title: Finite, integrable and bounded time embeddings for diffusions

abstract:
  We solve the Skorokhod embedding problem (SEP) for a general time-homogeneous
diffusion $X$: given a distribution $\rho$, we construct a stopping time $\tau$
such that the stopped process $X_{\tau}$ has the distribution $\rho$. Our
solution method makes use of martingale representations (in a similar way to
Bass (In Seminar on Probability XVII. Lecture Notes in Math. 784 (1983) 221-224
Springer) who solves the SEP for Brownian motion) and draws on law uniqueness
of weak solutions of SDEs. Then we ask if there exist solutions of the SEP
which are respectively finite almost surely, integrable or bounded, and when
does our proposed construction have these properties. We provide conditions
that guarantee existence of finite time solutions. Then, we fully characterize
the distributions that can be embedded with integrable stopping times. Finally,
we derive necessary, respectively sufficient, conditions under which there
exists a bounded embedding.


title: Relational symplectic groupoids and Poisson sigma models with boundary

abstract:
  We introduce the notion of relational symplectic groupoid as a way to
integrate Poisson manifolds in general, following the construction through the
Poisson sigma model (PSM) given by Cattaneo and Felder. We extend such
construction to the infinite dimensional setting, where we are able to describe
the relational symplectic groupoid in terms of immersed Lagrangian Bannach
submanifolds. This corresponds to a groupoid object in the "extended symplectic
category" and it can be related to the ususal version of symplectic groupoids
via reduction. We prove the existence of such an object for any Poisson
manifold and the uniqueness of a compatible Poisson structure on the base, for
a special type of relational symplectic groupoids. We develop the notion of
equivalence, that allows us to compare finite and infinite dimensional
examples.
  We discuss some other extensions to different categories, where the
relational construction still make sense, in an effort to understand better
geometric quantization of symplectic manifolds in this new perspective.


title:
Continuous reversal of Hanle resonances of counter-propagating pulse and
  continuous-wave field

abstract:
  In this work we study propagation dynamics of the two counter-propagating
lasers, the continuous-wave (CW) laser and the pulse of another laser, when
both lasers are tuned to the $F_{g}=2 \rightarrow F_{e}=1$ transition in
$^{87}$Rb, and therefore can develop Hanle electromagnetically induced
transparency (EIT) in Rb vapor. We calculate transmission of both lasers as a
function of applied magnetic field, and investigate how the propagation of the
pulse affects the transmission of the CW laser. And vice versa, we have found
conditions when the Gaussian pulse can either pass unchanged, or be
significantly absorbed in the vacuum Rb cell. This configuration is therefore
suitable for the convenient control of the pulse propagation and the system is
of interest for optically switching of the laser pulses. In terms of the
corresponding shapes of the coherent Hanle resonances, this is equivalent to
turning the coherent resonance from Hanle EIT into electromagnetically induced
absorption (EIA) peak. There is the range of intensities of both CW laser and
the laser pulse when strong drives of atomic coherences allow two lasers to
interact with each other through atomic coherence and can simultaneously
reverse signs of Hanle resonances of both.


title:
Semiclassical matrix elements for a chaotic propagator in the Scar
  functions basis

abstract:
  A semiclassical approximation for the matrix elements of a quantum chaotic
propagator in the scar function basis has been derived. The obtained expression
is solely expressed in terms of canonical invariant objects. For our purpose,
we have used, the recently developed, semiclassical matrix elements of the
propagator in coherent states, together with the linearization of the flux in
the neighborhood of a classically unstable periodic orbit of chaotic two
dimensional systems. The expression here derived is successfully verified to be
exact for a (linear) cat map, after the theory is adapted to a discrete phase
space appropriate to a quantized torus.


title: Multi-view in Lensless Compressive Imaging

abstract:
  Multi-view images are acquired by a lensless compressive imaging
architecture, which consists of an aperture assembly and multiple sensors. The
aperture assembly consists of a two dimensional array of aperture elements
whose transmittance can be individually controlled to implement a compressive
sensing matrix. For each transmittance pattern of the aperture assembly, each
of the sensors takes a measurement. The measurement vectors from the multiple
sensors represent multi-view images of the same scene. We present theoretical
framework for multi-view reconstruction and experimental results for enhancing
quality of image using multi-view.


title:
Efficient demagnetization protocol for the artificial triangular spin
  ice

abstract:
  In this work we study demagnetization protocols for an artificial spin ice in
a triangular geometry. Our results show that a simple hysteresis-like process
is very efficient in driving the system to its ground state, even for a
relatively strong disorder in the system, confirming previous expectations. In
addition, transitions between the magnetized state and the ground state were
observed to be mediated by the creation and propagation of vertices that behave
like magnetic monopoles pseudo-particles. This is an important step towards a
more detailed experimental study of monopole-like excitations in artificial
spin ice systems.


title: The quark masses and meson spectrum: A holographic approach

abstract:
  The spectrum of radially excited unflavored vector mesons is relatively well
measured, especially in the heavy-quark sector. This provides a unique
opportunity to observe the behavior of the hadron spectrum at fixed quantum
numbers as a function of the quark mass. The experimental data suggests the
approximately Regge form for the radial spectrum, M_n^2=An+B, where A and B are
growing functions of the quark mass. We use the bottom-up holographic approach
to find the functions A and B. The obtained result shows a good agreement with
the phenomenology and consistency with some predictions of the Veneziano-like
dual amplitudes.


title:
GRB 130606A as a Probe of the Intergalactic Medium and the Interstellar
  Medium in a Star-forming Galaxy in the First Gyr After the Big Bang

abstract:
  We present high signal-to-noise ratio Gemini and MMT spectroscopy of the
optical afterglow of the gamma-ray burst (GRB) 130606A at redshift z=5.913,
discovered by Swift. This is the first high-redshift GRB afterglow to have
spectra of comparable quality to those of z~6 quasars. The data exhibit a
smooth continuum at near-infrared wavelengths that is sharply cut off blueward
of 8410 Angs due to absorption from Ly-alpha at redshift z~5.91, with some flux
transmitted through the Ly-alpha forest between 7000-7800 Angs. We use column
densities inferred from metal absorption lines to constrain the metallicity of
the host galaxy between a lower limit of [Si/H]>-1.7 and an upper limit of
[S/H]<-0.5 set by the non-detection of S II absorption. We demonstrate
consistency between the dramatic evolution in the transmission fraction of
Ly-alpha seen in this spectrum over the redshift range z=4.9 to 5.85 with that
previously measured from observations of high-redshift quasars. There is an
extended redshift interval of Delta-z=0.12 in the Ly-alpha forest at z=5.77
with no detected transmission, leading to a 3-sigma upper limit on the mean
Ly-alpha transmission fraction of <0.2% (or tau_eff(Ly-alpha) > 6.4). This is
comparable to the lowest-redshift Gunn-Peterson troughs found in quasar
spectra. We set a 2-sigma upper limit of 0.11 on the neutral fraction of the
IGM at the redshift of the GRB from the lack of a Ly-alpha red damping wing,
assuming a model with a constant neutral density. Some Ly-beta and Ly-gamma
transmission is detected in this redshift window, indicating that it is not
completely opaque, and hence that the IGM is nonetheless mostly ionized at
these redshifts. GRB 130606A thus for the first time realizes the promise of
GRBs as probes of the first galaxies and cosmic reionization.


title:
On the approximation of turbulent fluid flows by the
  Navier-Stokes-$\alpha$ equations on bounded domains

abstract:
  The Navier-Stokes-$\alpha$ equations belong to the family of LES (Large Eddy
Simulation) models whose fundamental idea is to capture the influence of the
small scales on the large ones without computing all the whole range present in
the flow. The constant $\alpha$ is a regime flow parameter that has the
dimension of the smallest scale being resolvable by the model. Hence, when
$\alpha=0$, one recovers the classical Navier-Stokes equations for a flow of
viscous, incompressible, Newtonian fluids. Furthermore, the
Navier-Stokes-$\alpha$ equations can also be interpreted as a regularization of
the Navier-Stokes equations, where $\alpha$ stands for the regularization
parameter.
  In this paper we first present the Navier-Stokes-$\alpha$ equations on
bounded domains with no-slip boundary conditions by means of the Leray
regularization using the Helmholtz operator. Then we study the problem of
relating the behavior of the Galerkin approximations for the
Navier-Stokes-$\alpha$ equations to that of the solutions of the Navier-Stokes
equations on bounded domains with no-slip boundary conditions. The Galerkin
method is undertaken by using the eigenfunctions associated with the Stokes
operator. We will derive local- and global-in-time error estimates measured in
terms of the regime parameter $\alpha$ and the eigenvalues. In particular, in
order to obtain global-in-time error estimates, we will work with the concept
of stability for solutions of the Navier-Stokes equations in terms of the $L^2$
norm.


title: A Reconstruction of Quantum Mechanics

abstract:
  We formulate a general principle that supplants a Boolean \sigma-algebra of
intrinsic properties of a classical system by a \sigma-complex (a union of
\sigma-algebras) of extrinsic properties of a quantum system that are elicited
by interactions with other systems. We apply the canonical definitions of the
concepts of classical physics of observables, states, combined systems,
symmetries, and dynamics to derive the standard quantum characterizations,
including the Schr\"odinger equation and the von Neumann-L\"uder's Projection
Rule. This manifestly consistent reconstruction of quantum mechanics is then
used to discuss and resolve the dilemmas of the orthodox interpretation.


title: Measurement of the Fusion Probability, PCN, for Hot Fusion Reactions

abstract:
  Background: The cross section for forming a heavy evaporation residue in
fusion reactions depends on the capture cross section, the fusion probability,
PCN, i.e., the probability that the projectile-target system will evolve inside
the fission saddle point to form a completely fused system rather than
re-separating (quasifission), and the survival of the completely fused system
against fission. PCN is the least known of these quantities. Purpose: To
measure PCN for the reaction of 101.2 MeV 18O, 147.3 MeV 26Mg, 170.9 MeV 30Si
and 195.3 MeV 36S with 197Au. Methods: We measured the fission fragment angular
distributions for these reactions and used the formalism of Back to deduce the
fusion-fission and quasifission cross sections. From these quantities we
deduced PCN for each reaction. Results: The values of PCN for the reaction of
101.2 MeV 18O, 147.3 MeV 26Mg, 170.9 MeV 30Si and 195.3 MeV 36S with 197Au are
0.66, 1.00, 0.06, 0.13, respectively. Conclusions: The new measured values of
PCN agree roughly with the semi-empirical system- atic dependence of PCN upon
fissility for excited nuclei.


title: The Appliance Pervasive of Internet of Things in Healthcare Systems

abstract:
  In fact, information systems are the foundation of new productivity sources,
medical organizational forms, and erection of a global economy. IoT based
healthcare systems play a significant role in ICT and have contribution in
growth of medical information systems, which are underpinning of recent medical
and economic development strategies. However, to take advantages of IoT, it is
essential that medical enterprises and community should trust the IoT systems
in terms of performance, security, privacy, reliability and
return-on-investment, which are open challenges of current IoT systems. For
heightening of healthcare system; tracking, tracing and monitoring of patients
and medical objects are more essential. But due to the inadequate healthcare
situation, medical environment, medical technologies and the unique
requirements of some healthcare applications, the obtainable tools cannot meet
them accurately. The tracking, tracing and monitoring of patients and
healthcare actors activities in healthcare system are challenging research
directions for IoT researchers. State-of-the-art IoT based healthcare system
should be developed which ensure the safety of patients and other healthcare
activities. With this manuscript, we elaborate the essential role of IoT in
healthcare systems; immense prospects of Internet of things in healthcare
systems; extensive aspect of the use of IoT is dissimilar among different
healthcare components and finally the participation of IoT between the useful
research and present realistic applications. IoT and few other modern
technologies are still in underpinning stage; mainly in the healthcare system.


title: Subgroups of direct products closely approximated by direct sums

abstract:
  Let $I$ be an infinite set, $\{G_i:i\in I\}$ be a family of (topological)
groups and $G=\prod_{i\in I} G_i$ be its direct product. For $J\subseteq I$,
$p_{J}: G\to \prod_{j\in J} G_j$ denotes the projection. We say that a subgroup
$H$ of $G$ is: (i) \emph{uniformly controllable} in $G$ provided that for every
finite set $J\subseteq I$ there exists a finite set $K\subseteq I$ such that
$p_{J}(H)=p_{J}(H\cap\bigoplus_{i\in K} G_i)$; (ii) \emph{controllable} in $G$
provided that $p_{J}(H)=p_{J}(H\cap\bigoplus_{i\in I} G_i)$ for every finite
set $J\subseteq I$; (iii) \emph{weakly controllable} in $G$ if $H\cap
\bigoplus_{i\in I} G_i$ is dense in $H$, when $G$ is equipped with the
Tychonoff product topology. One easily proves that (i)$\to$(ii)$\to$(iii). We
thoroughly investigate the question as to when these two arrows can be
reversed. We prove that the first arrow can be reversed when $H$ is compact,
but the second arrow cannot be reversed even when $H$ is compact. Both arrows
can be reversed if all groups $G_i$ are finite. When $G_i=A$ for all $i\in I$,
where $A$ is an abelian group, we show that the first arrow can be reversed for
{\em all} subgroups $H$ of $G$ if and only if $A$ is finitely generated.
Connections with coding theory are highlighted.


title:
The Number of Terms and Documents for Pseudo-Relevant Feedback for
  Ad-hoc Information Retrieval

abstract:
  In Information Retrieval System (IRS), the Automatic Relevance Feedback (ARF)
is a query reformulation technique that modifies the initial one without the
user intervention. It is applied mainly through the addition of terms coming
from the external resources such as the ontologies and or the results of the
current research. In this context we are mainly interested in the local
analysis technique for the ARF in ad-hoc IRS on Arabic documents. In this
article, we have examined the impact of the variation of the two parameters
implied in this technique, that is to say, the number of the documents
{\guillemotleft}D{\guillemotright} and the number of terms
{\guillemotleft}T{\guillemotright}, on an Arabic IRS performance. The
experimentation, carried out on an Arabic corpus text, enables us to deduce
that there are queries which are not easily improvable with the query
reformulation. In addition, the success of the ARF is due mainly to the
selection of a sufficient number of documents D and to the extraction of a very
reduced set of relevant terms T for retrieval.


title: Grey Brownian motion local time: Existence and weak-approximation

abstract:
  In this paper we investigate the class of grey Brownian motions
$B_{\alpha,\beta}$ ($0<\alpha<2$, $0<\beta\leq1$). We show that grey Brownian
motion admits different representations in terms of certain known processes,
such as fractional Brownian motion, multivariate elliptical distribution or as
a subordination. The weak convergence of the increments of $B_{\alpha,\beta}$
in $t$, $w$-variables are studied. Using the Berman criterium we show that
$B_{\alpha,\beta}$ admits a $\lambda$-square integrable local time
$L^{B_{\alpha,\beta}}(\cdot,I)$ almost surely ($\lambda$ Lebesgue measure).
Moreover, we prove that this local time can be weak-approximated by the number
of crossings $C^{B_{\alpha,\beta}^{\varepsilon}}(x,I)$, of level $x$, of the
convolution approximation $B_{\alpha,\beta}^{\varepsilon}$ of grey Brownian
motion.


title:
Homological Projective Duality via Variation of Geometric Invariant
  Theory Quotients

abstract:
  We provide a geometric approach to constructing Lefschetz collections and
Landau-Ginzburg Homological Projective Duals from a variation of Geometric
Invariant Theory quotients. This approach yields homological projective duals
for Veronese embeddings in the setting of Landau Ginzburg models. Our results
also extend to a relative Homological Projective Duality framework.


title: High resolution near-infrared imaging of submillimeter galaxies

abstract:
  We present F110W (~J) and F160W (~H) observations of ten submillimeter
galaxies (SMGs) obtained with the Hubble Space Telescope's (HST's) NICMOS
camera. Our targets have optical redshifts in the range 2.20<z<2.81 confirmed
by millimeter CO or mid-IR spectroscopy, guaranteeing that the two bands sample
the rest-frame optical with the Balmer break falling between them. Eight of ten
are detected in both bands, while two are detected in F160W only. We study
their F160W morphologies, applying a maximum-deblending detection algorithm to
distinguish multiple- from single-component configurations, leading to
reassessments for several objects. Based on our NICMOS imaging and/or previous
dynamical evidence we identify five SMGs as multiple sources, which we
interpret as merging systems. Additionally, we calculate morphological
parameters asymmetry (A) and Gini coefficient (G); thanks to our sample's
limited redshift range we recover the trend that multiple-component,
merger-like morphologies are reflected in higher asymmetries. We analyze the
stellar populations of nine objects with F110W/F160W photometry, using archival
HST optical data when available. For multiple systems, we are able to model the
individual components that build up an SMG. With the available data we cannot
discriminate among star formation histories, but we constrain stellar masses
and mass ratios for merger-like SMG systems, obtaining a mean
log(M_*/M_sun)=10.9+/-0.2 for our full sample, with individual values
log(M_*/M_sun)~9.6-11.8. The morphologies and mass ratios of the least and most
massive systems match the predictions of the major-merger and cold accretion
SMG formation scenarios, respectively, suggesting that both channels may have a
role in the population's origin.


title:
A New Approach for Quality Management in Pervasive Computing
  Environments

abstract:
  This paper provides an extension of MDA called Context-aware Quality Model
Driven Architecture (CQ-MDA) which can be used for quality control in pervasive
computing environments. The proposed CQ-MDA approach based on
ContextualArchRQMM (Contextual ARCHitecture Quality Requirement MetaModel),
being an extension to the MDA, allows for considering quality and
resources-awareness while conducting the design process. The contributions of
this paper are a meta-model for architecture quality control of context-aware
applications and a model driven approach to separate architecture concerns from
context and quality concerns and to configure reconfigurable software
architectures of distributed systems. To demonstrate the utility of our
approach, we use a videoconference system.


title: An r-Process Kilonova Associated with the Short-Hard GRB 130603B

abstract:
  We present ground-based optical and Hubble Space Telescope optical and
near-IR observations of the short-hard GRB130603B at z=0.356, which demonstrate
the presence of excess near-IR emission matching the expected brightness and
color of an r-process powered transient (a "kilonova"). The early afterglow
fades rapidly with alpha<-2.6 at t~8-32 hr post-burst and has a spectral index
of beta=-1.5 (F_nu t^alpha*nu^beta), leading to an expected near-IR brightness
at the time of the first HST observation of m(F160W)>29.3 AB mag. Instead, the
detected source has m(F160W)=25.8+/-0.2 AB mag, corresponding to a rest-frame
absolute magnitude of M(J)=-15.2 mag. The upper limit in the HST optical
observations is m(F606W)>27.7 AB mag (3-sigma), indicating an unusually red
color of V-H>1.9 mag. Comparing the observed near-IR luminosity to theoretical
models of kilonovae produced by ejecta from the merger of an NS-NS or NS-BH
binary, we infer an ejecta mass of M_ej~0.03-0.08 Msun for v_ej=0.1-0.3c. The
inferred mass matches the expectations from numerical merger simulations. The
presence of a kilonova provides the strongest evidence to date that short GRBs
are produced by compact object mergers, and provides initial insight on the
ejected mass and the primary role that compact object merger may play in the
r-process. Equally important, it demonstrates that gravitational wave sources
detected by Advanced LIGO/Virgo will be accompanied by optical/near-IR
counterparts with unusually red colors, detectable by existing and upcoming
large wide-field facilities (e.g., Pan-STARRS, DECam, Subaru, LSST).


title:
Transition from one-dimensional antiferromagnetism to three-dimensional
  antiferromagnetic order in single-crystalline CuSb$_{2}$O$_{6}$

abstract:
  Measurements of magnetic susceptibility, heat capacity and thermal expansion
are reported for single crystalline CuSb$_{2}$O$_{6}$ in the temperature range
$5<T<350$ K. The magnetic susceptibility exhibits a broad peak centered near 60
K that is typical of one-dimensional antiferromagnetic compounds. Long-range
antiferromagnetic order at $T_N$ = 8.7 K is accompanied by an energy gap
($\Delta$ = 17.48(6) K). This transition represents a crossover from one- to
three-dimensional antiferromagnetic behavior. Both heat capacity and the
thermal expansion coefficients exhibit distinct jumps at $T_N$, which are
similar to those observed at the normal-superconducting phase transition in a
superconductor. This behavior is quite unusual, and is presumably associated
with a Spin-Peierls transition occurring as a result of three-dimensional
phonons coupling with {\it Jordan-Wigner-transformed} Fermions.


title: One flavor mass reweighting in lattice QCD

abstract:
  One flavor mass reweighting can be used in lattice QCD computations to fine
tune the quark masses to their physical values. We present a new method that
utilizes an unbiased stochastic estimation of the one flavor determinant. The
stochastic estimation is based on the integral representation of the
determinant of a complex matrix, which we prove. In contrast to other methods
it can also be applied in situations where the determinant has a complex phase.
The stochastic error is controlled by determinant factorizations based on mass
interpolation and Schur decomposition. As an example of an application we
demonstrate how the method can be used to tune the up-down quark mass
difference.


title:
High-Accuracy Quartic Force Field Calculations for the Spectroscopic
  Constants and Vibrational Frequencies of 1 ^1A' l-C3H-: A Possible Link to
  Lines Observed in the Horsehead Nebula PDR

abstract:
  It has been shown that rotational lines observed in the Horsehead nebula PDR
are probably not caused by l-C3H+, as was originally suggested. In the search
for viable alternative candidate carriers, quartic force fields are employed
here to provide highly accurate rotational constants, as well as fundamental
vibrational frequencies, for another candidate carrier: 1 ^1A' C3H-. The ab
initio computed spectroscopic constants provided in this work are, compared to
those necessary to define the observed lines, as accurate as the computed
spectroscopic constants for many of the known interstellar anions.
Additionally, the computed Deff for C3H- is three times closer to the D deduced
from the observed Horsehead nebula lines relative to l-C3H+. As a result, 1
^1A' C3H- is a more viable candidate for these observed rotational transitions.
It has been previously proposed that at least C6H- may be present in the
Horsehead nebular PDR formed by way of radiative attachment through its
dipole-bound excited state. C3H- could form in a similar way through its
dipole-bound state, but its valence excited state increases the number of
relaxation pathways possible to reach the ground electronic state. In turn, the
rate of formation for C3H- could be greater than the rate of its destruction.
C3H- would be the seventh confirmed interstellar anion detected within the past
decade and the first CnH- molecular anion with an odd n.


title: Constructing nearly Frobenius algebras

abstract:
  In the first part we study nearly Frobenius algebras. The concept of nearly
Frobenius algebras is a generalization of the concept of Frobenius algebras.
Nearly Frobenius algebras do not have traces, nor they are self-dual. We prove
that the known constructions: direct sums, tensor, quotient of nearly Frobenius
algebras admit natural nearly Frobenius structures.
  In the second part we study algebras associated to some families of quivers
and the nearly Frobenius structures that they admit. As a main theorem, we
prove that an indecomposable algebra associated to a bound quiver $(Q,I)$ with
no monomial relations admits a non trivial nearly Frobenius structure if and
only if the quiver is $\overrightarrow{\mb{A}_n}$ and I=0. We also present an
algorithm that determines the number of independent nearly Frobenius structures
for Gentle algebras without oriented cycles.


title:
On the theorem of the primitive element with applications to the
  representation theory of associative and Lie algebras

abstract:
  We describe of all finite dimensional uniserial representations of a
commutative associative (resp. abelian Lie) algebra over a perfect (resp.
sufficiently large perfect) field. In the Lie case the size of the field
depends on the answer to following question, considered and solved in this
paper. Let $K/F$ be a finite separable field extension and let $x,y\in K$. When
is $F[x,y]=F[\alpha x+\beta y]$ for some non-zero elements $\alpha,\beta\in F$?


title:
Self-interaction in the Bopp-Podolsky electrodynamics: Can the
  observable mass of a charged particle depend on its acceleration?

abstract:
  In this paper we obtain the expression for the self-force in the model with
the Lagrangian containing additional terms, quadratic in Maxwell tensor
derivatives (so-called Bopp-Podolsky electrodynamics). Features of this force
are analyzed for various limiting cases. When a charged particle moves along
straight line with a uniform acceleration, an explicit formula is found. In the
framework of the considered model, an observable renormalized particle mass is
shown to depend on its acceleration. This dependence allows, in principle, to
extract experimentally a value of the particle bare mass.


title: Generalized Artin-Schreier polynomials

abstract:
  Let $F$ be a field of prime characteristic $p$ containing $F_{p^n}$ as a
subfield. We refer to $q(X)=X^{p^n}-X-a\in F[X]$ as a generalized
Artin-Schreier polynomial. Suppose that $q(X)$ is irreducible and let
$C_{q(X)}$ be the companion matrix of $q(X)$. Then $ad\, C_{q(X)}$ has such
highly unusual properties that any $A\in{\mathfrak{ gl}}(m)$ such that $ad\, A$
has like properties is shown to be similar to the companion matrix of an
irreducible generalized Artin-Schreier polynomial.
  We discuss close connections with the decomposition problem of the tensor
product of indecomposable modules for a 1-dimensional Lie algebra over a field
of characteristic $p$, the problem of finding an explicit primitive element for
every intermediate field of the Galois extension associated to an irreducible
generalized Artin-Schreier polynomial, and the problem of finding necessary and
sufficient conditions for the irreducibility of a family of polynomials.


title:
Resonant interaction between an ultrashort pulse train and a two-level
  system: frequency domain analysis

abstract:
  We investigate the problem of two-level atoms driven by an ultrashort pulse
train in the frequency domain. At low intensity regime, we obtain a
perturbative analytical solution that allows us to discuss the role of the mode
number of the frequency comb near or at resonance on the temporal evolution of
the atomic coherence. At high intensities, the effect of the number of modes is
analyzed in the steady-state regime through numerical calculations.


title:
Interlacing Families II: Mixed Characteristic Polynomials and the
  Kadison-Singer Problem

abstract:
  We use the method of interlacing families of polynomials introduced to prove
two theorems known to imply a positive solution to the Kadison--Singer problem.
  The first is Weaver's conjecture $KS_{2}$ \cite{weaver}, which is known to
imply Kadison--Singer via a projection paving conjecture of Akemann and
Anderson. The second is a formulation due to Casazza, et al., of Anderson's
original paving conjecture(s), for which we are able to compute explicit paving
bounds.
  The proof involves an analysis of the largest roots of a family of
polynomials that we call the "mixed characteristic polynomials" of a collection
of matrices.


title:
Testing statistical significance of large quasar groups with sheets
  model of large scale structure

abstract:
  We argue that the largest group of quasars (LQG) U1.27 discovered by Clowes
et al. (2013) in the SDSS DR7 catalogue does not contradict the hypothesis of
Poisson distribution of quasars. We found that random catalogues with the same
shape and number of QSOs as the real sample may contain groups which resemble
U1.27. By simulating quasar catalogues with embedded model of the large scale
structure we also found that the size of LQGs selected by MST and similar
methods does not correspond to the scale of homogeneity of the Universe and can
be explained by the percolation process.


title: The pionic Drell-Yan process: a brief survey

abstract:
  The Drell-Yan process is an invaluable tool for probing the structure of
hadrons, and the pion-induced Drell-Yan process is unique in its sensitivity to
several subtleties of the partonic structure. This is a brief review of the
pionic Drell-Yan process with particular emphasis on the dilepton angular
distributions and nuclear modification of the parton distributions (the EMC
effect).


title:
A High-Resolution Study of the CO-H2 Conversion Factor in the Diffuse
  Cloud MBM 40

abstract:
  We made CO(1-0) observations of 103 lines of sight in the core and envelope
of the high-latitude cloud MBM 40 to determine how the CO-H_2 conversion factor
(X_CO) varies throughout the cloud. Calibrating X_CO with CH data at similar
resolution (1' for CO, 1.5' for CH) yields values of X_CO ranging from 0.6
10^20 to 3.3 10^20 cm^-2 [K km s^-1]^-1 with an average of 1.3 10^20 cm^-2 [K
km s^-1]^-1. Given that the cloud has a peak reddening of 0.24 mag, it should
be classed as a diffuse rather than a translucent molecular cloud. The mass
obtained from the CO data and our values of X_CO is 9.6 M(solar) for the core,
12 M(solar) for the envelope, and 10 M(solar) for the periphery of the cloud. A
third of the molecular mass of the cloud is found in a region with E(B-V) <
0.12 mag. With these mass estimates, we determine that the cloud is not
gravitationally bound.


title:
Chaotic dust dynamics and implications for the hemispherical color
  asymmetries of the Uranian satellites

abstract:
  Dust grains generated by the Uranian irregular satellites will undergo
chaotic large-amplitude eccentricity oscillations under the simultaneous action
of radiation forces and the highly misaligned quadrupole potentials of the
oblate planet and distant Sun. From a suite of orbital histories, we estimate
collision proba- bilities of dust particles with the regular satellites and
argue that this process may explain the observed hemispherical color
asymmetries of the outermost four regular satellites of Uranus.


title: Dispersed Indeterminacy

abstract:
  A state of a single particle can be represented by a quantum blob in the
corresponding phase space, or by a cell in its 2-D subspace. Its area is
frequently stated to be no less than one half of the Plank constant, implying
that such a cell is an indivisible quantum of the 2-D phase space. But this is
generally not true, as is evident, for instance, from representation of some
states in the basis of innately discrete observables like angular momentum.
Here we consider some dispersed states involving the evanescent waves (EW)
different from that in the total internal reflection. Such states are
represented by a set of separated point-like cells, but with a large total
indeterminacy. An idealized model has a discrete Wigner function forming an
infinite periodic array of dots on the phase plane. The question about the
total momentum indeterminacy in such state is discussed. We argue that the
transverse momentum eigenstates corresponding to the considered EW-s cannot be
singled out by any known measurement procedure, and the whole infinite set of
the corresponding eigenvalues can contribute only a certain fraction to the
observed momentum indeterminacy which remains finite.


title: Lifting/lowering Hopfield models ground state energies

abstract:
  In our recent work \cite{StojnicHopBnds10} we looked at a class of random
optimization problems that arise in the forms typically known as Hopfield
models. We viewed two scenarios which we termed as the positive Hopfield form
and the negative Hopfield form. For both of these scenarios we defined the
binary optimization problems whose optimal values essentially emulate what
would typically be known as the ground state energy of these models. We then
presented a simple mechanisms that can be used to create a set of theoretical
rigorous bounds for these energies. In this paper we create a way more powerful
set of mechanisms that can substantially improve the simple bounds given in
\cite{StojnicHopBnds10}. In fact, the mechanisms we create in this paper are
the first set of results that show that convexity type of bounds can be
substantially improved in this type of combinatorial problems.


title: Lifting $\ell_q$-optimization thresholds

abstract:
  In this paper we look at a connection between the $\ell_q,0\leq q\leq 1$,
optimization and under-determined linear systems of equations with sparse
solutions. The case $q=1$, or in other words $\ell_1$ optimization and its a
connection with linear systems has been thoroughly studied in last several
decades; in fact, especially so during the last decade after the seminal works
\cite{CRT,DOnoho06CS} appeared. While current understanding of $\ell_1$
optimization-linear systems connection is fairly known, much less so is the
case with a general $\ell_q,0<q<1$, optimization. In our recent work
\cite{StojnicLqThrBnds10} we provided a study in this direction. As a result we
were able to obtain a collection of lower bounds on various $\ell_q,0\leq q\leq
1$, optimization thresholds. In this paper, we provide a substantial conceptual
improvement of the methodology presented in \cite{StojnicLqThrBnds10}.
Moreover, the practical results in terms of achievable thresholds are also
encouraging. As is usually the case with these and similar problems, the
methodology we developed emphasizes their a combinatorial nature and attempts
to somehow handle it. Although our results' main contributions should be on a
conceptual level, they already give a very strong suggestion that $\ell_q$
optimization can in fact provide a better performance than $\ell_1$, a fact
long believed to be true due to a tighter optimization relaxation it provides
to the original $\ell_0$ sparsity finding oriented original problem
formulation. As such, they in a way give a solid boost to further exploration
of the design of the algorithms that would be able to handle $\ell_q,0<q<1$,
optimization in a reasonable (if not polynomial) time.


title: Compressed sensing of block-sparse positive vectors

abstract:
  In this paper we revisit one of the classical problems of compressed sensing.
Namely, we consider linear under-determined systems with sparse solutions. A
substantial success in mathematical characterization of an $\ell_1$
optimization technique typically used for solving such systems has been
achieved during the last decade. Seminal works \cite{CRT,DOnoho06CS} showed
that the $\ell_1$ can recover a so-called linear sparsity (i.e. solve systems
even when the solution has a sparsity linearly proportional to the length of
the unknown vector). Later considerations \cite{DonohoPol,DonohoUnsigned} (as
well as our own ones \cite{StojnicCSetam09,StojnicUpper10}) provided the
precise characterization of this linearity. In this paper we consider the
so-called structured version of the above sparsity driven problem. Namely, we
view a special case of sparse solutions, the so-called block-sparse solutions.
Typically one employs $\ell_2/\ell_1$-optimization as a variant of the standard
$\ell_1$ to handle block-sparse case of sparse solution systems. We considered
systems with block-sparse solutions in a series of work
\cite{StojnicCSetamBlock09,StojnicUpperBlock10,StojnicICASSP09block,StojnicJSTSP09}
where we were able to provide precise performance characterizations if the
$\ell_2/\ell_1$-optimization similar to those obtained for the standard
$\ell_1$ optimization in \cite{StojnicCSetam09,StojnicUpper10}. Here we look at
a similar class of systems where on top of being block-sparse the unknown
vectors are also known to have components of the same sign. In this paper we
slightly adjust $\ell_2/\ell_1$-optimization to account for the known signs and
provide a precise performance characterization of such an adjustment.


title: Asymmetric Little model and its ground state energies

abstract:
  In this paper we look at a class of random optimization problems that arise
in the forms typically known in statistical physics as Little models. In
\cite{BruParRit92} the Little models were studied by means of the well known
tool from the statistical physics called the replica theory. A careful
consideration produced a physically sound conclusion that the behavior of
almost all important features of the Little models essentially resembles the
behavior of the corresponding ones of appropriately scaled
Sherrington-Kirkpatrick (SK) model. In this paper we revisit the Little models
and consider their ground state energies as one of their main features. We then
rigorously show that they indeed can be lower-bounded by the corresponding ones
related to the SK model. We also provide a mathematically rigorous way to show
that the replica symmetric estimate of the ground state energy is in fact a
rigorous upper-bound of the ground state energy. Moreover, we then recall on a
set of powerful mechanisms we recently designed for a study of the Hopfield
models in \cite{StojnicHopBnds10,StojnicMoreSophHopBnds10} and show how one can
utilize them to substantially lower the upper-bound that the replica symmetry
theory provides.


title: Another look at the Gardner problem

abstract:
  In this paper we revisit one of the classical perceptron problems from the
neural networks and statistical physics. In \cite{Gar88} Gardner presented a
neat statistical physics type of approach for analyzing what is now typically
referred to as the Gardner problem. The problem amounts to discovering a
statistical behavior of a spherical perceptron. Among various quantities
\cite{Gar88} determined the so-called storage capacity of the corresponding
neural network and analyzed its deviations as various perceptron parameters
change. In a more recent work \cite{SchTir02,SchTir03} many of the findings of
\cite{Gar88} (obtained on the grounds of the statistical mechanics replica
approach) were proven to be mathematically correct. In this paper, we take
another look at the Gardner problem and provide a simple alternative framework
for its analysis. As a result we reprove many of now known facts and rigorously
reestablish a few other results.


title: Negative spherical perceptron

abstract:
  In this paper we consider the classical spherical perceptron problem. This
problem and its variants have been studied in a great detail in a broad
literature ranging from statistical physics and neural networks to computer
science and pure geometry. Among the most well known results are those created
using the machinery of statistical physics in \cite{Gar88}. They typically
relate to various features ranging from the storage capacity to typical overlap
of the optimal configurations and the number of incorrectly stored patterns. In
\cite{SchTir02,SchTir03,TalBook} many of the predictions of the statistical
mechanics were rigorously shown to be correct. In our own work
\cite{StojnicGardGen13} we then presented an alternative way that can be used
to study the spherical perceptrons as well. Among other things we reaffirmed
many of the results obtained in \cite{SchTir02,SchTir03,TalBook} and thereby
confirmed many of the predictions established by the statistical mechanics.
Those mostly relate to spherical perceptrons with positive thresholds (which we
will typically refer to as the positive spherical perceptrons). In this paper
we go a step further and attack the negative counterpart, i.e. the perceptron
with negative thresholds. We present a mechanism that can be used to analyze
many features of such a model. As a concrete example, we specialize our results
for a particular feature, namely the storage capacity. The results we obtain
for the storage capacity seem to indicate that the negative case could be more
combinatorial in nature and as such a somewhat harder challenge than the
positive counterpart.


title: High-J CO survey of low-mass protostars observed with Herschel-HIFI

abstract:
  The evolution of deeply embedded young stellar objects (YSOs) has
traditionally been traced through dust continuum spectral energy distributions
(SEDs), but the use of CO excitation as an evolutionary probe has not yet been
explored due to lack of high-J CO observations. The aim is to constrain the
physical characteristics (excitation, kinematics, column density) of the warm
gas toward 26 low-mass Class 0 and I YSOs using spectrally-resolved Herschel
Space Observatory data of high-J lines of CO. Data are complemented by
ground-based observations from APEX and the JCMT to compare those with the
colder gas traced by lower-J CO lines. This is the first large spectrally
resolved high-J CO survey conducted for these types of sources. The median
excitation temperatures for 12CO, 13CO and C18O derived from single-temperature
fits to the J_u=2-10 integrated intensities are ~70K, 48K and 37K,
respectively, with no significant difference between Class 0 and I sources and
no trend with M_env or L_bol. Thus, in contrast with the continuum SEDs, the
spectral line energy distributions (SLEDs) do not show an evolution during the
embedded stage. In contrast, the integrated line intensities of all CO
isotopologs show a clear decrease with evolutionary stage as the envelope is
dispersed. The H2O 110-101/CO 10-9 intensity ratio does not change
significantly with velocity, in contrast with the H2O/CO 3-2 ratio, indicating
that CO 10-9 is the lowest transition for which the line wings probe the same
warm shocked gas as H2O. Modeling of the full suite of C18O lines indicates an
abundance profile for Class 0 sources that is consistent with a freeze-out zone
below 25 K and evaporation at higher temperatures, with but some fraction of
the CO transformed into other species in the cold phase. In contrast,
observations for two Class I sources in Ophiuchus are consistent with a
constant high CO abundance profile.


title: Black branes in flux compactifications

abstract:
  We construct charged black branes in type IIA flux compactifications that are
dual to (2+1)-dimensional field theories at finite density. The internal space
is a general Calabi-Yau manifold with fluxes, with internal dimensions much
smaller than the AdS radius. Gauge fields descend from the 3-form RR potential
evaluated on harmonic forms of the Calabi-Yau, and Kaluza-Klein modes decouple.
Black branes are described by a four-dimensional effective field theory that
includes only a few light fields and is valid over a parametrically large range
of scales. This effective theory determines the low energy dynamics, stability
and thermodynamic properties. Tools from flux compactifications are also used
to construct holographic CFTs with no relevant scalar operators, that can lead
to symmetric phases of condensed matter systems stable to very low
temperatures. The general formalism is illustrated with simple examples such as
toroidal compactifications and manifolds with a single size modulus. We
initiate the classification of holographic phases of matter described by flux
compactifications, which include generalized Reissner-Nordstrom branes,
nonsupersymmetric $AdS_2 \times R^2$ and hyperscaling violating solutions.


title: New limits on dark matter annihilation from AMS cosmic ray positron data

abstract:
  The AMS experiment onboard the International Space Station has recently
provided cosmic ray electron and positron data with unprecedented precision in
the range from 0.5 to 350 GeV. The observed rise in the positron fraction at
energies above 10 GeV remains unexplained, with proposed solutions ranging from
local pulsars to TeV-scale dark matter. Here, we make use of this high quality
data to place stringent limits on dark matter with masses below ~300 GeV,
annihilating or decaying to leptonic final states, essentially independent of
the origin of this rise. We significantly improve on existing constraints, in
some cases by up to two orders of magnitude.


title: Inverse neutrino mass hierarchy in a flavour GUT model

abstract:
  We construct a supersymmetric SU(5) x A_4 flavour GUT model in which an
inverse neutrino mass hierarchy is realised without fine-tuning of parameters.
The model shares some properties with the normal hierarchy model which we
presented in arXiv:1305.6612 - in particular the relation theta_13^PMNS =
theta_C / sqrt(2). Besides these shared features, there are also important
differences, mainly due to the different neutrino sector. These differences not
only change the predictions in the lepton sector, but also in the quark sector,
and will allow to discriminate between the two models using the results of
present and future experiments. From a Markov Chain Monte Carlo fit we find
that the inverse hierarchy model is in excellent agreement with the present
experimental data.


title:
Anisotropic imprint of long-wavelength tensor perturbations on cosmic
  structure

abstract:
  Inflationary models predict a correlation between primordial density
perturbations (scalar metric perturbations) and gravitational waves (tensor
metric perturbations) in the form of a scalar-scalar-tensor three-point
correlation, or bispectrum in Fourier space. The squeezed limit of this
bispectrum implies a quadrupolar asymmetry in the observed local power spectrum
for matter and galaxies. Here we show (like others before) that an infrared
divergence in the amplitude of this power asymmetry predicted in single-field
slow-roll models is canceled by projection effects when considering the
observed power spectrum. We then further evaluate the nonzero, but finite,
residual quadrupolar power asymmetry that remains after the divergences are
canceled. While the quadrupolar power asymmetry is small, it is conceptually
important. Our calculation moreover clarifies how the predictions for this
power asymmetry may change in models with different scalar-scalar-tensor
bispectra, and shows that convincing detection of the quadrupolar power
asymmetry would rule out the single-field slow-roll models of inflation.


title:
Implications of Rapid Core Rotation in Red Giants for Internal Angular
  Momentum Transport in Stars

abstract:
  Core rotation rates have been measured for red giant stars using
asteroseismology. This data, along with helioseismic measurements and open
cluster spin down studies, provide powerful clues about the nature and
timescale for internal angular momentum transport in stars. We focus on two
cases: the metal poor red giant KIC 7341231 ("Otto") and intermediate mass core
helium burning stars. For both we examine limiting case studies for angular
momentum coupling between cores and envelopes under the assumption of rigid
rotation on the main sequence. We discuss the expected pattern of core rotation
as a function of mass and radius. In the case of Otto, strong
post-main-sequence coupling is ruled out and the measured core rotation rate is
in the range of 23 to 33 times the surface value expected from standard spin
down models. The minimum coupling time scale (.17 to .45 Gyr) is significantly
longer than that inferred for young open cluster stars. This implies
ineffective internal angular momentum transport in early first ascent giants.
By contrast, the core rotation rates of evolved secondary clump stars are found
to be consistent with strong coupling given their rapid main sequence rotation.
An extrapolation to the white dwarf regime predicts rotation periods between
330 and .0052 days depending on mass and decoupling time. We identify two key
ingredients that explain these features: the presence of a convective core and
inefficient angular momentum transport in the presence of larger mean molecular
weight gradients. Observational tests that can disentangle these effects are
discussed.


title:
Chiral Four-Dimensional F-Theory Compactifications With SU(5) and
  Multiple U(1)-Factors

abstract:
  We develop geometric techniques to determine the spectrum and the chiral
indices of matter multiplets for four-dimensional F-theory compactifications on
elliptic Calabi-Yau fourfolds with rank two Mordell-Weil group. The general
elliptic fiber is the Calabi-Yau onefold in dP_2. We classify its resolved
elliptic fibrations over a general base B. The study of singularities of these
fibrations leads to explicit matter representations, that we determine both for
U(1)xU(1) and SU(5)xU(1)xU(1) constructions. We determine for the first time
certain matter curves and surfaces using techniques involving prime ideals. The
vertical cohomology ring of these fourfolds is calculated for both cases and
general formulas for the Euler numbers are derived. Explicit calculations are
presented for a specific base B=P^3. We determine the general G_4-flux that
belongs to H^{(2,2)}_V of the resolved Calabi-Yau fourfolds. As a by-product,
we derive for the first time all conditions on G_4-flux in general F-theory
compactifications with a non-holomorphic zero section. These conditions have to
be formulated after a circle reduction in terms of Chern-Simons terms on the 3D
Coulomb branch and invoke M-theory/F-theory duality. New Chern-Simons terms are
generated by Kaluza-Klein states of the circle compactification. We explicitly
perform the relevant field theory computations, that yield non-vanishing
results precisely for fourfolds with a non-holomorphic zero section. Taking
into account the new Chern-Simons terms, all 4D matter chiralities are
determined via 3D M-theory/F-theory duality. We independently check these
chiralities using the subset of matter surfaces we determined. The presented
techniques are general and do not rely on toric data.


title:
Determination of the neutrino mass ordering by combining PINGU and Daya
  Bay II

abstract:
  The relatively large measured value of theta_13 has opened various
possiblities to determine the neutrino mass ordering, among them using PINGU,
the low-energy extention of the IceCube neutrino telescope, to observe matter
effects in atmospheric neutrinos, or a high statistics measurment of the
neutrino energy spectrum at a reactor neutrino experiment with a baseline of
around 60 km, such as the Daya Bay II project. In this work we point out a
synergy between these two approaches based on the fact that when data are
analysed with the wrong neutrino mass ordering the best fit occurs at different
values of |Delta m^2_31| for PINGU and Daya Bay II. Hence, the wrong mass
ordering can be excluded by a mismatch of the values inferred for |Delta
m^2_31|, thanks to the excellent accuracy for Delta m^2_31 of both experiments.
We perform numerical studies of PINGU and Daya Bay II sensitivities and show
that the synergy effect may lead to a high significance determination of the
mass ordering even in situations where the individual experiments obtain only
poor sensitivity.


title: On the universality of supersonic turbulence

abstract:
  Compressible turbulence shapes the structure of the interstellar medium of
our Galaxy and likely plays an important role also during structure formation
in the early Universe. The density PDF and the power spectrum of such
compressible, supersonic turbulence are the key ingredients for theories of
star formation. However, both the PDF and the spectrum are still a matter of
debate, because theoretical predictions are limited and simulations of
supersonic turbulence require enormous resolutions to capture the
inertial-range scaling. To advance our limited knowledge of compressible
turbulence, we here present and analyse the world's largest simulations of
supersonic turbulence. We compare hydrodynamic models with numerical
resolutions of 256^3-4096^3 mesh points and with two distinct driving
mechanisms, solenoidal (divergence-free) driving and compressive (curl-free)
driving. We find convergence of the density PDF, with compressive driving
exhibiting a much wider and more intermittent density distribution than
solenoidal driving. Analysing the power spectrum of the turbulence, we find a
pure velocity scaling close to Burgers turbulence with P(v) k^(-2) for both
driving modes in our hydrodynamical simulations with Mach = 17. The spectrum of
the density-weighted velocity rho^(1/3)v, however, does not provide the
previously suggested universal scaling for supersonic turbulence. We find that
the power spectrum P(rho^(1/3)v) scales with wavenumber as k^(-1.74) for
solenoidal driving, close to incompressible Kolmogorov turbulence, k^(-5/3),
but is significantly steeper with k^(-2.10) for compressive driving. We show
that this is consistent with a recent theoretical model for compressible
turbulence that predicts P(rho^(1/3)v) k^(-19/9) in the presence of a strong
div(v) component as is produced by compressive driving and remains remarkably
constant throughout the supersonic turbulent cascade.


title:
Stellar mass-gap as a probe of halo assembly history and concentration:
  youth hidden among old fossils

abstract:
  We investigate the use of the halo mass-gap statistic --- defined as the
logarithmic difference in mass between the host halo and its most massive
satellite subhalo --- as a probe of halo age and concentration. A cosmological
N-body simulation is used to study N ~25, 000 group/cluster sized halos in the
mass range 10^12.5 < M_halo/M_sol < 10^14.5. In agreement with previous work,
we find that halo mass-gap is related to halo formation time and concentration.
On average, older and more highly concentrated halos have larger halo
mass-gaps, and this trend is stronger than the mass-concentration relation over
a similar dynamic range. However, there is a large amount of scatter owing to
the transitory nature of the satellite subhalo population, which limits the use
of the halo mass-gap statistic on an object-by-object basis. For example, we
find that 20% of very large halo mass-gap systems (akin to "fossil groups") are
young, and have likely experienced a recent merger between a massive satellite
subhalo and the central subhalo. We relate halo mass-gap to the observable
stellar mass-gap via abundance matching. Using a galaxy group catalog
constructed from the Sloan Digital Sky Survey Data Release 7, we find that the
star formation and structural properties of galaxies at fixed mass show no
trend with stellar mass-gap. This is despite a variation in halo-age of ~2.5
Gyr over ~1.2 dex in stellar mass-gap. Thus, we find no evidence to suggest
that the halo formation history significantly affects galaxy properties.


title: Efficient Quantum Circuits for Diagonal Unitaries Without Ancillas

abstract:
  The accurate evaluation of diagonal unitary operators is often the most
resource-intensive element of quantum algorithms such as real-space quantum
simulation and Grover search. Efficient circuits have been demonstrated in some
cases but generally require ancilla registers, which can dominate the qubit
resources. In this paper, we point out a correspondence between Walsh functions
and a basis for diagonal operators that gives a simple way to construct
efficient circuits for diagonal unitaries without ancillas. This correspondence
reduces the problem of constructing the minimal-depth circuit within a given
error tolerance, for an arbitrary diagonal unitary $e^{if(\hat{x})}$ in the
$|x>$ basis, to that of finding the minimal-length Walsh-series approximation
to the function $f(x)$. We apply this approach to the quantum simulation of the
classical Eckart barrier problem of quantum chemistry, demonstrating that
high-fidelity quantum simulations can be achieved with few qubits and low
depth.


title: A gauge theory generalization of the fermion-doubling theorem

abstract:
  It is possible to characterize certain states of matter by properties of
their edge states. This implies a notion of `surface-only models': models which
can only be regularized at the edge of a higher-dimensional system. After
incorporating the fermion-doubling results of Nielsen and Ninomiya into this
framework, we employ this idea to identify new obstructions to
symmetry-preserving regulators of quantum field theory. We focus on an example
which forbids regulated models of Maxwell theory with manifest electromagnetic
duality symmetry.


title:
Weighing Galaxy Clusters with Gas. I. On the Methods of Computing
  Hydrostatic Mass Bias

abstract:
  Mass estimates of galaxy clusters from X-ray and Sunyeav-Zel'dovich
observations assume the intracluster gas is in hydrostatic equilibrium with
their gravitational potential. However, since galaxy clusters are dynamically
active objects whose dynamical states can deviate significantly from the
equilibrium configuration, the departure from the hydrostatic equilibrium
assumption is one of the largest sources of systematic uncertainties in cluster
cosmology. In the literature there has been two methods for computing the
hydrostatic mass bias based on the Euler and the modified Jeans equations,
respectively, and there has been some confusion about the validity of these two
methods. The word "Jeans" was a misnomer, which incorrectly implies that the
gas is collisionless. To avoid further confusion, we instead refer these
methods as "summation" and "averaging" methods respectively. In this work, we
show that these two methods for computing the hydrostatic mass bias are
equivalent by demonstrating that the equation used in the second method can be
derived from taking spatial averages of the Euler equation. Specifically, we
identify the correspondences of individual terms in these two methods
mathematically and show that these correspondences are valid to within a few
percent level using hydrodynamical simulations of galaxy cluster formation. In
addition, we compute the mass bias associated with the acceleration of gas and
show that its contribution is small in the virialized regions in the interior
of galaxy cluster, but becomes non-negligible in the cluster outskirts of
massive clusters where materials are being actively accreted. We discuss
implications for understanding the origin of hydrostatic mass biases and for
characterizing them using hydrodynamical simulations as well as observations.


title: Proper Motions of H-alpha filaments in the Supernova Remnant RCW 86

abstract:
  We present a proper motion study of the eastern shock-region of the supernova
remnant RCW 86 (MSH 14-63, G315.4-2.3), based on optical observations carried
out with VLT/FORS2 in 2007 and 2010. For both the northeastern and southeastern
regions, we measure an average proper motion of H-alpha filaments of 0.10 +/-
0.02 arcsec/yr, corresponding to 1200 +/- 200 km/s at 2.5kpc. There is
substantial variation in the derived proper motions, indicating shock
velocities ranging from just below 700 km/s to above 2200 km/s.
  The optical proper motion is lower than the previously measured X-ray proper
motion of northeastern region. The new measurements are consistent with the
previously measured proton temperature of 2.3 +/- 0.3 keV, assuming no
cosmic-ray acceleration. However, within the uncertainties, moderately
efficient (< 27 per cent) shock acceleration is still possible. The combination
of optical proper motion and proton temperature rule out the possibility that
RCW 86 has a distance less than 1.5kpc.
  The similarity of the proper motions in the northeast and southeast is
peculiar, given the different densities and X-ray emission properties of the
regions. The northeastern region has lower densities and the X-ray emission is
synchrotron dominated, suggesting that the shock velocities should be higher
than in the southeastern, thermal X-ray dominated, region. A possible solution
is that the H-alpha emitting filaments are biased toward denser regions, with
lower shock velocities. Alternatively, in the northeast the shock velocity may
have decreased rapidly during the past 200yr, and the X-ray synchrotron
emission is an afterglow from a period when the shock velocity was higher.


title: Boson-Sampling in the light of sample complexity

abstract:
  Boson-Sampling is a classically computationally hard problem that can - in
principle - be efficiently solved with quantum linear optical networks. Very
recently, a rush of experimental activity has ignited with the aim of
developing such devices as feasible instances of quantum simulators. Even
approximate Boson-Sampling is believed to be hard with high probability if the
unitary describing the optical network is drawn from the Haar measure. In this
work we show that in this setup, with probability exponentially close to one in
the number of bosons, no symmetric algorithm can distinguish the Boson-Sampling
distribution from the uniform one from fewer than exponentially many samples.
This means that the two distributions are operationally indistinguishable
without detailed a priori knowledge. We carefully discuss the prospects of
efficiently using knowledge about the implemented unitary for devising
non-symmetric algorithms that could potentially improve upon this. We conclude
that due to the very fact that Boson-Sampling is believed to be hard, efficient
classical certification of Boson-Sampling devices seems to be out of reach.


title:
New Production Mechanism for keV Sterile Neutrino Dark Matter by Decays
  of Frozen-In Scalars

abstract:
  We propose a new production mechanism for keV sterile neutrino Dark Matter.
In our setting, we assume the existence of a scalar singlet particle which
never entered thermal equilibrium in the early Universe, since it only couples
to the Standard Model fields by a really small Higgs portal interaction. For
suitable values of this coupling, the scalar can undergo the so-called
freeze-in process, and in this way be efficiently produced in the early
Universe. These scalars can then decay into keV sterile neutrinos and produce
the correct Dark Matter abundance. While similar settings in which the scalar
does enter thermal equilibrium and then freezes out have been studied
previously, the mechanism proposed here is new and represents a versatile
extension of the known case. We perform a detailed numerical calculation of the
DM production using a set of coupled Boltzmann equations, and we illustrate the
successful regions in the parameter space. Our production mechanism notably can
even work in models where active-sterile mixing is completely absent.


title:
The Weil representation of a unitary group associated to a ramified
  quadratic extension of a finite local ring

abstract:
  We find all irreducible constituents of the Weil representation of a unitary
group $U_m(A)$ of rank $m$ associated to a ramified quadratic extension $A$ of
a finite, commutative, local and principal ring $R$ of odd characteristic. We
show that this Weil representation is multiplicity free with monomial
irreducible constituents. We also find the number of these constituents and
describe them in terms of Clifford theory with respect to a congruence
subgroup. We find all character degrees in the special case when $R$ is a
field.


title: The spinor genus of the integral trace

abstract:
  Let $K$ be a number field of degree at least $3$. In this article we show
that the genus of the integral trace form of $K$ contains only one spinor
genus. Additionally we show that exactly $43%$ (resp. $29%$, resp. $58%$) of
quadratic (resp. real quadratic, resp. imaginary quadratic) fields have the
same property.


title: Holographic Fluctuations from Unitary de Sitter Invariant Field Theory

abstract:
  We continue the study of inflationary fluctuations in Holographic Space Time
models of inflation. We argue that the holographic theory of inflation provides
a physical context for what is often called dS/CFT. The holographic theory is a
quantum theory which, in the limit of a large number of e-foldings, gives rise
to a field theory on $S^3$, which is the representation space for a unitary
representation of SO(1,4). This is not a conventional CFT, and we do not know
the detailed non-perturbative axioms for correlation functions. However, the
two- and three-point functions are completely determined by symmetry, and
coincide up to a few constants (really functions of the background FRW
geometry) with those calculated in a single field slow-roll inflation model.
The only significant deviation from slow roll is in the tensor fluctuations. We
predict zero tensor tilt and roughly equal weight for all three conformally
invariant tensor 3-point functions (unless parity is imposed as a symmetry). We
discuss the relation between our results and those of Maldacena, McFadden,
Skenderis, and others. Current data can be explained in terms of symmetries and
a few general principles, and is consistent with a large class of models,
including HST.


title: Distributional Geometry of Squashed Cones

abstract:
  A regularization procedure developed in [1] for the integral curvature
invariants on manifolds with conical singularities is generalized to the case
of squashed cones. In general, the squashed conical singularities do not have
rotational O(2) symmetry in a subspace orthogonal to a singular surface
$\Sigma$ so that the surface is allowed to have extrinsic curvatures. A new
feature of the squashed conical singularities is that the surface terms in the
integral invariants, in the limit of small angle deficit, now depend also on
the extrinsic curvatures of $\Sigma$. A case of invariants which are quadratic
polynomials of the Riemann curvature is elaborated in different dimensions and
applied to several problems related to entanglement entropy. The results are in
complete agreement with computations of the logarithmic terms in entanglement
entropy of 4D conformal theories [2]. Among other applications of the suggested
method are logarithmic terms in entanglement entropy of non-conformal theories
and a holographic formula for entanglement entropy in theories with gravity
duals.


title:
Bifurcation of the Edge-State Width in the Two-Dimensional Topological
  Insulator

abstract:
  We examine the properties of edge states in a two-dimensional topological
insulator. Based on the Kane-Mele model, we derive two coupled equations for
the energy and the effective width of edge states at a given momentum in a
semi-infinite honeycomb lattice with a zigzag boundary. It is revealed that, in
a one-dimensional Brillouin zone, the edge states merge into the continuous
bands of the bulk states through a bifurcation of the edge-state width. We
discuss the implications of the results to the experiments in monolayer or thin
films of topological insulators.


title:
Deterministic entanglement of superconducting qubits by parity
  measurement and feedback

abstract:
  The stochastic evolution of quantum systems during measurement is arguably
the most enigmatic feature of quantum mechanics. Measuring a quantum system
typically steers it towards a classical state, destroying any initial quantum
superposition and any entanglement with other quantum systems. Remarkably, the
measurement of a shared property between non-interacting quantum systems can
generate entanglement starting from an uncorrelated state. Of special interest
in quantum computing is the parity measurement, which projects a register of
quantum bits (qubits) to a state with an even or odd total number of
excitations. Crucially, a parity meter must discern the two parities with high
fidelity while preserving coherence between same-parity states. Despite
numerous proposals for atomic, semiconducting, and superconducting qubits,
realizing a parity meter creating entanglement for both even and odd
measurement results has remained an outstanding challenge. We realize a
time-resolved, continuous parity measurement of two superconducting qubits
using the cavity in a 3D circuit quantum electrodynamics (cQED) architecture
and phase-sensitive parametric amplification. Using postselection, we produce
entanglement by parity measurement reaching 77% concurrence. Incorporating the
parity meter in a feedback-control loop, we transform the entanglement
generation from probabilistic to fully deterministic, achieving 66% fidelity to
a target Bell state on demand. These realizations of a parity meter and a
feedback-enabled deterministic measurement protocol provide key ingredients for
active quantum error correction in the solid state.


title: Robustness in Projected Entangled Pair States

abstract:
  We analyze a criterion which guarantees that the ground states of certain
many body systems are stable under perturbations. Specifically, we consider
PEPS, which are believed to provide an efficient description, based on local
tensors, for the low energy physics arising from local interactions. In order
to assess stability in the framework of PEPS, one thus needs to understand how
physically allowed perturbations of the local tensor affect the properties of
the global state. In this paper, we show that a restricted version of the Local
Topological Quantum Order (LTQO) condition provides a checkable criterion which
allows to assess the stability of local properties of PEPS under physical
perturbations. We moreover show that LTQO itself is stable under perturbations
which preserve the spectral gap, leading to nontrivial examples of PEPS which
possess LTQO and are thus stable under arbitrary perturbations.


title: Holographic entanglement plateaux

abstract:
  We consider the entanglement entropy for holographic field theories in finite
volume. We show that the Araki-Lieb inequality is saturated for large enough
subregions, implying that the thermal entropy can be recovered from the
knowledge of the region and its complement. We observe that this actually is
forced upon us in holographic settings due to non-trivial features of the
causal wedges associated with a given boundary region. In the process, we
present an infinite set of extremal surfaces in Schwarzschild-AdS geometry
anchored on a given entangling surface. We also offer some speculations
regarding the homology constraint required for computing holographic
entanglement entropy.


title: Euler observers in geometrodynamics

abstract:
  Euler observers are a fundamental tool for the study of spacetime evolution.
Cauchy surfaces are evolved through the use of hypersurface orthogonal fields
and their relationship to coordinate observers, that enable the use of already
developed algorithms. In geometrodynamics new tetrad vectors have been
introduced with outstanding simplifying properties. We are going to use these
already introduced tetrad vectors in the case where we consider a curved four
dimensional Lorentzian spacetime with the presence of electromagnetic fields.
These Einstein-Maxwell geometries will provide the new tetrad that we are going
to use in order to develop an algorithm to produce Cauchy evolution with
additional simplifying properties.


title:
A note on orthogonal Lie algebras in dimension 4 viewed as current Lie
  algebras

abstract:
  Orthogonal Lie algebras in dimension 4 are identified as current Lie
algebras, thus producing a natural decomposition for them over any field.


title:
Time-Dependent Hartree-Fock Solution of Gross-Neveu models: Twisted Kink
  Constituents of Baryons and Breathers

abstract:
  We find the general solution to the time-dependent Hartree-Fock problem for
the Gross-Neveu models, with both discrete (GN2) and continuous (NJL2) chiral
symmetry. We find new multi-baryon, multi-breather and twisted breather
solutions, and show that all GN2 baryons and breathers are composed of
constituent twisted kinks of the NJL2 model.


title:
Relating the entanglement spectrum of noninteracting band insulators to
  their quantum geometry and topology

abstract:
  We study the entanglement spectrum of noninteracting band insulators, which
can be computed from the two-point correlation function, when restricted to one
part of the system. In particular, we analyze a type of partitioning of the
system that maintains its full translational symmetry, by tracing over a subset
of local degrees of freedom, such as sublattice sites or spin orientations. The
corresponding single-particle entanglement spectrum is the band structure of an
entanglement Hamiltonian in the Brillouin zone. We find that the hallmark of a
nontrivial topological phase is a gapless entanglement spectrum with an
"entanglement Fermi surface." Furthermore, we derive a relation between the
entanglement spectrum and the quantum geometry of Bloch states contained in the
Fubini-Study metric. The results are illustrated with lattice models of Chern
insulators and Z_2 topological insulators.


title: On the Asymptotic Performance of Bit-Wise Decoders for Coded Modulation

abstract:
  Two decoder structures for coded modulation over the Gaussian and flat fading
channels are studied: the maximum likelihood symbol-wise decoder, and the
(suboptimal) bit-wise decoder based on the bit-interleaved coded modulation
paradigm. We consider a 16-ary quadrature amplitude constellation labeled by a
Gray labeling. It is shown that the asymptotic loss in terms of pairwise error
probability, for any two codewords caused by the bit-wise decoder, is bounded
by 1.25 dB. The analysis also shows that for the Gaussian channel the
asymptotic loss is zero for a wide range of linear codes, including all
rate-1/2 convolutional codes.


title:
Carrier-envelope phase control over pathway interference in strong-field
  dissociation of H$_2^+$

abstract:
  The dissociation of an H$_2^+$ molecular-ion beam by linearly polarized,
carrier-envelope-phase-tagged 5 fs pulses at 4$\times10^{14} $W/cm$^2$ with a
central wavelength of 730 nm was studied using a coincidence 3D momentum
imaging technique. Carrier-envelope-phase-dependent asymmetries in the emission
direction of H$^+$ fragments relative to the laser polarization were observed.
These asymmetries are caused by interference of odd and even photon number
pathways, where net-zero photon and 1-photon interference predominantly
contributes at H$^+$+H kinetic energy releases of 0.2 -- 0.45 eV, and
net-2-photon and 1-photon interference contributes at 1.65 -- 1.9 eV. These
measurements of the benchmark H$_2^+$ molecule offer the distinct advantage
that they can be quantitatively compared with \textit{ab initio} theory to
confirm our understanding of strong-field coherent control via the
carrier-envelope phase.


title: Gravitating Q-tubes and cylindrical spacetime

abstract:
  We consider a model involving a self-interacting complex scalar field
minimally coupled to gravity and emphasize the cylindrically symmetric
classical solutions. A general ansatz is performed which transforms the field
equations into a system of differential equations. In the generic case, the
scalar field depends on the four space-time coordinates. The underlying
Einstein vacuum equations are worth studying by themselve and lead to numerous
analytic results extending the Kasner solutions. The solutions of the coupled
system are -static as well as stationnary- gravitating Q-tubes of scalar matter
which deform space-time.


title: About $C^{1}$-minimality of the hyperbolic Cantor sets

abstract:
  In this work we prove that a $C^{1+\alpha}$-hyperbolic Cantor set contained
in $S^1$, close to an affine Cantor set, is not $C^{1}$-minimal.


title: The mass of the Milky Way and M31 using the method of least action

abstract:
  We constrain the most likely range of masses for the Milky Way and M31 using
an application of the Numerical Action Method (NAM) that optimizes the fit to
observed parameters over a large ensemble of NAM-generated solutions. Our 95%
confidence level mass ranges, 1.5-4.5 x 10^12 m_sun for MW and 1.5-5.5 x 10^12
m_sun for M31, are consistent with the upper range of estimates from other
methods and suggests that a larger proportion of the total mass becomes
detectable when the peculiar motions of many nearby satellites are taken into
account in the dynamical analysis. We test the method against simulated Local
Group catalogs extracted from the Millennium Run to confirm that mass
predictions are consistent with actual galaxy halo masses.


title: Universal shocks in the Wishart random-matrix ensemble - a sequel

abstract:
  We study the diffusion of complex Wishart matrices and derive a partial
differential equation governing the behavior of the associated averaged
characteristic polynomial. In the limit of large size matrices, the inverse
Cole-Hopf transform of this polynomial obeys a nonlinear partial differential
equation whose solutions exhibit shocks at the evolving edges of the eigenvalue
spectrum. In a particular scenario one of those shocks hits the origin that
plays the role of an impassable wall. To investigate the universal behavior in
the vicinity of this wall, a critical point, we derive an integral
representation for the averaged characteristic polynomial and study its
asymptotic behavior. The result is a Bessoid function.


title:
Broadening of plasmonic resonance due to electron collisions with
  nanoparticle boundary: quantum-mechanical consideration

abstract:
  We present a quantum mechanical approach to calculate broadening of plasmonic
resonances in metallic nanostructures due to collisions of electrons with the
surface of the structure. The approach is applicable if the characteristic size
of the structure is much larger than the de Broglie electron wavelength in the
metal. The approach can be used in studies of plasmonic properties of both
single nanoparticles and arrays of nanoparticles.


title: A comparison of Landau-Ginzburg models for odd dimensional Quadrics

abstract:
  In [Rie08], the second author defined a Landau-Ginzburg model for homogeneous
spaces G/P. In this paper, we reformulate this LG model in the case of the
odd-dimensional quadric X=Q_{2m-1}. Namely we introduce a regular function Wcan
on a variety Xcan x C*, where Xcan is the complement of a particular
anticanonical divisor in the the projective space CP^{2m-1}=P(H*(X,C)*).
Firstly we prove that the Jacobi ring associated to Wcan is isomorphic to the
quantum cohomology ring of the quadric, and that this isomorphism is compatible
with the identification of homogeneous coordinates on Xcan with elements of
H*(X,C). Secondly we find a very natural Laurent polynomial formula for Wcan by
restricting it to a `Lusztig torus' in Xcan. Thirdly we show that the Dubrovin
connection on H*(X,C[q]) embeds into the Gauss-Manin system associated to Wcan
and deduce a flat section formula in terms of oscillating integrals. Finally,
we compare (Xcan,Wcan) with previous Landau-Ginzburg models defined for odd
quadrics. Namely, we prove that it is a partial compactification of Givental's
original LG model [Giv96]. We show that our LG model is isomorphic to the
Lie-theoretic LG model from [Rie08]. Moreover it is birationally equivalent to
an LG model introduced by Gorbounov and Smirnov [GS13], and it is algebraically
isomorphic to Gorbounov and Smirnov's mirror for Q_3, implying a tameness
property in that case.


title:
The 2013 multiwavelength campaign on the Narrow-Line Seyfert 1 galaxy 1H
  0323+342: a rosetta stone for the jet/disk paradigm

abstract:
  Narrow-Line Seyfert 1 galaxies have been established as a new class of
gamma-ray emitting AGN with relatively low black hole masses, but
near-Eddington accretion rates. Other extragalactic gamma-ray sources observed
so far such as Flat Spectrum Radio Quasars, Radio Galaxies, and BL Lacertae
Objects generally exhibit much higher black hole masses and, in the case of BL
Lac objects and FRI Radio Galaxies, much lower accretions rates. The
multifrequency campaign of 2013 centered on the bright source 1H 0323+342 will
provide further insights into the nature of the jets and their gamma ray
production mechanisms in a largely unexplored corner of AGN parameter space.
Here, we show preliminary results of this campaign and discuss them.


title: Anomalous thermoelectric transport in two-dimensional Bose gas

abstract:
  In condensed matter physics, transport measurements are essential not only
for the characterization of materials, but also to discern between quantum
phases and identify new ones. The extension of these measurements into atomic
quantum gases is emerging and will expand the scope of quantum simulation and
atomtronics. To push this frontier, we demonstrate an innovative approach to
extract transport properties from the time-resolved redistribution of the
particles and energy of a trapped atomic gas. Based on the two-dimensional (2D)
Bose gas subject to weak three-body recombination we find clear evidence of
both conductive and thermoelectric currents. We then identify the contributions
to the currents from thermoelectric forces and determine the Seebeck
coefficient (a.k.a. thermopower) and Lorenz number, both showing anomalous
behavior in the fluctuation and superfluid regimes. Our results call for
further exploration of the transport properties, particularly thermoelectric
properties, of atomic quantum gases.


title: Zeta functions on tori using contour integration

abstract:
  A new, seemingly useful presentation of zeta functions on complex tori is
derived by using contour integration. It is shown to agree with the one
obtained by using the Chowla-Selberg series formula, for which an alternative
proof is thereby given. In addition, a new proof of the functional determinant
on the torus results, which does not use the Kronecker first limit formula nor
the functional equation of the non-holomorphic Eisenstein series. As a bonus,
several identities involving the Dedekind eta function are obtained as well.


title: BZT:a soft pseudo-spin glass

abstract:
  In an attempt to understand the origin of relaxor ferroelectricity, it is
shown that interesting behaviour of the onset of non-ergodicity and of
precursor nanodomains found in first principles simulations of the relaxor
alloy $\mathrm {Ba(Zr}_{1-x}\mathrm{Ti}_{x}\mathrm{)O}_3$ can be understood
easily by a simple mapping to a soft pseudo-spin glass.


title:
Reconstructing Native American Migrations from Whole-genome and
  Whole-exome Data

abstract:
  There is great scientific and popular interest in understanding the genetic
history of populations in the Americas. We wish to understand when different
regions of the continent were inhabited, where settlers came from, and how
current inhabitants relate genetically to earlier populations. Recent studies
unraveled parts of the genetic history of the continent using genotyping arrays
and uniparental markers. The 1000 Genomes Project provides a unique opportunity
for improving our understanding of population genetic history by providing over
a hundred sequenced low coverage genomes and exomes from Colombian (CLM),
Mexican-American (MXL), and Puerto Rican (PUR) populations. Here, we explore
the genomic contributions of African, European, and Native American ancestry to
these populations. Estimated Native American ancestry is 48% in MXL, 25% in
CLM, and 13% in PUR. Native American ancestry in PUR is most closely related to
populations surrounding the Orinoco River basin, confirming the Southern
America ancestry of the Ta\'ino people of the Caribbean. We present new methods
to estimate the allele frequencies in the Native American fraction of the
populations, and model their distribution using a demographic model for three
ancestral Native American populations. These ancestral populations likely split
in close succession: the most likely scenario, based on a peopling of the
Americas 16 thousand years ago (kya), supports that the MXL Ancestors split
12.2kya, with a subsequent split of the ancestors to CLM and PUR 11.7kya. The
model also features effective populations of 62,000 in Mexico, 8,700 in
Colombia, and 1,900 in Puerto Rico. Modeling Identity-by-descent and ancestry
tract length, we show that post-contact populations differ markedly in their
effective sizes and migration patterns, with Puerto Rico showing the smallest
effective size and the earlier migration from Europe.


title: Vickrey Auctions for Irregular Distributions

abstract:
  The classic result of Bulow and Klemperer \cite{BK96} says that in a
single-item auction recruiting one more bidder and running the Vickrey auction
achieves a higher revenue than the optimal auction's revenue on the original
set of bidders, when values are drawn i.i.d. from a regular distribution. We
give a version of Bulow and Klemperer's result in settings where bidders'
values are drawn from non-i.i.d. irregular distributions. We do this by
modeling irregular distributions as some convex combination of regular
distributions. The regular distributions that constitute the irregular
distribution correspond to different population groups in the bidder
population. Drawing a bidder from this collection of population groups is
equivalent to drawing from some convex combination of these regular
distributions. We show that recruiting one extra bidder from each underlying
population group and running the Vickrey auction gives at least half of the
optimal auction's revenue on the original set of bidders.


title:
Universality, exponents and anomaly cancellation in disordered Dirac
  fermions

abstract:
  Disordered 2D chiral fermions provide an effective description of several
materials including graphene and topological insulators. While previous
analysis considered delta correlated disorder and no ultraviolet cut-offs, we
consider here the effect of short range correlated disorder and the presence of
a momentum cut-off, providing a more realistic description of condensed matter
models. We show that the density of states is anomalous with a critical
exponent function of the disorder and that conductivity is universal only when
the ultraviolet cut-off is removed, as consequence of the supersymmetric
cancellation of the anomalies.


title: Discovery of an ultramassive pulsating white dwarf

abstract:
  We announce the discovery of the most massive pulsating hydrogen-atmosphere
(DA) white dwarf (WD) ever discovered, GD 518. Model atmosphere fits to the
optical spectrum of this star show it is a 12,030 +/- 210 K WD with a log(g) =
9.08 +/- 0.06, which corresponds to a mass of 1.20 +/- 0.03 Msun. Stellar
evolution models indicate that the progenitor of such a high-mass WD endured a
stable carbon-burning phase, producing an oxygen-neon-core WD. The discovery of
pulsations in GD 518 thus offers the first opportunity to probe the interior of
a WD with a possible oxygen-neon core. Such a massive WD should also be
significantly crystallized at this temperature. The star exhibits
multi-periodic luminosity variations at timescales ranging from roughly 425-595
s and amplitudes up to 0.7%, consistent in period and amplitude with the
observed variability of typical ZZ Ceti stars, which exhibit non-radial g-mode
pulsations driven by a hydrogen partial ionization zone. Successfully
unraveling both the total mass and core composition of GD 518 provides a unique
opportunity to investigate intermediate-mass stellar evolution, and can
possibly place an upper limit to the mass of a carbon-oxygen-core WD, which in
turn constrains SNe Ia progenitor systems.


title:
Role of noise and agents' convictions on opinion spreading in a
  three-state voter-like model

abstract:
  In this work we study the opinion formation in a voter-like model defined on
a square lattice of linear size $L$. The agents may be in three different
states, representing any public debate with three choices (yes, no, undecided).
We consider heterogeneous agents that have different convictions about their
opinions. These convictions limit the capacity of persuasion of the individuals
during the interactions. Moreover, there is a noise $p$ that represents the
probability of an individual spontaneously change his opinion to the undecided
state. Our simulations suggest that the system reaches stationary states for
all values of $p$, with consensus states occurring only for the noiseless case
$p=0$. In this case, the relaxation times are distributed according to a
log-normal function, with the average value $\tau$ growing with the lattice
size as $\tau\sim L^{\alpha}$, where $\alpha\approx$ 0.9. We found a threshold
value $p^{*}\approx$ 0.9 above which the stationary fraction of undecided
agents is greater than the fraction of decided ones. We also study the
consequences of the presence of external effects in the system, which models
the influence of mass media on opinion formation.


title: On the subgroup permutability degree of the simple Suzuki groups

abstract:
  We prove that the subgroup permutability degree of the simple Suzuki groups
vanishes asymptotically. In the course of the proof we establish that the limit
of the probability of a subgroup of $\Sz(q)$ being a 2-group is equal to 1.


title:
The algebraic structure behind the derivative nonlinear Schroedinger
  equation

abstract:
  The Kaup-Newell (KN) hierarchy contains the derivative nonlinear Schr\"
odinger equation (DNLSE) amongst others interesting and important nonlinear
integrable equations. In this paper, a general higher grading affine algebraic
construction of integrable hierarchies is proposed and the KN hierarchy is
established in terms of a $\hat{s\ell}_2$ Kac-Moody algebra and principal
gradation. In this form, our spectral problem is linear in the spectral
parameter. The positive and negative flows are derived, showing that some
interesting physical models arise from the same algebraic structure. For
instance, the DNLSE is obtained as the second positive, while the Mikhailov
model as the first negative flows, respectively. The equivalence between the
latter and the massive Thirring model is explicitly demonstrated also. The
algebraic dressing method is employed to construct soliton solutions in a
systematic manner for all members of the hierarchy. Finally, the equivalence of
the spectral problem introduced in this paper with the usual one, which is
quadratic in the spectral parameter, is achieved by setting a particular
automorphism of the affine algebra, which maps the homogeneous into principal
gradation.


title: A bright-rimmed cloud sculpted by the H ii region Sh2-48

abstract:
  To characterize a bright-rimmed cloud embedded in the HII region Sh2-48
searching for evidence of triggered star formation. We carried out observations
towards a region of 2'x2' centered at RA=18h 22m 11.39s, dec.=-14deg 35m 24.81s
(J2000) using the Atacama Submillimeter Telescope Experiment (ASTE; Chile) in
the 12CO J=3-2,13CO J=3-2, HCO+ J=4-3, and CS J=7-6 lines with an angular
resolution of about 22". We also present radio continuum observations at 5 GHz
carried out with the Jansky Very Large Array (JVLA; EEUU) interferometer with a
synthetized beam of 7"x5". The analysis of our molecular observations reveals
the presence of a relatively dense clump with n(H_2)~3x10^3 cm^-3, located in
projection onto the interior of the HII region Sh2-48. The emission
distribution of the four observed molecular transitions has, at VLSR~38 kms^-1,
morphological anti-correlation with the bright-rimmed cloud as seen in the
optical emission. From the new radio continuum observations we identify a thin
layer of ionized gas located at the border of the clump which is facing to the
ionizing star. The ionized gas has an electron density of about 73 cm^-3 which
supports the hypothesis that the clump is being photoionized by the nearby
star, BD-14 5014. From the evaluation of the pressure balance between the
ionized and molecular gas, we conclude that the clump would be in a
pre-pressure balance state with the shocks being driven into the surface layer.
Two YSO candidates (class I), are placed slightly beyond the bright rim
suggesting that their formation could have been triggered via the
radiation-driven implosion process.


title: Satisfiability Algorithms for Restricted Circuit Classes

abstract:
  In recent years, finding new satisfiability algorithms for various circuit
classes has been a very active line of research. Despite considerable progress,
we are still far away from a definite answer on which circuit classes allow
fast satisfiability algorithms. This survey takes a (far from exhaustive) look
at some recent satisfiability algorithms for a range of circuit classes and
high- lights common themes. A special focus is given to connections between
satisfiability algorithms and circuit lower bounds. A second focus is on
reductions from satisfiability algorithms to a range of polynomial time
problems, such as matrix multiplication and the Vector Domination Problem.


title: Canonical heights and division polynomials

abstract:
  We discuss a new method to compute the canonical height of an algebraic point
on a hyperelliptic jacobian over a number field. The method does not require
any geometrical models, neither $p$-adic nor complex analytic ones. In the case
of genus 2 we also present a version that requires no factorisation at all. The
method is based on a recurrence relation for the `division polynomials'
associated to hyperelliptic jacobians, and a diophantine approximation result
due to Faltings.


title:
The WiggleZ Dark Energy Survey: Star-formation in UV-luminous galaxies
  from their luminosity functions

abstract:
  We present the ultraviolet (UV) luminosity function of galaxies from the
GALEX Medium Imaging Survey with measured spectroscopic redshifts from the
first data release of the WiggleZ Dark Energy Survey. This sample selects
galaxies with high star formation rates: at 0.6 < z < 0.9 the median star
formation rate is at the upper 95th percentile of optically-selected (r<22.5)
galaxies and the sample contains about 50 per cent of all NUV < 22.8, 0.6 < z <
0.9 starburst galaxies within the volume sampled.
  The most luminous galaxies in our sample (-21.0>M_NUV>-22.5) evolve very
rapidly with a number density declining as (1+z)^{5\pm 1} from redshift z = 0.9
to z = 0.6. These starburst galaxies (M_NUV<-21 is approximately a star
formation rate of 30 \msuny) contribute about 1 per cent of cosmic star
formation over the redshift range z=0.6 to z=0.9. The star formation rate
density of these very luminous galaxies evolves rapidly, as (1+z)^{4\pm 1}.
Such a rapid evolution implies the majority of star formation in these large
galaxies must have occurred before z = 0.9.
  We measure the UV luminosity function in 0.05 redshift intervals spanning
0.1<z<0.9, and provide analytic fits to the results. At all redshifts greater
than z=0.55 we find that the bright end of the luminosity function is not well
described by a pure Schechter function due to an excess of very luminous
(M_NUV<-22) galaxies. These luminosity functions can be used to create a radial
selection function for the WiggleZ survey or test models of galaxy formation
and evolution. Here we test the AGN feedback model in Scannapieco et al.
(2005), and find that this AGN feedback model requires AGN feedback efficiency
to vary with one or more of the following: stellar mass, star formation rate
and redshift.


title:
On Russian Roulette Estimates for Bayesian Inference with
  Doubly-Intractable Likelihoods

abstract:
  A large number of statistical models are "doubly-intractable": the likelihood
normalising term, which is a function of the model parameters, is intractable,
as well as the marginal likelihood (model evidence). This means that standard
inference techniques to sample from the posterior, such as Markov chain Monte
Carlo (MCMC), cannot be used. Examples include, but are not confined to,
massive Gaussian Markov random fields, autologistic models and Exponential
random graph models. A number of approximate schemes based on MCMC techniques,
Approximate Bayesian computation (ABC) or analytic approximations to the
posterior have been suggested, and these are reviewed here. Exact MCMC schemes,
which can be applied to a subset of doubly-intractable distributions, have also
been developed and are described in this paper. As yet, no general method
exists which can be applied to all classes of models with doubly-intractable
posteriors. In addition, taking inspiration from the Physics literature, we
study an alternative method based on representing the intractable likelihood as
an infinite series. Unbiased estimates of the likelihood can then be obtained
by finite time stochastic truncation of the series via Russian Roulette
sampling, although the estimates are not necessarily positive. Results from the
Quantum Chromodynamics literature are exploited to allow the use of possibly
negative estimates in a pseudo-marginal MCMC scheme such that expectations with
respect to the posterior distribution are preserved. The methodology is
reviewed on well-known examples such as the parameters in Ising models, the
posterior for Fisher-Bingham distributions on the $d$-Sphere and a large-scale
Gaussian Markov Random Field model describing the Ozone Column data. This leads
to a critical assessment of the strengths and weaknesses of the methodology
with pointers to ongoing research.