title: The Case for Explicit Coupling Constraints

abstract:
  A software element defined in one place is typically used in many places.
When it is changed, all its occurrences may need to be changed too, which can
severely hinder software evolution. This has led to the support of
encapsulation in modern programming languages. Unfortunately, as is shown in
this paper, this is not enough to express all the constraints that are needed
to decouple programming elements that evolve at different paces.
  In this paper we show that: a language can be defined to easily express very
general coupling constraints; violations to these constraints can be detected
automatically. We then demonstrate several places where the need for coupling
constraints arose in open-source Java projects. These constraints were
expressed in comments when explicit constraints would have enabled automatic
treatment.


title:
Implementation of non-equilibrium vertex corrections in KKR: transport
  through disordered layers

abstract:
  The theoretical description of modern nanoelectronic devices requires a
quantum mechanical treatment and often involves disorder, e.g. form alloys.
Therefore, the ab initio theory of transport using non-equilibrium Green's
functions is extended to the case of disorder described by the coherent
potential approximation. This requires the calculation of non-equilibrium
vertex corrections. We implement the vertex corrections in a
Korringa-Kohn-Rostoker multiple scattering scheme. In order to verify our
implementation and to demonstrate the accuracy and applicability we investigate
a system of an iron-cobalt alloy layer embedded in copper. The results obtained
with the coherent potential approximation are compared to supercell
calculations. It turns out that vertex corrections play an important role for
this system.


title:
On the singular sheaves in the fine Simpson moduli spaces of
  1-dimensional sheaves supported on plane quartics

abstract:
  In the case of the fine Simpson moduli spaces of 1-dimensional sheaves
supported on plane quartics, the subvariety of sheaves that are not locally
free on their support is connected, singular, and has codimension 2.


title:
Ethics of using language editing services in an era of digital
  communication and heavily multiauthored papers

abstract:
  Scientists of many countries in which English is not the primary language
routinely use a variety of manuscript preparation, correction or editing
services, a practice that is openly endorsed by many journals and scientific
institutions. These services vary tremendously in their scope; at one end there
is simple proof-reading, and at the other extreme there is in-depth and
extensive peer-reviewing, proposal preparation, statistical analyses,
re-writing and co-writing. In this paper, the various types of service are
reviewed, along with authorship guidelines, and the question is raised of
whether the high-end services surpass most guidelines' criteria for authorship.
Three other factors are considered. First, the ease of collaboration possible
in the internet era allows multiple iterations between authors and the editing
service, so essentially, papers can be co-written. Second, 'editing services'
often offer subject-specific experts who comment not only on the language, but
interpret and improve scientific content. Third, the trend towards heavily
multi-authored papers implies that the threshold necessary to earn authorship
is declining. The inevitable conclusion is that at some point the contributions
by 'editing services' should be deemed sufficient to warrant authorship. Trying
to enforce any guidelines would likely be futile, but nevertheless, it might be
time to revisit the ethics of using some of the high-end 'editing services'. In
an increasingly international job market, recognizing this problem might prove
progressively more important in authorship disputes, the allocation of research
grants, and hiring decisions


title: Architecture and Production Readiness Reviews in Practice

abstract:
  Detailed description of procedures around architecture reviews. In order to
succeed in building and deploying complex software solutions, an architecture
is essential. For many in the industry structured reviews of these
architectures is also de rigor. Practices for such reviews have been developed
and reported on for years. One aspect that does not receive as much attention
but is no less important is the relationship between these architectures and
the requirements for deploying them into production environments. At Wolters
Kluwer's Corporate Legal Services we first established a typical architecture
review process and then established a two phase production preparation review
process. This paper describes in detail how these practices work and some of
the technical results of these reviews including the frequency and style of the
reviews, the process automation around them, and the number and nature of some
of the technical flaws eliminated by enforcing these reviews. This paper lays
the ground work for others who would be interested in following similar
practices.


title: Gravity induced from quantum spacetime

abstract:
  We show that tensoriality constraints in noncommutative Riemannian geometry
in the 2-dimensional bicrossproduct model quantum spacetime algebra
[x,t]=\lambda x drastically reduce the moduli of possible metrics g up to
normalisation to a single real parameter which we interpret as a time in the
past from which all timelike geodesics emerge and a corresponding time in the
future at which they all converge. Our analysis also implies a reduction of
moduli in n-dimensions and we study the suggested spherically symmetric
classical geometry in n=4 in detail, identifying two 1-parameter subcases where
the Einstein tensor matches that of a perfect fluid for (a) positive pressure,
zero density and (b) negative pressure and positive density with ratio
w_Q=-{1\over 2}. The classical geometry is conformally flat and its geodesics
motivate new coordinates which we extend to the quantum case as a new
description of the quantum spacetime model as a quadratic algebra. The
noncommutative Riemannian geometry is fully solved for $n=2$ and includes the
quantum Levi-Civita connection and a second, nonperturbative, Levi-Civita
connection which blows up as \lambda\to 0. We also propose a `quantum Einstein
tensor' which is identically zero for the main part of the moduli space of
connections (as classically in 2D). However, when the quantum Ricci tensor and
metric are viewed as deformations of their classical counterparts there would
be an O(\lambda^2) correction to the classical Einstein tensor and an
O(\lambda) correction to the classical metric.


title: A product formula for multivariate Rogers-Szeg\"o polynomials

abstract:
  Let $H_n(t)$ denote the classical Rogers-Szeg\"o polynomial, and let
$\tH_n(t_1, \ldots, t_l)$ denote the homogeneous Rogers-Szeg\"o polynomial in
$l$ variables, with indeterminate $q$. There is a classical product formula for
$H_k(t)H_n(t)$ as a sum of Rogers-Szeg\"o polynomials with coefficients being
polynomials in $q$. We generalize this to a product formula for the
multivariate homogeneous polynomials $\tH_n(t_1, \ldots, t_l)$. The
coefficients given in the product formula are polynomials in $q$ which are
defined recursively, and we find closed formulas for several interesting cases.
We then reinterpret the product formula in terms of symmetric function theory,
where these coefficients become structure constants.


title:
Demonstration of Surface Electron Rejection with Interleaved Germanium
  Detectors for Dark Matter Searches

abstract:
  The SuperCDMS experiment in the Soudan Underground Laboratory searches for
dark matter with a 9-kg array of cryogenic germanium detectors. Symmetric
sensors on opposite sides measure both charge and phonons from each particle
interaction, providing excellent discrimination between electron and nuclear
recoils, and between surface and interior events. Surface event rejection
capabilities were tested with two $^{210}$Pb sources producing $\sim$130 beta
decays/hr. In $\sim$800 live hours, no events leaked into the 8--115 keV signal
region, giving upper limit leakage fraction $1.7 \times 10^{-5}$ at 90% C.L.,
corresponding to $< 0.6$ surface event background in the future 200-kg
SuperCDMS SNOLAB experiment.


title: The Large-$N$ Limit of the Segal--Bargmann Transform on $\mathbb{U}_N$

abstract:
  We study the (two-parameter) Segal--Bargmann transform $\mathbf{B}_{s,t}^N$
on the unitary group $\mathbb{U}_N$, for large $N$. Acting on matrix valued
functions that are equivariant under the adjoint action of the group, the
transform has a meaningful limit $\mathscr{G}_{s,t}$ as $N\to\infty$, which can
be identified as an operator on the space of complex Laurent polynomials. We
introduce the space of {\em trace polynomials}, and use it to give effective
computational methods to determine the action of the heat operator, and thus
the Segal--Bargmann transform. We prove several concentration of measure and
limit theorems, giving a direct connection from the finite-dimensional
transform $\mathbf{B}_{s,t}^N$ to its limit $\mathscr{G}_{s,t}$. We
characterize the operator $\mathscr{G}_{s,t}$ through its inverse action on the
standard polynomial basis. Finally, we show that, in the case $s=t$, the limit
transform $\mathscr{G}_{t,t}$ is the ``free Hall transform'' $\mathscr{G}^t$
introduced by Biane.


title:
Diffractive photoproduction of radially excited psi(2S) mesons in
  photon-Pomeron reactions in PbPb collisions at the CERN LHC

abstract:
  In this work we investigate the photoproduction of radially excited vector
mesons off nuclei in heavy ion relativistic collisions. In particular, we
analyze the exclusive photoproduction of psi(2S) off nuclei, evaluating the
coherent and the incoherent contributions to that process. The theoretical
framework used in the present analysis is the light-cone dipole formalism and
predictions are done for PbPb collisions at the CERN-LHC energy of 2.76 TeV.
The theoretical uncertainties are analyzed and comparison is also done to the
recent ALICE Collaboration data for the psi(1S) state photoproduction.


title: Non-amenability of product replacement graphs

abstract:
  We prove non-amenability of the product replacement graphs \Gamma_n(G) for
uniformly non-amenable groups. We also prove it for Z-large groups, when n is
sufficiently large. It follows that \Gamma_n(G) is non-amenable when n is
sufficiently large for hyperbolic groups, linear groups, and elementary
amenable groups.


title: Weak Measurement and (Bohmian) Conditional Wave Functions

abstract:
  It was recently pointed out (and demonstrated experimentally) by Lundeen et
al. that the wave function of a particle (more precisely, the wave function
possessed by each member of an ensemble of identically-prepared particles) can
be "directly measured" using weak measurement. Here it is shown that if this
same technique is applied, with appropriate post-selection, to one particle
from a (perhaps entangled) multi-particle system, the result is precisely the
so-called "conditional wave function" of Bohmian mechanics. Thus, a plausibly
operationalist method for defining the wave function of a quantum mechanical
sub-system corresponds to the natural definition of a sub-system wave function
which Bohmian mechanics (uniquely) makes possible. Similarly, a
weak-measurement-based procedure for directly measuring a sub-system's density
matrix should yield, under appropriate circumstances, the Bohmian "conditional
density matrix" as opposed to the standard reduced density matrix. Experimental
arrangements to demonstrate this behavior -- and also thereby reveal the
non-local dependence of sub-system state functions on distant interventions --
are suggested and discussed.


title:
On the electronic structure of silicene on Ag substrate: strong
  hybridization effects

abstract:
  The electronic structure of the recently synthesised (3x3) reconstructed
silicene on (4x4) Ag(111) is investigated by first-principles calculations. New
states emerge due to the strong hybridization between silicene and Ag.
Analyzing the nature and composition of these hybridized states, we show that
i) it is possible to clearly distinguish them from states coming from the Dirac
cone of free-standing silicene or from the sp-bands of bulk Ag and ii) assign
their contribution to the description of the linearly dispersing band observed
in photoemission. Furthermore, we show that silicene atoms contribute to the
Fermi level, which leads to similar STM patterns as observed below or above the
Fermi level. Our findings are crucial for the proper interpretation of
experimental observations.


title:
Orientational tuning of the 2D-superconductivity in LaAlO3/SrTiO3
  interfaces

abstract:
  The discovery of a two-dimensional (2D) electron gas at the (110)-oriented
LaAlO3/SrTiO3 in- terface provided us with the opportunity to probe the effect
of crystallographic orientation and the ensuing electronic reconstructions on
interface properties beyond the conventional (001)-orientation. At temperatures
below 200 mK, we have measured 2D superconductivity with a spatial extension
significantly larger (d approx. 24 - 30 nm) than previously reported for
(001)-oriented LaAlO3/SrTiO3 interfaces (d approx. 10 nm). The more extended
superconductivity brings about the absence of violation of the Pauli
paramagnetic limit for the upper critical fields, signaling the distinctive
nature of the electronic structure of the (110)-oriented interface with respect
to their (001)-counterparts


title: Thick-skinned 3-manifolds

abstract:
  We show that if the totally geodesic boundary of a compact hyperbolic
3-manifold M has a large collar of depth d, then the diameter of the skinning
map of M is no more than A exp(-d) for some A depending only on the genus and
injectivity radius of the boundary of M.


title:
Ultra-faint Ultraviolet Galaxies at z~2 Behind the Lensing Cluster Abell
  1689: the Luminosity Function, Dust Extinction and Star Formation Rate
  Density

abstract:
  We identified the z~2 Lyman break galaxies using deep HST ultraviolet
(F275W/F336W) imaging of Abell 1689. Because of the imaging depth and the large
magnification provided by the cluster, we detect galaxies 100x fainter (-19.5<
M_1500 <-13) than previous surveys at this redshift. We are able to calculate
the intrinsic sensitivity of the observations as a function of source plane
position, allowing determinations of effective volume as a function of
luminosity. We fit the faint-end slope of the luminosity function to be alpha =
-1.74 +/-0.08, consistent with the values obtained for 2.5 < z < 6. There is no
turnover in the luminosity function down to MUV = -13. The trend of
increasingly redder UV spectral slopes with luminosity at higher redshifts is
observed in our sample, but with redder slopes at all luminosities and average
reddening of < E(B - V) >= 0.15. We assume the stars in these galaxies are
metal poor (0.2Z_sun) compared to their brighter counterparts (Z_sun),
resulting in bluer assumed intrinsic UV slopes and larger derived dust
extinction. The total UV luminosity density at z ~ 2 is 4.31x10^26
erg/s/Hz/Mpc^3, more than 70% of which is emitted by galaxies in the luminosity
range of our sample. We determine the star formation rate density at z ~ 2
(assuming constant dust extinction correction of 4.2 over all luminosities and
a Kroupa IMF) of 0.148 M/yr/Mpc^3, significantly higher than previous
determinations because of the additional population of fainter galaxies and the
larger dust correction factors.[abridged]


title: Gauge Dynamics and Topological Insulators

abstract:
  A non-abelian magnetic field in Yang-Mills theory induces the formation of a
"W-boson" vortex lattice. We study the propagation of fundamental fermions in
the presence of this lattice in 2+1 dimensions. We show that the spectrum for
massless fermions contains four topologically-protected Dirac points with
non-zero Bloch momentum. For massive fermions, we compute topological
invariants of the band structure and show that it is possible to realise a Z2
topological insulator within Yang-Mills theory.


title: Exponentiated Gradient LINUCB for Contextual Multi-Armed Bandits

abstract:
  We present Exponentiated Gradient LINUCB, an algorithm for con-textual
multi-armed bandits. This algorithm uses Exponentiated Gradient to find the
optimal exploration of the LINUCB. Within a deliberately designed offline
simulation framework we conduct evaluations with real online event log data.
The experimental results demonstrate that our algorithm outperforms surveyed
algorithms.


title: Quantum theory of light double-slit diffraction

abstract:
  In this paper, we study the light double-slit diffraction experiment with
quantum theory approach. Firstly, we calculate the light wave function in slits
by quantum theory of photon. Secondly, we calculate the diffraction wave
function with Kirchhoff's law. Thirdly, we give the diffraction intensity of
light double-slit diffraction, which is proportional to the square of
diffraction wave function. Finally, we compare calculation result of quantum
theory and classical electromagnetic theory with the experimental data. We find
the quantum calculate result is accordance with the experiment data, and the
classical calculation result with certain deviation. So, the quantum theory is
more accurately approach for studying light diffraction.


title: Full Quantum Theory of ${C_{60}}$ Double-slit Diffraction

abstract:
  In this paper, we apply the full new method of quantum theory to study the
double-slit diffraction of ${C_{60}}$ molecules. We calculate the double-slit
wave functions of ${C_{60}}$ molecules by Schr\"{o}dinger equation, and
calculate the diffraction wave function behind the slits with the Feynman path
integral quantum theory, and then give the relation between the diffraction
intensity of double-slit and diffraction pattern position. We compare the
calculation results with two different double-slit diffraction experiments.
When the decoherence effects are considered, the calculation results are in
good agreement with the two experimental data.


title:
Modified Gravity-GADGET: A new code for cosmological hydrodynamical
  simulations of modified gravity models

abstract:
  We present a new massively parallel code for N-body and cosmological
hydrodynamical simulations of modified gravity models. The code employs a
multigrid-accelerated Newton-Gauss-Seidel relaxation solver on an adaptive mesh
to efficiently solve for perturbations in the scalar degree of freedom of the
modified gravity model. As this new algorithm is implemented as a module for
the P-Gadget3 code, it can at the same time follow the baryonic physics
included in P-Gadget3, such as hydrodynamics, radiative cooling and star
formation. We demonstrate that the code works reliably by applying it to simple
test problems that can be solved analytically, as well as by comparing
cosmological simulations to results from the literature. Using the new code, we
perform the first non-radiative and radiative cosmological hydrodynamical
simulations of an f(R)-gravity model. We also discuss the impact of AGN
feedback on the matter power spectrum, as well as degeneracies between the
influence of baryonic processes and modifications of gravity.


title: pMSSM Benchmark Models for Snowmass 2013

abstract:
  We present several benchmark points in the phenomenological Minimal
Supersymmetric Standard Model (pMSSM). We select these models as experimentally
well-motivated examples of the MSSM which predict the observed Higgs mass and
dark matter relic density while evading the current LHC searches. We also use
benchmarks to generate spokes in parameter space by scaling the mass parameters
in a manner which keeps the Higgs mass and relic density approximately
constant.


title: Abell 2142 at large scales: An extreme case for sloshing?

abstract:
  We present results obtained with a new XMM-Newton observation of A2142, a
famous textbook example of cluster with multiple cold fronts, which has been
studied in detail with Chandra but whose large scale properties are presented
here for the first time. We report the discovery of a a new cold front, the
most distant one ever detected in a galaxy cluster, at about one Mpc from the
center to the SE. Residual images, thermodynamics and metal abundance maps are
qualitatively in agreement with predictions from numerical simulations of the
sloshing phenomenon. However, the scales involved are much larger, similarly to
what recently observed in the Perseus cluster. These results show that sloshing
is a cluster-wide phenomenon, not confined in the cores, which extends well
beyond the cooling region involving a large fraction of the ICM up to almost
half of the virial radius. The absence of a cool core and a newly discovered
giant radio halo in A2142, in spite of its relaxed X-ray morphology, suggest
that large scale sloshing, or the intermediate merger which caused it, may
trigger Mpc-scale radio emission and may lead to the disruption of the cluster
cool core


title: Two-loop Sudakov Form Factor in ABJM

abstract:
  We compute the two-loop Sudakov form factor in three-dimensional N=6
superconformal Chern-Simons theory, using generalised unitarity. As an
intermediate step, we derive the non-planar part of the one-loop four-point
amplitude in terms of box integrals. Our result for the Sudakov form factor is
given by a single non-planar tensor integral with uniform degree of
transcendentality, and is in agreement with the known infrared divergences of
two-loop amplitudes in ABJM theory. We also discuss a number of interesting
properties satisfied by related three-dimensional integral functions.


title: Form Factors of Chiral Primary Operators at Two Loops in ABJ(M)

abstract:
  We calculate the colour-ordered form factor for chiral primary operators
built from J scalar fields of ABJ(M) theory to J scalar final states. We work
in the 't Hooft limit and show that the leading quantum correction is order
lambda squared, where lambda is the 't Hooft coupling. We evaluate this leading
correction using standard Feynman diagrams and dimensional regularization, and
find that the leading divergence is 1/epsilon^2 where the spacetime dimension
is d = 3 - 2 epsilon. We further find that the result respects maximal
transcendentality.


title:
An obstruction for existence of codimension two contact embeddings in a
  Darboux chart

abstract:
  We prove the vanishing of the first Chern class of a codimension 2 closed
contact submanifold of a cooriented contact manifold with trivial integral
2-dimensional cohomology group. Hence the first Chern class is an obstruction
for the existence of codimension 2 contact embeddings in a Darboux chart. For
the existence of such an embedding, we prove that a closed cooriented contact
3-manifold can be a contact submanifold of the 5-dimensional Euclidean space
for a certain contact structure, if its first Chern class vanishes.


title: Searching for Signs of the Second Higgs Doublet

abstract:
  The search for evidence of extended electroweak symmetry breaking has entered
a new phase with the discovery of a Standard Model (SM)-like Higgs at the LHC.
The measurement of Higgs couplings and direct searches for additional scalars
provide complementary avenues for the discovery of new degrees of freedom. This
complementarity is particularly sharp in two Higgs doublet models (2HDMs) where
the couplings of the SM-like Higgs may be directly related to the LHC signals
of additional scalars. In this work we develop a strategy for searching for the
second Higgs doublet given the LHC signals of the recently discovered SM-like
Higgs. We focus on a motivated parameter space of flavor- and CP-conserving
2HDMs in which the couplings of all scalars to SM states are controlled by two
parameters. We construct fits in this parameter space to the signals of the
SM-like Higgs and translate these fits into signal expectations for future
measurements of both the SM-like Higgs and additional scalars, identifying the
most promising search channels for discovery or exclusion of new physics. When
kinematically accessible, decays of the heavy neutral scalar Higgs to two light
Higgs scalars, $H \to hh$, and decays of the pseudoscalar Higgs to a light
Higgs scalar and $Z$ boson, $A \to Zh$, provide promising avenues for discovery
even when the couplings of the light Higgs are within a few percent of SM
predictions. When the couplings of the light Higgs are exceptionally close to
those of the SM, decays of heavier neutral scalars to $\gamma \gamma$ and
$\tau^+ \tau^-$ become particularly important for discovery.


title: The non-commutative n-th Chern number

abstract:
  The theory of the higher Chern numbers in the presence of strong disorder is
developed. Sharp quantization and homotopy invariance conditions are provided.
The relevance of the result to the field of strongly disordered topological
insulators is discussed.

categories: math-ph cond-mat.str-el math.KT math.MP math.OA


title:
Towards a Better Approximation of Full Domain Hash - or - The Reef and
  Shoal Integrity Arrangement

abstract:
  For RSA and Rabin-Williams public key digital signatures, proper message
hashing and padding procedures are critical to the overall digital signature
security. The theoretical work in this field coined the term `full domain hash'
for a conceptually simple approach, a message hashing step with an output value
as large as the signature public modulus. The practitioners learned from the
theory but did not adopt the full domain hash as originally expressed. The Reef
and Shoal proposal revisits the original concept and proposes the concatenation
of a conventional cryptographic hash and an independent large non-cryptographic
hash as an approximation of the full domain hash. The Badderlocks version 0.1
concrete proposal uses the CRC computation with large primitive polynomials
preceded by an S-box message expansion phase.


title:
Constraining the flavor changing Higgs couplings to the top-quark at the
  LHC

abstract:
  We study the flavor-changing couplings of the Higgs-boson with the top-quark
using the processes: (a) pp --> tt, (b) pp --> t_bar j, and, (c) pp --> t_bar j
h at the LHC in light of current discovery of a 126 GeV Higgs-Boson.
Sensitivities for the flavor-changing couplings are estimated using the LHC
data that was collected until spring 2013. It is found that the process (c) is
the most capable of yielding the best upper bound on the flavor-changing
couplings with 2 sigma level sensitivities of {|xi_{tc}^2 + xi_{tu}^2|}^{1/2}
<= 4.2 x 10^{-3} and <= 1.7 x 10^{-3} resulting from t --> b l nu_l, h --> jj
with the 7 TeV and 8 TeV centre-of-mass energies respectively using existing
data from the LHC. The corresponding bounds from h --> b b_bar are worse by a
factor of about 1.8.


title: Integral Models of $X_0(N)$ and Their Degrees

abstract:
  In this paper we compute the degree of a curve which is the image of a
mapping $z\longmapsto (f(z): g(z): h(z))$ constructed out of three linearly
independent modular forms of the same even weight $\ge 4$ into $\mathbb P^2$.
We prove that in most cases this map is a birational equivalence and defined
over $\mathbb Z$. We use this to construct models of $X_0(N)$, $N\ge 2$, using
modular forms in $M_{12}(\Gamma_0(N))$ with integral $q$--expansion. The models
have degree equal to $\psi(N)$ (a classical Dedekind psi function). When genus
is at least one, we show the existence of models constructed using cuspidal
forms in $S_4(\Gamma_0(N))$ of degree $\le \psi(N)/3$ and in
$S_6(\Gamma_0(11))$ of degree 4. As an example of a different kind, we compute
the formula for the total degree i.e., the degree considered as a polynomial of
two (independent) variables of the classical modular polynomial (or the degree
of the canonical model of $X_0(N)$).


title: 3d Chern-Simons Theory from M5-branes

abstract:
  We study 5d N=2 maximally supersymmetric Yang-Mills theory with a gauge group
G on S^2 x M_3, where M_3 is a 3-manifold. By explicit localization computation
we show that the path-integral of the 5d N=2 theory reduces to that of the 3d
G_C Chern-Simons theory on M_3, where G_C is the complexification of G. This
gives a direct derivation of the appearance of the Chern-Simons theory from the
compactification of the 6d (2,0) theory, confirms the predictions from the
3d/3d correspondence for G=SU(N), and suggests the generalization of the
correspondence to more general gauge groups.


title: The Structure of the Milky Way's Hot Gas Halo

abstract:
  The Milky Way's million degree gaseous halo contains a considerable amount of
mass that, depending on its structural properties, can be a significant mass
component. In order to analyze the structure of the Galactic halo, we use
XMM-Newton Reflection Grating Spectrometer archival data and measure OVII K
alpha absorption-line strengths toward 26 active galactic nuclei, LMC X-3, and
two Galactic sources (4U 1820-30 and X1735-444). We assume a beta-model as the
underlying gas density profile and find best-fit parameters of n_o =
0.46^{+0.74}_{-0.35} cm^-3, r_c = 0.35^{+0.29}_{-0.27} kpc, and beta =
0.71^{+0.13}_{-0.14}. These parameters result in halo masses ranging between
M(18 kpc) = 7.5^{+22.0}_{-4.6} x 10^8 M_sun and M(200 kpc) = 3.8^{+6.0}_{-0.5}
x 10^{10} M_sun assuming a gas metallicity of Z = 0.3 Z_sun, which are
consistent with current theoretical and observational work. The maximum baryon
fraction from our halo model of f_b = 0.07^{+0.03}_{-0.01} is significantly
smaller than the universal value of f_b = 0.171, implying the mass contained in
the Galactic halo accounts for 10% - 50% of the missing baryons in the Milky
Way. We also discuss our model in the context of several Milky Way observables,
including ram pressure stripping in dwarf spheroidal galaxies, the observed
X-ray emission measure in the 0.5 - 2 keV band, the Milky Way's star formation
rate, spatial and thermal properties of cooler gas (~10^5 K) and the observed
Fermi bubbles toward the Galactic center. Although the metallicity of the halo
gas is a large uncertainty in our analysis, we place a lower limit on the halo
gas between the Sun and the Large Magellanic Cloud (LMC). We find that Z >~ 0.2
Z_sun based on the pulsar dispersion measure toward the LMC.


title: Large restricted sumsets in general abelian group

abstract:
  Let A, B and S be three subsets of a finite Abelian group G. The restricted
sumset of A and B with respect to S is defined as A\wedge^{S} B= {a+b: a in A,
b in B and a-b not in S}. Let L_S=max_{z in G}| {(x,y): x,y in G, x+y=z and x-y
in S}|. A simple application of the pigeonhole principle shows that
|A|+|B|>|G|+L_S implies A\wedge^S B=G. We then prove that if |A|+|B|=|G|+L_S
then |A\wedge^S B|>= |G|-2|S|. We also characterize the triples of sets (A,B,S)
such that |A|+|B|=|G|+L_S and |A\wedge^S B|= |G|-2|S|. Moreover, in this case,
we also provide the structure of the set G\setminus (A\wedge^S B).


title: Small Support Equilibria in Large Games

abstract:
  In this note we provide a new proof for the results of Lipton et al. on the
existence of an approximate Nash equilibrium with logarithmic support size.
Besides its simplicity, the new proof leads to the following contributions:
  1. For n-player games, we improve the bound on the size of the support of an
approximate Nash equilibrium.
  2. We generalize the result of Daskalakis and Papadimitriou on small
probability games from the two-player case to the general n-player case.
  3. We provide a logarithmic bound on the size of the support of an
approximate Nash equilibrium in the case of graphical games.


title: Carbon Deflagration in Type Ia Supernova: I. Centrally Ignited Models

abstract:
  A leading model for Type Ia supernovae (SNe Ia) begins with a white dwarf
near the Chandrasekhar mass that ignites a degenerate thermonuclear runaway
close to its center and explodes. In a series of papers, we shall explore the
consequences of ignition at several locations within such dwarfs. Here we
assume central ignition, which has been explored before, however, the problem
is worth revisiting, if only to validate those previous studies and to further
elucidate the relevant physics for future work. A perturbed sphere of hot iron
ash with a radius of ~100 km is initialized at the middle of the star. The
subsequent explosion is followed in several simulations using a thickened flame
model in which the flame speed is either fixed --- within the range expected
from turbulent combustion --- or based on the local turbulent intensity. Global
results, including the explosion energy and bulk nucleosynthesis (e.g. 56Ni of
0.48--0.56 $\Msun$) turn out to be insensitive to this speed. In all completed
runs, the energy released by the nuclear burning is adequate to unbind the
star, but not enough to give the energy and brightness of typical SNe Ia. As
found previously, the chemical stratification observed in typical events is not
reproduced. These models produce a large amount of unburned carbon and oxygen
in central low velocity regions, which is inconsistent with spectroscopic
observations, and the intermediate mass elements and iron group elements are
strongly mixed during the explosion.


title: Nontrapping surfaces of revolution with long living resonances

abstract:
  We study resonances of surfaces of revolution obtained by removing a disk
from a cone and attaching a hyperbolic cusp in its place. These surfaces
include ones with nontrapping geodesic flow (every maximally extended
non-reflected geodesic is unbounded) and yet infinitely many long living
resonances (resonances with uniformly bounded imaginary part, i.e. decay rate).


title: A few algebraic problems in the theory of quantum entanglement

abstract:
  We present solutions to a set of problems that arise in quantum entanglement
theory, whose common trait is the use of algebraic methods. The backbone of the
thesis consists of two general theorems, pertaining to specific convex sets of
quantum maps. They are complemented by solutions of many more specific problems
of rather technical character. These problems concerned questions such as the
higher rank numerical ranges, the lengths of separable states, the solutions of
compression equations, the completely entangled subspaces, and maximally
entangled states. The solutions were obtained partly by hand, and partly by
using the Groebner basis toolset available in computer algebra systems. The
main results, which are those of general nature, consist of a characterization
of mapping cones, which is a full analogue of the positive maps criterion for
separability, as well as of a full characterization of
positive-partial-transpose entangled states of minimum rank. The thesis also
contains an introduction to the theory of quantum entanglement and to basic
algebraic geometry, whose methods have been used


title:
Regularized M-estimators with nonconvexity: Statistical and algorithmic
  theory for local optima

abstract:
  We provide novel theoretical results regarding local optima of regularized
$M$-estimators, allowing for nonconvexity in both loss and penalty functions.
Under restricted strong convexity on the loss and suitable regularity
conditions on the penalty, we prove that \emph{any stationary point} of the
composite objective function will lie within statistical precision of the
underlying parameter vector. Our theory covers many nonconvex objective
functions of interest, including the corrected Lasso for errors-in-variables
linear models; regression for generalized linear models with nonconvex
penalties such as SCAD, MCP, and capped-$\ell_1$; and high-dimensional
graphical model estimation. We quantify statistical accuracy by providing
bounds on the $\ell_1$-, $\ell_2$-, and prediction error between stationary
points and the population-level optimum. We also propose a simple modification
of composite gradient descent that may be used to obtain a near-global optimum
within statistical precision $\epsilon$ in $\log(1/\epsilon)$ steps, which is
the fastest possible rate of any first-order method. We provide simulation
studies illustrating the sharpness of our theoretical results.


title: Las Cumbres Observatory Global Telescope Network

abstract:
  Las Cumbres Observatory Global Telescope (LCOGT) is a young organization
dedicated to time-domain observations at optical and (potentially) near-IR
wavelengths. To this end, LCOGT is constructing a world-wide network of
telescopes, including the two 2m Faulkes telescopes, as many as 17 x 1m
telescopes, and as many as 23 x 40cm telescopes. These telescopes initially
will be outfitted for imaging and (excepting the 40cm telescopes) spectroscopy
at wavelengths between the atmospheric UV cutoff and the roughly 1-micron limit
of silicon detectors. Since the first of LCOGT's 1m telescopes are now being
deployed, we lay out here LCOGT's scientific goals and the requirements that
these goals place on network architecture and performance, we summarize the
network's present and projected level of development, and we describe our
expected schedule for completing it. In the bulk of the paper, we describe in
detail the technical approaches that we have adopted to attain the desired
performance. In particular, we discuss our choices for the number and location
of network sites, for the number and sizes of telescopes, for the
specifications of the first generation of instruments, for the software that
will schedule and control the network's telescopes and reduce and archive its
data, and for the structure of the scientific and educational programs for
which the network will provide observations.


title: Charge on tableaux and the poset of k-shapes

abstract:
  A poset on a certain class of partitions known as k-shapes was recently
introduced to provide a combinatorial rule for the expansion of a (k-1)-Schur
functions into k-Schur functions at t=1. The main ingredient in this
construction was a bijection, which we call the weak bijection, that associates
to a k-tableau a pair made out of a (k-1)-tableau and a path in the poset of
k-shapes. We define here a concept of charge on k-tableaux (which conjecturally
gives a combinatorial interpretation for the expansion coefficients of
Hall-Littlewood polynomials into k-Schur functions), and show that it is
compatible in the standard case with the weak bijection. In particular, we
obtain that the usual charge of a standard tableau of size n is equal to the
sum of the charges of its corresponding paths in the poset of k-shapes, for
k=2,3...n.


title:
Statistical multifragmentation model with discretized energy and the
  generalized Fermi breakup. I. Formulation of the model

abstract:
  The Generalized Fermi Breakup recently demonstrated to be formally equivalent
to the Statistical Multifragmentation Model, if the contribution of excited
states are included in the state densities of the former, is implemented. Since
this treatment requires the application of the Statistical Multifragmentation
Model repeatedly on the hot fragments until they have decayed to their ground
states, it becomes extremely computational demanding, making its application to
the systems of interest extremely difficult. Based on exact recursion formulae
previously developed by Chase and Mekjian to calculate the statistical weights
very efficiently, we present an implementation which is efficient enough to
allow it to be applied to large systems at high excitation energies. Comparison
with the GEMINI++ sequential decay code shows that the predictions obtained
with our treatment are fairly similar to those obtained with this more
traditional model.


title: Rate Region of the (4,3,3) Exact-Repair Regenerating Codes

abstract:
  Exact-repair regenerating codes are considered for the case (n,k,d)=(4,3,3),
for which a complete characterization of the rate region is provided. This
characterization answers in the affirmative the open question whether there
exists a non-vanishing gap between the optimal bandwidth-storage tradeoff of
the functional-repair regenerating codes (i.e., the cut-set bound) and that of
the exact-repair regenerating codes. The converse proof relies on the existence
of symmetric optimal solutions. For the achievability, only one non-trivial
corner point of the rate region needs to be addressed, for which an explicit
binary code construction is given.


title: Superhorizon entanglement entropy from particle decay in inflation

abstract:
  In inflationary cosmology all particle states decay as a consequence of the
lack of kinematic thresholds. The decay of an initial single particle state
yields an \emph{entangled quantum state of the product particles}. We
generalize and extend a manifestly unitary field theoretical method to obtain
the time evolution of the quantum state. We consider the decay of a light
scalar field with mass $M\ll H$ with a cubic coupling in de Sitter space-time.
Radiative corrections feature an infrared enhancement manifest as poles in
$\Delta=M^2/3H^2$ and we obtain the quantum state in an expansion in $\Delta$.
To leading order in $\Delta$ the pure state density matrix describing the decay
of a particle with sub-horizon wavevector is dominated by the emission of
superhorizon quanta, describing \emph{entanglement between superhorizon and
subhorizon fluctuations and correlations across the horizon}. Tracing over the
superhorizon degrees of freedom yields a mixed state density matrix from which
we obtain the entanglement entropy. Asymptotically this entropy grows with the
\emph{physical} volume as a consequence of more modes of the decay products
crossing the Hubble radius. A generalization to localized wave packets is
provided. The cascade decay of single particle states into many particle states
is discussed. We conjecture on \emph{possible} impact of these results on
non-gaussianity and on the ``low multipole anomalies'' of the CMB.

categories: astro-ph.CO gr-qc hep-ph hep-th quant-ph


title:
Ondas gravitacionales y objetos compactos (Gravitational waves and
  compact objects)

abstract:
  It is presented a brief review on gravitational waves (GWs). It is shown how
the wave equation is obtained from Einstein's equations and how many and how
are the polarization modes of these waves. It is discussed the reasons why GWs
sources should be of astrophysical or cosmological origin. Thus, it is
discussed what would be the most likely sources of GWs to be detected by the
detectors of GWs currently in operation and those that should be operational in
the future, emphasizing in particular the sources involving compact objects.
The compact objects such as neutron stars, black holes and binary systems
involving compact stars can be important sources of GWs. Last but not least, it
is discussed the GWs astrophysics that is already possible to do, in particular
involving the compact objects.


title: Spin dynamics in a spin-orbit coupled Fermi gas

abstract:
  We study the dynamics of a non-degenerate, harmonically trapped Fermi gas
following a sudden ramp of the spin-orbit coupling strength. In the
non-interacting limit, we solve the Boltzmann equation in the presence of spin
orbit coupling analytically, and derive expressions for the dynamics of an
arbitrary initial spin state. In particular we show that for a fully spin
polarized initial state, the total magnetization exhibits collapse and revival
dynamics in time with a period set by the trapping potential. In real space,
this corresponds to oscillations between a fully polarized state and a spin
helix. We numerically study the effect of interactions on the dynamics using a
collisionless Boltzmann equation.


title: The S-Procedure via Dual Cone Calculus

abstract:
  Given a quadratic function $h$ that satisfies a Slater condition,
Yakubovich's S-Procedure (or S-Lemma) gives a characterization of all other
quadratic functions that are copositive with $h$ in a form that is amenable to
numerical computations. In this paper we present a deep-rooted connection
between the S-Procedure and the dual cone calculus formula $(K_1\cap K_2)^*=
K_1^*+K_2^*$, which holds for closed convex cones in $\R^2$. To establish the
link with the S-Procedure, we generalize the dual cone calculus formula to a
situation where $K_1$ is nonclosed, nonconvex and nonconic but exhibits
sufficient mathematical resemblance to a closed convex cone. As a result, we
obtain a new proof of the S-Lemma and an extension to Hilbert space kernels.


title: Polytype control of spin qubits in silicon carbide

abstract:
  Crystal defects can confine isolated electronic spins and are promising
candidates for solid-state quantum information. Alongside research focusing on
nitrogen vacancy centers in diamond, an alternative strategy seeks to identify
new spin systems with an expanded set of technological capabilities, a
materials driven approach that could ultimately lead to "designer" spins with
tailored properties. Here, we show that the 4H, 6H and 3C polytypes of SiC all
host coherent and optically addressable defect spin states, including spins in
all three with room-temperature quantum coherence. The prevalence of this spin
coherence shows that crystal polymorphism can be a degree of freedom for
engineering spin qubits. Long spin coherence times allow us to use double
electron-electron resonance to measure magnetic dipole interactions between
spin ensembles in inequivalent lattice sites of the same crystal. Together with
the distinct optical and spin transition energies of such inequivalent spins,
these interactions provide a route to dipole-coupled networks of separately
addressable spins.


title:
Approximately Optimal Mechanisms for Strategyproof Facility Location:
  Minimizing $L_p$ Norm of Costs

abstract:
  We consider the problem of locating a single facility on the real line. This
facility serves a set of agents, each of whom is located on the line, and
incurs a cost equal to his distance from the facility. An agent's location is
private information that is known only to him. Agents report their location to
a central planner who decides where to locate the facility. The planner's
objective is to minimize a "social" cost function that depends on the
agent-costs. However, agents might not report truthfully; to address this
issue, the planner must restrict himself to {\em strategyproof} mechanisms, in
which truthful reporting is a dominant strategy for each agent. A mechanism
that simply chooses the optimal solution is generally not strategyproof, and so
the planner aspires to use a mechanism that effectively {\em approximates} his
objective function. In our paper, we study the problem described above with the
social cost function being the $L_p$ norm of the vector of agent-costs. We show
that the median mechanism (which is known to be strategyproof) provides a
$2^{1-\frac{1}{p}}$ approximation ratio, and that is the optimal approximation
ratio among all deterministic strategyproof mechanisms. For randomized
mechanisms, we present two results. First, we present a negative result: we
show that for integer $\infty>p>2$, no mechanism---from a rather large class of
randomized mechanisms--- has an approximation ratio better than that of the
median mechanism. This is in contrast to the case of $p=2$ and $p=\infty$ where
a randomized mechanism provably helps improve the worst case approximation
ratio. Second, for the case of 2 agents, we show that a mechanism called LRM,
first designed by Procaccia and Tennenholtz for the special case of
$L_{\infty}$, provides the optimal approximation ratio among all randomized
mechanisms.


title:
Stellar Velocity Dispersion Measurements in High-Luminosity Quasar Hosts
  and Implications for the AGN Black Hole Mass Scale

abstract:
  We present new stellar velocity dispersion measurements for four luminous
quasars with the NIFS instrument and the ALTAIR laser guide star adaptive
optics system on the Gemini North 8-m telescope. Stellar velocity dispersion
measurements and measurements of the supermassive black hole masses in luminous
quasars are necessary to investigate the coevolution of black holes and
galaxies, trace the details of accretion, and probe the nature of feedback. We
find that higher-luminosity quasars with higher-mass black holes are not offset
with respect to the MBH-sigma relation exhibited by lower-luminosity AGNs with
lower-mass black holes, nor do we see correlations with galaxy morphology. As
part of this analysis, we have recalculated the virial products for the entire
sample of reverberation-mapped AGNs and used these data to redetermine the mean
virial factor hfi that places the reverberation data on the quiescent
M_BH-sigma relation. With our updated measurements and new additions to the AGN
sample, we obtain <f> = 4.31 +/- 1.05, which is slightly lower than, but
consistent with, most previous determinations.


title: Streams Going Notts: The tidal debris finder comparison project

abstract:
  While various codes exist to systematically and robustly find haloes and
subhaloes in cosmological simulations (Knebe et al., 2011, Onions et al.,
2012), this is the first work to introduce and rigorously test codes that find
tidal debris (streams and other unbound substructure) in fully cosmological
simulations of structure formation. We use one tracking and three non-tracking
codes to identify substructure (bound and unbound) in a Milky Way type
simulation from the Aquarius suite (Springel et al., 2008) and post-process
their output with a common pipeline to determine the properties of these
substructures in a uniform way. By using output from a fully cosmological
simulation, we also take a step beyond previous studies of tidal debris that
have used simple toy models. We find that both tracking and non-tracking codes
agree well on the identification of subhaloes and more importantly, the {\em
unbound tidal features} associated with them. The distributions of basic
properties of the total substructure distribution (mass, velocity dispersion,
position) are recovered with a scatter of $\sim20%$. Using the tracking code as
our reference, we show that the non-tracking codes identify complex tidal
debris with purities of $\sim40%$. Analysing the results of the substructure
finders, we find that the general distribution of {\em substructures} differ
significantly from the distribution of bound {\em subhaloes}. Most importantly,
both bound and unbound {\em substructures} together constitute $\sim18%$ of the
host halo mass, which is a factor of $\sim2$ higher than the fraction in
self-bound {\em subhaloes}. However, this result is restricted by the remaining
challenge to cleanly define when an unbound structure has become part of the
host halo. Nevertheless, the more general substructure distribution provides a
more complete picture of a halo's accretion history.


title: Cascadic Multilevel Algorithms for Symmetric Saddle Point Systems

abstract:
  In this paper, we introduce a multilevel algorithm for approximating
variational formulations of symmetric saddle point systems. The algorithm is
based on availability of families of stable finite element pairs and on the
availability of fast and accurate solvers for it symmetric positive definite
systems. On each fixed level an efficient solver such as the gradient or the
conjugate gradient algorithm for inverting a Schur complement is implemented.
The level change criterion follows the cascade principle and requires that the
iteration error be close to the expected discretization error. We prove new
estimates that relate the iteration error and the residual for the constraint
equation. The new estimates are the key ingredients in imposing an efficient
level change criterion. The first iteration on each new level uses information
about the best approximation of the discrete solution from the previous level.
The theoretical results and experiments show that the algorithms achieve
optimal or close to optimal approximation rates by performing a non-increasing
number of iterations on each level. Even though numerical results supporting
the efficiency of the algorithms are presented for the Stokes system, the
algorithms can be applied to a large class of boundary value problems,
including first order systems that can be reformulated at the continuous level
as symmetric saddle point problems, such as the Maxwell equations.


title: Testing the Equivalence Principle with Unstable Particles

abstract:
  We develop a framework to test the Equivalence Principle (EP) under
conditions where the quantum aspects of nature cannot be neglected,
specifically in the context of interference phenomena with unstable particles.
We derive the nonrelativistic quantum equation that describes the evolution of
the wavefunction of unstable particles under the assumption of the validity of
the EP and when small deviations are assumed to occur. As an example, we study
the propagation of unstable particles in a COW experiment, and we briefly
discuss the experimental implications of our formalism.


title: Long-Range Interaction of Singlet-Triplet Qubits via Ferromagnets

abstract:
  We propose a mechanism of a long-range coherent interaction between two
singlet-triplet qubits dipolarly coupled to a dogbone-shaped ferromagnet. An
effective qubit-qubit interaction Hamiltonian is derived and the coupling
strength is estimated. Furthermore we derive the effective coupling between two
spin-1/2 qubits that are coupled via dipolar interaction to the ferromagnet and
that lie at arbitrary positions and deduce the optimal positioning. We consider
hybrid systems consisting of spin-1/2 and ST qubits and derive the effective
Hamiltonian for this case. We then show that operation times vary between 1MHz
and 100MHz and give explicit estimates for GaAs, Silicon, and NV-center based
spin qubits. Finally, we explicitly construct the required sequences to
implement a CNOT gate. The resulting quantum computing architecture retains all
the single qubit gates and measurement aspects of earlier approaches, but
allows qubit spacing at distances of order 1$\,\mu$m for two-qubit gates,
achievable with current semiconductor technology.


title:
Stochastic Collapsed Variational Bayesian Inference for Latent Dirichlet
  Allocation

abstract:
  In the internet era there has been an explosion in the amount of digital text
information available, leading to difficulties of scale for traditional
inference algorithms for topic models. Recent advances in stochastic
variational inference algorithms for latent Dirichlet allocation (LDA) have
made it feasible to learn topic models on large-scale corpora, but these
methods do not currently take full advantage of the collapsed representation of
the model. We propose a stochastic algorithm for collapsed variational Bayesian
inference for LDA, which is simpler and more efficient than the state of the
art method. We show connections between collapsed variational Bayesian
inference and MAP estimation for LDA, and leverage these connections to prove
convergence properties of the proposed algorithm. In experiments on large-scale
text corpora, the algorithm was found to converge faster and often to a better
solution than the previous method. Human-subject experiments also demonstrated
that the method can learn coherent topics in seconds on small corpora,
facilitating the use of topic models in interactive document analysis software.


title: A Reverse Shock in GRB 130427A

abstract:
  We present extensive radio and millimeter observations of the unusually
bright GRB 130427A at z=0.340, spanning 0.67 to 12 days after the burst. Taken
in conjunction with detailed multi-band UV, optical, NIR, and X-ray
observations we find that the broad-band afterglow emission is composed of
distinct reverse shock and forward shock contributions. The reverse shock
emission dominates in the radio/millimeter and at <0.1 days in the
UV/optical/NIR, while the forward shock emission dominates in the X-rays and at
>0.1 days in the UV/optical/NIR. We further find that the optical and X-ray
data require a Wind circumburst environment, pointing to a massive star
progenitor. Using the combined forward and reverse shock emission we find that
the parameters of the burst are an isotropic kinetic energy of E_Kiso~2e53 erg,
a mass loss rate of Mdot~3e-8 Msun/yr (for a wind velocity of 1,000 km/s), and
a Lorentz factor at the deceleration time of Gamma(200s)~130. Due to the low
density and large isotropic energy, the absence of a jet break to ~15 days
places only a weak constraint on the opening angle of theta_j>2.5 deg, and
therefore a total energy of E_gamma+E_K>1.2e51 erg, similar to other GRBs. The
reverse shock emission is detectable in this burst due to the low circumburst
density, which leads to a slow cooling shock. We speculate that this is a
required property for the detectability of reverse shocks in the radio and
millimeter bands. Following on GRB 130427A as a benchmark event, observations
of future GRBs with the exquisite sensitivity of VLA and ALMA, coupled with
detailed modeling of the reverse and forward shock contributions will test this
hypothesis.


title:
Flux Enhancement of Slow-moving Particles by Sun or Jupiter: Can they be
  Detected on Earth?

abstract:
  Slow-moving particles capable of interacting solely with gravity might be
detected on Earth as a result of the gravitational lensing induced focusing
action of the Sun. The deflection experienced by these particles are inversely
proportional to the square of their velocities and as a result their focal
lengths will be shorter. We investigate the velocity dispersion of these
slow-moving particles, originating from distant point-like sources, for
imposing upper and lower bounds on the velocities of such particles in order
for them to be focused onto Earth. We find that fluxes of such slow-moving and
non-interacting particles must have speeds between ~0.01 and ~0.14 times the
speed of light, $c$. Particles with speeds less than ~0.01 c will undergo way
too much deflection to be focused, although such individual particles could be
detected. At the caustics, the magnification factor could be as high as ~10E+6.
  We impose lensing constraints on the mass of these particles in order for
them to be detected with large flux enhancements to be greater than E-9 eV. An
approximate mass density profile for Jupiter is used to constrain particle
velocities for lensing by Jupiter. We show that Jupiter could potentially focus
particles with speeds as low as ~0.001c, which the Sun cannot. As a special
case, the perfect alignment of the planet Jupiter with the Sun is also
considered.


title:
Geometric treatment of conduction electron scattering by crystal lattice
  strains and dislocations

abstract:
  A theory for conduction electron scattering by inhomogeneous crystal lattice
strains is developed, based on the differential geometric treatment of
deformations in solids. The resulting fully covariant Schr\"odinger equation
shows that the electrons can be described as moving in a non-Euclidean
background space in the continuum limit of the deformed lattice. Unlike
previous work, the formalism is applicable to cases involving purely elastic
strains as well as discrete and continuous distributions of dislocations --- in
the latter two cases it clearly demarcates the effects of the dislocation
strain field and core and differentiates between elastic and plastic strain
contributions respectively. The electrical resistivity due to the strain field
of edge dislocations is then evaluated using perturbation theory and the
Boltzmann transport equation. The resulting numerical estimate for Cu shows
good agreement with experimental values, indicating that the electrical
resistivity of edge dislocations is not entirely due to the core, contrary to
current models. Possible application to the study of strain effects in
constrained quantum systems is also discussed.


title: Nowhere-Zero $\vec k$-Flows on Graphs

abstract:
  We introduce and study a multivariate function that counts nowhere-zero flows
on a graph G, in which each edge of G has an individual capacity. We prove that
the associated counting function is a piecewise-defined polynomial in these
capacities, which satisfy a combinatorial reciprocity law that incorporates
totally cyclic orientations of G.


title:
Demonstration of Motion Transduction Based on Parametrically Coupled
  Mechanical Resonators

abstract:
  Universal sensing the motion of mechanical resonators with high precision and
low back-action is of paramount importance in ultra-weak signal detection which
plays a fundamental role in modern physics. Here we present a universal scheme
that transfer mechanically the motion of the resonator not directly measurable
to the one can be precisely measured using mechanical frequency conversion.
Demonstration of the scheme at room temperature shows that both the motion
imprecision and the back-action force are below the intrinsic level of the
objective resonator, which agree well with our theoretical prediction. The
scheme developed here provides an effective interface between an arbitrary
mechanical resonator and a high quantum efficient displacement sensor, and is
expected to find extensive applications in high-demanding mechanical-based
force measurements.


title:
An Erdos-Turan Inequality For Compact Simply-Connected Semisimple Lie
  Groups

abstract:
  The classical Erd{\" o}s-Turan Inequality bounds how far a sequence of points
in the circle is from being equidistributed in terms of its exponential
moments. We prove an analogous inequality for all compact simply-connected
semisimple Lie groups, bounding how far a sequence is from being
equidistributed in the conjugacy classes of the group in terms of the moments
of irreducible characters.


title: Interference Alignment in Distributed Antenna Systems

abstract:
  Interference alignment (IA) is a cooperative transmission strategy that
improves spectral efficiency in high signal-to-noise ratio (SNR) environments,
yet performs poorly in low-SNR scenarios. This limits IA's utility in cellular
systems as it is ineffective in improving cell-edge data rates. Modern cellular
architectures such as distributed antenna systems (DAS), however, promise to
boost cell-edge SNR, creating the environment needed to realize practical IA
gains. Existing IA solutions cannot be applied to DAS as they neglect the
per-remote-radio power constraints imposed on distributed precoders. This paper
considers two types of distributed antenna IA systems: ones with a limit on
maximum per-radio power, and ones with a strict equality constraint on
per-radio power. The rate-loss incurred by a simple power back-off strategy,
used in systems with maximum power constraints, is characterized analytically.
It is also shown that enforcing strict power constraints avoids such a
rate-loss but negatively affects IA feasibility. For such systems, an IA
algorithm is proposed and feasibility conditions are derived based on the
concept of system properness. Finally, numerical results validate the analysis
and demonstrate that IA and DAS can be successfully combined to mitigate
inter-cell interference and improve performance for most mobile users,
especially those at the cell-edge.


title: Spatially Sparse Precoding in Millimeter Wave MIMO Systems

abstract:
  Millimeter wave (mmWave) signals experience orders-of-magnitude more pathloss
than the microwave signals currently used in most wireless applications. MmWave
systems must therefore leverage large antenna arrays, made possible by the
decrease in wavelength, to combat pathloss with beamforming gain. Beamforming
with multiple data streams, known as precoding, can be used to further improve
mmWave spectral efficiency. Both beamforming and precoding are done digitally
at baseband in traditional multi-antenna systems. The high cost and power
consumption of mixed-signal devices in mmWave systems, however, make analog
processing in the RF domain more attractive. This hardware limitation restricts
the feasible set of precoders and combiners that can be applied by practical
mmWave transceivers. In this paper, we consider transmit precoding and receiver
combining in mmWave systems with large antenna arrays. We exploit the spatial
structure of mmWave channels to formulate the precoding/combining problem as a
sparse reconstruction problem. Using the principle of basis pursuit, we develop
algorithms that accurately approximate optimal unconstrained precoders and
combiners such that they can be implemented in low-cost RF hardware. We present
numerical results on the performance of the proposed algorithms and show that
they allow mmWave systems to approach their unconstrained performance limits,
even when transceiver hardware constraints are considered.


title: Numerical Reparametrization of Rational Parametric Plane Curves

abstract:
  In this paper, we present an algorithm for reparametrizing algebraic plane
curves from a numerical point of view. That is, we deal with mathematical
objects that are assumed to be given approximately. More precisely, given a
tolerance $\epsilon>0$ and a rational parametrization $\cal P$ with perturbed
float coefficients of a plane curve $\cal C$, we present an algorithm that
computes a parametrization $\cal Q$ of a new plane curve $\cal D$ such that
${\cal Q}$ is an {\it $\epsilon$--proper reparametrization} of $\cal D$. In
addition, the error bound is carefully discussed and we present a formula that
measures the "closeness" between the input curve $\cal C$ and the output curve
$\cal D$.


title: Characterization of Rational Ruled Surfaces

abstract:
  The ruled surface is a typical modeling surface in computer aided geometric
design. It is usually given in the standard parametric form. However, it can
also be in the forms than the standard one. For these forms, it is necessary to
determine and find the standard form. In this paper, we present algorithms to
determine whether a given implicit surface is a rational ruled surface. A
parametrization of the surface is computed for the affirmative case. We also
consider the parametric situation. More precisely, after a given rational
parametric surface is determined as a ruled one, we reparameterize it to the
standard form.


title: Determination and (re)parametrization of rational developable surfaces

abstract:
  The developable surface is an important surface in computer aided design,
geometric modeling and industrial manufactory. It is often given in the stan-
dard parametric form, but it can also be in the implicit form which is commonly
used in algebraic geometry. Not all algebraic developable surfaces have
rational parametrizations. In this paper, we focus on the rational developable
surfaces. For a given algebraic surface, we first determine whether it is
developable by geometric inspection, and we give a rational proper
parametrization for the af- firmative case. For a rational parametric surface,
we can also determine the developability and give a proper reparametrization
for the developable surface.


title: Quantum Zeno Effect of General Quantum Operations

abstract:
  In this paper, we show that the quantum Zeno effect occurs for any frequent
quantum measurements or operations. As a result of the Zeno effect, for
non-selective measurements (or trace preserving completely positive maps), the
evolution of a measurement invariant state is governed by an effective
Hamiltonian defined by the measurements and the free-evolution Hamiltonian. For
selective measurements, the state may change randomly with time according to
measurement outcomes, while some physical quantities (operators) still evolve
as the effective dynamics.


title: Polite actions of non-compact Lie groups

abstract:
  Based mainly on examples of interest in mechanics, we define the notion of a
polite group action. One may view this as not only trying to give a more
general notion than properness of a group action, but also to more fully
understand the role of invariant functions in describing just about everything
of interest in reduction.
  We show that a polite action of a symmetry group of a dynamical system admits
reduction and reconstruction.


title: Gravitational Waves from Gamma-Ray Pulsar Glitches

abstract:
  We use data from pulsar gamma-ray glitches recorded by the Fermi Large Area
Telescope as input to theoretical models of gravitational wave signals the
glitches might generate. We find that the typical peak amplitude of the gravity
wave signal from gamma-ray pulsar glitches lies between 10^{-23} and 10^{-35}
in dimensionless units, with peak frequencies in the range of 1 to 1000 Hz,
depending on the model. We estimate the signal-to-noise for all gamma-ray
glitches, and discuss detectability with current gravity wave detectors. Our
results indicate that the strongest predicted signals are potentially within
reach of current detectors, and that pulsar gamma-ray glitches are promising
targets for gravity wave searches by current and next-generation detectors.


title: 3-coloring triangle-free planar graphs with a precolored 8-cycle

abstract:
  Let G be a planar triangle-free graph and let C be a cycle in G of length at
most 8. We characterize all situations where a 3-coloring of C does not extend
to a proper 3-coloring of the whole graph.


title: Fooling-sets and rank in nonzero characteristic (extended abstract)

abstract:
  An n\times n matrix M is called a fooling-set matrix of size n, if its
diagonal entries are nonzero, whereas for every k\ne \ell we have M_{k,\ell}
M_{\ell,k} = 0. Dietzfelbinger, Hromkovi\v{c}, and Schnitger (1996) showed that
n \le (\rk M)^2, regardless of over which field the rank is computed, and asked
whether the exponent on \rk M can be improved.
  We settle this question for nonzero characteristic by constructing a family
of matrices for which the bound is asymptotically tight. The construction uses
linear recurring sequences.


title:
The Dawes Review 1: Kinematic studies of star-forming galaxies across
  cosmic time

abstract:
  The last seven years have seen an explosion in the number of Integral Field
galaxy surveys, obtaining resolved 2D spectroscopy, especially at
high-redshift. These have taken advantage of the mature capabilities of 8-10 m
class telescopes and the development of associated technology such as AO.
Surveys have leveraged both high spectroscopic resolution enabling internal
velocity measurements and high spatial resolution from AO techniques and sites
with excellent natural seeing. For the first time, we have been able to glimpse
the kinematic state of matter in young, assembling star-forming galaxies and
learn detailed astrophysical information about the physical processes and
compare their kinematic scaling relations with those in the local Universe.
Observers have measured disc galaxy rotation, merger signatures, and
turbulence-enhanced velocity dispersions of gas-rich discs. Theorists have
interpreted kinematic signatures of galaxies in a variety of ways (rotation,
merging, outflows, and feedback) and attempted to discuss evolution vs.
theoretical models and relate it to the evolution in galaxy morphology. A key
point that has emerged from this activity is that substantial fractions of
high-redshift galaxies have regular kinematic morphologies despite irregular
photometric morphologies and this is likely due to the presence of a large
number of highly gas-rich discs. There has not yet been a review of this
burgeoning topic. In this first Dawes review, I will discuss the extensive
kinematic surveys that have been done and the physical models that have arisen
for young galaxies at high-redshift.


title:
Topological Surface Transport in Epitaxial SnTe Thin Films Grown on
  Bi2Te3

abstract:
  The topological crystalline insulator SnTe has been grown epitaxially on a
Bi2Te3 buffer layer by molecular beam epitaxy. In a 30-nm-thick SnTe film, p-
and n-type carriers are found to coexist, and Shubnikov--de Haas oscillation
data suggest that the n-type carriers are Dirac fermions residing on the SnTe
(111) surface. This transport observation of the topological surface state in a
p-type topological crystalline insulator became possible due to a downward band
bending on the free SnTe surface, which appears to be of intrinsic origin.


title:
Operator Monotone Functions: Characterizations and Integral
  Representations

abstract:
  Operator monotone functions, introduced by Lowner in 1934, are an important
class of real-valued functions. They arise naturally in matrix and operator
theory and have various applications in other branches of mathematics and
related fields. This concept is closely related to operator convex/concave
functions. In this paper, we provide their important examples and
characterizations in terms of matrix of divided differences. Various
characterizations and the relationship between operator monotonicity and
operator convexity are given by Hansen-Pedersen characterizations. Moreover,
operator monotone functions on the nonnegative reals have special properties,
namely, they admit integral representations with respect to suitable Borel
measures.


title: Repeated interactions in open quantum systems

abstract:
  Analyzing the dynamics of open quantum systems has a long history in
mathematics and physics. Depending on the system at hand, basic physical
phenomena that one would like to explain are, for example, convergence to
equilibrium, the dynamics of quantum coherences (decoherence) and quantum
correlations (entanglement), or the emergence of heat and particle fluxes in
non-equilibrium situations. From the mathematical physics perspective, one of
the main challenges is to derive the irreversible dynamics of the open system,
starting from a unitary dynamics of the system and its environment.
  The repeated interactions systems considered in these notes are models of
non-equilibrium quantum statistical mechanics. They are relevant in quantum
optics, and more generally, serve as a relatively well treatable approximation
of a more difficult quantum dynamics. In particular, the repeated interaction
models allow to determine the large time (stationary) asymptotics of quantum
systems out of equilibrium.


title:
Affine Invariant Divergences associated with Composite Scores and its
  Applications

abstract:
  In statistical analysis, measuring a score of predictive performance is an
important task. In many scientific fields, appropriate scores were tailored to
tackle the problems at hand. A proper score is a popular tool to obtain
statistically consistent forecasts. Furthermore, a mathematical
characterization of the proper score was studied. As a result, it was revealed
that the proper score corresponds to a Bregman divergence, which is an
extension of the squared distance over the set of probability distributions. In
the present paper, we introduce composite scores as an extension of the typical
scores in order to obtain a wider class of probabilistic forecasting. Then, we
propose a class of composite scores, named Holder scores, that induce
equivariant estimators. The equivariant estimators have a favorable property,
implying that the estimator is transformed in a consistent way, when the data
is transformed. In particular, we deal with the affine transformation of the
data. By using the equivariant estimators under the affine transformation, one
can obtain estimators that do no essentially depend on the choice of the system
of units in the measurement. Conversely, we prove that the Holder score is
characterized by the invariance property under the affine transformations.
Furthermore, we investigate statistical properties of the estimators using
Holder scores for the statistical problems including estimation of regression
functions and robust parameter estimation, and illustrate the usefulness of the
newly introduced scores for statistical forecasting.


title:
Evolution of blue supergiants and \alpha Cygni variables; Puzzling CNO
  surface abundances

abstract:
  A massive star can enter the blue supergiant region either evolving directly
from the main-sequence, or evolving from a previous red supergiant stage. The
fractions of the blue supergiants having different histories depend on the
internal mixing and mass-loss during the red supergiant stage. We study the
possibility to use diagnostics based on stellar pulsation to discriminate blue
supergiants having different evolution histories. For this purpose we have
studied the pulsation property of massive star models calculated with the
Geneva stellar evolution code for initial masses ranging from 8 to 50 M$_\odot$
with a solar metallicity of $Z=0.014$. We have found that radial pulsations are
excited in the blue-supergiant region only in the models that had been
red-supergiants before. This would provide us with a useful mean to diagnose
the history of evolution of each blue-supergiant. At a given effective
temperature, much more nonradial pulsations are excited in the model after the
red-supergiant stage than in the model evolving towards the red-supergiant. The
properties of radial and nonradial pulsations in blue supergiants are
discussed. Predicted periods are compared with period ranges observed in some
\alpha-Cygni variables in the Galaxy and NGC 300. We have found that blue
supergiant models after the red-supergiant stage roughly agree with observed
period ranges in most cases. However, we are left with the puzzle that the
predicted surface N/C and N/O ratios seem to be too high compared with those of
Deneb and Rigel.


title: Rayleigh-Taylor instability in an ionized medium

abstract:
  We study linear theory of the magnetized Rayleigh-Taylor instability in a
system consisting of ions and neutrals. Both components are affected by a
uniform vertical gravitational field. We consider ions and neutrals as two
separate fluid systems where they can exchange momentum through collisions.
However, ions have direct interaction with the magnetic field lines but
neutrals are not affected by the field directly. The equations of our two-fluid
model are linearized and by applying a set of proper boundary conditions, a
general dispersion relation is derived for our two superposed fluids separated
by a horizontal boundary. We found two unstable modes for a range of the
wavenumbers. It seems that one of the unstable modes corresponds to the ions
and the other one is for the neutrals. Both modes are reduced with increasing
the collision rate of the particles and the ionization fraction. We show that
if the two-fluid nature is considered, RT instability would not be suppressed
and also show that the growth time of the perturbations increases. As an
example, we apply our analysis to the Local clouds which seems to have arisen
because of the RT instability. Assuming that the clouds are partially ionized,
we find that the growth rate of these clouds increases in comparison to a fully
ionized case.


title: Fourier methods for smooth distribution function estimation

abstract:
  In this paper we show how to use Fourier transform methods to analyze the
asymptotic behavior of kernel distribution function estimators. Exact
expressions for the mean integrated squared error in terms of the
characteristic function of the distribution and the Fourier transform of the
kernel are employed to obtain the limit value of the optimal bandwidth sequence
in its greatest generality. The assumptions in our results are mild enough so
that they are applicable when the kernel used in the estimator is a
superkernel, or even the sinc kernel, and this allows to extract some
interesting consequences, as the existence of a class of distributions for
which the kernel estimator achieves a first-order improvement in efficiency
over the empirical distribution function.


title:
Magnetic Properties of the Spin-1/2 Deformed Kagome Antiferromagnet
  Edwardsite

abstract:
  We prepared a powder sample of edwardsite Cd2Cu3(SO4)2(OH)6 4H2O, which is a
new candidate compound for the spin-1/2 kagome antiferromagnet, and studied its
magnetic properties by magnetic susceptibility and heat capacity measurements.
Edwardsite has a deformed kagome lattice with an average antiferromagnetic
interaction of 51 K between nearby spins and shows an antiferromagnetic order
accompanied by a small ferromagnetic moment below 4.3 K. The weak
ferromagnetism is likely due to spin canting caused by sizable
Dzyaloshinsky-Moriya interactions, which may stabilize the long-range magnetic
order instead of a spin-liquid state expected for the kagome antiferromagnet.


title:
An evaluation of the exposure in nadir observation of the JEM-EUSO
  mission

abstract:
  We evaluate the exposure during nadir observations with JEM-EUSO, the Extreme
Universe Space Observatory, on-board the Japanese Experiment Module of the
International Space Station. Designed as a mission to explore the extreme
energy Universe from space, JEM-EUSO will monitor the Earth's nighttime
atmosphere to record the ultraviolet light from tracks generated by extensive
air showers initiated by ultra-high energy cosmic rays. In the present work, we
discuss the particularities of space-based observation and we compute the
annual exposure in nadir observation. The results are based on studies of the
expected trigger aperture and observational duty cycle, as well as, on the
investigations of the effects of clouds and different types of background
light. We show that the annual exposure is about one order of magnitude higher
than those of the presently operating ground-based observatories.


title:
Quantum teleportation of spin coherent states: beyond continuous
  variables teleportation

abstract:
  We introduce a quantum teleportation scheme that can transfer a macroscopic
spin coherent state between two locations. In the scheme a large number of
copies of a qubit, such as realized in a coherent two-component Bose-Einstein
condensate, is teleported onto a distant macroscopic spin coherent state using
only elementary operations and measurements. We analyze the error of the
protocol with the number of particles N in the spin coherent state under
decoherence and find that it scales favorably with N.


title: Weight Distribution for Non-binary Cluster LDPC Code Ensemble

abstract:
  In this paper, we derive the average weight distributions for the irregular
non-binary cluster low-density parity-check (LDPC) code ensembles. Moreover, we
give the exponential growth rate of the average weight distribution in the
limit of large code length. We show that there exist $(2,d_c)$-regular
non-binary cluster LDPC code ensembles whose normalized typical minimum
distances are strictly positive.


title: Multiplication Conditional Expectation Type Operators On Orlicz Spaces

abstract:
  In this paper we consider a generalized conditional-type Holder- inequality
and investigate some classic properties of multiplication conditional
expectation type operators on Orlicz-spaces.


title: On the genus of birational maps between 3-folds

abstract:
  In this note we present two equivalent definitions for the genus of a
birational map X --> Y between smooth complex projective 3-folds. The first one
is the definition introduced in 1973 by M. A. Frumkin, the second one was
recently suggested to me by S. Cantat. By focusing first on proving that these
two definitions are equivalent, one can obtain all the results of the paper of
Frumkin in a much shorter way. In particular, the genus of an automorphism of
$\mathbb{C}^3$, view as a birational self-map of the projective space, will
easily be proved to be 0.


title:
Evolutionary constraints on the planetary hypothesis for transition
  discs

abstract:
  We assume a scenario in which transition discs (i.e. discs around young stars
that have signatures of cool dust but lack significant near infra-red emission
from warm dust) are associated with the presence of planets (or brown dwarfs).
These are assumed to filter the dust content of any gas flow within the
planetary orbit and produce an inner `opacity hole'. In order to match the
properties of transition discs with the largest (~50 A.U. scale) holes, we
place such `planets' at large radii in massive discs and then follow the
evolution of the tidally coupled disc-planet system, comparing the system's
evolution in the plane of mm flux against hole radius with the properties of
observed transition discs. We find that, on account of the high disc masses in
these systems, all but the most massive `planets' (100 Jupiter masses) are
conveyed to small radii by Type II migration without significant fading at
millimetre wavelengths. Such behaviour would contradict the observed lack of mm
bright transition discs with small (<10 A.U.) holes. On the other hand, imaging
surveys clearly rule out the presence of such massive companions in transition
discs. We conclude that this is a serious problem for models that seek to
explain transition discs in terms of planetary companions unless some mechanism
can be found to halt inward migration and/or suppress mm flux production. We
suggest that the dynamical effects of substantial accretion on to the
planet/through the gap may offer the best prospect for halting such migration
but that further long term simulations are required to clarify this issue.


title: Resonant leptogenesis with mild degeneracy

abstract:
  Under the assumption of hierarchical right-handed neutrino masses, masses of
right-handed neutrinos must be larger than $10^8$ GeV in the standard thermal
leptogenesis scenario, while the mass can be reduced to around 5 TeV in a
neutrinophilic two Higgs doublet model. On the other hand, resonant
leptogenesis can work with the masses of TeV-scale. However, necessary
degeneracy between the lightest and the second lightest right-handed neutrino
masses means unnatural fine-tuning of the order of $10^9$. In this paper, we
will investigate the resonant leptogenesis scenario in a neutrinophilic two
Higgs doublet model. We will find the mass can be reduced to 2 TeV and the
degeneracy becomes much milder as of the order of $10^4$. We will also show
that degenerate mass spectrum of active neutrinos is disfavored in this setup.


title: Mass and motion of globulettes in the Rosette Nebula

abstract:
  We have investigated tiny molecular clumps in the Rosette Nebula. Radio
observations were made of molecular line emission from 16 globulettes
identified in a previous optical survey. In addtion, we collected images in the
NIR broad-band JHKs and narrow-band Paschen beta and H2. Ten objects, for which
we collected information from several transitions in 12CO and 13CO were
modelled using a spherically symmetric model. The best fit to observed line
ratios and intensities was obtained by assuming a model composed of a cool and
dense centre and warm and dense surface layer. The average masses derived range
from about 50 to 500 Jupiter masses, which is similar to earlier estimates
based on extinction measures. The globulettes selected are dense, with very
thin layers of fluorescent H2 emission. The NIR data shows that several
globulettes are very opaque and contain dense cores. Because of the high
density encountered already at the surface, the rims become thin, as evidenced
by our P beta images.
  We conclude that the entire complex of shells, elephant trunks, and
globulettes in the northern part of the nebula is expanding with nearly the
same velocity of ~22 km/s, and with a very small spread in velocity among the
globulettes. Some globulettes are in the process of detaching from elephant
trunks and shells, while other more isolated objects must have detached long
ago and are lagging behind in the general expansion of the molecular shell. The
suggestion that some globulettes might collapse to form planetary-mass objects
or brown dwarfs is strengthened by our finding of dense cores in several
objects.


title: An inverse spectral problem for a star graph of Krein strings

abstract:
  We solve an inverse spectral problem for a star graph of Krein strings, where
the known spectral data comprises the spectrum associated with the whole graph,
the spectra associated with the individual edges as well as so-called coupling
matrices. In particular, we show that these spectral quantities uniquely
determine the weight within the class of Borel measures on the graph, which
give rise to trace class resolvents. Furthermore, we obtain a concise
characterization of all possible spectral data for this class of weights.


title:
A coupling problem for entire functions and its application to the
  long-time asymptotics of integrable wave equations

abstract:
  We propose a novel technique for analyzing the long-time asymptotics of
integrable wave equations in the case when the underlying isospectral problem
has purely discrete spectrum. To this end, we introduce a natural coupling
problem for entire functions, which serves as a replacement for the usual
Riemann-Hilbert problem, which does not apply in these cases. As a prototypical
example, we investigate the long-time asymptotics of the dispersionless
Camassa-Holm equation.


title: QED with a parabolic mirror

abstract:
  We investigate the quantum electrodynamics of a single two-level atom located
at the focus of a parabolic cavity. We first work out the modifications of the
spontaneous emission induced by the presence of this boundary in the optical
regime, where the dipole and the rotating-wave approximations apply.
Furthermore, the single-photon state that leaves the cavity asymptotically is
determined. The corresponding time-reversed single-photon quantum state is
capable of exciting the atom in this extreme multimode scenario with near-unit
probability. Using semiclassical methods, we derive a photon-path
representation for the relevant transition amplitudes and show that it
constitutes a satisfactory approximation for a wide range of wavelengths.


title: The extremal solution for the fractional Laplacian

abstract:
  We study the extremal solution for the problem $(-\Delta)^s u=\lambda f(u)$
in $\Omega$, $u\equiv0$ in $\R^n\setminus\Omega$, where $\lambda>0$ is a
parameter and $s\in(0,1)$. We extend some well known results for the extremal
solution when the operator is the Laplacian to this nonlocal case. For general
convex nonlinearities we prove that the extremal solution is bounded in
dimensions $n<4s$. We also show that, for exponential and power-like
nonlinearities, the extremal solution is bounded whenever $n<10s$. In the limit
$s\uparrow1$, $n<10$ is optimal. In addition, we show that the extremal
solution is $H^s(\R^n)$ in any dimension whenever the domain is convex.
  To obtain some of these results we need $L^q$ estimates for solutions to the
linear Dirichlet problem for the fractional Laplacian with $L^p$ data. We prove
optimal $L^q$ and $C^\beta$ estimates, depending on the value of $p$. These
estimates follow from classical embedding results for the Riesz potential in
$\R^n$.
  Finally, to prove the $H^s$ regularity of the extremal solution we need an
$L^\infty$ estimate near the boundary of convex domains, which we obtain via
the moving planes method. For it, we use a maximum principle in small domains
for integro-differential operators with decreasing kernels.


title:
Combining Drift Analysis and Generalized Schema Theory to Design
  Efficient Hybrid and/or Mixed Strategy EAs

abstract:
  Hybrid and mixed strategy EAs have become rather popular for tackling various
complex and NP-hard optimization problems. While empirical evidence suggests
that such algorithms are successful in practice, rather little theoretical
support for their success is available, not mentioning a solid mathematical
foundation that would provide guidance towards an efficient design of this type
of EAs. In the current paper we develop a rigorous mathematical framework that
suggests such designs based on generalized schema theory, fitness levels and
drift analysis. An example-application for tackling one of the classical
NP-hard problems, the "single-machine scheduling problem" is presented.


title:
Theoretical investigations on magnetic field induced $2p^53s^3P_{0,2} -
  2p^6^1S_0$ transitions in Ne-like ions without nuclear spin

abstract:
  We report theoretical results for magnetic field induced $2p^53s^3P_{0,2} -
2p^6^1S_0$ E1 transitions in Ne-like ions with zero nuclear spin (I=0) between
Mg III and Zn XXI as well as in Ne I. We demonstrate that it is important to
include both ``perturber'' states $2p^53s^1P_1$ and $2p^53s^3P_1$ in order to
produce reliable transition rates. Furthermore, we investigate the trends of
the rates along the isoelectronic sequence of the $2p^53s^3P_{0,2} - 2p^6^1S_0$
transitions and their competition with the $2p^53s^3P_0 - 2p^53s^3P_1$ M1 and
the $2p^53s^3P_2 - 2p^6^1S_0$ M2 decays. For the $2p^53s^3P_0$ state the
magnetic field induced transition becomes the dominant decay channel for the
light elements even in a relatively weak magnetic field, and it will therefore
prove useful in diagnostics of the strength of magnetic fields in different
plasmas. The influence of an external magnetic field on the lifetime of the
$2p^53s^3P_2$ state is much smaller but still observable for the ions near the
neutral end of the sequence. As a special case, the magnetic field effect on
the lifetimes of $2p^53s^3P_{0,2}$ states of neutral $^{20}$Ne is discussed. It
is found that the lifetimes are drastically reduced by a magnetic field, which
may be an underlying reason for the discrepancies in the lifetime of the
$2p^53s^3P_2$ state between experiment (14.73(14) s) and theory (17.63 s).


title: Quantum reflection from an oscillating surface

abstract:
  We describe an experimentally realistic situation of the quantum reflection
of helium atoms from an oscillating surface. The temporal modulation of the
potential induces clear sidebands in the reflection probability as a function
of momentum. Theses sidebands could be exploited to slow down atoms and
molecules in the experiment.


title: Do Tsallis distributions really originate from the finite baths?

abstract:
  It is often stated that heat baths with finite degrees of freedom i.e.,
finite baths, are sources of Tsallis distributions for the classical
Hamiltonian systems. By using well-known fundamental statistical mechanical
expressions, we rigorously show that Tsallis distributions with fat tails are
possible \textit{only} for finite baths with constant negative heat capacity
while constant positive heat capacity finite baths yield decays with sharp
cut-off with no fat tails. However, the correspondence between Tsallis
distributions and finite baths holds at the expense of violating equipartition
theorem for finite classical systems at equilibrium. Finally, we comment on the
implications of the finite bath for the recent attempts towards a
$q$-generalized central limit theorem.


title:
Computing Solution Operators of Boundary-value Problems for Some Linear
  Hyperbolic Systems of PDEs

abstract:
  We discuss possibilities of application of Numerical Analysis methods to
proving computability, in the sense of the TTE approach, of solution operators
of boundary-value problems for systems of PDEs. We prove computability of the
solution operator for a symmetric hyperbolic system with computable real
coefficients and dissipative boundary conditions, and of the Cauchy problem for
the same system (we also prove computable dependence on the coefficients) in a
cube $Q\subseteq\mathbb R^m$. Such systems describe a wide variety of physical
processes (e.g. elasticity, acoustics, Maxwell equations). Moreover, many
boundary-value problems for the wave equation also can be reduced to this case,
thus we partially answer a question raised in Weihrauch and Zhong (2002).
Compared with most of other existing methods of proving computability for PDEs,
this method does not require existence of explicit solution formulas and is
thus applicable to a broader class of (systems of) equations.


title:
Equivariant $\KK$-theory for generalised actions and Thom isomorphism in
  groupoid twisted $\K$-theory

abstract:
  We develop equivariant KK-theory for locally compact groupoid actions by
Morita equivalences on real and complex graded C*-algebras. Functoriality with
respect to generalised morphisms and Bott periodicity are discussed. We
introduce Stiefel-Whitney classes for real or complex equivariant vector
bundles over locally compact groupoids to establish the Thom isomorphism
theorem in twisted groupoid K-theory.


title:
Perturbation centrality and Turbine: a novel centrality measure obtained
  using a versatile network dynamics tool

abstract:
  Analysis of network dynamics became a focal point to understand and predict
changes of complex systems. Here we introduce Turbine, a generic framework
enabling fast simulation of any algorithmically definable dynamics on very
large networks. Using a perturbation transmission model inspired by
communicating vessels, we define a novel centrality measure: perturbation
centrality. Hubs and inter-modular nodes proved to be highly efficient in
perturbation propagation. High perturbation centrality nodes of the Met-tRNA
synthetase protein structure network were identified as amino acids involved in
intra-protein communication by earlier studies. Changes in perturbation
centralities of yeast interactome nodes upon various stresses well
recapitulated the functional changes of stressed yeast cells. The novelty and
usefulness of perturbation centrality was validated in several other model,
biological and social networks. The Turbine software and the perturbation
centrality measure may provide a large variety of novel options to assess
signaling, drug action, environmental and social interventions. The Turbine
algorithm is available at: http://www.turbine.linkgroup.hu

categories: q-bio.MN cond-mat.dis-nn cs.SI physics.bio-ph


title:
An embedding theorem for weighted Sobolev classes on a John domain: case
  of weights that are functions of a distance to a certain h-set

abstract:
  Let $\Omega$ be a John domain, and let $\Gamma\subset \partial \Omega$ be an
$h$-set. For some functions $h$ and some weight functions depending on distance
from $\Gamma$, embedding theorems for a weighted Sobolev class is obtained.


title:
A Further Generalization of the Finite-Population Geiringer-like Theorem
  for POMDPs to Allow Recombination Over Arbitrary Set Covers

abstract:
  A popular current research trend deals with expanding the Monte-Carlo tree
search sampling methodologies to the environments with uncertainty and
incomplete information. Recently a finite population version of Geiringer
theorem with nonhomologous recombination has been adopted to the setting of
Monte-Carlo tree search to cope with randomness and incomplete information by
exploiting the entrinsic similarities within the state space of the problem.
The only limitation of the new theorem is that the similarity relation was
assumed to be an equivalence relation on the set of states. In the current
paper we lift this "curtain of limitation" by allowing the similarity relation
to be modeled in terms of an arbitrary set cover of the set of state-action
pairs.