title:
SN 2010jl: Optical to hard X-ray observations reveal an explosion
  embedded in a ten solar mass cocoon

abstract:
  (Abridged) Some supernovae (SNe) may be powered by the interaction of the SN
ejecta with a large amount of circumstellar matter (CSM). Here we outline a
method to measure the mass of the optically thick CSM around such SNe. We
present observations of SN2010jl, including the first detection of a SN using
NuSTAR. The total radiated luminosity of SN2010jl is extreme, at least 9e50
erg. By modeling the visible-light data, we robustly show that the mass of the
circumstellar material within ~1e16 cm of the progenitor was in excess of 10
solar masses, likely ejected tens of years prior to the SN explosion. Our
modeling suggests that the shock velocity during shock breakout was ~6000 km/s,
decelerating to ~2600 km/s about two years after maximum light. Our late-time
NuSTAR+XMM spectra of the SN presumably provide the first direct measurement of
SN shock velocity two years after the SN maximum light -- measured to be in the
range of 2000 to 4500 km/s if the ions and electrons are in equilibrium, and
>~2000 km/s if they are not in equilibrium. This measurement is in agreement
with the shock velocity predicted by our modeling of the optical data. We also
show that the mean radial density distribution of the CSM roughly follows an
r^-2 law. A possible explanation for the massive CSM with a wind-like profile
is that they are the result of multiple pulsational pair instability events
prior to the SN explosion, separated from each other by years.


title: Cooper-pair based photon entanglement without isolated emitters

abstract:
  We propose a novel approach for efficient generation of entangled photons,
based on Cooper-pair luminescence in semiconductors, which does not require
isolated emitters such as single atoms or quantum dots. We show that in bulk
materials, electron-spin entanglement in Cooper pairs should not be expected to
be translated into pure entangled photons despite the selection rules, due to
mixing introduced by light-hole heavy-hole degeneracy. Semiconductor quantum
wells, however, remove this degeneracy, allowing efficient photon entanglement
generation in simple electrically-driven structures, taking advantage of the
superconducting macroscopic coherence. The second-order decay of two-electron
states in Cooper-pair luminescence leaves no which-path information, resulting
in perfect coherence between two pathways and hence in principle, perfect
entanglement. We calculate the purity of the entangled-photon state and find
that it increases for larger light-hole heavy-hole energy splitting and for
lower temperatures. These results provide new insights into light-matter
interaction in solids and enable realization of novel quantum photonics based
on matter condensates.


title:
A highly inclined orbit for the 110-day period M-dwarf companion
  KOI-368.01

abstract:
  We report the detection of asymmetry in the transit light curves of the
110-day period companion to KOI-368, a rapidly rotating A-dwarf. The
significant distortion in the transit light curve is attributed to spin-orbit
misalignment between the transiting companion and the gravity darkened host
star. Our analysis was based on 11 Long Cadence and 2 Short Cadence transits of
KOI-368.01 from the Kepler mission, as well as stellar parameters determined
from our follow-up spectroscopic observation. We measured the true obliquity
between the orbit normal and the stellar rotation axis to be 69 +9/-10 deg. We
also find a secondary eclipse event with depth 29 +/- 3 ppm at phase 0.59, from
which the temperature of the companion is constrained to 3060 +/- 50 K,
indicating that KOI-368.01 is a late M-dwarf. The eccentricity is also
calculated from the eclipse to be 0.1429 +/- 0.0007. The long period, high
obliquity, and low eccentricity of KOI-368.01 allow us to limit a number of
proposed theories for the misalignment of binary systems.


title: The extent of magnetic fields around galaxies out to z ~ 1

abstract:
  Radio quasar sightlines with strong MgII absorption lines display
statistically enhanced Faraday Rotation Measures (RM) indicating the presence
of additional magneto-active plasma with respect to sightlines free of such
absorption. In this letter, we use multi-color optical imaging to identify the
likely galaxies hosting the magneto-active plasma, and to constrain the
location of the latter with respect to the putative parent halo. We find that
all of the sightlines with high |RM| pass within 50 kpc of a galaxy and that
the |RM| distribution for low impact parameters, D < 50 kpc, is significantly
different than for larger impact parameters. In addition, we find a decrease in
the ratio of the polarization at 21 cm and 1.5 cm, p_{21}/p_{1.5}, towards
lower D. These two effects are most likely related, strengthen the association
of excess |RM| with intervening galaxies, and suggest that intervening galaxies
operate as inhomogeneous Faraday screens. These results are difficult to
reconciliate with only a disk model for the magnetic field but are consistent
with highly magnetized winds associated with MgII systems. We infer strong
magnetic fields of a few tens of mikro Gauss, consistent with values required
by the lack of evolution of the FIR-radio correlation at high redshifts.
Finally, these findings lends support to the idea that the small scale helicity
bottleneck of alpha-Omega galactic dynamos can be significantly alleviated via
galatic winds.


title: Predicting Merger-Induced Gas Motions in Lambda-CDM Galaxy Clusters

abstract:
  In the hierarchical structure formation model, clusters of galaxies form
through a sequence of mergers and continuous mass accretion, which generate
significant random gas motions especially in their outskirts where material is
actively accreting. Non-thermal pressure provided by the internal gas motions
affects the thermodynamic structure of the X-ray emitting intracluster plasma
and introduces biases in the physical interpretation of X-ray and
Sunyaev-Zeldovich effect observations. However, we know very little about the
nature of gas motions in galaxy clusters. The ASTRO-H X-ray mission, scheduled
to launch in 2015, will have a calorimeter capable of measuring gas motions in
galaxy clusters at the level of <100 km/s. In this work, we predict the level
of merger-induced gas motions expected in the Lambda-CDM model using
hydrodynamical simulations of galaxy cluster formation. We show that the gas
velocity dispersion is larger in more massive clusters, but exhibits a large
scatter. We show that systems with large gas motions are morphologically
disturbed, while early forming, relaxed groups show a smaller level of gas
motions. By analyzing mock ASTRO-H observations of simulated clusters, we show
that such observations can accurately measure the gas velocity dispersion out
to the outskirts of nearby relaxed galaxy clusters. ASTRO-H analysis of merging
clusters, on the other hand, requires multi-component spectral fitting and
enables unique studies of substructures in galaxy clusters by measuring both
the peculiar velocities and the velocity dispersion of gas within individual
sub-clusters.


title:
Simulated NNLO for high-pT observables in vector boson + jets production
  at the LHC

abstract:
  We present a study of higher order QCD corrections beyond NLO to processes
with an electroweak vector boson, W or Z, in association with jets. We focus on
the regions of high transverse momenta of commonly used differential
distributions. We employ the LoopSim method to merge NLO samples of different
multiplicity obtained from MCFM and from BLACKHAT+SHERPA in order to compute
the dominant part of the NNLO corrections for high-pT observables. We find that
these corrections are indeed substantial for a number of experimentally
relevant observables. For other observables, they lead to significant reduction
of scale uncertainties.


title:
On the Validity of the Effective Field Theory for Dark Matter Searches
  at the LHC

abstract:
  We discuss the limitations to the use of the effective field theory approach
to study dark matter at the LHC. We introduce and study a few quantities, some
of them independent of the ultraviolet completion of the dark matter theory,
which quantify the error made when using effective operators to describe
processes with very high momentum transfer. Our criteria indicate up to what
cutoff energy scale, and with what precision, the effective description is
valid, depending on the dark matter mass and couplings.


title:
Search for gravitational lens candidates in the XMM-LSS/CFHTLS common
  field

abstract:
  Our aim was to identify gravitational lens candidates among some 5500 optical
counterparts of the X-ray point-like sources in the medium-deep ~11 sq. deg.
XMM-LSS survey. We have visually inspected the optical counterparts of each
QSOs/AGN using CFHTLS T006 images. We have selected compact pairs and groups of
sources which could be multiply imaged QSO/AGN. We have measured the colors and
characterized the morphological types of the selected sources using the
multiple PSF fitting technique. We found three good gravitational lens
candidates: J021511.4-034306, J022234.3-031616 and J022607.0-040301 which
consist of pairs of point-like sources having similar colors. On the basis of a
color-color diagram and X-ray properties we could verify that all these sources
are good QSO/AGN candidates rather than stars. Additional secondary
gravitational lens candidates are also reported.


title: Classical mechanics of minimal tori in S^3

abstract:
  We formulate a class of minimal tori in S^3 in terms of classical mechanics,
reveal a curious property of the Clifford torus, and note that the question of
periodicity can be made more explicit in a simple way.


title: Quench-induced Floquet topological p-wave superfluids

abstract:
  Ultracold atomic gases in two dimensions tuned close to a p-wave Feshbach
resonance were expected to exhibit topological superfluidity, but these were
found to be experimentally unstable. We show that one can induce a topological
Floquet superfluid if weakly interacting atoms are brought suddenly close
("quenched") to such a resonance, in the time before the instability kicks in.
The resulting superfluid possesses Majorana edge modes, yet differs from a
conventional Floquet system as it is not driven externally. Instead, the
periodic modulation is self-generated by the dynamics.


title:
The effect of electron dielectric response on the quantum capacitance of
  graphene in a strong magnetic field

abstract:
  The quantum capacitance of graphene can be negative when the graphene is
placed in a strong magnetic field, which is a clear experimental signature of
positional correlations between electrons. Here we show that the quantum
capacitance of graphene is also strongly affected by its dielectric
polarizability, which in a magnetic field is wave vector-dependent. We study
this effect both theoretically and experimentally. We develop a theory and
numerical procedure for accounting for the graphene dielectric response, and we
present measurements of the quantum capacitance of high-quality graphene
capacitors on boron nitride. Theory and experiment are found to be in good
agreement.


title:
Preparing two-atom entangled state in a cavity and probing it via
  quantum non-demolition measurement

abstract:
  We propose a probabilistic scheme to prepare a maximally entangled state
between a pair of two-level atoms inside a leaking cavity, without requiring
precise time-controlling of the system evolution and initial atomic state. We
show that the steady state of this dissipative system is a mixture of two
parts: either the atoms being in their ground state or in a maximally entangled
one. Then, by applying a weak probe field on the cavity mode we are able to
distinguish those states without disturbing the atomic system, i.e., performing
a quantum non-demolition measurement via the cavity transmission. In this
scheme, one has nonzero cavity transmission only when the atomic system is in
an entangled state so that a single click in the detector is enough to ensure
that the atoms are in an maximally entangled state. Our scheme relies on an
interference effect as it happens in electromagnetically induced transparency
phenomenon so that it works out even in the limit of decay rate of the cavity
mode much stronger than the atom-field coupling.


title:
New Measurements of the Ionizing Ultraviolet Background over 2 < z < 5
  and Implications for Hydrogen Reionization

abstract:
  We present new measurements of the intensity of the ionizing ultraviolet
background and the global emissivity of ionizing photons over 2 < z < 5. Our
results are based on a suite of updated measurements of physical properties of
the high-redshift intergalactic medium (IGM), including gas temperatures and
the opacity of the IGM to Ly-alpha and ionizing photons. Consistent with
previous works, we find a relatively flat hydrogen photoionization rate over 2
< z < 5, although our measurements are roughly a factor of two higher than the
2008 values of Faucher-Giguere et al., due primarily to our lower gas
temperatures. The ionizing emissivity we derive is also generally higher than
other recent estimates due to a combination of lower gas temperatures, higher
ionizing opacity, and an accounting of cosmological radiative transfer effects.
We find evidence that the emissivity increases from z~3 to 5, reaching ~5
ionizing photons per atom per gigayear at z=4.75 for realistic galaxy spectra.
We further find that galaxies must dominate the emissivity near 1 Ryd at z > 4,
and possibly at all redshifts z > 2.4. Our results suggest that the
globally-averaged ionizing "efficiency" of star-forming galaxies increases
substantially with redshift over 3.2 < z < 4.75. This trend is consistent with
the conclusion often drawn from reionization models that the ionizing
efficiency of galaxies must be higher during reionization in order for galaxies
to reionize the IGM by z=6. Our emissivity values at z~5 suggest that ionizing
photons may have been a factor of two more abundant during the final stages of
reionization than previously indicated. The evolution of the ionizing
emissivity over 2 < z < 5 suggests, moreover, that the steep decline in the
photoionization rate from z~5 to 6 may indicate a rapid evolution in the mean
free path at z > 5.


title: Functional identities of one variable

abstract:
  Let $A$ be a centrally closed prime algebra over a characteristic 0 field
$k$, and let $q:A\to A$ be the trace of a $d$-linear map (i.e.,
$q(x)=M(x,...,x)$ where $M:A^d\to A$ is a $d$-linear map). If $[q(x),x]=0$ for
every $x\in A$, then $q$ is of the form $q(x) =\sum_{i=0}^{d} \mu_i(x)x^i$
where each $\mu_i$ is the trace of a $(d-i)$-linear map from $A$ into $k$. For
infinite dimensional algebras and algebras of dimension $>d^2$ this was proved
by Lee, Lin, Wang, and Wong in 1997. In this paper we cover the remaining case
where the dimension is $ \le d^2$. Using this result we are able to handle
general functional identities of one variable on $A$; more specifically, we
describe the traces of $d$-linear maps $q_i:A\to A$ that satisfy $\sum_{i=0}^m
x^i q_i(x)x^{m-i}\in k$ for every $x\in A$.


title: Di-boson and Tri-boson production at the LHC

abstract:
  The status of di-boson and tri-boson production is shortly review. Using the
VBFNLO and the LOOPSIM package, approximated results at NNLO QCD are given for
WZ production. Results for waa + jet at NLO QCD are also shown.


title: Approximate the k-Set Packing Problem by Local Improvements

abstract:
  We study algorithms based on local improvements for the $k$-Set Packing
problem. The well-known local improvement algorithm by Hurkens and Schrijver
has been improved by Sviridenko and Ward from $\frac{k}{2}+\epsilon$ to
$\frac{k+2}{3}$, and by Cygan to $\frac{k+1}{3}+\epsilon$ for any $\epsilon>0$.
In this paper, we achieve the approximation ratio $\frac{k+1}{3}+\epsilon$ for
the $k$-Set Packing problem using a simple polynomial-time algorithm based on
the method by Sviridenko and Ward. With the same approximation guarantee, our
algorithm runs in time singly exponential in $\frac{1}{\epsilon^2}$, while the
running time of Cygan's algorithm is doubly exponential in
$\frac{1}{\epsilon}$. On the other hand, we construct an instance with locality
gap $\frac{k+1}{3}$ for any algorithm using local improvements of size
$O(n^{1/5})$, here $n$ is the total number of sets. Thus, our approximation
guarantee is optimal with respect to results achievable by algorithms based on
local improvements.


title: Topological solutions in ungauged Supergravity

abstract:
  A new general class of solutions of ungauged four-dimensional Supegravity, in
one-to-one correspondence with spherically symmetric, static black-hole
solutions and Lifshitz solutions with Hyperscaling violation (\emph{hvLif}) is
studied. The causal structure of the space-time is then elucidated.


title:
Cosmic-ray leptons, magnetic fields and interstellar synchrotron
  emission

abstract:
  Interstellar synchrotron emission depends on Galactic magnetic fields and on
cosmic-ray leptons. Observations of radio emission are an important tool for
studying cosmic-ray propagation models and interstellar electron spectrum and
distribution in the Galaxy. We present the latest developments in our modeling
of Galactic synchrotron emission with the GALPROP code, including polarization,
absorption, and free-free emission. Using surveys over a wide range of radio
frequencies and polarization measurements, we derive constraints on the
low-energy interstellar cosmic-ray electron spectrum, magnetic fields and
cosmic-ray propagation models. This work is of interest for studies of
interstellar gamma-ray emission with Fermi-LAT, and synchrotron for the Planck
mission.


title: Enzo: An Adaptive Mesh Refinement Code for Astrophysics

abstract:
  This paper describes the open-source code Enzo, which uses block-structured
adaptive mesh refinement to provide high spatial and temporal resolution for
modeling astrophysical fluid flows. The code is Cartesian, can be run in 1, 2,
and 3 dimensions, and supports a wide variety of physics including
hydrodynamics, ideal and non-ideal magnetohydrodynamics, N-body dynamics (and,
more broadly, self-gravity of fluids and particles), primordial gas chemistry,
optically-thin radiative cooling of primordial and metal-enriched plasmas (as
well as some optically-thick cooling models), radiation transport, cosmological
expansion, and models for star formation and feedback in a cosmological
context. In addition to explaining the algorithms implemented, we present
solutions for a wide range of test problems, demonstrate the code's parallel
performance, and discuss the Enzo collaboration's code development methodology.


title:
Elliptic theory of differential edge operators, II: boundary value
  problems

abstract:
  This is a continuation of the first author's development of the theory of
elliptic differential operators with edge degeneracies. That first paper
treated basic mapping theory, focusing on semi-Fredholm properties on weighted
Sobolev and H\"older spaces and regularity in the form of asymptotic expansions
of solutions. The present paper builds on this through the formulation of
boundary conditions and the construction of parametrices for the associated
boundary problems. As before, the emphasis is on the geometric microlocal
structure of the Schwartz kernels of parametrices and generalized inverses.


title: Nature of the phases in the frustrated XY model on the honeycomb lattice

abstract:
  We study the phase diagram of the frustrated XY model on the honeycomb
lattice by using accurate correlated wave functions and variational Monte Carlo
simulations. Our results suggest that a spin-liquid state is energetically
favorable in the region of intermediate frustration, intervening between two
magnetically ordered phases. The latter ones are represented by classically
ordered states supplemented with a long-range Jastrow factor, which includes
relevant correlations and dramatically improves the description provided by the
purely classical solution of the model. The construction of the spin-liquid
state is based on a decomposition of the underlying bosonic particles in terms
of spin-1/2 fermions (partons), with a Gutzwiller projection enforcing no
single occupancy, as well as a long-range Jastrow factor.


title: Commutators from a hyperplane of matrices

abstract:
  Denote by $M_n(K)$ the algebra of $n$ by $n$ matrices with entries in the
field $K$. A theorem of Albert and Muckenhoupt states that every trace zero
matrix of $M_n(K)$ can be expressed as $AB-BA$ for some pair $(A,B)$ of
matrices of $M_n(K)$. Assuming that $n>2$ and that $K$ has more than 3
elements, we prove that the matrices $A$ and $B$ can be required to belong to
an arbitrary given hyperplane of $M_n(K)$.


title:
General aspects of heterotic string compactifications on stacks and
  gerbes

abstract:
  In this paper we work out some basic results concerning heterotic string
compactifications on stacks and, in particular, gerbes. A heterotic string
compactification on a gerbe can be understood as, simultaneously, both a
compactification on a space with a restriction on nonperturbative sectors, and
also, a gauge theory in which a subgroup of the gauge group acts trivially on
the massless matter. Gerbes admit more bundles than corresponding spaces, which
suggests they are potentially a rich playground for heterotic string
compactifications. After we give a general characterization of heterotic
strings on stacks, we specialize to gerbes, and consider three different
classes of `building blocks' of gerbe compactifications. We argue that
heterotic string compactifications on one class is equivalent to
compactification of the same heterotic string on a disjoint union of spaces,
compactification on another class is dual to compactifications of other
heterotic strings on spaces, and compactification on the third class is not
perturbatively consistent, so that we do not in fact recover a broad array of
new heterotic compactifications, just combinations of existing ones. In
appendices we explain how to compute massless spectra of heterotic strings on
stacks, derive some new necessary conditions for a heterotic string on a stack
or orbifold to be well-defined, and also review some basic properties of
bundles on gerbes.


title: Euclidian 4d quantum gravity with a non-trivial measure term

abstract:
  We explore an extended coupling constant space of 4d regularized Euclidean
quantum gravity, defined via the formalism of dynamical triangulations. We add
a measure term which can also serve as a generalized higher curvature term and
determine the phase diagram and the geometries dominating in the various
regions. A first order phase transition line is observed, but no second order
transition point is located. As a consequence we cannot attribute any continuum
physics interpretation to the so-called crinkled phase of 4d dynamical
triangulations.


title:
The effect of episodic accretion on the phase transition of CO and CO_2
  in low-mass star formation

abstract:
  We study the evaporation and condensation of CO and CO_2 during the embedded
stages of low-mass star formation by using numerical simulations. We focus on
the effect of luminosity bursts, similar in magnitude to FUors and EXors, on
the gas-phase abundance of CO and CO_2 in the protostellar disk and infalling
envelope. The evolution of a young protostar and its environment is followed
based on hydrodynamical models using the thin-disk approximation, coupled with
a stellar evolution code and phase transformations of CO and CO_2. The
accretion and associated luminosity bursts in our model are caused by disk
gravitational fragmentation followed by quick migration of the fragments onto
the forming protostar. We found that bursts with luminosity on the order of
100-200 L_sun can evaporate CO ices in part of the envelope. The typical
freeze-out time of the gas-phase CO onto dust grains in the envelope (a few
kyr) is much longer than the burst duration (100-200 yr). This results in an
increased abundance of the gas-phase CO in the envelope long after the system
has returned into a quiescent stage. In contrast, luminosity bursts can
evaporate CO_2 ices only in the disk, where the freeze-out time of the
gas-phase CO_2 is comparable to the burst duration. We thus confirm that
luminosity bursts can leave long-lasting traces in the abundance of gas-phase
CO in the infalling envelope, enabling the detection of recent bursts as
suggested by previous semi-analytical studies.


title:
Spin injection and detection in lanthanum- and niobium-doped SrTiO3
  using the Hanle technique

abstract:
  There has been much interest in the injection and detection of spin polarized
carriers in semiconductors for the purposes of developing novel spintronic
devices. Here we report the electrical injection and detection of
spin-polarized carriers into Nb-doped strontium titanate (STO) single crystals
and La-doped STO epitaxial thin films using MgO tunnel barriers and the
three-terminal Hanle technique. Spin lifetimes of up to ~100 ps are measured at
room temperature and vary little as the temperature is decreased to low
temperatures. However, the mobility of the STO has a strong temperature
dependence. This behavior and the carrier doping dependence of the spin
lifetime suggest that the spin lifetime is limited by spin-dependent scattering
at the MgO/STO interfaces, perhaps related to the formation of doping induced
Ti3+. Our results reveal a severe limitation of the three-terminal Hanle
technique for measuring spin lifetimes within the interior of the subject
material.


title: Spin thermopower in the overscreened Kondo model

abstract:
  We study the spin thermopower in the two-channel spin-1/2 Kondo model which
exhibits the phenomenon of impurity spin overscreening and non-Fermi-liquid
properties. While magnetic field lower than the Kondo temperature does not
strongly polarize the impurity spin, we show that it nevertheless strongly
affects the low-energy part of the spectral function. In turn, this leads to
characteristic saturation of the spin Seebeck coefficient at the value of
0.388kB/|e| at T ~ T*, where T* ~ B^2/TK is the scale of the crossover between
the intermediate-temperature non-Fermi-liquid regime and the low-temperature
Fermi-liquid regime. We show that measuring the spin thermopower at low
magnetic fields would provide a sensitive test for distinguishing regular Fermi
liquid, singular Fermi liguid, and non-Fermi liquid behaviour in nanodevices.


title: Pipage Rounding, Pessimistic Estimators and Matrix Concentration

abstract:
  Pipage rounding is a dependent random sampling technique that has several
interesting properties and diverse applications. One property that has been
particularly useful is negative correlation of the resulting vector.
Unfortunately negative correlation has its limitations, and there are some
further desirable properties that do not seem to follow from existing
techniques. In particular, recent concentration results for sums of independent
random matrices are not known to extend to a negatively dependent setting.
  We introduce a simple but useful technique called concavity of pessimistic
estimators. This technique allows us to show concentration of submodular
functions and concentration of matrix sums under pipage rounding. The former
result answers a question of Chekuri et al. (2009). To prove the latter result,
we derive a new variant of Lieb's celebrated concavity theorem in matrix
analysis.
  We provide numerous applications of these results. One is to spectrally-thin
trees, a spectral analog of the thin trees that played a crucial role in the
recent breakthrough on the asymmetric traveling salesman problem. We show a
polynomial time algorithm that, given a graph where every edge has effective
conductance at least $\kappa$, returns an $O(\kappa^{-1} \cdot \log n / \log
\log n)$-spectrally-thin tree. There are further applications to rounding of
semidefinite programs, to the column subset selection problem, and to a
geometric question of extracting a nearly-orthonormal basis from an isotropic
distribution.


title: Condensation phenomena in nonlinear drift equations

abstract:
  We study nonnegative, measure-valued solutions to nonlinear drift type
equations modelling concentration phenomena related to Bose-Einstein particles.
In one spatial dimension, we prove existence and uniqueness for measure
solutions. Moreover, we prove that all solutions blow up in finite time leading
to a concentration of mass only at the origin, and the concentrated mass
absorbs increasingly the mass converging to the total mass as time goes to
infinity. Our analysis makes a substantial use of independent variable scalings
and pseudo-inverse functions techniques.


title: Black String Flow

abstract:
  We give an exact description of the steady flow of a black string into a
planar horizon. The event horizon is out of equilibrium and provides a simple,
exact instance of a `flowing black funnel' in any dimension D>=5. It is also an
approximation to a smooth intersection between a black string and a black hole,
in the limit in which the black hole is much larger than the black string
thickness. The construction extends easily to more general flows, in particular
charged flows.


title:
The quenched limiting distributions of a one-dimensional random walk in
  random scenery

abstract:
  For a one-dimensional random walk in random scenery (RWRS) on Z, we determine
its quenched weak limits by applying Strassen's functional law of the iterated
logarithm. As a consequence, conditioned on the random scenery, the
one-dimensional RWRS does not converge in law, in contrast with the
multi-dimensional case.


title: Collective Philanthropy: Describing and Modeling the Ecology of Giving

abstract:
  Reflective of income and wealth distributions, philanthropic gifting appears
to follow an approximate power-law size distribution as measured by the size of
gifts received by individual institutions. We explore the ecology of gifting by
analysing data sets of individual gifts for a diverse group of institutions
dedicated to education, medicine, art, public support, and religion. We find
that the detailed forms of gift-size distributions differ across but are
relatively constant within charity categories. We construct a model for how a
donor's income affects their giving preferences in different charity
categories, offering a mechanistic explanation for variations in institutional
gift-size distributions. We discuss how knowledge of gift-sized distributions
may be used to assess an institution's gift-giving profile, to help set
fundraising goals, and to design an institution-specific giving pyramid.


title: Self-Organized Topological State with Majorana Fermions

abstract:
  Topological phases, quite generally, are difficult to come by. They either
occur under rather extreme conditions (e.g. the quantum Hall liquids, which
require high sample purity, strong magnetic fields and low temperatures) or
demand fine tuning of system parameters, as in the majority of known
topological insulators. Many perfectly sensible topological phases, such as the
Weyl semimetals and topological superconductors, remain experimentally
undiscovered. Here we introduce a system in which a key dynamical parameter
adjusts itself in response to the changing external conditions so that the
ground state naturally favours the topological phase. The system consists of a
quantum wire formed of individual magnetic atoms placed on the surface of an
ordinary s-wave superconductor. It realizes the Kitaev paradigm of topological
superconductivity when the wavevector characterizing the emergent spin helix
dynamically self-tunes to support the topological phase.


title: Internal States of Hadrons in Relativistic Reference Frames

abstract:
  The internal state of a composite particle and its transformation, when
changing from the reference frame, where this composite particle is at rest, to
a reference frame, where it moves relativistically, have been considered. It is
supposed that the internal state of the composite particle in its rest frame
can be considered in the non-relativistic approximation. This internal state is
shown to remain the same, when changing from one inertial reference frame to
another one. In other words, a particle that is spherically symmetric in its
rest frame does not change its form in any other reference frame and does not
undergo the Lorentz contraction in the direction of motion of any reference
frame with respect to the rest one. A possible application of the results
obtained to describe the scattering of hadrons considered as bound states of
quarks has been discussed.


title: Exact relativistic models of perfect fluid disks in a magnetic field

abstract:
  Using the well-known ``displace, cut and reflect'' method we construct thin
disks made of a perfect fluid in presence of a magnetic field. The models are
based in a magnetic Reissner-Nordstrom metric of Einstein-Maxwell equations for
a conformastatic spacetime. The influence of the magnetic field on the matter
properties of the disk are analyzed. We also study the motion of charged test
particles around the disks. We construct models of perfect fluid disks
satisfying all the energy conditions.


title: Visualizing the Charge Density Wave Transition in 2H-NbSe2 in Real Space

abstract:
  We report the direct observation in real space of the charge density wave
(CDW) phase transition in pristine 2H-NbSe2 using atomic-resolution scanning
tunneling microscopy (STM). We find that static CDW order is established in
nanoscale regions in the vicinity of defects at temperatures that are several
times the bulk transition temperature Tcdw. On lowering the temperature, the
correlation length of these patches increases steadily until CDW order is
established in all of space, demonstrating the crucial role played by defects
in the physics of the transition region. The nanoscale CDW order has an energy
and temperature-independent wavelength. Spectroscopic imaging measurements of
the real-space phase of the CDW indicate that an energy gap in NbSe2 occurs at
0.7eV below the Fermi energy in the CDW phase, suggesting that strong
electron-lattice interactions and not Fermi surface physics is the dominant
cause for CDW formation in NbSe2.


title: Now Broadcasting in Planck Definition

abstract:
  If reality has finite information content, space has finite fidelity. The
quantum wave function that encodes spatial relationships may be limited to
information that can be transmitted in a "Planck broadcast", with a bandwidth
given by the inverse of the Planck time, about $2\times 10^{43}$ bits per
second. Such a quantum system can resemble classical space-time on large
scales, but locality emerges only gradually and imperfectly. Massive bodies are
never perfectly at rest, but very slightly and slowly fluctuate in transverse
position, with a spectrum of variation given by the Planck time. This
distinctive new kind of noise associated with quantum geometry would not have
been noticed up to now, but may be detectable in a new kind of experiment.


title:
Climatology of the Martian Polar Regions: Three Mars Years of
  CRISM/MARCI Observations of Atmospheric Clouds and Dust

abstract:
  We present the synthesis of CRISM EPF and MARCI data to examine the evolution
of atmospheric water ice and dust opacity at both poles for MY 28-30.


title: Inflection point as a characteristic of the QCD critical point

abstract:
  The appearance of the inflection point in the equation of state (EoS) is
associated with the second order phase transition. The high cumulants of
conserved quantities near the critical point are corresponding to the high
derivatives of the EoS near the inflection point. The critical behavior of high
cumulants of conserved charge near the QCD critical point, in particular, the
sign change, is closely related to the appearance of inflection point. We show
in general how the times of sign change of high cumulants relate to the order
of derivative. We also demonstrate that the character of inflection point of
EoS is as visible as the sign change of high cumulants in 3 systems, i.e., van
der Waals equation of fluid, magnetization of spin models and the baryon number
density of QCD matter. Therefore, we propose that the EoS, or the mean of
baryon number density, should be measured and studied together with its higher
cumulants in exploring QCD critical point in heavy ion collisions.


title: Scattering and transport properties of tight-binding random networks

abstract:
  We study numerically scattering and transport statistical properties of
tight-binding random networks characterized by the number of nodes $N$ and the
average connectivity $\alpha$. We use a scattering approach to electronic
transport and concentrate on the case of a small number of single-channel
attached leads. We observe a smooth crossover from insulating to metallic
behavior in the average scattering matrix elements $\bra |S_{mn}|^2 \ket$, the
conductance probability distribution $w(T)$, the average conductance $\bra T
\ket$, the shot noise power $P$, and the elastic enhancement factor $F$ by
varying $\alpha$ from small ($\alpha \to 0$) to large ($\alpha \to 1$) values.
We also show that all these quantities are invariant for fixed $\xi=\alpha N$.
Moreover, we proposes a heuristic and universal relation between $\bra
|S_{mn}|^2 \ket$, $\bra T \ket$, and $P$ and the disorder parameter $\xi$.


title:
Dynamical symmetry approach and topological field theory for path
  integrals of quantum spin systems

abstract:
  We develop a dynamical symmetry approach to path integrals for general
interacting quantum spin systems. The time-ordered exponential obtained after
the Hubbard-Stratonovich transformation can be disentangled into the product of
a finite number of the usual exponentials. This procedure leads to a set of
stochastic differential equations on the group manifold, which can be further
formulated in terms of the supersymmetric effective action. This action has the
form of the Witten topological field theory in the continuum limit. As a
consequence, we show how it can be used to obtain the exact results for a
specific quantum many-body system which can be otherwise solved only by the
Bethe ansatz. To our knowledge this represents the first example of a many-body
system treated exactly using the path integral formulation. Moreover, our
method can deal with time-dependent parameters, which we demonstrate
explicitly.


title: Quantum Disentangled Liquids

abstract:
  We propose and explore a new finite temperature phase of translationally
invariant multi-component liquids which we call a "Quantum Disentangled Liquid"
(QDL) phase. We contemplate the possibility that in fluids consisting of two
(or more) species of indistinguishable quantum particles with a large mass
ratio, the light particles might "localize" on the heavy particles. We give a
precise, formal definition of this Quantum Disentangled Liquid phase in terms
of the finite energy density many-particle wavefunctions. While the heavy
particles are fully thermalized, for a typical fixed configuration of the heavy
particles, the entanglement entropy of the light particles satisfies an area
law; this implies that the light particles have not thermalized. Thus, in a QDL
phase, thermal equilibration is incomplete, and the canonical assumptions of
statistical mechanics are not fully operative. We explore the possibility of
QDL in water, with the light proton degrees of freedom becoming "localized" on
the oxygen ions. We do not presently know whether a local, generic Hamiltonian
can have eigenstates of the QDL form, and if it can not, then the non-thermal
behavior discussed here will exist as an interesting crossover phenomena at
time scales that diverge as the ratio of the mass of the heavy to the light
species also diverges.

categories: cond-mat.str-el cond-mat.quant-gas cond-mat.stat-mech hep-th quant-ph


title: Anybody but Hubble!

abstract:
  The recent literature of astronomy and cosmology has included a good many
suggestions for "who first recognized the expansion of the universe?" with
cases having been made for Lemaitre, Lundmark, de Sitter, Slipher, Shapley,
Friedmann, Wirtz, and perhaps others. I touch on these but also mention others
(some of whose names have not come down to us) who might reasonably be credited
with some part of the basic idea, but conclude that "Hubble's Law" is the right
choice ("because it was discovered by Lundmark" in accordance with Stigler's
Law). Of course there are a couple of previously unsung heroes (Dose and
Zoellner), and the discussion bears some traces of its origin as an
after-dinner talk. The full context goes back to ideas from China and forward
to the struggle to correct Hubble's erroneous value of his constant.


title: Superconducting phases of strange quark matter in the NJL model

abstract:
  We analyze the color-flavor-locked phase of strange quark matter modelled by
the three-flavor Nambu-Jona-Lasinio (NJL) framework with and without magnetic
field and discuss some additional constraints on the stability scenario when a
high magnetic field is applied. We compare the results obtained by employing
the MIT Bag Model and discuss the pairing gap behavior and its influence on the
equation of state.


title: Mori cones of holomorphic symplectic varieties of K3 type

abstract:
  We determine the Mori cone of holomorphic symplectic varieties deformation
equivalent to the punctual Hilbert scheme on a K3 surface. Our description is
given in terms of Markman's extended Hodge lattice.


title:
Fourier integrals and a new representation of Maslov's canonical
  operator near caustics

abstract:
  We suggest a new representation of Maslov's canonical operator in a
neighborhood of the caustics using a special class of coordinate systems
("eikonal coordinates") on Lagrangian manifolds.


title: Runaway stars: their impact on the intestellar medium

abstract:
  Runaway, massive stars are not among the most numerous. However, the bow
shocks built by their supersonic movement in the interstellar medium have been
detected in the infrared range in many cases. Most recently, the stellar bow
shocks have been proposed as particle acceleration sites, as radio data
analysis at high angular resolution have shown. We present results of different
manifestations of the stellar bowshock phenomenon, revealed from modern IR
databases.


title: A General Framework for Privacy-Preserving Distributed Greedy Algorithm

abstract:
  Increasingly more attention is paid to the privacy in online applications due
to the widespread data collection for various analysis purposes. Sensitive
information might be mined from the raw data during the analysis, and this led
to a great privacy concern among people (data providers) these days. To deal
with this privacy concerns, multitudes of privacy-preserving computation
schemes are proposed to address various computation problems, and we have found
many of them fall into a class of problems which can be solved by greedy
algorithms.
  In this paper, we propose a framework for distributed greedy algorithms in
which instances in the feasible set come from different parties. By our
framework, most generic distributed greedy algorithms can be converted to a
privacy preserving one which achieves the same result as the original greedy
algorithm while the private information associated with the instances is still
protected.


title: Duality Codes and the Integrality Gap Bound for Index Coding

abstract:
  This paper considers a base station that delivers packets to multiple
receivers through a sequence of coded transmissions. All receivers overhear the
same transmissions. Each receiver may already have some of the packets as side
information, and requests another subset of the packets. This problem is known
as the index coding problem and can be represented by a bipartite digraph. An
integer linear program is developed that provides a lower bound on the minimum
number of transmissions required for any coding algorithm. Conversely, its
linear programming relaxation is shown to provide an upper bound that is
achievable by a simple form of vector linear coding. Thus, the information
theoretic optimum is bounded by the integrality gap between the integer program
and its linear relaxation. In the special case when the digraph has a planar
structure, the integrality gap is shown to be zero, so that exact optimality is
achieved. Finally, for non-planar problems, an enhanced integer program is
constructed that provides a smaller integrality gap. The dual of this problem
corresponds to a more sophisticated partial clique coding strategy that
time-shares between Reed-Solomon erasure codes. This work illuminates the
relationship between index coding, duality, and integrality gaps between
integer programs and their linear relaxations.


title: Extragalactic Nova Populations

abstract:
  Nova rates have now been measured for more than a dozen galaxies spanning a
wide range of Hubble types. When normalized to the infrared K-band luminosity
of the galaxy, the luminosity-specific nova rates typically fall in the range
of 1-3 novae per year per 10^10 solar luminosities in K, and do not vary
significantly across the Hubble sequence. Preliminary nova rates are presented
for three Virgo ellipticals (M49, M84, and M87) with differing globular cluster
specific frequencies. No dependence of the luminosity-specific nova rate on
globular cluster specific frequency was found. Photometric and spectroscopic
observations of novae in the Local Group suggest that galaxies dominated by a
younger stellar population (M33 and the LMC) are characterized by novae with a
generally faster photometric evolution, and by a higher fraction of He/N novae
compared with novae in M31. The recurrent nova population in the LMC appears to
be higher than that seen in M31 and the Galaxy.


title: Multivariate two-sample extended empirical likelihood

abstract:
  Jing (1995) and Liu et al. (2008) studied the two-sample empirical likelihood
and showed it is Bartlett correctable for the univariate and multivariate
cases, respectively. We expand its domain to the full parameter space and
obtain a two-sample extended empirical likelihood which is more accurate and
can also achieve the second-order accuracy of the Bartlett correction.


title:
Determining Structurally Identifiable Parameter Combinations Using
  Subset Profiling

abstract:
  Identifiability is a necessary condition for successful parameter estimation
of dynamic system models. A major component of identifiability analysis is
determining the identifiable parameter combinations, the functional forms for
the dependencies between unidentifiable parameters. Identifiable combinations
can help in model reparameterization and also in determining which parameters
may be experimentally measured to recover model identifiability. Several
numerical approaches to determining identifiability of differential equation
models have been developed, however the question of determining identifiable
combinations remains incompletely addressed. In this paper, we present a new
approach which uses parameter subset selection methods based on the Fisher
Information Matrix, together with the profile likelihood, to effectively
estimate identifiable combinations. We demonstrate this approach on several
example models in pharmacokinetics, cellular biology, and physiology.


title:
Stellar and circumstellar properties of visual binaries in the Orion
  Nebula Cluster

abstract:
  Our general understanding of multiple star and planet formation is primarily
based on observations of young multiple systems in low density regions like
Tau-Aur and Oph. Since many, if not most, of the stars are born in clusters,
observational constraints from young binaries in those environments are
fundamental for understanding both the formation of multiple systems and
planets in multiple systems throughout the Galaxy. We build upon the largest
survey for young binaries in the Orion Nebula Cluster (ONC) which is based on
Hubble Space Telescope observations to derive both stellar and circumstellar
properties of newborn binary systems in this cluster environment. We present
Adaptive Optics spatially-resolved JHKL'-band photometry and K-band
R$\sim$\,5000 spectra for a sample of 8 ONC binary systems from this database.
We characterize the stellar properties of binary components and obtain a census
of protoplanetary disks through K-L' color excess. For a combined sample of ONC
binaries including 7 additional systems with NIR spectroscopy from the
literature, we derive mass ratio and relative age distributions. We compare the
stellar and circumstellar properties of binaries in ONC with those in Tau-Aur
and Oph from samples of binaries with stellar properties derived for each
component from spectra and/or visual photometry and with a disk census obtained
through K-L color excess. The mass ratio distribution of ONC binaries is found
to be indistinguishable from that of Tau-Aur and, to some extent, to that of
Oph in the separation range 85-560\,AU and for primary mass in the range 0.15
to 0.8\,M$_{\sun}$.A trend toward a lower mass ratio with larger separation is
suggested in ONC binaries which is not seen in Tau-Aur binaries.The components
of ONC binaries are found to be significantly more coeval than the overall ONC
population and as coeval as components of binaries in Tau-Aur and Oph[...]


title: ExoMol line lists II: The ro-vibrational spectrum of SiO

abstract:
  Accurate rotation-vibration line lists are calculated for silicon monoxide.
Line lists are presented for the main isotopologue, $^{28}$Si$^{16}$O, and for
four monosubsituted isotopologues ($^{29}$Si$^{16}$O, $^{30}$Si$^{16}$O,
$^{28}$Si$^{18}$O and $^{28}$Si$^{17}$O), in their ground electronic states.
These line lists are suitable for high temperatures (up to 9000 K) including
those relevant to exoplanetary atmospheres and cool stars. A combination of
empirical and \textit{ab initio} methods is used: the potential energy curves
are determined to high accuracy by fitting to extensive data from the analysis
of both laboratory and sunspot spectra; a high quality {\it ab initio} dipole
moment curve is calculated at the large basis set, multi-reference
configuration interaction level. A partition function plus full line lists of
rotation-vibration transitions are made available in an electronic form as
supplementary data to this article and at \url{www.exomol.com}.


title:
Concentrating standing waves for the fractional nonlinear Schr\"odinger
  equation

abstract:
  We consider the semilinear equation $$ \epsilon^{2s} (-\Delta)^s u + V(x)u -
u^p = 0, \quad u>0, \quad u\in H^{2s}(\R^N) $$ where $0<s<1,\
1<p<\frac{N+2s}{N-2s}$, $ V(x)$ is a sufficiently smooth potential with
$\inf_\R V(x)> 0$, and $\epsilon>0$ is a small number. Letting $w_\lambda$ be
the radial ground state of $(-\Delta)^s w_\lambda + \lambda w_\lambda -
w_\lambda^p=0$ in $H^{2s}(\R^N)$, we build solutions of the form $$
u_\epsilon(x) \sim \sum_{i=1}^k w_{\lambda_i} ((x-\xi_i^\epsilon)/\epsilon),$$
where $\lambda_i = V(\xi_i^\epsilon)$ and the $\xi_i^\epsilon $ approach
suitable critical points of $V$. Via a Lyapunov Schmidt variational reduction,
we recover various existence results already known for the case $s=1$. In
particular such a solution exists around $k$ nondegenerate critical points of
$V$. For $s=1$ this corresponds to the classical results by Floer-Weinstein and
Oh.


title: The blessing of transitivity in sparse and stochastic networks

abstract:
  The interaction between transitivity and sparsity, two common features in
empirical networks, implies that there are local regions of large sparse
networks that are dense. We call this the blessing of transitivity and it has
consequences for both modeling and inference. Extant research suggests that
statistical inference for the Stochastic Blockmodel is more difficult when the
edges are sparse. However, this conclusion is confounded by the fact that the
asymptotic limit in all of the previous studies is not merely sparse, but also
non-transitive. To retain transitivity, the blocks cannot grow faster than the
expected degree. Thus, in sparse models, the blocks must remain asymptotically
small. \n Previous algorithmic research demonstrates that small "local"
clusters are more amenable to computation, visualization, and interpretation
when compared to "global" graph partitions. This paper provides the first
statistical results that demonstrate how these small transitive clusters are
also more amenable to statistical estimation. Theorem 2 shows that a "local"
clustering algorithm can, with high probability, detect a transitive stochastic
block of a fixed size (e.g. 30 nodes) embedded in a large graph. The only
constraint on the ambient graph is that it is large and sparse--it could be
generated at random or by an adversary--suggesting a theoretical explanation
for the robust empirical performance of local clustering algorithms.


title: Apparent Solar Tornado - Like Prominences

abstract:
  Recent high-resolution observations from the Solar Dynamics Observatory (SDO)
have reawakened interest in the old and fascinating phenomenon of solar
tornado-like prominences. This class of prominences was first introduced by
Pettit (1932), who studied them over many years. Observations of tornado
prominences similar to the ones seen by SDO had already been documented by
Secchi (1877) in his famous "Le Soleil". High resolution and high cadence
multiwavelength data obtained by SDO reveal that the tornado-like appearance of
these prominences is mainly an illusion due to projection effects. We discuss
two different cases where prominences on the limb might appear to have a
tornado-like behavior. One case of apparent vortical motions in prominence
spines and barbs arises from the (mostly) 2D counterstreaming plasma motion
along the prominence spine and barbs together with oscillations along
individual threads. The other case of apparent rotational motion is observed in
prominence cavities and results from the 3D plasma motion along the writhed
magnetic fields inside and along the prominence cavity as seen projected on the
limb. Thus, the "tornado" impression results either from counterstreaming and
oscillations or from the projection on the plane of the sky of plasma motion
along magnetic field lines, rather than from a true vortical motion around an
(apparent) vertical or horizontal axis. We discuss the link between
tornado-like prominences, filament barbs, and photospheric vortices at their
base.


title:
Star Polymers Confined in a Nanoslit: A Simulation Test of Scaling and
  Self-Consistent Field Theories

abstract:
  The free energy cost of confining a star polymer where $f$ flexible polymer
chains containing $N$ monomeric units are tethered to a central unit in a slit
with two parallel repulsive walls a distance $D$ apart is considered, for good
solvent conditions. Also the parallel and perpendicular components of the
gyration radius of the star polymer, and the monomer density profile across the
slit are obtained. Theoretical descriptions via Flory theory and scaling
treatments are outlined, and compared to numerical self-consistent field
calculations (applying the Scheutjens-Fleer lattice theory) and to Molecular
Dynamics results for a bead-spring model. It is shown that Flory theory and
self-consistent field (SCF) theory yield the correct scaling of the parallel
linear dimension of the star with $N$, $f$ and $D$, but cannot be used for
estimating the free energy cost reliably. We demonstrate that the same problem
occurs already for the confinement of chains in cylindrical tubes. We also
briefly discuss the problem of a free or grafted star polymer interacting with
a single wall, and show that the dependence of confining force on the
functionality of the star is different for a star confined in a nanoslit and a
star interacting with a single wall, which is due to the absence of a symmetry
plane in the latter case.


title: SL(n,R)-Toda Black Holes

abstract:
  We consider D-dimensional Einstein gravity coupled to (n-1) U(1) vector
fields and (n-2) dilatonic scalars. We find that for some appropriate
exponential dilaton couplings of the field strengths, the equations of motion
for the static charged ansatz can be reduced to a set of one-dimensional
SL(n,R) Toda equations. This allows us to obtain a general class of explicit
black holes with mass and (n-1) independent charges. The near-horizon geometry
in the extremal limit is AdS_2 x S^{D-2}. The n=2 case gives the
Reissner-Nordstrom solution, and the n=3 example includes the Kaluza-Klein
dyon. We study the global structure and the black hole thermodynamics and
obtain the universal entropy product formula. We also discuss the
characteristics of extremal multi-charge black holes that have positive, zero
or negative binding energies.


title: Surfaces of small diameter with large width

abstract:
  Given a 2-dimensional surface M and a constant C we construct a Riemannian
metric g, so that diameter diam(M,g)=1 and every 1-cycle dividing M into two
regions of equal area has length >C. It follows that there exists no universal
inequality bounding 1-width of M in terms of its diameter. This answers a
question of Stephane Sabourau.


title:
Bridging Information Criteria and Parameter Shrinkage for Model
  Selection

abstract:
  Model selection based on classical information criteria, such as BIC, is
generally computationally demanding, but its properties are well studied. On
the other hand, model selection based on parameter shrinkage by $\ell_1$-type
penalties is computationally efficient. In this paper we make an attempt to
combine their strengths, and propose a simple approach that penalizes the
likelihood with data-dependent $\ell_1$ penalties as in adaptive Lasso and
exploits a fixed penalization parameter. Even for finite samples, its model
selection results approximately coincide with those based on information
criteria; in particular, we show that in some special cases, this approach and
the corresponding information criterion produce exactly the same model. One can
also consider this approach as a way to directly determine the penalization
parameter in adaptive Lasso to achieve information criteria-like model
selection. As extensions, we apply this idea to complex models including
Gaussian mixture model and mixture of factor analyzers, whose model selection
is traditionally difficult to do; by adopting suitable penalties, we provide
continuous approximators to the corresponding information criteria, which are
easy to optimize and enable efficient model selection.


title:
Single (anti-)top quark production in association with a lightest
  neutralino at LHeC

abstract:
  In this paper we examine thoroughly the single (anti-)top quark production
associated with a lightest neutralino at the possible CERN Large Hadron
Electron Collider (LHeC). We calculate the full next-to-leading order (NLO) QCD
corrections to the process including all the nonresonant diagrams and do not
assume the production and decay factorization for the possible resonant top
squarks in the R-parity violating minimal supersymmetric standard model with 19
unrelated parameters. We investigate numerically the effects of the relevant
supersymmetry (SUSY) parameters on the cross section, and present the
transverse momentum distributions of final (anti-)top quark at both the
leading-order (LO) and the QCD NLO. We find that the NLO QCD corrections
enhance the LO cross sections in most chosen parameter space, and the NLO QCD
impacts on the transverse momentum distributions of the final (anti-)top quark
might be resolvable in some cases. We conclude that even with recently known
experimental constraints the on SUSY parameters, the production rate could
still achieve notable value in the admissible parameter space.


title: Crystallization Dynamics on Curved Surfaces

abstract:
  We study the evolution from a liquid to a crystal phase in two-dimensional
curved space. At early times, while crystal seeds grow preferentially in
regions of low curvature, the lattice frustration produced in regions with high
curvature is rapidly relaxed through isolated defects. Further relaxation
involves a mechanism of crystal growth and defect annihilation where regions
with high curvature act as sinks for the diffusion of domain walls. The pinning
of grain boundaries at regions of low curvature leads to the formation of a
metastable structure of defects, characterized by asymptotically slow dynamics
of ordering and activation energies dictated by the largest curvatures of the
system. These glassy-like ordering dynamics may completely inhibit the
appearance of the ground state structures.


title: 2\pi-grafting and complex projective structures with generic holonomy

abstract:
  Let S be an oriented closed surface of genus at least two. We show that,
given a generic representation in the PSL(2,C)-character variety of S,
(2\pi-)graftings produce all projective structures on S with the holonomy
representation.


title: Tunneling inhibition for subwavelength light

abstract:
  We show that light tunneling inhibition may take place in suitable
dynamically modulated waveguide arrays for light spots whose features are
remarkably smaller than the wavelength of light. We found that tunneling
between neighboring waveguides can be suppressed for specific frequencies of
the out-of-phase refractive index modulation, affording undistorted propagation
of the input subwavelength light spots over hundreds of Rayleigh lengths.
Tunneling inhibition turns out to be effective only when the waveguide
separation in the array is above a critical threshold. Inclusion of a weak
focusing nonlinearity is shown to improve localization. We analyze the
phenomenon in purely dielectric structures and also in arrays containing
periodically spaced metallic layers.


title: Bayesian Discovery of Multiple Bayesian Networks via Transfer Learning

abstract:
  Bayesian network structure learning algorithms with limited data are being
used in domains such as systems biology and neuroscience to gain insight into
the underlying processes that produce observed data. Learning reliable networks
from limited data is difficult, therefore transfer learning can improve the
robustness of learned networks by leveraging data from related tasks. Existing
transfer learning algorithms for Bayesian network structure learning give a
single maximum a posteriori estimate of network models. Yet, many other models
may be equally likely, and so a more informative result is provided by Bayesian
structure discovery. Bayesian structure discovery algorithms estimate posterior
probabilities of structural features, such as edges. We present transfer
learning for Bayesian structure discovery which allows us to explore the shared
and unique structural features among related tasks. Efficient computation
requires that our transfer learning objective factors into local calculations,
which we prove is given by a broad class of transfer biases. Theoretically, we
show the efficiency of our approach. Empirically, we show that compared to
single task learning, transfer learning is better able to positively identify
true edges. We apply the method to whole-brain neuroimaging data.


title: Improved Submatrix Maximum Queries in Monge Matrices

abstract:
  We present efficient data structures for submatrix maximum queries in Monge
matrices and Monge partial matrices. For $n\times n$ Monge matrices, we give a
data structure that requires O(n) space and answers submatrix maximum queries
in $O(\log n)$ time. The best previous data structure [Kaplan et al., SODA`12]
required $O(n \log n)$ space and $O(\log^2 n)$ query time. We also give an
alternative data structure with constant query-time and $ O(n^{1+\varepsilon})$
construction time and space for any fixed $\varepsilon<1$. For $n\times n$ {\em
partial} Monge matrices we obtain a data structure with O(n) space and $O(\log
n \cdot \alpha(n))$ query time. The data structure of Kaplan et al. required
$O(n \log n \cdot \alpha(n))$ space and $O(\log^2 n)$ query time.
  Our improvements are enabled by a technique for exploiting the structure of
the upper envelope of Monge matrices to efficiently report column maxima in
skewed rectangular Monge matrices. We hope this technique can be useful in
obtaining faster search algorithms in Monge partial matrices. In addition, we
give a linear upper bound on the number of breakpoints in the upper envelope of
a Monge partial matrix. This shows that the inverse Ackermann $\alpha(n)$ term
in the analysis of the data structure of Kaplan et. al is superfluous.


title:
From the Attempt of Certain Classical Reformulations of Quantum
  Mechanics to Quasi-Probability Representations

abstract:
  The concept of an injective affine embedding of the quantum states into a set
of classical states, i.e., into the set of the probability measures on some
measurable space, as well as its relation to statistically complete observables
is revisited, and its limitation in view of a classical reformulation of the
statistical scheme of quantum mechanics is discussed. In particular, on the
basis of a theorem concerning a non-denseness property of a set of coexistent
effects, it is shown that an injective classical embedding of the quantum
states cannot be supplemented by an at least approximate classical description
of the quantum mechanical effects. As an alternative approach, the concept of
quasi-probability representations of quantum mechanics is considered.


title: Shell and isospin effects in nuclear charge radii

abstract:
  The shell effect and isospin effect in nuclear charge radii are
systematically investigated and a four-parameter formula is proposed for the
description of the root-mean-square (rms) charge radii by combining the shell
corrections and deformations of nuclei obtained from the Weizs\"acker-Skyrme
mass model. The rms deviation with respect to the 885 measured charge radii
falls to 0.022 fm. The proposed formula is also applied for the study of the
charge radii of super-heavy nuclei and nuclear symmetry energy. The linear
relationship between the slope parameter L of the nuclear symmetry energy and
the rms charge radius difference of 30S - 30Si mirror pair is clearly observed.
The estimated slope parameter is about $L=54 \pm 19$ MeV from the coefficient
of the isospin term in the proposed charge radius formula.


title:
Transformations of polar Grassmannians preserving certain intersecting
  relations

abstract:
  Let $\Pi$ be a polar space of rank $n\ge 3$. Denote by ${\mathcal
G}_{k}(\Pi)$ the polar Grassmannian formed by singular subspaces of $\Pi$ whose
projective dimension is equal to $k$. Suppose that $k$ is an integer not
greater than $n-2$ and consider the relation ${\mathfrak R}_{i,j}$, $0\le i\le
j\le k+1$ formed by all pairs $(X,Y)\in {\mathcal G}_{k}(\Pi)\times {\mathcal
G}_{k}(\Pi)$ such that $\dim_{p}(X^{\perp}\cap Y)=k-i$ and $\dim_{p} (X\cap
Y)=k-j$ ($X^{\perp}$ consists of all points of $\Pi$ collinear to every point
of $X$). We show that every bijective transformation of ${\mathcal G}_{k}(\Pi)$
preserving ${\mathfrak R}_{1,1}$ is induced by an automorphism of $\Pi$ and the
same holds for the relation ${\mathfrak R}_{0,t}$ if $n\ge 2t\ge 4$ and
$k=n-t-1$. In the case when $\Pi$ is a finite classical polar space, we
establish that the valencies of ${\mathfrak R}_{i,j}$ and ${\mathfrak
R}_{i',j'}$ are distinct if $(i,j)\ne (i',j')$.


title: Fermions in a warped resolved conifold

abstract:
  We investigated the localization of the spinorial field in a braneworld built
as a warped product between a 3-brane and a 2-cycle of the resolved conifold.
This scenario provides a geometric flow that controls the singularity at the
origin and changes the properties of the fermion in this background.
Furthermore, due the cylindrical symmetry according to the 3-brane and a
smoothed warp factor, this geometry can be regarded as a near brane correction
of the string-like branes. This geometry allows a normalizable and well-defined
massless mode whose decay and value on the brane depend on the resolution
parameter. For the Kaluza-Klein modes, resolution parameter also controls the
height of the barrier of the volcano potential.


title:
Efficient electron refrigeration using superconductor/spin-filter
  devices

abstract:
  Efficient electron-refrigeration based on a
normal-metal/spin-filter/superconductor junction is proposed and demonstrated
theoretically. The spin-filtering effect leads to values of the cooling power
much higher than in conventional
normal-metal/nonmagnetic-insulator/superconductor coolers and allows for an
efficient extraction of heat from the normal metal. We demonstrate that highly
efficient cooling can be realized in both ballistic and diffusive multi-channel
junctions in which the reduction of the electron temperature from 300 mK to
around 50 mK can be achieved. Our results indicate the practical usefulness of
spin-filters for efficiently cooling detectors, sensors, and quantum devices.


title:
Upper bounds for the number of primitive ray class characters with
  conductor below a given bound

abstract:
  We present upper bounds on certain sums which are related to Artin's
primitive root conjecture and are also used in counting ray class characters.


title:
Dynamic Partial Cooperative MIMO System for Delay-Sensitive Applications
  with Limited Backhaul Capacity

abstract:
  Considering backhaul consumption in practical systems, it may not be the best
choice to engage all the time in full cooperative MIMO for interference
mitigation. In this paper, we propose a novel downlink partial cooperative MIMO
(Pco-MIMO) physical layer (PHY) scheme, which allows flexible tradeoff between
the partial data cooperation level and the backhaul consumption. Based on this
Pco-MIMO scheme, we consider dynamic transmit power and rate allocation
according to the imperfect channel state information at transmitters (CSIT) and
the queue state information (QSI) to minimize the average delay cost subject to
average backhaul consumption constraints and average power constraints. The
delay-optimal control problem is formulated as an infinite horizon average cost
constrained partially observed Markov decision process (CPOMDP). By exploiting
the special structure in our problem, we derive an equivalent Bellman Equation
to solve the CPOMDP. To reduce computational complexity and facilitate
distributed implementation, we propose a distributed online learning algorithm
to estimate the per-flow potential functions and Lagrange multipliers (LMs) and
a distributed online stochastic partial gradient algorithm to obtain the power
and rate control policy. The proposed low-complexity distributed solution is
based on local observations of the system states at the BSs and is very robust
against model variations. We also prove the convergence and the asymptotic
optimality of the proposed solution.


title: Methyl Cyanide Observations Toward Massive Protostars

abstract:
  We report the results of a survey in the CH3CN J= 12-11 transition toward a
sample of massive proto-stellar candidates. The observations were carried out
with the 10 m Submillimeter telescope on Mount Graham, AZ. We detected this
molecular line in 9 out of 21 observed sources. In six cases this is the first
detection of this transition. We also obtained full beam sampled cross-scans
for five sources which show that the lower K-components can be extended on the
arcminute angular scale. The higher K-components however are always found to be
compact with respect to our 36" beam. A Boltzmann population diagram analysis
of the central spectra indicates CH3CN column densities of about 10^14 cm^(-2),
and rotational temperatures above 50 K, which confirms these sources as hot
molecular cores. Independent fits to line velocity and width for the individual
K-components resulted in the detection of an increasing blue shift with
increasing line excitation for four sources. Comparison with mid-infrared
images from the SPITZER GLIMPSE/IRAC archive for six sources show that the
CH3CN emission is generally coincident with a bright mid-IR source. Our data
clearly show that the CH3CN J= 12-11 transition is a good probe of the hot
molecular gas near massive protostars, and provide the basis for future
interferometric studies.


title: A new physical phenomenon in ultra-high energy collisions

abstract:
  We show that combining the published Pierre Auger Observatory measurements of
the longitudinal_and_ lateral properties of UHE atmospheric showers, points to
an unforeseen change in the nature of particle interactions at ultrahigh
energy. A "toy model" of UHE proton-air interactions is presented which
provides the first fully consistent description of air shower observations. It
demonstrates that the observed energy dependence of the depth-of-shower-maximum
distribution may not indicate a transition to a heavier composition, as
commonly assumed. While fundamentally phenomenological, the model is based on
considerations of how the normal vacuum of QCD might be vaporized and chiral
symmetry restored by the extreme energy densities produced in UHE collisions.
Whatever its origin, understanding this unexpected phenomenon opens exciting
directions in particle physics and may impact Early Universe cosmology.


title: Bounding Polynomial Entanglement Measures for Mixed States

abstract:
  We generalize the notion of the best separable approximation (BSA) and best
W-class approximation (BWA) to arbitrary pure state entanglement measures,
defining the best zero-$E$ approximation (BEA). We show that for any polynomial
entanglement measure $E$, any mixed state $\rho$ admits at least one
"$S$-decomposition," i.e., a decomposition in terms of a mixed state on which
$E$ is equal to zero, and a single additional pure state with (possibly)
non-zero $E$. We show that the BEA is not in general the optimal
$S$-decomposition from the point of view of bounding the entanglement of
$\rho$, and describe an algorithm to construct the entanglement-minimizing
$S$-decomposition for $\rho$ and place an upper bound on $E(\rho)$. When
applied to the three-tangle, the cost of the algorithm is linear in the rank
$d$ of the density matrix and has accuracy comparable to a steepest descent
algorithm whose cost scales as $d^8 \log d$. We compare the upper bound to a
lower bound algorithm given by Eltschka and Siewert for the three-tangle, and
find that on random rank-two three-qubit density matrices, the difference
between the upper and lower bounds is $0.14$ on average. We also find that the
three-tangle of random full-rank three qubit density matrices is less than
$0.023$ on average.


title:
A new Eulerian theory of turbulence constrained by random Galilean
  invariance

abstract:
  We propose a new Eulerian turbulence theory to obtain a closed set of
equations for homogeneous, isotropic turbulent velocity field correlations and
propagator functions by incorporating constraints of random Galilean
invariance. This incorporation generates a few different equations for
propagator and the present theory suggests a way to utilize them into the
closure solutions of two-time and single-time velocity correlations' equations
so as to properly account for random sweeping phenomena. The present theory
yields exact solutions when applied to simple model problem of random
oscillator.

categories: math-ph cond-mat.stat-mech math.MP nlin.CD physics.flu-dyn


title: A Simple Kontinuit\"atssatz

abstract:
  We are interested in several informal statements referred as
"Kontinuit\"atssatz" in the recent literature on analytic continuation. The
basic (unstated) principle that seems to be in use in these works appears to be
a folk theorem. We provide a precise statement of this folk Kontinuit\"atssatz
and give a proof of it.


title:
Differential Harnack inequalities and Perelman type entropy formulae for
  subelliptic operators

abstract:
  In this paper, under the generalized curvature-dimension inequality recently
introduced by F. Baudoin and N. Garofalo, we obtain differential Harnack
inequalities for the positive solutions to the Sch\"odinger equation associated
to subelliptic operator with potential. As applications of the differential
Harnack inequality, we derive the corresponding parabolic Harnack inequality.
Also we define the Perelman type entropy associated to subelliptic operators
and derive its monotonicity.


title: Magnetic monopoles and unusual transport effects in magnetoelectrics

abstract:
  It is argued that in magnetoelectrics with diagonal magnetoelectric coupling
there should be a monopole-like distribution of magnetization around electric
charge. It may lead to nontrivial transport properties of such materials, to
understand which the picture of magnetic monopoles attached to electric charges
may be very useful.


title: A Haskell Library for Term Rewriting

abstract:
  We present a Haskell library for first-order term rewriting covering basic
operations on positions, terms, contexts, substitutions and rewrite rules. This
effort is motivated by the increasing number of term rewriting tools that are
written in Haskell.


title: Polymer optical fiber fuse

abstract:
  Although high-transmission-capacity optical fibers are in demand, the problem
of the fiber fuse phenomenon needs to be resolved to prevent the destruction of
fibers. As polymer optical fibers become more prevalent, clarifying their fuse
properties has become important. Here, we experimentally demonstrate a fuse
propagation velocity of 21.9 mm/s, which is 1 to 2 orders of magnitude slower
than that in standard silica fibers. The achieved threshold power density and
proportionality constant between the propagation velocity and the power density
are respectively 1/186 of and 16.8 times the values for silica fibers. An
oscillatory continuous curve instead of periodic voids is formed after the
passage of the fuse. An easy fuse termination method is presented herein, along
with its potential plasma applications.


title:
Two optimal inequalities for anti-holomorphic submanifolds and their
  applications

abstract:
  The CR $\delta$-invariant for CR-submanifolds was introduced in a recent
article [B. Y. Chen, An optimal inequality for CR-warped products in complex
space forms involving CR $\delta$-invariant, Internat. J. Math. 23} (2012), no.
3, 1250045 (17 pages)]. In this paper, we prove two new optimal inequalities
for anti-holomorphic submanifolds in complex space forms involving the CR
$\delta$-invariant. Moreover, we obtain some classification results for certain
anti-holomorphic submanifolds in complex space forms which satisfy the equality
case of either inequality.


title:
Cloudbreak: Accurate and Scalable Genomic Structural Variation Detection
  in the Cloud with MapReduce

abstract:
  The detection of genomic structural variations (SV) remains a difficult
challenge in analyzing sequencing data, and the growing size and number of
sequenced genomes have rendered SV detection a bona fide big data problem.
MapReduce is a proven, scalable solution for distributed computing on huge data
sets. We describe a conceptual framework for SV detection algorithms in
MapReduce based on computing local genomic features, and use it to develop a
deletion and insertion detection algorithm, Cloudbreak. On simulated and real
data sets, Cloudbreak achieves accuracy improvements over popular SV detection
algorithms, and genotypes variants from diploid samples. It provides
dramatically shorter runtimes and the ability to scale to big data volumes on
large compute clusters. Cloudbreak includes tools to set up and configure
MapReduce (Hadoop) clusters on cloud services, enabling on-demand cluster
computing. Our implementation and source code are available at
http://github.com/cwhelan/cloudbreak .


title: Determinantal Martingales and Interacting Particle Systems

abstract:
  Determinantal process is a dynamical extension of a determinantal point
process such that any spatio-temporal correlation function is given by a
determinant specified by a single continuous function called the correlation
kernel. Noncolliding diffusion processes are important examples of
determinantal processes. In the present lecture, we introduce determinantal
martingales and show that if the interacting particle system (IPS) has
determinantal-martingale representation, then it becomes a determinantal
process. From this point of view, the reason why noncolliding diffusion
processes and noncolliding random walk are determinantal is simply explained by
the fact that the harmonic transform with the Vandermonde determinant provides
a proper determinantal martingale. Recently O'Connell introduced an interesting
IPS, which can be regarded as a stochastic version of a quantum Toda lattice.
It is a geometric lifting of the noncolliding Brownian motion and is not
determinantal, but Borodin and Corwin discovered a determinant formula for a
special observable for it. We also discuss this new topic from the present
view-point of determinantal martingale.

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


title: Flow in channels with superhydrophobic trapezoidal textures

abstract:
  Superhydrophobic one-dimensional surfaces reduce drag and generate transverse
hydrodynamic phenomena by combining hydrophobicity and roughness to trap gas
bubbles in microscopic textures. Recent works in this area have focused on
specific cases of superhydrophobic stripes. Here we provide some theoretical
results to guide the optimization of the forward flow and transverse
hydrodynamic phenomena in a parallel-plate channel with a superhydrophobic
trapezoidal texture, varying on scales larger than the channel thickness. The
permeability of such a thin channel is shown to be equivalent to that of a
striped one with greater average slip. The maximization of a transverse flow
normally requires largest possible slip at the gas areas, similarly to a
striped channel. However, in case of trapezoidal textures with a very small
fraction of the solid phase this maximum occurs at a finite slip at the gas
areas. Exact numerical calculations show that our analysis, based on a
lubrication theory, can also be applied for a larger gap. However, in this case
it overestimates a permeability of the channel, and underestimates an
anisotropy of the flow. Our results provide a framework for the rational design
of superhydrophobic surfaces for microfluidic applications.


title: Notes on general SIC-POVMs

abstract:
  An unavoidable task in quantum information processing is how to obtain data
about the state of an individual system by suitable measurements.
Informationally complete measurements are relevant in quantum state tomography,
quantum cryptography, quantum cloning, and other questions. Symmetric
informationally complete measurements (SIC-POVMs) form an especially important
class of such measurements. We formulate some novel properties and relations
for general SIC-POVMs in a finite-dimensional Hilbert space. For a given
density matrix and any general SIC-POVM, the so-called index of coincidence of
generated probability distribution is exactly calculated. Using this result, we
obtain state-dependent entropic bounds for a single general SIC-POVM. Lower
entropic bounds are derived in terms of the R\'{e}nyi $\alpha$-entropies for
$\alpha\in[2;\infty)$ and the Tsallis $\alpha$-entropies for $\alpha\in(0;2]$.
A lower bound on the min-entropy of a SIC-POVM is separately examined. For a
pair of general SIC-POVMs, entropic uncertainty relations of the Maassen-Uffink
type are considered.


title:
Fabrication of High Aspect Ratio Micro-Penning-Malmberg Gold Plated
  Silicon Trap Arrays

abstract:
  Acquiring a portable high density charged particles trap might consist of an
array of micro-Penning-Malmberg traps (microtraps) with substantially lower end
barriers potential than conventional Penning-Malmberg traps [1]. We report on
the progress of the fabrication of these microtraps designed for antimatter
storage such as positrons. The fabrication of large length to radius aspect
ratio (1000:1) microtrap arrays involved advanced techniques including
photolithography, deep reactive ion etching (DRIE) of silicon wafers to achieve
through-vias, gold sputtering of the wafers on the surfaces and inside the
vias, and thermal compression bonding of the wafers. This paper describes the
encountered issues during fabrication and addresses geometry errors and
asymmetries. In order to minimize the patch effects on the lifetime of the
trapped positrons, the bonded stacks were gold electroplated to achieve a
uniform gold surface. We show by simulation and analytical calculation that how
positrons confinement time depends on trap imperfections.


title:
Density functional studies on the hollow resonances in Li-isoelectronic
  sequence (Z=4--10

abstract:
  In this sequel to our work on triply excited hollow resonances in
three-electron atomic systems, a density functional theory (DFT)-based
formalism is employed to investigate similar resonances in Li-isoelectronic
series (Z=4--10). A combination of the work-function-based local nonvariational
exchange potential and the popular gradient plus Laplacian included
Lee-Yang-Parr correlation energy functional is used. First, all the 8 n=2
intrashell states of B$^{2+}$, N$^{4+}$ and F$^{6+}$ are presented, which are
relatively less studied in the literature compared to the remaining 4 members.
Then calculations are performed for the 8 $2l2l'$n$l"$ (3$\leq$n$\leq$6) hollow
resonance series; {\em viz.,} 2s$^2$ns $^2$S$^e$, 2s$^2$np $^2$P$^o$, 2s$^2$nd
$^2$D$^e$, 2s2pns $^4$P$^o$, 2s2pnp $^4$D$^e$, 2p$^2$ns $^4$P$^e$, 2p$^2$np
$^4$D$^o$ and 2p$^2$ns $^2$D$^e$, of all the 7 positive ions. Next, as an
illustration, higher resonance positions of the 2s$^2$ns $^2$S$^e$ series are
calculated for all the ions with a maximum of n=25. The excitation energies
calculated from this single-determinantal approach are in excellent agreement
with the available literature data (for the n=2 intrashell states the deviation
is within 0.125% and excepting only one case, the same for the resonance series
is well below 0.50%). With an increase in Z, the deviations tend to decrease.
Radial densities are also presented for some of the selected states. The only
result available in the literature for the lower resonances (corresponding to a
maximum of n=17) have been reported very recently. The n$>$16 ($>17$ for
F$^{6+}$) resonances are examined here for the first time. This gives a
promising viable and general DFT scheme for the accurate calculation of these
and other hollow resonances in many-electron atoms.


title: Anisotropic parabolic problems with slowly or rapidly growing terms

abstract:
  We consider an abstract parabolic problem in a framework of maximal monotone
graphs, possibly multi-valued with growth conditions formulated with help of an
$x-$dependent $N-$function. The main novelty of the paper consists in the lack
of any growth restrictions on the ${N}$--function combined with its anisotropic
character, namely we allow the dependence on all the directions of the
gradient, not only on its absolute value. This leads us to use the notion of
modular convergence and studying in detail the question of density of compactly
supported smooth functions with respect to the modular convergence.


title:
Uniform logarithmic Sobolev inequalities for conservative spin systems
  with super-quadratic single-site potential

abstract:
  We consider a noninteracting unbounded spin system with conservation of the
mean spin. We derive a uniform logarithmic Sobolev inequality (LSI) provided
the single-site potential is a bounded perturbation of a strictly convex
function. The scaling of the LSI constant is optimal in the system size. The
argument adapts the two-scale approach of Grunewald, Villani, Westdickenberg
and the second author from the quadratic to the general case. Using an
asymmetric Brascamp-Lieb-type inequality for covariances, we reduce the task of
deriving a uniform LSI to the convexification of the coarse-grained
Hamiltonian, which follows from a general local Cram\'{e}r theorem.


title: Cooling-induced structure formation and evolution in collapsars

abstract:
  The collapse of massive rotating stellar cores and the associated accretion
onto the newborn compact object is thought to power long gamma ray bursts
(GRBs). The physical scale and dynamics of the accretion disk are initially set
by the angular momentum distribution in the progenitor, and the physical
conditions make neutrino emission the main cooling agent in the flow. The
formation and evolution of structure in these disks is potentially very
relevant for the energy release and its time variability, which ultimately
imprint on the observed GRB properties. To begin to characterize these, taking
into account the three dimensional nature of the problem, we have carried out
an initial set of calculations of the collapse of rotating polytropic cores in
three dimensions, making use of a pseudo-relativistic potential and a
simplified cooling prescription. We focus on the effects of self gravity and
cooling on the overall morphology and evolution of the flow for a given
rotation rate in the context of the collapsar model. For the typical cooling
times expected in such a scenario we observe the appearance of strong
instabilities on the cooling time scale following disk formation, which
modulate the properties of the flow. Such instabilities, and the interaction
they produce between the disk and the central object lead to significant
variability in the obtained mass accretion and energy loss rates, which will
likely translate into variations in the power of the relativistic outflow that
ultimately results in a GRB.


title: Proton polarizabilities: status, relevance, prospects

abstract:
  This is a brief review of the status of understanding the proton
polarizabilities in chiral perturbation theory and of their relevance to the
`proton charge radius puzzle'.


title:
Star-planet magnetic interaction and evaporation of planetary
  atmospheres

abstract:
  Stars interact with their close-in planets through radiation, gravitation,
and magnetic fields. We investigate the energy input to a planetary atmosphere
by reconnection between stellar and planetary magnetic fields and compare it to
the energy input of the extreme ultraviolet (EUV) radiation field of the star.
We quantify the power released by magnetic reconnection at the boundary of the
planetary magnetosphere that is conveyed to the atmosphere by accelerated
electrons. We introduce simple models to evaluate the energy spectrum of the
accelerated electrons and the energy dissipated in the atmospheric layers in
the polar regions of the planet upon which they impinge. A simple transonic
isothermal wind flow along field lines is considered to estimate the increase
in mass loss rate in comparison with a planet irradiated only by the EUV flux
of its host star. We find that energetic electrons can reach levels down to
column densities of 10^{23}-10^{25} m^{-2}, comparable with or deeper than EUV
photons, and increase the mass loss rate up to a factor of 30-50 in close-in (<
0.10 AU), massive (> 1.5 Jupiter masses) planets. Mass loss rates up to
(0.5-1.0)x10^{9} kg/s are found for atmospheres heated by electrons accelerated
by magnetic reconnection at the boundary of planetary magnetospheres. On the
other hand, average mass loss rates up to (0.3-1.0)x10^{10} kg/s are found in
the case of magnetic loops interconnecting the planet with the star. The
star-planet magnetic interaction provides a remarkable source of energy for
planetary atmospheres, generally comparable with or exceeding that of stellar
EUV radiation for close-in planets. Therefore, it must be included in models of
chemical evolution or evaporation of planetary atmospheres as well as in
modelling of light curves of transiting planets at UV wavelengths.


title: Model Selection with Low Complexity Priors

abstract:
  Regularization plays a pivotal role when facing the challenge of solving
ill-posed inverse problems, where the number of observations is smaller than
the ambient dimension of the object to be estimated. A line of recent work has
studied regularization models with various types of low-dimensional structures.
In such settings, the general approach is to solve a regularized optimization
problem, which combines a data fidelity term and some regularization penalty
that promotes the assumed low-dimensional/simple structure. This paper provides
a general framework to capture this low-dimensional structure through what we
coin partly smooth functions relative to a linear manifold. These are convex,
non-negative, closed and finite-valued functions that will promote objects
living on low-dimensional subspaces. This class of regularizers encompasses
many popular examples such as the L1 norm, L1-L2 norm (group sparsity), as well
as several others including the Linfty norm. We also show that the set of
partly smooth functions relative to a linear manifold is closed under addition
and pre-composition by a linear operator, which allows to cover mixed
regularization, and the so-called analysis-type priors (e.g. total variation,
fused Lasso, finite-valued polyhedral gauges). Our main result presents a
unified sharp analysis of exact and robust recovery of the low-dimensional
subspace model associated to the object to recover from partial measurements.
This analysis is illustrated on a number of special and previously studied
cases, and on an analysis of the performance of Linfty regularization in a
compressed sensing scenario.


title:
On the geometry of regular maps from a quasi-projective surface to a
  curve

abstract:
  By exploring the consequences of the triviality of the monodromy group for a
class of surfaces of which the mixed Hodge structure is pure, we extend results
of Miyanishi and Sugie, Dimca, Zaidenberg and Kaliman.


title:
Time Response Dynamics of Plasmon Excitation in Cobalt Nanoparticles on
  Glass Substrate

abstract:
  We use ultrafast pump-probe transmission spectroscopy to measure the
electronic relaxation time for electrons in cobalt nanoparticles embedded on
glass substrate using femtosecond laser pulses. We found that the plasmon
excitation is inhomogenously broadening with a fast excitation time of 23 fs.
and a plasmonic relaxation time of 97fs. The femtosecond laser pulses used in
this experiment were come from a Ti:Sapphire resonator that uses a
self-mode-locking mechanism based on the nonlinear Kerr effect. The pulses were
found to have repetition rate of 103.52MHz with a pulse width of 64.5 fs at
FWHM, and 810nm center wavelength.


title: Dark Matter Search Perspectives with GAMMA-400

abstract:
  GAMMA-400 is a future high-energy gamma-ray telescope, designed to measure
the fluxes of gamma-rays and cosmic-ray electrons + positrons, which can be
produced by annihilation or decay of dark matter particles, and to survey the
celestial sphere in order to study point and extended sources of gamma-rays,
measure energy spectra of Galactic and extragalactic diffuse gamma-ray
emission, gamma-ray bursts, and gamma-ray emission from the Sun. GAMMA-400
covers the energy range from 100 MeV to ~3000 GeV. Its angular resolution is
~0.01 deg(Eg > 100 GeV), and the energy resolution ~1% (Eg > 10 GeV). GAMMA-400
is planned to be launched on the Russian space platform Navigator in 2019. The
GAMMA-400 perspectives in the search for dark matter in various scenarios are
presented in this paper


title:
Anisotropic spin fluctuations in the quasi one-dimensional frustrated
  magnet LiCuVO_4

abstract:
  We report results of NMR experiments on a single crystal of the quasi
one-dimensional frustrated magnet LiCuVO_4. The NMR spectra of ^7Li and ^{51}V
nuclei indicate a helical spin order in a magnetic field of 4 T with the
helical spin plane perpendicular to the field and a spin-density-wave (SDW)
order at 10 T with modulation in the magnitude of the moments aligned along the
field, in agreement with earlier reports. The nuclear spin-lattice relaxation
rate 1/T_1 at ^{51}V nuclei, which is selectively coupled to the transverse
spin fluctuations perpendicular to the field, shows a pronounced peak near the
helical ordering temperature in the field of 4 T applied along the a-axis. In
the field of 10 T, however, such a peak is absent. Instead 1/T_1 at ^7Li nuclei
probing longitudinal spin fluctuations shows divergent behavior towards the SDW
ordering temperature. These results are qualitatively consistent with the
theoretical description that the SDW correlation is due to bound magnon pairs,
which produce an energy gap in the transverse spin excitation spectrum.


title:
Combinatorial decomposition approaches for efficient counting and random
  generation FPTASes

abstract:
  Given a combinatorial decomposition for a counting problem, we resort to the
simple scheme of approximating large numbers by floating-point representations
in order to obtain efficient Fully Polynomial Time Approximation Schemes
(FPTASes) for it. The number of bits employed for the exponent and the mantissa
will depend on the error parameter $0 < \varepsilon \leq 1$ and on the
characteristics of the problem. Accordingly, we propose the first FPTASes with
$1 \pm \varepsilon$ relative error for counting and generating uniformly at
random a labeled DAG with a given number of vertices. This is accomplished
starting from a classical recurrence for counting DAGs, whose values we
approximate by floating-point numbers.
  After extending these results to other families of DAGs, we show how the same
approach works also with problems where we are given a compact representation
of a combinatorial ensemble and we are asked to count and sample elements from
it. We employ here the floating-point approximation method to transform the
classic pseudo-polynomial algorithm for counting 0/1 Knapsack solutions into a
very simple FPTAS with $1 - \varepsilon$ relative error. Its complexity
improves upon the recent result (\v{S}tefankovi\v{c} et al., SIAM J. Comput.,
2012), and, when $\varepsilon^{-1} = \Omega(n)$, also upon the best-known
randomized algorithm (Dyer, STOC, 2003). To show the versatility of this
technique, we also apply it to a recent generalization of the problem of
counting 0/1 Knapsack solutions in an arc-weighted DAG, obtaining a faster and
simpler FPTAS than the existing one.