Children's gender essentialism and prejudice: Testing causal links via an experimental manipulation.

Despite increases in visibility, gender-nonconforming young people continue to be at risk for bullying and discrimination. Prior work has established that gender essentialism in children correlates with prejudice against people who do not conform to gender norms, but to date no causal link has been established. The present study investigated this link more directly by testing whether children's gender essentialism and prejudice against gender nonconformity can be reduced by exposure to anti-essentialist messaging. Children ages 6-10 years of age (N = 102) in the experimental condition viewed a short video describing similarities between boys and girls and variation within each gender; children in the control condition (N = 102) viewed a corresponding video describing similarities between two types of climate and variation within each. Children then received measures of gender essentialism and prejudice against gender nonconformity. Finally, to ask whether manipulating children's gender essentialism extends to another domain, we included assessments of racial essentialism and prejudice. We found positive correlations between gender essentialism and prejudice against gender nonconformity; both also correlated negatively with participant age. However, we observed no differences between children in the experimental versus control conditions in overall essentialism or prejudice, indicating that our video was largely ineffective in manipulating essentialism. Accordingly, we were unable to provide evidence of a causal relationship between essentialism and prejudice. We did, however, see a difference between conditions on the discreteness measure, which is most closely linked to the wording in the video. This finding suggests that specific aspects of essentialism in young children may be modifiable. RESEARCH HIGHLIGHTS: Consistent with prior research, we found that greater gender essentialism was associated with greater prejudice against gender-nonconforming children; both decreased with age. We randomly assigned children to view either an anti-essentialist video manipulation or a control video to test if this relation was causal in nature. The anti-essentialist video did not reduce overall essentialism as compared to the control, so we did not find support for a causal link. We observed a reduction in the dimension of essentialism most closely linked to the anti-essentialist video language, suggesting the potential utility of anti-essentialist messaging.

Atomic and Molecular Layer Deposition of Chiral Thin Films Showing up to 99% Spin Selective Transport.

Spin electronics is delivering a much desired combination of properties such as high speed, low power, and high device densities for the next generation of memory devices. Utilizing chiral-induced spin selectivity (CISS) effect is a promising path toward efficient and simple spintronic devices. To be compatible with state-of-the-art integrated circuits manufacturing methodologies, vapor phase methodologies for deposition of spin filtering layers are needed. Here, we present vapor phase deposition of hybrid organic-inorganic thin films with embedded chirality. The deposition scheme relies on a combination of atomic and molecular layer deposition (A/MLD) utilizing enantiomeric pure alaninol molecular precursors combined with trimethyl aluminum (TMA) and water. The A/MLD deposition method deliver highly conformal thin films allowing the fabrication of several types of nanometric scale spintronic devices. The devices showed high spin polarization (close to 100%) for 5 nm thick spin filter layer deposited by A/MLD. The procedure is compatible with common device processing methodologies.

How to Get to Where They Are: Notes From an Open Group With Unhoused LGBTQIA2S+ Youth.

Mental health professionals aim to engage our clients with "accurate empathy": a nonjudgmental understanding of each person's starting point and experiences that is in tune with their perspective. This article explores the challenges and importance of developing this type of engagement in complex contexts, using the lens of group work with a disparate set of LGBTQIA2S+ young adults whose identities, backgrounds, and experiences differed from one another and from the facilitator. The author reflects on experiences from a grant-based position creating and running a trauma-informed support group in an emergency shelter for unhoused LGBTQIA2S+ young adults in a major U.S. city, including the impact of common issues in the field such as staff turnover, confusion about roles and needs, and support. The article describes lessons learned about the importance of language choice, self-reflection, and the need to confront and build on differences to create a shared process of support.

Energy, Momentum, and Angular Momentum Transfer between Electrons and Nuclei.

The recently developed exact factorization approach condenses all electronic effects on the nuclear subsystem into scalar and vector potentials that appear in an effective time dependent Schrödinger equation. Starting from this equation, we derive subsystem Ehrenfest identities characterizing the energy, momentum, and angular momentum transfer between electrons and nuclei. An effective electromagnetic force operator induced by the electromagnetic field corresponding to the effective scalar and vector potentials appears in all three identities. The effective magnetic field has two components that can be identified with the Berry curvature calculated with (a) different Cartesian coordinates of the same nucleus and (b) arbitrary Cartesian coordinates of two different nuclei. (a) has a classical interpretation as the induced magnetic field felt by the nucleus, while (b) has no classical analog. Subsystem Ehrenfest identities are ideally suited for quantifying energy transfer in electron-phonon systems. With two explicit examples we demonstrate the usefulness of the new identities.

A Scoping Review of Empirical Asexuality Research in Social Science Literature.

Research on asexuality as a part of the experience of human sexuality has increased over the last two decades. However, there has not yet been a systematic review of the extant literature on asexuality. This paper aims to provide a systematic scoping review of literature on asexuality with articles published in 2004 through August 2021. After a systematic search procedure, 48 studies were included. A codebook was developed to extract broad information about the literature on asexuality, including sampling techniques, research participant sociodemographics, and conceptualization of asexuality. Results of the review indicate that the research is currently split between qualitative and quantitative methods. The literature primarily relied on convenience sampling within asexual online communities. The primary online community was Asexual Visibility and Education Network (AVEN), which may have contributed to the majority of participants being White, presumptively cisgender, women between the ages of 20-30. Analysis of the overall literature scope demonstrates no support for asexuality as a medical condition (i.e., a disorder requiring treatment) and instead supports the need to recognize asexuality as a complex identity and sexual orientation. Implications for research are discussed, such as the need for additional research on the topic of human sexuality that includes asexuality as a sexual orientation as well as the need for more intersectional research within the literature.

Fock-Space Embedding Theory: Application to Strongly Correlated Topological Phases.

A many-body wave function can be factorized in Fock space into a marginal amplitude describing a set of strongly correlated orbitals and a conditional amplitude for the remaining weakly correlated part. The marginal amplitude is the solution of a Schrödinger equation with an effective Hamiltonian that can be viewed as embedding the marginal wave function in the environment of weakly correlated electrons. Here, the complementary equation for the conditional amplitude is replaced by a generalized Kohn-Sham equation, for which an orbital-dependent functional approximation is shown to reproduce the topological phase diagram of a multiband Hubbard model as a function of crystal field and Hubbard parameters. The roles of band filling and interband fluctuations are elucidated.

Individual differences in behaviour and gut bacteria are associated in collared peccary (Mammalia, Tayassuidae).

AIMS: We tested the hypothesis that the behaviour of an individual is associated with the diversity of its gut bacteria, using the collared peccary (Pecari tajacu) as a model. METHODS AND RESULTS: In all, 24 adult male collared peccaries received either low- (n = 12) or high-fibre diet (n = 12) to induce contrasting gut fermentation profiles. They were submitted to three short-term challenges, allowing us to rate the animals in a coping-style dimension named 'calmness'. At the end of the experimental period, we collected samples of peccaries' forestomach contents to characterize bacterial diversity. We found a significant positive association between individual 'calmness' z-scores and the bacterial evenness index in gut bacteria (and a similar trend with the Simpson's diversity index), suggesting a more homogeneous bacterial community of calmer individuals. We also found a positive association between fibres digestibility and gut bacterial diversity in the peccaries' forestomach, but no effect of the dietary fibre level. CONCLUSIONS: Gut bacteria evenness increases with 'calmness' z-scores, suggesting a more homogeneous bacterial community of calmer individuals, compared with the more heterogeneous of the most distressed ones. Our results also suggest associations between the digestibility of ADF with the gut bacterial diversity indices and with the relative abundance of the Actinobacteria phylum. SIGNIFICANCE AND IMPACT OF THE STUDY: Our data showed that the hosts' individual behavioural differences are potentially aligned with gut bacterial diversity. The behaviour-microbiota link is correlated with host feed efficiency and, ultimately, may have implications for animal health and welfare of farm animals.

Combining Eliashberg Theory with Density Functional Theory for the Accurate Prediction of Superconducting Transition Temperatures and Gap Functions.

We propose a practical alternative to Eliashberg equations for the ab initio calculation of superconducting transition temperatures and gap functions. Within the recent density functional theory for superconductors, we develop an exchange-correlation functional that retains the accuracy of Migdal's approximation to the many-body electron-phonon self-energy, while having a simple analytic form. Our functional is based on a parametrization of the Eliashberg self-energy for a superconductor with a single Einstein frequency, and enables density functional calculations of experimental excitation gaps. By merging electronic structure methods and Eliashberg theory, the present approach sets a new standard in quality and computational feasibility for the prediction of superconducting properties.

Extending Solid-State Calculations to Ultra-Long-Range Length Scales.

We present a method that enables solid-state density functional theory calculations to be applied to systems of almost unlimited size. Computations of physical effects up to the micron length scale but which nevertheless depend on the microscopic details of the electronic structure, are made possible. Our approach is based on a generalization of the Bloch state, which involves an additional sum over a finer grid in reciprocal space around each k point. We show that this allows for modulations in the density and magnetization of arbitrary length on top of a lattice-periodic solution. Based on this, we derive a set of ultra-long-range Kohn-Sham equations. We demonstrate our method with a sample calculation of bulk LiF subjected to an arbitrary external potential containing nearly 3500 atoms. We also confirm the accuracy of the method by comparing the spin density wave state of bcc Cr against a direct supercell calculation starting from a random magnetization density. Furthermore, the spin spiral state of γ-Fe is correctly reproduced.

Competing Spin Transfer and Dissipation at Co/Cu(001) Interfaces on Femtosecond Timescales.

By combining interface-sensitive nonlinear magneto-optical experiments with femtosecond time resolution and ab initio time-dependent density functional theory, we show that optically excited spin dynamics at Co/Cu(001) interfaces proceeds via spin-dependent charge transfer and back transfer between Co and Cu. This ultrafast spin transfer competes with dissipation of spin angular momentum mediated by spin-orbit coupling already on sub 100 fs timescales. We thereby identify the fundamental microscopic processes during laser-induced spin transfer at a model interface for technologically relevant ferromagnetic heterostructures.

Density functional theory of electron transfer beyond the Born-Oppenheimer approximation: Case study of LiF.

We perform model calculations for a stretched LiF molecule, demonstrating that nonadiabatic charge transfer effects can be accurately and seamlessly described within a density functional framework. In alkali halides like LiF, there is an abrupt change in the ground state electronic distribution due to an electron transfer at a critical bond length R = Rc, where an avoided crossing of the lowest adiabatic potential energy surfaces calls the validity of the Born-Oppenheimer approximation into doubt. Modeling the R-dependent electronic structure of LiF within a two-site Hubbard model, we find that nonadiabatic electron-nuclear coupling produces a sizable elongation of the critical Rc by 0.5 bohr. This effect is very accurately captured by a simple and rigorously derived correction, with an M-1 prefactor, to the exchange-correlation potential in density functional theory, M = reduced nuclear mass. Since this nonadiabatic term depends on gradients of the nuclear wave function and conditional electronic density, ∇Rχ(R) and ∇Rn(r, R), it couples the Kohn-Sham equations at neighboring R points. Motivated by an observed localization of nonadiabatic effects in nuclear configuration space, we propose a local conditional density approximation-an approximation that reduces the search for nonadiabatic density functionals to the search for a single function y(n).

Exact Single-Electron Approach to the Dynamics of Molecules in Strong Laser Fields.

We present an exact single-electron picture that describes the correlated electron dynamics in strong laser fields. Our approach is based on the factorization of the electronic wave function as a product of a marginal and a conditional amplitude. The marginal amplitude, which depends only on one electronic coordinate and yields the exact one-electron density and current density, obeys a time-dependent Schrödinger equation with an effective time-dependent potential. The exact equations are used to derive an approximation that is a step towards general and feasible ab initio single-electron calculations for molecules. The derivation also sheds new light on the usual interpretation of the single-active electron approximation. From the study of model systems, we find that the exact and approximate single-electron potentials for processes with negligible two-electron ionization lead to qualitatively similar dynamics, but that the ionization barrier in the exact single-electron potential may be explicitly time dependent.

Spin Flips versus Spin Transport in Nonthermal Electrons Excited by Ultrashort Optical Pulses in Transition Metals.

A joint theoretical and experimental investigation is performed to understand the underlying physics of laser-induced demagnetization in Ni and Co films with varying thicknesses excited by 10 fs optical pulses. Experimentally, the dynamics of spins is studied by determining the time-dependent amplitude of the Voigt vector, retrieved from a full set of magnetic and nonmagnetic quantities performed on both sides of films, with absolute time reference. Theoretically, ab initio calculations are performed using time-dependent density functional theory. Overall, we demonstrate that spin-orbit induced spin flips are the most significant contributors with superdiffusive spin transport, which assumes only that the transport of majority spins without spin flips induced by scattering does not apply in Ni. In Co it plays a significant role during the first ∼20 fs only. Our study highlights the material dependent nature of the demagnetization during the process of thermalization of nonequilibrium spins.

Electron-nuclear wave-packet dynamics through a conical intersection.

We investigate the coupled electron-nuclear dynamics in a model system showing a conical intersection (CoIn) between two excited state potential energy surfaces. Within the model, a single electron and nucleus move in two dimensions in an external static field. It is demonstrated that the nuclear density conserves its initial Gaussian shape when directly passing the CoIn, whereas the electronic density remains approximately constant. This is in sharp contrast to the picture which evolves from an analysis within the basis of adiabatic electronic states. There, dramatic changes are seen in the dynamics of the different nuclear components of the total wave function. It is thus documented that, in the case of a highly efficient population transfer between the respective adiabatic states, neither the nuclear nor the electronic density is influenced by the existence of a CoIn. This is the case because the nuclear-electronic wave packet moves on the complete potential energy surface which changes its topology smoothly as a function of all particle coordinates.

Exact Factorization-Based Density Functional Theory of Electrons and Nuclei.

The ground state energy of a system of electrons (r=r_{1},r_{2},…) and nuclei (R=R_{1},R_{2},…) is proven to be a variational functional of the electronic density n(r,R) and paramagnetic current density j_{p}(r,R) conditional on R, the nuclear wave function χ(R), an induced vector potential A_{µ}(R) and a quantum geometric tensor T_{µν}(R). n, j_{p}, A_{µ} and T_{µν} are defined in terms of the conditional electronic wave function Φ_{R}(r). The ground state (n,j_{p},χ,A_{µ},T_{µν}) can be calculated by solving self-consistently (i) conditional Kohn-Sham equations containing effective scalar and vector potentials v_{s}(r) and A_{xc}(r) that depend parametrically on R, (ii) the Schrödinger equation for χ(R), and (iii) Euler-Lagrange equations that determine T_{µν}. The theory is applied to the E⊗e Jahn-Teller model.

High spatial resolution mapping of chemically-active self-assembled N-heterocyclic carbenes on Pt nanoparticles.

The properties of many functional materials critically depend on the spatial distribution of surface active sites. In the case of solid catalysts, the geometric and electronic properties of different surface sites will directly impact their catalytic properties. However, the detection of catalytic sites at the single nanoparticle level cannot be easily achieved and most spectroscopic measurements are performed with ensemble-based measurements in which the reactivity is averaged over millions of nanoparticles. It is hereby demonstrated that chemically-functionalized N-heterocyclic carbene molecules can be attached to the surfaces of Pt nanoparticles and utilized as a model system for studying catalytic reactions on single metallic nanoparticles. The formation of a carbene self-assembled layer on the surface of a Pt nanoparticle and its stability under oxidizing conditions were investigated. IR nanospectroscopy measurements detected the chemical properties of surface-anchored molecules on single nanoparticles. A direct correlation was identified between IR nanospectroscopy measurements and macroscopic ATR-IR measurements. These results demonstrate that high spatial resolution mapping of the catalytic reactivity on single nanoparticles can be achieved with this approach.

Electronic Flux Density beyond the Born-Oppenheimer Approximation.

In the Born-Oppenheimer approximation, the electronic wave function is typically real-valued and hence the electronic flux density (current density) seems to vanish. This is unfortunate for chemistry, because it precludes the possibility to monitor the electronic motion associated with the nuclear motion during chemical rearrangements from a Born-Oppenheimer simulation of the process. We study an electronic flux density obtained from a correction to the electronic wave function. This correction is derived via nuclear velocity perturbation theory applied in the framework of the exact factorization of electrons and nuclei. To compute the correction, only the ground state potential energy surface and the electronic wave function are needed. For a model system, we demonstrate that this electronic flux density approximates the true one very well, for coherent tunneling dynamics as well as for over-the-barrier scattering, and already for mass ratios between electrons and nuclei that are much larger than the true mass ratios.

An exact factorization perspective on quantum interferences in nonadiabatic dynamics.

Nonadiabatic quantum interferences emerge whenever nuclear wavefunctions in different electronic states meet and interact in a nonadiabatic region. In this work, we analyze how nonadiabatic quantum interferences translate in the context of the exact factorization of the molecular wavefunction. In particular, we focus our attention on the shape of the time-dependent potential energy surface-the exact surface on which the nuclear dynamics takes place. We use a one-dimensional exactly solvable model to reproduce different conditions for quantum interferences, whose characteristic features already appear in one-dimension. The time-dependent potential energy surface develops complex features when strong interferences are present, in clear contrast to the observed behavior in simple nonadiabatic crossing cases. Nevertheless, independent classical trajectories propagated on the exact time-dependent potential energy surface reasonably conserve a distribution in configuration space that mimics one of the exact nuclear probability densities.

First-Principles Calculation of the Real-Space Order Parameter and Condensation Energy Density in Phonon-Mediated Superconductors.

We show that the superconducting order parameter and condensation energy density of phonon-mediated superconductors can be calculated in real space from first principles density functional theory for superconductors. This method highlights the connection between the chemical bonding structure and the superconducting condensation and reveals new and interesting properties of superconducting materials. Understanding this connection is essential to describe nanostructured superconducting systems where the usual reciprocal space analysis hides the basic physical mechanism. In a first application we present results for MgB2, CaC6 and hole-doped graphane.

Coupled-Trajectory Quantum-Classical Approach to Electronic Decoherence in Nonadiabatic Processes.

We present a novel quantum-classical approach to nonadiabatic dynamics, deduced from the coupled electronic and nuclear equations in the framework of the exact factorization of the electron-nuclear wave function. The method is based on the quasiclassical interpretation of the nuclear wave function, whose phase is related to the classical momentum and whose density is represented in terms of classical trajectories. In this approximation, electronic decoherence is naturally induced as an effect of the coupling to the nuclei and correctly reproduces the expected quantum behavior. Moreover, the splitting of the nuclear wave packet is captured as a consequence of the correct approximation of the time-dependent potential of the theory. This new approach offers a clear improvement over Ehrenfest-like dynamics. The theoretical derivation presented in this Letter is supported by numerical results that are compared to quantum mechanical calculations.