Exact nonadiabatic part of the Kohn-Sham potential and its fluidic approximation

We present a simple geometrical "fluidic" approximation to the nonadiabatic part of the Kohn-Sham potential, vKS, of time-dependent density-functional theory (DFT). This part of vKS is often crucial, but most practical functionals utilize an adiabatic approach based on ground-state DFT, limiting their accuracy in many situations. For a variety of model systems, we calculate the exact time-dependent electron density and find that the fluidic approximation corrects a large part of the error arising from the "exact adiabatic" approach, even when the system is evolving far from adiabatically

An Improved Penalty-Based Excited-State Variational Monte Carlo Approach with Deep-Learning Ansatzes

We introduce several improvements to the penalty-based variational quantum Monte Carlo (VMC) algorithm for computing electronic excited states of Entwistle et al. [Nat. Commun. 14, 274 (2023)] and demonstrate that the accuracy of the updated method is competitive with other available excited-state VMC approaches. A theoretical comparison of the computational aspects of these algorithms is presented, where several benefits of the penalty-based method are identified. Our main contributions include an automatic mechanism for tuning the scale of the penalty terms, an updated form of the overlap penalty with proven convergence properties, and a new term that penalizes the spin of the wave function, enabling the selective computation of states with a given spin. With these improvements, along with the use of the latest self-attention-based ansatz, the penalty-based method achieves a mean absolute error below 1 kcal/mol for the vertical excitation energies of a set of 26 atoms and molecules, without relying on variance matching schemes. Considering excited states along the dissociation of the carbon dimer, the accuracy of the penalty-based method is on par with that of natural-excited-state (NES) VMC, while also providing results for additional sections of the potential energy surface, which were inaccessible with the NES method. Additionally, the accuracy of the penalty-based method is improved for a conical intersection of ethylene, with the predicted angle of the intersection agreeing well with both NES-VMC and multireference configuration interaction

Electronic excited states in deep variational Monte Carlo

Obtaining accurate ground and low-lying excited states of electronic systems is crucial in a multitude of important applications. One ab initio method for solving the Schrödinger equation that scales favorably for large systems is variational quantum Monte Carlo (QMC). The recently introduced deep QMC approach uses ansatzes represented by deep neural networks and generates nearly exact ground-state solutions for molecules containing up to a few dozen electrons, with the potential to scale to much larger systems where other highly accurate methods are not feasible. In this paper, we extend one such ansatz (PauliNet) to compute electronic excited states. We demonstrate our method on various small atoms and molecules and consistently achieve high accuracy for low-lying states. To highlight the method’s potential, we compute the first excited state of the much larger benzene molecule, as well as the conical intersection of ethylene, with PauliNet matching results of more expensive high-level methods

Approaches to study in higher education portuguese students: a portuguese version of the Approaches and Study Skills Inventory for Students (ASSIST)

This paper examines the validity of the Approaches and Study Skills Inventory for Students—short version (ASSIST; Tait et al. in Improving student learning: Improving students as learners, 1998), to be used with Portuguese undergraduate students. The ASSIST was administrated to 566 students, in order to analyse a Portuguese version of this inventory. Exploratory factor analysis (principal axis factor analysis followed by direct oblimin rotation) reproduced the three main factors that correspond to the original dimensions of the inventory (deep, surface apathetic and strategic approaches to learning). The results are consistent with the background theory on approaches to learning. Additionally, the reliability analysis revealed acceptable internal consistency indexes for the main scales and subscales. This inventory might represent a valuable research tool for the assessment of approaches to learning among Portuguese higher education students

Exact exchange-correlation kernels for optical spectra of model systems

For two prototype systems, we calculate the exact exchange-correlation kernels fxc(x,x′,ω) of time-dependent density functional theory. fxc, the key quantity for optical absorption spectra of electronic systems, is normally subject to uncontrolled approximation. We find that, up to the first excitation energy, the exact fxc has weak frequency dependence and a simple, though nonlocal, spatial form. For higher excitations, the spatial behavior and frequency dependence become more complex. The accuracy of the underlying exchange-correlation potential is of crucial importance

Textiles as Material Gestalt: Cloth as a Catalyst in the Co-designing Process

Textiles is the common language within Emotional Fit, a collaborative research project investigating a person-centred, sustainable approach to fashion for an ageing female demographic (55+). Through the co-designing of a collection of research tools, textiles have acted as a material gestalt for exploring our research participants' identities by tracing their embodied knowledge of fashionable dress. The methodology merges Interpretative Phenomenological Analysis, co-design and a simultaneous approach to textile and garment design. Based on an enhanced understanding of our participants textile preferences, particular fabric qualities have catalysed silhouettes, through live draping and geometric pattern cutting to accommodate multiple body shapes and customisation. Printedtextiles have also been digitally crafted in response to the contours of the garment and body and personal narratives of wear. Sensorial and tactile interactions have informed the engineering and scaling of patterns within zero-waste volumes. The article considers the functional and aesthetic role of textiles

Suited for Success? : Suits, Status, and Hybrid Masculinity

This document is the Accepted Manuscript version. The final, definitive version of this paper has been published in Men and Masculinities, March 2017, doi: https://doi.org/10.1177/1097184X17696193, published by SAGE Publishing, All rights reserved.This article analyzes the sartorial biographies of four Canadian men to explore how the suit is understood and embodied in everyday life. Each of these men varied in their subject positions—body shape, ethnicity, age, and gender identity—which allowed us to look at the influence of men’s intersectional identities on their relationship with their suits. The men in our research all understood the suit according to its most common representation in popular culture: a symbol of hegemonic masculinity. While they wore the suit to embody hegemonic masculine configurations of practice—power, status, and rationality—most of these men were simultaneously marginalized by the gender hierarchy. We explain this disjuncture by using the concept of hybrid masculinity and illustrate that changes in the style of hegemonic masculinity leave its substance intact. Our findings expand thinking about hybrid masculinity by revealing the ways subordinated masculinities appropriate and reinforce hegemonic masculinity.Peer reviewe

Accurate total energies from the adiabatic-connection fluctuation-dissipation theorem

In the context of inhomogeneous one-dimensional finite systems, recent numerical advances [Phys. Rev. B 103, 125155 (2021)2469-995010.1103/PhysRevB.103.125155] allow us to compute the exact coupling-constant dependent exchange-correlation kernel fxcλ(x,x′,ω) within linear response time-dependent density-functional theory. This permits an improved understanding of ground-state total energies derived from the adiabatic-connection fluctuation-dissipation theorem (ACFDT). We consider both one-shot and self-consistent ACFDT calculations, and demonstrate that chemical accuracy is reliably preserved when the frequency dependence in the exact functional fxc[n](ω=0) is neglected. This performance is understood on the grounds that the exact fxc[n] varies slowly over the most relevant ω range (but not in general), and hence the spatial structure in fxc[n](ω=0) is able to largely remedy the principal issue in the present context: self-interaction (examined from the perspective of the exchange-correlation hole). Moreover, we find that the implicit orbitals contained within a self-consistent ACFDT calculation utilizing the adiabatic exact kernel fxc[n](ω=0) are remarkably similar to the exact Kohn-Sham orbitals, thus further establishing that the majority of the physics required to capture the ground-state total energy resides in the spatial dependence of fxc[n] at ω=0