pinecone/core-2020-05-10-deduplication huggingface dataset:
M(atrix) Theory : a Pedagogical Introduction

I attempt to give a pedagogical introduction to the matrix model of M-theory
as developed by Banks, Fischler, Shenker and Susskind (BFSS). In the first
lecture, I introduce and review the relevant aspects of D-branes with the
emergence of the matrix model action. The second lecture deals with the
appearance of eleven-dimensional supergravity and M-theory in strongly coupled
type IIA superstring theory. The third lecture combines the material of the two
previous ones to arrive at the BFSS conjecture and explains the evidence
presented by these authors. The emphasis is not on most recent developments but
on a hopefully pedagogical presentation.Comment: 20 pages in double-column format, Latex, uses espcrc2.tex, 2 figure
Ideals of Quasi-Symmetric Functions and Super-Covariant Polynomials for
  S_n

The aim of this work is to study the quotient ring R_n of the ring
Q[x_1,...,x_n] over the ideal J_n generated by non-constant homogeneous
quasi-symmetric functions. We prove here that the dimension of R_n is given by
C_n, the n-th Catalan number. This is also the dimension of the space SH_n of
super-covariant polynomials, that is defined as the orthogonal complement of
J_n with respect to a given scalar product. We construct a basis for R_n whose
elements are naturally indexed by Dyck paths. This allows us to understand the
Hilbert series of SH_n in terms of number of Dyck paths with a given number of
factors.Comment: LaTeX, 3 figures, 12 page
Bicrossproduct approach to the Connes-Moscovici Hopf algebra

We give a rigorous proof that the (codimension one) Connes-Moscovici Hopf
algebra H_CM is isomorphic to a bicrossproduct Hopf algebra linked to a group
factorisation of the group of positively-oriented diffeomorphisms of the real
line. We construct a second bicrossproduct U_CM equipped with a nondegenerate
dual pairing with H_CM. We give a natural quotient Hopf algebra of H_CM and
Hopf subalgebra of U_CM which again are in duality. All these Hopf algebras
arise as deformations of commutative or cocommutative Hopf algebras that we
describe in each case. Finally we develop the noncommutative differential
geometry of the quotient of H_CM by studying covariant first order differential
calculi of small dimension over this algebra.Comment: 21 page
Ground state particle-particle correlations and double beta decay

A self-consistent formalism for the double beta decay of Fermi type is
provided. The particle-particle channel of the two-body interaction is
considered first in the mean field equations and then in the QRPA. The
resulting approach is called the QRPA with a self-consistent mean field
(QRPASMF). The mode provided by QRPASMF, does not collapse for any strength of
the particle-particle interaction. The transition amplitude for double beta
decay is almost insensitive to the variation of the particle-particle
interaction. Comparing it with the result of the standard pnQRPA, it is smaller
by a factor 6. The prediction for transition amplitude agrees quite well with
the exact result. The present approach is the only one which produces a strong
decrease of the amplitude and at the same time does not alter the stability of
the ground state.Comment: 23 pages, 7 figure
A fully ab initio quartic force field of spectroscopic quality for SO_3

The quartic force field of SO$_3$ was computed fully ab initio using coupled
cluster (CCSD(T)) methods and basis sets of up to $spdfgh$ quality. The effect
of inner-shell correlation was taken into account. The addition of tight $d$
functions is found to be essential for accurate geometries and harmonic
frequencies. The equilibrium geometry and vibrational fundamentals are
reproduced to within 0.0003 \AA and (on average) 1.15 cm^{-1}, respectively. We
recommend the following revised values for the harmonic frequencies: $\omega_1
= 1082.7, \omega_2 = 502.6, \omega_3 = 1415.4, \omega_4 = 534.0 cm^{-1}$. In
addition, we have shown that the addition of inner polarization functions to
second-row elements is highly desirable even with more approximate methods like
B3LYP, and greatly improves the quality of computed geometries and harmonic
frequencies of second-row compounds at negligible extra computational cost. For
larger such molecules, the B3LYP/VTZ+1 level of theory should be a very good
compromise between accuracy and computational cost.Comment: RevTeX, 22 pages; for special issue of Spectrochimica Acta A
  "Theoretical spectroscopy, state of the science" (eds. T. J. Lee, M.
  Head-Gordon
Feature detection using spikes: the greedy approach

A goal of low-level neural processes is to build an efficient code extracting
the relevant information from the sensory input. It is believed that this is
implemented in cortical areas by elementary inferential computations
dynamically extracting the most likely parameters corresponding to the sensory
signal. We explore here a neuro-mimetic feed-forward model of the primary
visual area (VI) solving this problem in the case where the signal may be
described by a robust linear generative model. This model uses an over-complete
dictionary of primitives which provides a distributed probabilistic
representation of input features. Relying on an efficiency criterion, we derive
an algorithm as an approximate solution which uses incremental greedy inference
processes. This algorithm is similar to 'Matching Pursuit' and mimics the
parallel architecture of neural computations. We propose here a simple
implementation using a network of spiking integrate-and-fire neurons which
communicate using lateral interactions. Numerical simulations show that this
Sparse Spike Coding strategy provides an efficient model for representing
visual data from a set of natural images. Even though it is simplistic, this
transformation of spatial data into a spatio-temporal pattern of binary events
provides an accurate description of some complex neural patterns observed in
the spiking activity of biological neural networks.Comment: This work links Matching Pursuit with bayesian inference by providing
  the underlying hypotheses (linear model, uniform prior, gaussian noise
  model). A parallel with the parallel and event-based nature of neural
  computations is explored and we show application to modelling Primary Visual
  Cortex / image processsing.
  http://incm.cnrs-mrs.fr/perrinet/dynn/LaurentPerrinet/Publications/Perrinet04tau
Numerical analyses of deflagration initiation by a hot jet

Numerical simulations of axisymmetric reactive jets with one-step Arrhenius kinetics
are used to investigate the problem of deflagration initiation in a premixed fuel–air
mixture by the sudden discharge of a hot jet of its adiabatic reaction products. For the
moderately large values of the jet Reynolds number considered in the computations,
chemical reaction is seen to occur initially in the thin mixing layer that separates the hot
products from the cold reactants. This mixing layer is wrapped around by the starting
vortex, thereby enhancingmixing at the jet head, which is followed by an annular mixing
layer that trails behind, connecting the leading vortex with the orifice rim. A successful
deflagration is seen to develop for values of the orifice radius larger than a critical
value aϲ in the order of the flame thickness of the planar deflagration δL. Introduction
of appropriate scales provides the dimensionless formulation of the problem, with
flame initiation characterised in terms of a critical Damk¨ohler number ∆ϲ = (aϲ/δL)²,
whose parametric dependence is investigated. The numerical computations reveal that,
while the jet Reynolds number exerts a limited influence on the criticality conditions,
the effect of the reactant diffusivity on ignition is much more pronounced, with the
value of ∆ϲ increasing significantly with increasing Lewis numbers Le. The reactant
diffusivity affects also the way ignition takes place, so that for reactants with Le ≳ 1 the
flame develops as a result of ignition in the annular mixing layer surrounding the developing
jet stem, whereas for highly diffusive reactants with Lewis numbers sufficiently
smaller than unity combustion is initiated in the mixed core formed around the starting
vortex. The analysis provides increased understanding of deflagration initiation processes,
including the effects of differential diffusion, and points to the need for further
investigations incorporating detailed chemistry models for specific fuel–air mixtures.This work was supported by the SpanishMCINN through project numbers ENE2008-06515-C01 and CSD2010-00010 and by the Comunidad de Madrid through project number S2009/ENE-1597
Constraining the properties of AGN host galaxies with Spectral Energy
  Distribution modeling

[abridged] We use the latest release of CIGALE, a galaxy SED fitting model
relying on energy balance, to study the influence of an AGN in estimating both
the SFR and stellar mass in galaxies, as well as the contribution of the AGN to
the power output of the host. Using the galaxy formation SAM GALFORM, we create
mock galaxy SEDs using realistic star formation histories (SFH) and add an AGN
of Type 1, Type 2, or intermediate type whose contribution to the bolometric
luminosity can be variable. We perform an SED fitting of these catalogues with
CIGALE assuming three different SFHs: a single- and
double-exponentially-decreasing, and a delayed SFH. Constraining
thecontribution of an AGN to the LIR (fracAGN) is very challenging for
fracAGN<20%, with uncertainties of ~5-30% for higher fractions depending on the
AGN type, while FIR and sub-mm are essential. The AGN power has an impact on
the estimation of $M_*$ in Type 1 and intermediate type AGNs but has no effect
for galaxies hosting Type 2 AGNs. We find that in the absence of AGN emission,
the best estimates of $M_*$ are obtained using the
double-exponentially-decreasing model but at the expense of realistic ages of
the stellar population. The delayed SFH model provides good estimates of $M_*$
and SFR, with a maximum offset of 10% as well as better estimates of the age.
Our analysis shows that the underestimation of the SFR increases with fracAGN
for Type 1 systems, as well as for low contributions of an intermediate AGN
type, but it is quite insensitive to the emission of Type 2 AGNs up to
fracAGN~45%. Similarly the UV emission is critical in accurately retrieving the
$M_*$ for Type 1 and intermediate type AGN, and the SFR of all of the three AGN
types. We show that the presence of AGN emission introduces a scatter to the
SFR-$M_*$ main sequence relation derived from SED fitting, which is driven by
the uncertainties on $M_*$.Comment: 20 pages, Accepted for publication in A&
Non-relativistic twistor theory and Newton--Cartan geometry

We develop a non-relativistic twistor theory, in which Newton--Cartan
structures of Newtonian gravity correspond to complex three-manifolds with a
four-parameter family of rational curves with normal bundle ${\mathcal
O}\oplus{\mathcal O}(2)$. We show that the Newton--Cartan space-times are
unstable under the general Kodaira deformation of the twistor complex
structure. The Newton--Cartan connections can nevertheless be reconstructed
from Merkulov's generalisation of the Kodaira map augmented by a choice of a
holomorphic line bundle over the twistor space trivial on twistor lines. The
Coriolis force may be incorporated by holomorphic vector bundles, which in
general are non--trivial on twistor lines. The resulting geometries agree with
non--relativistic limits of anti-self-dual gravitational instantons.Comment: 28 pages, 4 figures, Twistorial reality conditions clarified. Final
  version to appear in Communications in Mathematical Physic
On one-loop corrections in the standard model effective field theory;
  the $\Gamma(h \rightarrow \gamma \, \gamma)$ case

We calculate one loop contributions to $\Gamma(h \rightarrow \gamma \,
\gamma)$ from higher dimensional operators, in the Standard Model Effective
Field Theory (SMEFT). Some technical challenges related to determining
Electroweak one loop "finite terms" are discussed and overcome. Although we
restrict our attention to $\Gamma(h \rightarrow \gamma \, \gamma)$, several
developments we report have broad implications. Firstly, the running of the
vacuum expectation value modifies the $\log(\mu)$ dependence of processes in a
manner that is not captured in some past SMEFT Renormalization Group (RG)
calculations. Secondly, higher dimensional operators can source ghost
interactions in $R_\xi$ gauges due to a modified gauge fixing procedure.
Lastly, higher dimensional operators can contribute with pure finite terms at
one loop in a manner that is not anticipated in a RG analysis. These results
cast recent speculation on the nature of one loop corrections in the SMEFT in
an entirely new light.Comment: 25 pages, 5 figures, v3: Acknowledgement updated with grant number
The classical double copy for Taub-NUT spacetime

The double copy is a much-studied relationship between gauge theory and
gravity amplitudes. Recently, this was generalised to an infinite family of
classical solutions to Einstein's equations, namely stationary Kerr-Schild
geometries. In this paper, we extend this to the Taub-NUT solution in gravity,
which has a double Kerr-Schild form. The single copy of this solution is a
dyon, whose electric and magnetic charges are related to the mass and NUT
charge in the gravity theory. Finally, we find hints that the classical double
copy extends to curved background geometries.Comment: 13 pages, no figures. Minor edits to match journal versio
$\bar B\to X_s \gamma$ with a warped bulk Higgs

We study the decay $\bar B\to X_s\gamma$ in Randall-Sundrum models with an
IR-localised bulk Higgs. The two models under consideration are a minimal model
as well as a model with a custodial protection mechanism. We include the
effects of tree- and one-loop diagrams involving 5D gluon and Higgs exchanges
as well as QCD corrections arising from the evolution from the Kaluza-Klein
scale to the typical scale of the decay. We find the RS corrections to the
branching fraction can be sizeable for large Yukawas and moderate KK scales
$T$; for small Yukawas the RS contribution is small enough to be invisible in
current experimental data.Comment: 20 pages, 5 figures(V2: references added, matches version published
  in Nuclear Physics B
Magnetic field amplification and evolution in turbulent collisionless magnetohydrodynamics : an application to the intracluster medium

R.S.L. acknowledges support from a grant of the Brazilian Agency FAPESP (2007/04551-0 and 2013/15115-8), EMGDP from FAPESP (2006/50654-3 and 2011/53275-4) and CNPq (306598/2009-4) grants. G.K. also acknowledges support from FAPESP (2009/50053-8, 2013/04073-2, and 2013/18815-0). D.F.G. thanks the European Research Council (ADG-2011 ECOGAL) and the Brazilian agencies CNPq (no. 300382/2008-1), CAPES (3400-13-1), and FAPESP (no.2011/12909-8) for financial support. A.L. acknowledges the NSF grant AST 1212096, the NSF-sponsored Center for Magnetic Self-Organization, as well as the stimulating atmosphere of the International Institute of Physics (Natal, Brazil) and of the Harvard University during his sabbatical, and of the Vilas Associate Award. M.S.N. acknowledges support from FAPESP (2010/50298-8). The numerical simulations of this work were performed with the supercomputer of the Laboratory of Astro-informatics LAi (IAG/USP, NAT/Unicsul), whose purchase was made possible by FAPESP (grant 2009/54006-4).The amplification of magnetic fields (MFs) in the intracluster medium (ICM) is attributed to turbulent dynamo (TD) action, which is generally derived in the collisional-MHD framework. However, this assumption is poorly justified a priori, since in the ICM the ion mean free path between collisions is of the order of the dynamical scales, thus requiring a collisionless MHD description. The present study uses an anisotropic plasma pressure that brings the plasma within a parametric space where collisionlessinstabilities take place. In this model, a relaxation term of the pressure anisotropy simulates the feedback of the mirror and firehose instabilities, in consistency with empirical studies. Our three-dimensional numerical simulations of forced transonic turbulence, aiming the modeling of the turbulent ICM, were performed for different initial values of the MF intensity and different relaxation rates of the pressure anisotropy. We found that in the high-β plasma regime corresponding to the ICM conditions, a fast anisotropy relaxation rate gives results that are similar to the collisional-MHD model, as far as the statistical properties of the turbulence are concerned. Also, the TD amplification of seed MFs was found to be similar to the collisional-MHD model. The simulations that do not employ the anisotropy relaxation deviate significantly from the collisional-MHD results and show more power at the small-scale fluctuations of both density and velocity as a result of the action of the instabilities. For these simulations, the large-scale fluctuations in the MF are mostly suppressed and the TD fails in amplifying seed MFs.Publisher PDFPeer reviewe
Search for squarks and gluinos in events with isolated leptons, jets and missing transverse momentum at $\sqrt{s}=8$ TeV with the ATLAS detector

The results of a search for supersymmetry in final states containing at least one isolated lepton (electron or muon), jets and large missing transverse momentum with the ATLAS detector at the Large Hadron Collider (LHC) are reported. The search is based on proton-proton collision data at a centre-of-mass energy $\sqrt{s} = 8$ TeV collected in 2012, corresponding to an integrated luminosity of 20 $fb^{-1}$. No significant excess above the Standard Model expectation is observed. Limits are set on the parameters of a minimal universal extra dimensions model, excluding a compactification radius of $1/R_c=950$ GeV for a cut-off scale times radius ($\Lambda R_c$) of approximately 30, as well as on sparticle masses for various supersymmetric models. Depending on the model, the search excludes gluino masses up to 1.32 TeV and squark masses up to 840 GeV
Diferencias individuales en la predicción del éxito ocupacional: el efecto de la heterogeneidad de la población

Using a sample of 339 university graduates from the University of Alicante (Spain) three years after completion of their studies, we studied the relationships between general intelligence (GI), personality traits, emotional intelligence (EI), academic performance, and occupational attainment and compared the results of conventional regression analysis with the results obtained from applying regression mixture models. The results reveal the influence of unobserved population heterogeneity (latent class) on the relationship between predictors and criteria and the improvement in the prediction obtained from applying regression mixture models compared to applying a conventional regression model.Mediante una muestra de 339 graduados universitarios de la Universidad de Alicante, España, tres años después de acabar los estudios, hemos estudiado la relación entre inteligencia general (IG), rasgos de personalidad, inteligencia emocional (IE), rendimiento académico y consecución de empleo, comparando los resultados del análisis de regresión tradicional con los resultados obtenidos aplicando los modelos mixtos de regresión. Los resultados muestran la influencia de una heterogeneidad poblacional no observada (clase latente) en la relación entre predictores y criterios y la mejoría en la predicción a partir de la aplicación de los modelos mixtos de regresión en comparación con la aplicación del modelo convencional de regresión.This study was part of the research project ref. PSI2009-12696,funded by the Spanish Ministry of Science and Innovation
From Tevatron’s top and lepton-based asymmetries to the LHC

We define a lepton-based asymmetry in semi-leptonic t t ¯ $$ t\overline{t} $$ production at the LHC. We show that the ratio of this lepton-based asymmetry and the t t ¯ $$ t\overline{t} $$ charge asymmetry, measured as a function of the lepton transverse momentum or the t t ¯ $$ t\overline{t} $$ invariant mass is a robust observable in the Standard Model. It is stable against higher order corrections and mis-modeling effects. We show that this ratio can be also a powerful discriminant among different models of new physics and between them and the Standard Model. Finally, we show that a related ratio defined at the Tevatron is also robust as a function of the t t ¯ $$ t\overline{t} $$ invariant mass
Charge symmetry breaking in dd→He4π0 with WASA-at-COSY

Charge symmetry breaking (CSB) observables are a suitable experimental tool to examine effects induced by quark masses on the nuclear level. Previous high precision data from TRIUMF and IUCF are currently used to develop a consistent description of CSB within the framework of chiral perturbation theory. In this work the experimental studies on the reaction dd→He4π0 have been extended towards higher excess energies in order to provide information on the contribution of p -waves in the final state. For this, an exclusive measurement has been carried out at a beam momentum of pd=1.2 GeV/c using the WASA-at-COSY facility. The total cross section amounts to σtot=(118±18stat±13sys±8ext) pb and first data on the differential cross section are consistent with s -wave pion production
Four dimensional superconformal theories from M 5 branes

We study N=1 superconformal theories in four dimensions obtained wrapping M5 branes on a Riemann surface. We propose a method to determine from the spectral curve the scaling dimension of chiral operators in the SCFT. Whenever the R-symmetry has to be determined via a-maximization, our procedure allows us to determine the charge of chiral operators under the “trial” R-symmetry. Our proposal reduces to the correct prescription in the special case of N=2 theories of class S $$ \mathcal{S} $$ . We perform several consistency checks and apply our method to study some new SCFT’s such as N=1 deformations of Argyres-Douglas theories
A robust jet reconstruction algorithm for high-energy lepton colliders

We propose a new sequential jet reconstruction algorithm for future lepton colliders at the energy frontier. The Valencia algorithm combines the natural distance criterion for lepton colliders with the greater robustness against backgrounds of algorithms adapted to hadron colliders. Results on a detailed Monte Carlo simulation of tt¯ and ZZ production at future linear e+e− colliders (ILC and CLIC) with a realistic level of background overlaid, show that it achieves better performance in the presence of background than the classical algorithms used at previous e+e− colliders
Inverse decays and the relic density of the sterile sneutrino.

15 pages, 4 figures.-- Pre-print archive.We consider a weak scale supersymmetric seesaw model where the higgsino is the next-to-lightest supersymmetric particle and the right-handed sneutrino is the dark matter candidate. It is shown that, in this model, inverse decays, which had been previously neglected, may suppress the sneutrino relic density by several orders of magnitude. After including such processes and numerically solving the appropriate Boltzmann equation, we study the dependence of the relic density on the μ parameter, the sneutrino mass, and the neutrino Yukawa coupling. We find that, even though much smaller than in earlier calculations, the sneutrino relic density is still larger than the observed dark matter density.I am supported by the Juan de la Cierva program of the Ministerio de Educacion y Ciencia of Spain, by Proyecto Nacional FPA2006-01105, and by the Comunidad de Madrid under Proyecto HEPHACOS S-0505/ESP-0346. I would like to thank W. Porod and Ki-Young Choi for comments and suggestions.Peer reviewe