerically illustrated on several test
cases. Some elements of analysis are also provided.


title: Metric properties and distortion in some nilpotent groups of matrices

abstract:
  Metric estimates are quantities that approximate the word metric of a
finitely presented group up to multiplicative constants. In this paper, they
are computed for some nilpotent groups and used to compute the distortion
functions of several embeddings between them.


title: A Comprehensive Model of Dark Energy, Inflation AND Black Holes

abstract:
  We derive two new equations of quantum gravity and combine them with
reinterpretations of previously proposed concepts of dark energy, black holes,
inflation, the arrow of time and the energy at which rest-mass first manifests
itself into a theory which may be a first step toward a comprehensive
description of all these phenomena. The resulting theory also predicts new
tests which can be experimentally checked within a few years.


title:
Construction of free commutative integro-differential algebras by the
  method of Gr\"{o}bner-Shirshov bases

abstract:
  In this paper, we construct a canonical linear basis for free commutative
integro-differential algebras by applying the method of Gr\"obner-Shirshov
bases. We establish the Composition-Diamond Lemma for free commutative
differential Rota-Baxter algebras of order $n$. We also obtain a weakly
monomial order on these algebras, allowing us to obtain Gr\"{o}bner-Shirshov
bases for free commutative integro-differential algebras on a set. We finally
generalize the concept of functional derivations to free differential algebras
with arbitrary weight and generating sets from which to construct a canonical
linear basis for free commutative integro-differential algebras.


title: Spin polynomial functors and representations of Schur superalgebras

abstract:
  We introduce categories of homogeneous strict polynomial functors,
$\Pol^\I_{d,\k}$ and $\Pol^\II_{d,\k}$, defined on vector superspaces over a
field $\k$ of characteristic not equal 2. These categories are related to
polynomial representations of the supergroups $GL(m|n)$ and Q(n), respectively.
In particular, we prove an equivalence between $\Pol^\I_{d,\k}$,
$\Pol^\II_{d,\k}$ and the category of finite dimensional supermodules over the
Schur superalgebra $\Sc(m|n,d)$, $\Qc(n,d)$ respectively provided $m,n \ge d$.
We also discuss some aspects of Sergeev duality from the viewpoint of the
category $\Pol^\II_{d,\k}$.


title: Linearized gravitational waves near space-like and null infinity

abstract:
  Linear perturbations on Minkowski space are used to probe numerically the
remote region of an asymptotically flat space-time close to spatial infinity.
The study is undertaken within the framework of Friedrich's conformal field
equations and the corresponding conformal representation of spatial infinity as
a cylinder. The system under consideration is the (linear) zero-rest-mass
equation for a spin-2 field. The spherical symmetry of the underlying
background is used to decompose the field into separate non-interacting
multipoles. It is demonstrated that it is possible to reach null-infinity from
initial data on an asymptotically Euclidean hyper-surface and that the
physically important radiation field can be extracted accurately on $\scri^+$.


title: Virtual Genus of Satellite Links

abstract:
  The virtual genus of a virtual satellite link is equal to that of its
companion.


title:
Photonic spatial Bell-state analysis for robust quantum secure direct
  communication using quantum dot-cavity systems

abstract:
  Recently, experiments showed that the spatial-mode states of entangled
photons are more robust than their polarization-mode states in quantum
communications. Here we construct a complete and deterministic protocol for
analyzing the spatial Bell states using the interaction between a photon and an
electron spin in a charged quantum dot inside a one-side micropillar
microcavity. A quantum nondemolition detector (QND) for checking the parity of
a two-photon system can be constructed with the giant optical Faraday rotation
in this solid state system. With this parity-check QND, we present a complete
and deterministic proposal for the analysis of the four spatial-mode Bell
states. Moreover, we present a robust two-step quantum secure direct
communication protocol based on the spatial-mode Bell states and the photonic
spatial Bell-state analysis. Our analysis shows that our BSA proposal works in
both the strong and the weak coupling regimes if the side leakage and cavity
loss rate is small.


title:
Universal quantum gates for hybrid systems assisted by quantum dots
  inside double-sided optical microcavities

abstract:
  We present some deterministic schemes to construct universal quantum gates,
that is, controlled- NOT, three-qubit Toffoli, and Fredkin gates, between
flying photon qubits and stationary electron-spin qubits assisted by quantum
dots inside double-sided optical microcavities. The control qubit of our gates
is encoded on the polarization of the moving single photon and the target
qubits are encoded on the confined electron spins in quantum dots inside
optical microcavities. Our schemes for these universal quantum gates on a
hybrid system have some advantages. First, all the gates are accomplished with
the success probability of 100% in principle. Second, our schemes require no
additional qubits. Third, the control qubits of the gates are easily
manipulated and the target qubits are perfect for storage and processing.
Fourth, the gates do not require that the transmission for the uncoupled cavity
is balanceable to the reflectance for the coupled cavity, in order to get a
high fidelity. Fifth, the devices for the three universal gates work in both
the weak coupling and the strong coupling regimes, and they are feasible in
experiment.


title: High-fidelity readout and control of a nuclear spin qubit in silicon

abstract:
  A single nuclear spin holds the promise of being a long-lived quantum bit or
quantum memory, with the high fidelities required for fault-tolerant quantum
computing. We show here that such promise could be fulfilled by a single
phosphorus (31P) nuclear spin in a silicon nanostructure. By integrating
single-shot readout of the electron spin with on-chip electron spin resonance,
we demonstrate the quantum non-demolition, electrical single-shot readout of
the nuclear spin, with readout fidelity better than 99.8% - the highest for any
solid-state qubit. The single nuclear spin is then operated as a qubit by
applying coherent radiofrequency (RF) pulses. For an ionized 31P donor we find
a nuclear spin coherence time of 60 ms and a 1-qubit gate control fidelity
exceeding 98%. These results demonstrate that the dominant technology of modern
electronics can be adapted to host a complete electrical measurement and
control platform for nuclear spin-based quantum information processing.


title: Systems of parameters and holonomicity of A-hypergeometric systems

abstract:
  The main result is an elementary proof of holonomicity for A-hypergeometric
systems, with no requirements on the behavior of their singularities,
originally due to Adolphson [Ado94] after the regular singular case by Gelfand
and Gelfand [GG86]. Our method yields a direct de novo proof that
A-hypergeometric systems form holonomic families over their parameter spaces,
as shown by Matusevich, Miller, and Walther [MMW05].


title: New Examples of Torsion-Free Non-unique Product Groups

abstract:
  We give an infinite family of torsion-free groups that do not satisfy the
unique product property. For these examples, we also show that each group
contains arbitrarily large sets whose square has no uniquely represented
element.


title:
Universal Wyner-Ziv Coding for Distortion Constrained General
  Side-Information

abstract:
  We investigate the Wyner-Ziv coding in which the statistics of the principal
source is known but the statistics of the channel generating the
side-information is unknown except that it is in a certain class. The class
consists of channels such that the distortion between the principal source and
the side-information is smaller than a threshold, but channels may be neither
stationary nor ergodic. In this situation, we define a new rate-distortion
function as the minimum rate such that there exists a Wyner-Ziv code that is
universal for every channel in the class. Then, we show an upper bound and a
lower bound on the rate-distortion function, and derive a matching condition
such that the upper and lower bounds coincide. The relation between the new
rate-distortion function and the rate-distortion function of the Heegard-Berger
problem is also discussed.


title:
Vortex Structures in Model p-Wave Superconducting Sr2RuO4 -- Single
  2-Dimensional Band v.s. Quasi-1-Dimensional Band

abstract:
  There have been an interesting debate on the primary source of chiral p-wave
superconductivity in Sr2RuO4. We present a comparative study on the vortex
structure between a single 2-dimensional (2D) band and quasi-1D band model by
using Bogoliubov-de Gennes theory. The pattern of the iso-values of the local
density of state around a vortex has a diamond shape in the quasi-1D model and
is much more isotropic in the 2D model. The spin lattice relaxation rate well
below the superconducting transition temperature is greatly enhanced in the
vortex state in the 2D model but not in the quasi-1D model. These features can
be tested by using scanning tunneling microscope and NMR to distinguish the
models for the superconductivity in Sr2RuO4.


title:
Precise QCD predictions on $W_HZ_H$ production in the littlest Higgs
  Model with $T$ parity at the LHC

abstract:
  We investigate the effects of the littlest Higgs model with $T$ parity up to
the QCD next-to-leading order (NLO) on the $W_H^{\pm} Z_H$ productions at the
CERN Large Hadron Collider (LHC), and discuss the kinematic distributions of
final decay products and the theoretical dependence of the cross section on the
factorization/renormalization scale. We find the QCD NLO corrections reduce the
scale uncertainty of the leading order cross section in case of $\mu_F=\mu_R$.
By adopting the PROSPINO subtraction scheme (scheme (II)) in analysing the QCD
NLO contributions, we can obtain the numerical results which keep the
convergence of the perturbative QCD description. Our results by adopting scheme
(II) at the $14 {\rm TeV}$ ($8 {\rm TeV}$) LHC show that the $K$-factor for the
$W_H^+ Z_H$ production varies in the range of $1.01 \sim 1.10$ ($1.00 \sim
1.08$), while the $K$-factor for the $W_H^- Z_H$ production varies in the range
of $1.11 \sim 1.13$ ($1.11 \sim 1.12$), when the global symmetry breaking scale
$f$ goes from $400 {\rm GeV}$ to $1.5 {\rm TeV}$ ($1 {\rm TeV}$).


title:
Study of the process $e^+e^-\to 3(\pi^+\pi^-)$ in the c.m.energy range
  1.5--2.0 gev with the cmd-3 detector

abstract:
  The cross section of the process $e^+e^- \to 3(\pi^+\pi^-)$ has been measured
using 22 pb$^{-1}$ of integrated luminosity collected with the CMD-3 detector
at the VEPP-2000 $e^+e^-$ collider in the c.m. energy range 1.5 -- 2.0 GeV. The
measured cross section exhibits a sharp drop near the $p\bar p$ threshold. A
first study of dynamics of six-pion production has been performed.


title:
Cr-K Emission Line as a Constraint on the Progenitor Properties of
  Supernova Remnants

abstract:
  We perform a survey of the Cr, Mn and Fe-K emission lines in young supernova
remnants (SNRs) with the Japanese X-ray astronomy satellite {\sl Suzaku}. The
Cr and/or Mn emission lines are detected in 3C\,397 and 0519-69.0 for the first
time. We also confirm the detection of these lines in Kepler, W49B, N103B and
Cas A. We derive the line parameters (i.e., the line centroid energy, flux and
equivalent width [EW]) for these six sources and perform a correlation analysis
for the line center energies of Cr, Mn and Fe. Also included in the correlation
analysis are Tycho and G344.7-0.1 for which the Cr, Mn and Fe-K line parameters
were available in the literature through {\sl Suzaku} observations. We find
that the line center energies of Cr correlates very well with that of Fe and
that of Mn. This confirms our previous findings that the Cr, Mn and Fe are
spatially co-located, share a similar ionization state, and have a common
origin in the supernova nucleo-synthesis. We find that the ratio of the EW of
the Cr emission line to that of Fe ($\EWR\equiv \EWCr/\EWFe$) provides useful
constraints on the SNR progenitors and on the SN explosion mechanisms: for SNRs
with $\EWR > 2%$, a type Ia origin is favored (e.g., N103B, G344.7-0.1, 3C\,397
and 0519-69.0); for SNRs with $\EWR < 2%$, they could be of either
core-collpase origin or carbon-deflagration Ia origin.


title: Study of e+e- --> p anti-p via initial-state radiation at BABAR

abstract:
  The process e+e- --> p anti-p gamma is studied using 469 fb-1 of integrated
luminosity collected with the BABAR detector at the PEP-II collider, at an e+e-
center-of-mass energy of 10.6 GeV. From the analysis of the p anti-p invariant
mass spectrum, the energy dependence of the cross section for e+e- --> p anti-p
is measured from threshold to 4.5 GeV. The energy dependence of the ratio of
electric and magnetic form factors, |G_E/G_M|, and the asymmetry in the proton
angular distribution are measured for p anti-p masses below 3 GeV. We also
measure the branching fractions for the decays J/psi --> p anti-p and psi(2S)
--> p anti p.


title: Synthesis of Multivalued Quantum Logic Circuits by Elementary Gates

abstract:
  We propose the generalized controlled X (GCX) gate as the two-qudit
elementary gate, and based on Cartan decomposition, we also give the one-qudit
elementary gates. Then we discuss the physical implementation of these
elementary gates and show that it is feasible with current technology. With
these elementary gates many important qudit quantum gates can be synthesized
conveniently. We provide efficient methods for the synthesis of various kinds
of controlled qudit gates and greatly simplify the synthesis of existing
generic multi-valued quantum circuits. Moreover, we generalize the quantum
Shannon decomposition (QSD), the most powerful technique for the synthesis of
generic qubit circuits, to the qudit case. A comparison of ququart (d=4)
circuits and qubit circuits reveals that using ququart circuits may have an
advantage over the qubit circuits in the synthesis of quantum circuits.


title: Enhancing Optical Gradient Forces with Metamaterials

abstract:
  We demonstrate how the optical gradient force between two waveguides can be
enhanced using transformation optics. A thin layer of double-negative or
single-negative metamaterial can shrink the interwaveguide distance perceived
by light, resulting in a more than tenfold enhancement of the optical force.
This process is remarkably robust to the dissipative loss normally observed in
metamaterials. Our results provide an alternative way to boost optical gradient
forces in nanophotonic actuation systems and may be combined with existing
resonator-based enhancement methods to produce optical forces with an
unprecedented amplitude.


title:
Limit Theory for the Sample Autocovariance for Heavy Tailed Stationary
  Infinitely Divisible Processes Generated by Conservative Flows

abstract:
  This study aims to develop the limit theorems on the sample autocovariances
and sample autocorrelations for certain stationary infinitely divisible
processes. We consider the case where the infinitely divisible process has
heavy tail marginals and is generated by a conservative flow. Interestingly,
the growth rate of the sample autocovariances is determined by not only heavy
tailedness of the marginals but also memory length of the process. Although
this feature was first observed by \cite{resnick:samorodnitsky:xue:2000} for
some very specific processes, we will propose a more general framework from the
viewpoint of infinite ergodic theory. Consequently, the asymptotics of the
sample autocovariances can be more comprehensively discussed.


title:
A coding approach to guarantee information integrity against a Byzantine
  relay

abstract:
  This paper presents a random coding scheme with which two nodes can exchange
information with guaranteed integrity over a two-way Byzantine relay. This
coding scheme is employed to obtain an inner bound on the capacity region with
guaranteed information integrity. No pre-shared secret or secret transmission
is needed for the proposed scheme. Hence the inner bound obtained is generally
larger than those achieved based on secret transmission schemes. This approach
advocates the separation of supporting information integrity and secrecy.


title:
Collision Kernels from Velocity-Selective Optical Pumping with Magnetic
  Depolarization

abstract:
  We experimentally demonstrate how magnetic depolarization of
velocity-selective optical pumping can be used to single out the collisional
cusp kernel best describing spin and velocity relaxing collisions between
potassium atoms and low pressure helium. The range of pressures and transverse
fields used simulate the novel optical pumping regime pertinent to sodium
guidestars employed in adaptive optics. We measure the precession of
spin-velocity modes under the application of transverse magnetic fields,
simulating the natural configuration of mesospheric sodium optical pumping in
the geomagnetic field. We also provide a full theoretical account of the
experimental data using the recently developed cusp kernels, which
realistically quantify velocity damping collisions in this novel optical
pumping regime. A single cusp kernel with a sharpness $s=13\pm 2$ provides a
global fit to the K-He data.


title: Most odd degree hyperelliptic curves have only one rational point

abstract:
  Consider the smooth projective models C of curves y^2=f(x) with f(x) in Z[x]
monic and separable of degree 2g+1. We prove that for g >= 3, a positive
fraction of these have only one rational point, the point at infinity. We prove
a lower bound on this fraction that tends to 1 as g tends to infinity. Finally,
we show that C(Q) can be algorithmically computed for such a fraction of the
curves. The method can be summarized as follows: using p-adic analysis and an
idea of McCallum, we develop a reformulation of Chabauty's method that shows
that certain computable conditions imply #C(Q)=1; on the other hand, using
further p-adic analysis, the theory of arithmetic surfaces, a new result on
torsion points on hyperelliptic curves, and crucially the Bhargava-Gross
equidistribution theorem for nonzero 2-Selmer group elements, we prove that
these conditions are often satisfied for p=2.


title:
Classical and quantum ordering of protons in cold solid hydrogen under
  megabar pressures

abstract:
  A combination of state-of-the-art theoretical methods has been used to obtain
an atomic-level picture of classical and quantum ordering of protons in cold
high-pressure solid hydro-gen. We focus mostly on phases II and III of
hydrogen, exploring the effects of quantum nuclear motion on certain features
of these phases (through a number of ab initio path-integral molecular dynamics
(PIMD) simulations at particular points on the phase diagram). We also examine
the importance of van der Waals forces in this system by performing
calculations using the optB88-vdW density functional, which accounts for
non-local correlations. Our calculations reveal that the transition between
phases I and II is strongly quantum in nature, resulting from a competition
between anisotropic inter-molecular interactions that restrict molecular
rotation and thermal plus quantum fluctuations of the nuclear positions that
facilitate it. The transition from phase II to III is more classical because
quantum nuclear motion plays only a secondary role and the transition is
determined primarily by the underlying potential energy surface. A structure of
P21c symmetry with 24 atoms in the primitive unit cell is found to be stable
when anharmonic quantum nuclear vibrational motion is included at finite
temperatures using the PIMD method. This structure gives a good account of the
infra-red (IR) and Raman vibron frequencies of phase II. We find ad-ditional
support for C2/c structure as a strong candidate for phase III, since it
remains transparent up to 300 GPa, even when quantum nuclear effects are
included. Finally, we find that accounting for van der Waals forces improves
the agreement between experiment and theory for the parts of the phase diagram
considered, when compared to previous work which employed the widely-used
Perdew-Burke-Ernzerhof (PBE) exchange-correlation functional.


title:
Unveiling the impurity band inducing ferromagnetism in magnetic
  semiconductor (Ga,Mn)As

abstract:
  (Ga,Mn)As is a paradigm diluted magnetic semiconductor which shows
ferromagnetism induced by doped hole carriers. With a few controversial models
emerged from numerous experimental and theoretical studies, the mechanism of
the ferromagnetism in (Ga,Mn)As still remains a puzzling enigma. In this
Letter, we use soft x-ray angle-resolved photoemission spectroscopy to
positively identify the ferromagnetic Mn 3d-derived impurity band in (Ga,Mn)As.
The band appears hybridized with the light-hole band of the host GaAs. These
findings conclude the picture of the valence band structure of (Ga,Mn)As
disputed for more than a decade. The non-dispersive character of the IB and its
location in vicinity of the valence-band maximum indicate that the Mn
3d-derived impurity band is formed as a split-off Mn-impurity state predicted
by the Anderson impurity model. Responsible for the ferromagnetism in (Ga,Mn)As
is the transport of hole carriers in the impurity band.


title:
Near-lunar proton velocity distribution explained by electrostatic
  acceleration

abstract:
  The observation of parallel ion velocity in the near-lunar wake approximately
equal to external solar wind velocity \emph{can} be explained within
uncertainties by an analytic electrostatic expansion model. The one-dimensional
model frequently used is inadequate because it does not account for the moon's
spherical shape. However, application of a more recent generalization to
three-dimensions of the solution along characteristics predicts higher
velocities, and is probably sufficient to account for the SARA observations on
the Chandrayaan-1 space-craft.


title:
Pauli Equation on a Curved Surface and Rashba Splitting on a Corrugated
  Surface

abstract:
  The Schroedinger equation for a spinless charged particle on a curved surface
under an electromagnetic field has been obtained by adopting a proper gauge
which allows the separation of the on-surface and transverse dynamics. [Phys.
Rev. Lett. 100 (2008) 230403] As its extension, I provide the Pauli equation
for a charged spin-1/2 particle confined to a curved surface under an
electromagnetic field. Energy spectra of a sphere and a corrugated surface to
which a particle is confined are given as simple applications of the equation.
The energy levels obtained exhibit splittings due to the relativistic effect
known as the Rashba effect.


title:
Electronic Properties and Persistent Spin Currents of Nanospring under
  Static Magnetic Field

abstract:
  Relativistic electronic properties of a nanospring under a static magnetic
field are theoretically investigated in the present study. The wave equation
accounting for the spin-orbit interaction is derived for the nanospring as a
special case of the Pauli equation for a spin-1/2 particle confined to a curved
surface under an electromagnetic field. We define the helical momentum operator
and show that it commutes with the Hamiltonian owing to the helical geometry of
the nanospring. The energy eigenstates are hence also the eigenstates of the
helical momentum. We solve the equation numerically to obtain the surface wave
functions and the energy spectra. The electronic properties are systematically
examined by varying the parameters that characterize the system. It is
demonstrated that either the nonzero spin-orbit interaction or the nonzero
external magnetic field suffices for the occurrence of the persistent spin
current on the nanospring. Two different mechanisms are shown to generate the
persistent spin current. One employs the spin-orbit interaction coming from the
local inversion asymmetry on the surface, while the other employs the curvature
coupling with the external magnetic field.


title:
A direct reduction of PPAD Lemke-verified linear complementarity
  problems to bimatrix games

abstract:
  The linear complementarity problem, LCP(q,M), is defined as follows. For
given M,q find z such that q+Mz>=0, z>=0, z(q + M z)=0,or certify that there is
no such z. It is well known that the problem of finding a Nash equilibrium for
a bimatrix game (2-NASH) can be formulated as a linear complementarity problem
(LCP). In addition, 2-NASH is known to be complete in the complexity class PPAD
(Polynomial-time Parity Argument Directed). However, the ingeniously
constructed reduction (which is designed for any PPAD problem) is very
complicated, so while of great theoretical significance, it is not practical
for actually solving an LCP via 2-NASH, and it may not provide the potential
insight that can be gained from studying the game obtained from a problem
formulated as an LCP (e.g. market equilibrium). The main goal of this paper is
the construction of a simple explicit reduction of any LCP(q,M) that can be
verified as belonging to PPAD via the graph induced by the generic Lemke
algorithm with some positive covering vector d, to a symmetric 2-NASH. In
particular, any endpoint of this graph (with the exception of the initial point
of the algorithm) corresponds to either a solution or to a so-called secondary
ray. Thus, an LCP problem is verified as belonging to PPAD if any secondary ray
can be used to construct, in polynomial time, a certificate that there is no
solution to the problem. We achieve our goal by showing that for any M,q and a
positive d satisfying a certain nondegeneracy assumption with respect to M, we
can simply and directly construct a symmetric 2-NASH whose Nash equilibria
correspond one-to-one to the end points of the graph induced by LCP(q,M) and
the Lemke algorithm with a covering vector d. We note that for a given M the
reduction works for all positive d with the exception of a subset of measure 0.


title: XMM-Newton Observations of the TeV \gamma-ray Source HESS J1804-216

abstract:
  We have analyzed three XMM-Newton observations of the central part of the
unidentified TeV \gamma-ray source HESS J1804-216. We focus on two X-ray
sources 2XMMi J180442.0-214221 (Src 1) and 2XMMi J180432.5-214009 (Src 2),
which were suggested to be the possible X-ray counterparts to the TeV source.
We discover a 2.93 hr X-ray periodicity from Src 1, with the pulse profile
explained with a self-eclipsing pole in an eclipsing polar. Src 2 exhibits a
strong Fe emission line (FWHM ~0.3 keV and equivalent width ~0.8 keV) and large
X-ray variability on timescales of hours and is probably an intermediate polar.
Thus Src 1 and Src 2 are probably two field sources not responsible for the TeV
emission. The observations were contaminated by strong straylight from a nearby
bright source, and we see no clear extended X-ray emission that can be
attributed to the supernova remnant G8.7-0.1, a popular possible association
with the TeV source. The other possible association, the pulsar wind nebula
candidate PSR J1803-2137, shows little long-term variability, compared with a
previous Chandra observation. Many point sources were serendipitously detected,
but most of them are probably normal stars. Three new candidate compact object
systems (other than Src 1, Src 2 and PSR J1803-2137) are also found. They are
far away from the TeV source and are probably also magnetic cataclysmic
variables, thus unlikely to be responsible for the TeV emission.


title:
Evolutionary games on the lattice: Payoffs affecting birth and death
  rates

abstract:
  This article investigates an evolutionary game based on the framework of
interacting particle systems. Each point of the square lattice is occupied by a
player who is characterized by one of two possible strategies and is attributed
a payoff based on her strategy, the strategy of her neighbors and a payoff
matrix. Following the traditional approach of evolutionary game theory, this
payoff is interpreted as a fitness: the dynamics of the system is derived by
thinking of positive payoffs as birth rates and the absolute value of negative
payoffs as death rates. The nonspatial mean-field approximation obtained under
the assumption that the population is well mixing is the popular replicator
equation. The main objective is to understand the consequences of the inclusion
of local interactions by investigating and comparing the phase diagrams of the
spatial and nonspatial models in the four dimensional space of the payoff
matrices. Our results indicate that the inclusion of local interactions induces
a reduction of the coexistence region of the replicator equation and the
presence of a dominant strategy that wins even when starting at arbitrarily low
density in the region where the replicator equation displays bistability. We
also discuss the implications of these results in the parameter regions that
correspond to the most popular games: the prisoner's dilemma, the stag hunt
game, the hawk-dove game and the battle of the sexes.


title:
Towards the full information chain theory: solution methods for optimal
  information acquisition problem

abstract:
  When additional information sources are available in decision making problems
that allow stochastic optimization formulations, an important question is how
to optimally use the information the sources are capable of providing. A
framework that relates information accuracy determined by the source's
knowledge structure to its relevance determined by the problem being solved was
proposed in a companion paper. There, the problem of optimal information
acquisition was formulated as that of minimization of the expected loss of the
solution subject to constraints dictated by the information source knowledge
structure and depth. Approximate solution methods for this problem are
developed making use of probability metrics method and its application for
scenario reduction in stochastic optimization.


title: Construction of Bh[g] sets in product of groups

abstract:
  A subset A of an abelian group G is a Bh[g] set on G if every element of G
can be written at most g ways as sum of h elements in A. In this work we
present three constructions of Bh[g] sets on product of groups.


title: Dynamic 2D Dictionary Matching in Small Space

abstract:
  The dictionary matching problem preprocesses a set of patterns and finds all
occurrences of each of the patterns in a text when it is provided. We focus on
the dynamic setting, in which patterns can be inserted to and removed from the
dictionary, without reprocessing the entire dictionary. This article presents
the first algorithm that performs \emph{dynamic} dictionary matching on
two-dimensional data within small space. The time complexity of our algorithm
is almost linear. The only slowdown is incurred by querying the compressed
self-index that replaces the dictionary. The dictionary is updated in time
proportional to the size of the pattern that is being inserted to or removed
from the dictionary. Our algorithm is suitable for rectangular patterns that
are of uniform size in one dimension.


title: Multiple harmonic sums and Wolstenholme's theorem

abstract:
  We give a family of congruences for the binomial coefficients ${kp-1\choose
p-1}$ in terms of multiple harmonic sums, a generalization of the harmonic
numbers. Each congruence in this family (which depends on an additional
parameter $n$) involves a linear combination of $n$ multiple harmonic sums, and
holds $\mod{p^{2n+3}}$. The coefficients in these congruences are integers
depending on $n$ and $k$, but independent of $p$. More generally, we construct
a family of congruences for ${kp-1\choose p-1} \mod{p^{2n+3}}$, whose members
contain a variable number of terms, and show that in this family there is a
unique "optimized" congruence involving the fewest terms. The special case
$k=2$ and $n=0$ recovers Wolstenholme's theorem ${2p-1\choose p-1}\equiv
1\mod{p^3}$, valid for all primes $p\geq 5$. We also characterize those triples
$(n, k, p)$ for which the optimized congruence holds modulo an extra power of
$p$: they are precisely those with either $p$ dividing the numerator of the
Bernoulli number $B_{p-2n-k}$, or $k \equiv 0, 1 \mod p$.


title:
Intrinsic superconducting properties and vortex dynamics in heavily
  overdoped Ba(Fe$_{0.86}$Co$_{0.14}$)$_2$As$_2$ single crystal

abstract:
  In this work we report the influence of intrinsic superconducting parameters
on the vortex dynamics in an overdoped Ba(Fe$_{1-x}$Co$_x$)$_2$As$_2$ (x=0.14)
single crystal. We find a superconducting critical temperature of 13.5 K,
magnetic penetration depth $\lambda_{ab}$(0) = 660 $\pm$ 50 nm, coherence
length $\xi_{ab}$(0) = 5 nm, and the upper critical field anisotropy
$\gamma_{T\rightarrow Tc}$ $\approx$ 3.7. In fact, the Ginzburg-Landau model
may explain the angular dependent $H_{c2}$ for this anisotropic
three-dimensional superconductor. The vortex phase diagram, in comparison with
the optimally doped compound, presents a narrow collective creep regime. In
addition, we found no sign of correlated pinning along the c axis. Our results
show that vortex core to defect size ratio and $\lambda$ play an important role
in the resulting vortex dynamics in materials with similar intrinsic thermal
fluctuations.


title: Rigidity and regularity of co-dimension one Sobolev isometric immersions

abstract:
  We prove the developability and $C^{1,1/2}$ regularity of $W^{2,2}$ isometric
immersions of $n$-dimensional domains into $R^{n+1}$. As a conclusion we show
that any such Sobolev isometry can be approximated by smooth isometries in the
$W^{2,2}$ strong norm, provided the domain is $C^1$ and convex. Both results
fail to be true if the Sobolev regularity is weaker than $W^{2,2}$.


title:
XMM-Newton/RGS Detection of the Missing Interstellar OVII Kalpha
  Absorption Line in the Spectrum of Cyg X-2

abstract:
  The hot interstellar medium is an important part of the Galactic ecosystem
and can be effectively characterized through X-ray absorption line
spectroscopy. However, in a study of the hot medium using the accreting neutron
star X-ray binary, Cyg X-2, as a background light source, a mystery came about
when the putatively strong OVII Kalpha line was not detected in Chandra grating
observations, while other normally weaker lines such as OVII Kbeta as well as
OVI and OVIII Kalpha are clearly present (Yao et al. 2009). We have
investigated the grating spectra of Cyg X-2 from 10 XMM-Newton observations, in
search of the missing line. We detect it consistently in nine of these
observations, but the line is absent in the remaining one observation or is
inconsistent with the detection in others at a 4sigma confidence level. This
absence of the line resembles that seen in the Chandra observations. Similarly,
the OVI Kalpha line is found to disappear occasionally, but not in concert with
the variation of the OVII Kalpha line. All these variations are most likely due
to the presence of changing OVII and OVI Kalpha emission lines of Cyg X-2,
which are blurred together with the absorption ones in the X-ray spectra. A
re-examination of the Chandra grating data indeed shows evidence for a narrow
emission line slightly off the OVI Kalpha absorption line. We further show that
narrow NV emission lines with varying centroids and fluxes are present in
far-UV spectra from the Cosmic Origins Spectrograph aboard the Hubble Space
Telescope. These results provide new constraints on the accretion around the
neutron star and on the X-ray-heating of the stellar companion. The
understanding of these physical processes is also important to the fidelity of
using such local X-ray binaries for interstellar absorption line spectroscopy.


title: Sparse MRI for motion correction

abstract:
  MR image sparsity/compressibility has been widely exploited for imaging
acceleration with the development of compressed sensing. A sparsity-based
approach to rigid-body motion correction is presented for the first time in
this paper. A motion is sought after such that the compensated MR image is
maximally sparse/compressible among the infinite candidates. Iterative
algorithms are proposed that jointly estimate the motion and the image content.
The proposed method has a lot of merits, such as no need of additional data and
loose requirement for the sampling sequence. Promising results are presented to
demonstrate its performance.


title:
A supplement to Fujino's paper: On isolated log canonical singularities
  with index one

abstract:
  Let $E$ be the essential part of the exceptional locus of a good resolution
of an isolated, log canonical singularity of index one. We describe the
dimension of the dual complex of $E$ in terms of the Hodge type of $H^{n-1}(E,
O_E)$, which is one of the main results of the paper [1] of Fujino. Our proof
uses only an elementary classical method, while Fujino's argument depends on
the recent development in minimal model theory.


title: $\Xi$ baryon strong decays in a chiral quark model

abstract:
  The strong decays of $\Xi$ baryons up to N=2 shell were studied in a chiral
quark model. The strong decay properties of these well-established ground
decuplet baryons were reasonably described. We found that (i) $\Xi(1690)$ and
$\Xi(1820)$ could be assigned to the spin-parity $J^P=1/2^-$ state
$|70,^{2}{8},1,1,1/2^->$ and the spin-parity $J^P=3/2^-$ state
$|70,^{2}{8},1,1,3/2^->$, respectively. Slight configuration mixing might exist
in these two negative parity states. (ii) $\Xi(1950)$ might correspond to
several different $\Xi$ resonances. The broad states ($\Gamma\sim 100$ MeV)
observed in the $\Xi\pi$ channel could be classified as the pure $J^P=5/2^-$
octet state $\Xi^0|70,^{4}8,1,1,5/2^->$ or the mixed state $|\Xi 1/2^->_3 $
with $J^P=1/2^-$. The $\Xi$ resonances with moderate width ($\Gamma\sim 60$
MeV) observed in the $\Xi\pi$ channel might correspond to the $J^P=1/2^+$
excitation $|56,^{4}10,2,2,1/2^+>$. The second orbital excitation
$|56,^{4}10,2,2,3/2^+>$ and the mixed state $|\Xi 1/2^->_1$ might be candidates
for the narrow width state observed in the $\Lambda \bar{K}$ channel, however,
their spin-parity numbers are incompatible with the moment analysis of the
data. (iii) $\Xi(2030)$ could not be assigned to either any spin-parity
$J^P=7/2^+$ states or any pure $J^P=5/2^+$ configurations. It seems to favor
the $|70,^{2}8,2,2,3/2^+>$ assignment, however, its spin conflicts with the
moment analysis of the data. To find more $\Xi$ resonances, the observations in
the $\Xi(1530)\pi$ and $\Sigma(1385) \bar{K}$ channels are necessary.


title: Some combinatorial interpretations in perturbative quantum field theory

abstract:
  This paper will describe how combinatorial interpretations can help us
understand the algebraic structure of two aspects of perturbative quantum field
theory, namely analytic Dyson-Schwinger equations and periods of scalar Feynman
graphs. The particular examples which will be looked at are, a better reduction
to geometric series for Dyson-Schwinger equations, a subgraph which yields
extra denominator reductions in scalar Feynman integrals, and an explanation of
a trick of Brown and Schnetz to get one extra step in the denominator reduction
of an important particular graph.


title:
Robust Compressive Phase Retrieval via L1 Minimization With Application
  to Image Reconstruction

abstract:
  Phase retrieval refers to a classical nonconvex problem of recovering a
signal from its Fourier magnitude measurements. Inspired by the compressed
sensing technique, signal sparsity is exploited in recent studies of phase
retrieval to reduce the required number of measurements, known as compressive
phase retrieval (CPR). In this paper, l1 minimization problems are formulated
for CPR to exploit the signal sparsity and alternating direction algorithms are
presented for problem solving. For real-valued, nonnegative image
reconstruction, the image of interest is shown to be an optimal solution of the
formulated l1 minimization in the noise free case. Numerical simulations
demonstrate that the proposed approach is fast, accurate and robust to
measurements noises.


title: Distribution-Free Distribution Regression

abstract:
  `Distribution regression' refers to the situation where a response Y depends
on a covariate P where P is a probability distribution. The model is Y=f(P) +
mu where f is an unknown regression function and mu is a random error.
Typically, we do not observe P directly, but rather, we observe a sample from
P. In this paper we develop theory and methods for distribution-free versions
of distribution regression. This means that we do not make distributional
assumptions about the error term mu and covariate P. We prove that when the
effective dimension is small enough (as measured by the doubling dimension),
then the excess prediction risk converges to zero with a polynomial rate.


title:
Update of the 2HDM-III with a four-zero texture in the Yukawa matrices
  and phenomenology of the charged Higgs Boson

abstract:
  We update the flavor-violating constraints on the charged Higgs sector of the
2-Higgs Doublet Model Type-III (2HDM-III), using a four-zero texture in the
Yukawa matrices. We give a generic Lagrangian of the 2HDM-III. In order to show
the relevance of the off-diagonal terms of such a texture, we utilize the main
constraints from $B$-physics, $\mu -e$ universality in $\tau$ decays and the
radiative decay $Z\to b \bar{b}$ presented recently in arXiv:1212.6818
[hep-ph]. In particular, we show that the $H^- c \bar{b}$ coupling can be very
large and very different with respect to 2HDMs with a flavor discrete symmetry
(i.e., ${\mathcal{Z}}_2$). We also discuss the possible enhancements of the
vertices $H^\pm W^\mp V$ ($V=Z, \gamma$) that arise at one-loop level.