Miracle-dz/UniFAR-FTUs huggingface dataset:
Influence of Lifshitz transitions and correlation effects on the scattering rates of the charge carriers in iron-based superconductors

Minimum model calculations on the co-action of hole vanishing Lifshitz transitions and correlation effects in ferropnictides are presented. The calculations predict non-Fermi-liquid behaviour and huge mass enhancements of the charge carriers at the Fermi level. The findings are compared with recent ARPES experiments and with measurements of transport and thermal properties of ferropnictides. The results from the calculation can be also applied to other unconventional superconductors and question the traditional view of quantum-critical points.
Transition to turbulence in wall-bounded flows: Where do we stand?

In this essay, we recall the specificities of the transition to turbulence in wall-bounded flows and present recent achievements in the understanding of this problem. The transition is abrupt with laminar-turbulent coexistence over a finite range of Reynolds numbers, the transitional range. The archetypical cases of Poiseuille pipe flow and plane Couette flow are first reviewed at the phenomenological level, together with a few other flow configurations. Theoretical approaches are then examined with particular emphasis on the existence of special nontrivial solutions to the Navier-Stokes equations at finite distance from laminar flow. Dynamical systems theory is most appropriate to analyze their role, in particular with respect to the transient character of turbulence in the lower transitional range. The extensions needed to deal with the prominent spatiotemporal features of the transition are then discussed. Turbulence growth/decay in terms of statistical physics of many-body systems and the relevance of directed percolation as a stochastic process able to account for it are next scrutinized. To conclude, we advocate the recourse to well-designed modeling able to provide us with a conceptually coherent picture of the full transitional range and put forward some open issues.
An exact solution to the temperature equation in a column of ice and bedrock

We construct a solution of a pure conduction problem in ice and bedrock. This solution is suitable for, and is used in this paper for, verifying a numerical scheme for conservation of energy. This exact solution forms one of a suite of verification tests for PISM (Parallel Ice Sheet Model; this https URL).
Gravitational radiation from first-order phase transitions

It is believed that first-order phase transitions at or around the GUT scale will produce high-frequency gravitational radiation. This radiation is a consequence of the collisions and coalescence of multiple bubbles during the transition. We employ high-resolution lattice simulations to numerically evolve a system of bubbles using only scalar fields, track the anisotropic stress during the process and evolve the metric perturbations associated with gravitational radiation. Although the radiation produced during the bubble collisions has previously been estimated, we find that the coalescence phase enhances this radiation even in the absence of a coupled fluid or turbulence. We comment on how these simulations scale and propose that the same enhancement should be found at the Electroweak scale; this modification should make direct detection of a first-order electroweak phase transition easier.
From the Equations of Motion to the Canonical Commutation Relations

The problem of whether or not the equations of motion of a quantum system determine the commutation relations was posed by E.P.Wigner in 1950. A similar problem (known as ”The Inverse Problem in the Calculus of Variations”) was posed in a classical setting as back as in 1887 by H.Helmoltz and has received great attention also in recent times. The aim of this paper is to discuss how these two apparently unrelated problems can actually be discussed in a somewhat unified framework. After reviewing briefly the Inverse Problem and the existence of alternative structures for classical systems, we discuss the geometric structures that are intrinsically present in Quantum Mechanics, starting from finite-level systems and then moving to a more general setting by using the Weyl-Wigner approach, showing how this approach can accomodate in an almost natural way the existence of alternative structures in Quantum Mechanics as well.
Temperature and high-pressure dependent x-ray absorption of SmNiO3 at the Ni K and Sm L3 edges

We report on x-ray absorption near-edge structure (XANES) and extended x-ray absorption fine structure (EXAFS) measurements of SmNiO3 from 20 K to 600 K and up to 38 GPa at the Ni K and Sm L3 edges. A multiple component pre-Ni K edge tail is understood, originating from 1 s transitions to 3d-4p states while a post-edge shoulder increases distinctively smoothly, at about the insulator to metal phase transition (TIM), due to the reduction of electron–phonon interactions as the Ni 3d and O 2p band overlap triggers the metallic phase. This effect is concomitant with pressure-induced Ni-O-Ni angle increments toward more symmetric Ni3+ octahedra of the rhombohedral R¯3c space group. Room temperature pressure-dependent Ni white line peak energies have an abrupt ∼3.10 ± 0.04 GPa valence discontinuity from non-equivalent Ni3+δ + Ni3–δ charge disproportionate net unresolved absorber turning at ∼TIM into Ni3+ of the orthorhombic Pbnm metal oxide phase. At 20 K the overall white line response, still distinctive at TIM ∼8.1 ± 0.6 GPa is much smoother due to localization. Octahedral bond contraction up to 38 GPa and at 300 K and 20 K show breaks in its monotonic increase at the different structural changes. The Sm L3 edge does not show distinctive behaviors either at 300 K or 20 K up to about 35 GPa but the perovskite Sm cage, coordinated to eight oxygen atoms, undergoes strong uneven bond contractions at intermediate pressures where we found the coexistence of octahedral and rhombohedral superexchange angle distortions. We found that the white line pressure-dependent anomaly may be used as an accurate alternative for delineating pressure–temperature phase diagrams.
Experimental investigation of Popper’s proposed ghost-diffraction experiment

In an effort to challenge the Copenhagen interpretation of quantum mechanics, Karl Popper proposed an experiment involving spatially separated entangled particles. In this experiment, one of the particles passes through a very narrow slit, and thereby its position becomes well-defined. This particle therefore diffracts into a large divergence angle; this effect can be understood as a consequence of the Heisenberg uncertainty principle. Popper further argued that its entangled partner would become comparably localized in position, and that, according to his understanding of the Copenhagen interpretation of quantum mechanics, the ‘mere knowledge’ of the position of this particle would cause it also to diffract into a large divergence angle. Popper recognized that such behavior could violate the principle of causality in that the slit could be removed and the partner particle would be expected to respond instantaneously. Popper thus concluded that it was most likely the case that, in an actual experiment, the partner photon would not undergo increased diffractive spreading and thus that the Copenhagen interpretation is incorrect. Here, we report and analyze the results of an implementation of Popper’s proposal. We find that the partner beam does not undergo increased diffractive spreading. Our work helps to clarify the issues raised in Popper’s proposal, and it provides further insight into the nature of entanglement and its relation to the uncertainty principle as applied to correlated particles.
Transcriptional glucocorticoid effects in the brain: Finding the relevant target genes

Glucocorticoids are powerful modulators of brain function. They act via mineralocorticoid and glucocorticoid receptors (MR and GR). These are best understood as transcription factors. Although many glucocorticoid effects depend on the modulation of gene transcription, it is a major challenge to link gene expression to function given the large‐scale, apparently pleiotropic genomic responses. The extensive sets of MR and GR target genes are highly specific per cell type, and the brain contains many different (neuronal and non‐neuronal) cell types. Next to the set “trait” of cellular context, the “state” of other active signaling pathways will affect MR and GR transcriptional activity. Here, we discuss receptor specificity and contextual factors that determine the transcriptional outcome of MR/GR signaling, experimental possibilities offered by single‐cell transcriptomics approaches, and reflect on how to make sense of lists of target genes in relation to understanding the functional effects of steroid receptor activation.
An entropy-driven cosmic expansion

We examine the evolution of the Friedman Universe within our recent model of space-time identified with an elastic continuous medium whose deformations are described by a vector field constrained to obey a generalized four-dimensional version of the equilibrium equations of standard elasticity. It is found that the demand that the entropy associated with such elastic deformations be always extremal during the expansion of such a Universe turns these equilibrium equations into a single differential equation governing the evolution of the Hubble parameter H. The solution to the resulting dynamics admits both a power-law expansion, analogous to the one induced by an inflaton field, as well as a power-law expansion analogous to the one induced by a phantom field. Analyzing both types of expansions via the induced elastic energy and pressure permits to assign the former to the early Universe and the latter to its late-time expansion. It is argued, however, that the present model does not exclude a phantom-like inflation for the early Universe. We discuss the possible way for the dynamics to avoid the Big Rip singularity that would otherwise result. We succinctly discuss the possible way to avoid also the Big Bang singularity and how to obtain the large scale structure of the Universe from the present model.
Neutrino masses and mixing: a flavour symmetry roadmap

Over the last ten years tri‐bimaximal mixing has played an important role in modeling the flavour problem. We give a short review of the status of flavour symmetry models of neutrino mixing. We concentrate on non‐Abelian discrete symmetries, which provide a simple way to account for the TBM pattern. We discuss phenomenological implications such as neutrinoless double beta decay, lepton flavour violation as well as theoretical aspects such as the possibility to explain quarks and leptons within a common framework, such as grand unified models.
SIMULAÇÕES COMPUTACIONAIS APLICADAS À TOMADA DE DECISÃO PÚBLICA

As publicações do Ipea estão disponíveis para download gratuito nos formatos PDF (todas) e EPUB (livros e periódicos). Acesse: http://www.ipea. gov.br/portal/publicacoes As opiniões emitidas nesta publicação são de exclusiva e inteira responsabilidade dos autores, não exprimindo, necessariamente, o ponto de vista do Instituto de Pesquisa Econômica Aplicada ou do Ministério da Economia. É permitida a reprodução deste texto e dos dados nele contidos, desde que citada a fonte. Reproduções para fins comerciais são proibidas. ‘
Attention Trajectories Capture Utility Accumulation and Predict Brand Choice

Trajectories of attention capture the accumulation of brand utility during complex decision-making tasks. Thus, attention trajectories, as reflected in eye movements, predict the final brand choice of 85% of consumers before they implement it. Even when observing eye movements in only the first quarter of the decision process, attention already predicts brand choice much better (45%) than chance levels (20%). This superior prediction performance is due to a “double attention lift” for the chosen brand: The chosen brand receives progressively more attention toward the moment of choice, and more of this attention is devoted to integrating information about the brand rather than to comparing it with other options. In contrast, the currently owned brand grabs attention early in the task, and its attention gain persists for brand-loyal consumers and shifts for brand-switching consumers. A new attention and choice model used in tandem with the Bayesian K-fold cross-validation methodology on eye-tracking data from 325 representative consumers uncovered these attention trajectory effects. The findings contribute to closing important knowledge gaps in the attention and choice literature and have implications for marketing research and managerial practice.
The fuzzy S 2 structure of M2-M5 systems in ABJM membrane theories

We analyse the fluctuations of the ground-state/funnel solutions proposed to describe M2-M5 systems in the level-k mass-deformed/pure Chern-Simons-matter ABJM theory of multiple membranes. We show that in the large N limit the fluctuations approach the space of functions on the 2-sphere rather than the naively expected 3-sphere. This is a novel realisation of the fuzzy 2-sphere in the context of Matrix Theories, which uses bifundamental instead of adjoint scalars. Starting from the multiple M2-brane action, a U(1) Yang-Mills theory on 2,1 × S2 is recovered at large N, which is consistent with a single D4-brane interpretation in Type IIA string theory. This is as expected at large k, where the semiclassical analysis is valid. Several aspects of the fluctuation analysis, the ground-state/funnel solutions and the mass-deformed/pure ABJM equations can be understood in terms of a discrete noncommutative realisation of the Hopf fibration. We discuss the implications for the possibility of finding an M2-brane worldvolume derivation of the classical S3 geometry of the M2-M5 system. Using a rewriting of the equations of the SO(4)-covariant fuzzy 3-sphere construction, we also directly compare this fuzzy 3-sphere against the ABJM ground-state/funnel solutions and show them to be different.
Magnetization dynamics in optically excited nanostructured nickel films

In this work, the laser-induced magnetization dynamics of nanostructured nickel films is investigated. The influence of the nanosize is discussed considering the timescale of hundreds of femtoseconds as well as the GHz regime. While no nanosize effect is observed on the short timescale, the excited magnetic mode in the GHz regime can be identified by comparison with micromagnetic simulations. The thickness dependence reveals insight into the dipole interaction between single nickel structures. Also, transient reflectivity changes are discussed.
The fate of close encounters between binary stars and binary supermassive black holes

The evolution of main sequence binaries that reside in the Galactic Centre can be heavily influenced by the central supermassive black hole (SMBH). Due to these perturbative effects, the stellar binaries in dense environments are likely to experience mergers, collisions or ejections through secular and/or non-secular interactions. More direct interactions with the central SMBH are thought to produce hypervelocity stars (HVSs) and tidal disruption events (TDEs). In this paper, we use N-body simulations to study the dynamics of stellar binaries orbiting a central SMBH primary with an outer SMBH secondary orbiting this inner triple. The effects of the secondary SMBH on the event rates of HVSs, TDEs and stellar mergers are investigated, as a function of the SMBH-SMBH binary mass ratio. Our numerical experiments reveal that, relative to the isolated SMBH case, the TDE and HVS rates are enhanced for, respectively, the smallest and largest mass ratio SMBH-SMBH binaries. This suggests that the observed event rates of TDEs and HVSs have the potential to serve as a diagnostic of the mass ratio of a central SMBH-SMBH binary. The presence of a secondary SMBH also allows for the creation of hypervelocity binaries. Observations of these systems could thus constrain the presence of a secondary SMBH in the Galactic Centre.
PULSATIONS IN HYDROGEN BURNING LOW-MASS HELIUM WHITE DWARFS

Helium core white dwarfs (WDs) with mass M ≲ 0.20 M☉ undergo several Gyr of stable hydrogen burning as they evolve. We show that in a certain range of WD and hydrogen envelope masses, these WDs may exhibit g-mode pulsations similar to their passively cooling, more massive carbon/oxygen core counterparts, the ZZ Cetis. Our models with stably burning hydrogen envelopes on helium cores yield g-mode periods and period spacings longer than the canonical ZZ Cetis by nearly a factor of 2. We show that core composition and structure can be probed using seismology since the g-mode eigenfunctions predominantly reside in the helium core. Though we have not carried out a fully nonadiabatic stability analysis, the scaling of the thermal time in the convective zone with surface gravity highlights several low-mass helium WDs that should be observed in search of pulsations: NLTT 11748, SDSS J0822+2753, and the companion to PSR J1012+5307. Seismological studies of these He core WDs may prove especially fruitful, as their luminosity is related (via stable hydrogen burning) to the hydrogen envelope mass, which eliminates one model parameter.
THE SPECTRAL EVOLUTION OF THE FIRST GALAXIES. I. JAMES WEBB SPACE TELESCOPE DETECTION LIMITS AND COLOR CRITERIA FOR POPULATION III GALAXIES

The James Webb Space Telescope (JWST) is expected to revolutionize our understanding of the high-redshift universe, and may be able to test the prediction that the first, chemically pristine (Population III) stars are formed with very high characteristic masses. Since isolated Population III stars are likely to be beyond the reach of JWST, small Population III galaxies may offer the best prospects of directly probing the properties of metal-free stars. Here, we present Yggdrasil, a new spectral synthesis code geared toward the first galaxies. Using this model, we explore the JWST imaging detection limits for Population III galaxies and investigate to what extent such objects may be identified based on their JWST colors. We predict that JWST should be able to detect Population III galaxies with stellar population masses as low as ∼105 M☉ at z ≈ 10 in ultra deep exposures. Over limited redshift intervals, it may also be possible to use color criteria to select Population III galaxy candidates for follow-up spectroscopy. The colors of young Population III galaxies dominated by direct starlight can be used to probe the stellar initial mass function (IMF), but this requires almost complete leakage of ionizing photons into the intergalactic medium. The colors of objects dominated by nebular emission show no corresponding IMF sensitivity. We also note that a clean selection of Population III galaxies at z ≈ 7–8 can be achieved by adding two JWST/MIRI filters to the JWST/NIRCam filter sets usually discussed in the context of JWST ultra deep fields.
Les Houches 2017: Physics at TeV Colliders Standard Model Working Group Report

This Report summarizes the proceedings of the 2017 Les Houches workshop on Physics at TeV Colliders. Session 1 dealt with (I) new developments relevant for high precision Standard Model calculations, (II) theoretical uncertainties and dataset dependence of parton distribution functions, (III) new developments in jet substructure techniques, (IV) issues in the theoretical description of the production of Standard Model Higgs bosons and how to relate experimental measurements, (V) phenomenological studies essential for comparing LHC data from Run II with theoretical predictions and projections for future measurements, and (VI) new developments in Monte Carlo event generators.
Networks of gravitational wave detectors and three figures of merit

This paper develops a general framework for studying the effectiveness of networks of interferometric gravitational wave detectors and then uses it to show that enlarging the existing LIGO–VIRGO network with one or more planned or proposed detectors in Japan (LCGT), Australia, and India brings major benefits, including much larger detection rate increase than previously thought. I focus on detecting bursts, i.e. short-duration signals, with optimal coherent data-analysis methods. I show that the polarization-averaged sensitivity of any network of identical detectors to any class of sources can be characterized by two numbers—the visibility distance of the expected source from a single detector and the minimum signal-to-noise ratio (SNR) for a confident detection—and one angular function, the antenna pattern of the network. I show that there is a universal probability distribution function (PDF) for detected SNR values, which implies that the most likely SNR value of the first detected event will be 1.26 times the search threshold. For binary systems, I also derive the universal PDF for detected values of the orbital inclination, taking into account the Malmquist bias; this implies that the number of gamma-ray bursts associated with detected binary coalescences should be 3.4 times larger than expected from just the beaming fraction of the gamma burst. Using network antenna patterns, I propose three figures of merit (f.o.m.'s) that characterize the relative performance of different networks. These measure (a) the expected rate of detection by the network and any sub-networks of three or more separated detectors, taking into account the duty cycle of the interferometers, (b) the isotropy of the network antenna pattern, and (c) the accuracy of the network at localizing the positions of events on the sky. I compare various likely and possible networks, based on these f.o. m. 's. Adding any new site to the planned LIGO–VIRGO network can dramatically increase, by factors of 2–4, the detected event rate by allowing coherent data analysis to reduce the spurious instrumental coincident background. Moving one of the LIGO detectors to Australia additionally improves direction finding by a factor of 4 or more. Adding LCGT to the original LIGO–VIRGO network not only improves direction finding but will further increase the detection rate over the extra-site gain by factors of almost 2, partly by improving the network duty cycle. Including LCGT, LIGO-Australia, and a detector in India gives a network with position error ellipses a factor of 7 smaller in area and boosts the detected event rate a further 2.4 times above the extra-site gain over the original LIGO–VIRGO network. Enlarged advanced networks could look forward to detecting 300–400 neutron star binary coalescences per year.