The authors present SHarmonic, a new implementation of the spherical harmonics targeted for electronic-structure calculations. Their approach is to use explicit formulas for the harmonics written in terms of normalized Cartesian coordinates. This approach results in a code that is as precise as other implementations while being at least one order of magnitude more computationally efficient. The library can run on graphics processing units as well, achieving an additional order of magnitude in execution speed. This new implementation is simple to use and is provided under an open-source license; it can be readily used by other codes to avoid the error-prone and cumbersome implementation of the spherical harmonics.

Time-dependent density functional theory (TDDFT) is a theory that describes the time evolution of quantum mechanical many-electron systems under the influence of external time-dependent electric and magnetic fields. INQ is a specially designed software to efficiently solve the real-time TDDFT equations on graphics processing units (GPUs), which aim to overcome the computational limitation of time and size scales of non-equilibrium quantum dynamics. In this work we will present an implementation of non-collinear TDDFT for the INQ code to simulate spin dynamics in real time and discuss the implementation of non-collinear magnetic effects into the code. We will discuss the implementation of exchange-correlation magnetic fields, spin-orbit coupling, and the interaction between the electronic system and external magnetic fields. We will then consider several prototypical examples of spin dynamics in magnetic clusters and solids after light excitation. Potential applications range from the study of real-time dynamics of magnons to ultrafast spin dynamics under linear and circularly polarized laser excitation, as well as spectroscopic signatures such as magnetic circular dichroism and pump-probe Kerr rotation.

We present first-principles theoretical calculations for the electronic stopping power (SP) of both protons and anti-protons in LiF. Our results show the presence of the Barkas effect: a higher stopping for positively charged particles than their negatively charged antiparticles. In contrast, a previous study has predicted an anti-Barkas effect (higher stopping for negative charges) at low velocity [Qi, Bruneval and Maliyov, Phys. Rev. Lett. 128, 043401 (2022)]. We explain this discrepancy by showing that this anti-Barkas effect appears for highly symmetric trajectories and disappears when considering trajectories that better reproduce the experimental setup. Our low-velocity results show that the SP of both protons and anti-proton vanish for velocities under 0.1 a.u. .

La gobernanza territorial se fundamenta en la interacción entre actores territoriales afin de lograr una gestión participativa, eficiente y transparente. El propósito de este artículo esanalizar el nivel de participación de la ciudadanía en el proceso de gobernanza territorial delGobierno Autónomo Descentralizado del cantón Manta, provincia de Manabí, entre 2022-2023. Se utilizó un diseño no experimental de corte transversal, con un alcance descriptivo yenfoque mixto, la investigación de campo fue dividida en tres fases: identificación demecanismos de participación ciudadana, descripción de procesos de gobernanza ydeterminación de la percepción del cumplimiento de criterios de participación. Se emplearonmétodos analíticos y sintéticos, así como entrevista y encuestas para comprender el nivel departicipación de los ciudadanos en la gestión territorial del municipio en estudio. Los resultadosmuestran una activa participación del público a través de consultas públicas, la formación deveedurías ciudadanas y consejos consultivos, reflejando interés en la transparencia y lainclusión en decisiones. Aunque la mayoría de los actores territoriales percibe que se cumplenlos criterios de participación ciudadana existen diferencias entre actores públicos y sociales.Se concluye que el nivel de participación ciudadana corresponde al “poder delegado”,implicando colaboración efectiva entre la entidad pública y la ciudadanía. Sin embargo, seobserva una subutilización de los mecanismos de participación, generando desigualdades enel conocimiento y atención a los requerimientos de la población.

First principles real-time time dependent density functional theory (rt-TDDFT) calculations reveal the existence of ballistic photocurrents generated by Coulomb scattering, which has not previously been considered as a mechanism for the bulk photovoltaic effect. With monolayer GeS as an example, it is predicted that ballistic currents can be comparable to shift currents under experimentally accessible conditions.

Due to a beneficial balance of computational cost and accuracy, real-time time-dependent density-functional theory has emerged as a promising first-principles framework to describe electron real-time dynamics. Here we discuss recent implementations around this approach, in particular in the context of complex, extended systems. Results include an analysis of the computational cost associated with numerical propagation and when using absorbing boundary conditions. We extensively explore the shortcomings for describing electron-electron scattering in real time and compare to many-body perturbation theory. Modern improvements of the description of exchange and correlation are reviewed. In this work, we specifically focus on the Qb@ll code, which we have mainly used for these types of simulations over the last years, and we conclude by pointing to further progress needed going forward.

We present inq, a new implementation of density functional theory (DFT) and time-dependent DFT (TDDFT) written from scratch to work on graphic processing units (GPUs). Besides GPU support, inq makes use of modern code design features and takes advantage of newly available hardware. By designing the code around algorithms, rather than against specific implementations and numerical libraries, we aim to provide a concise and modular code. The result is a fairly complete DFT/TDDFT implementation in roughly 12 000 lines of open-source C++ code representing a modular platform for community-driven application development on emerging high-performance computing architectures.

We studied the directional dependency of electronic stopping power of swift light ions in nickel using real-time time-dependent density functional theory. We report a variation of electronic stopping for moving ions as the projectile probes different electronic densities of the host material. These results show that while the predicted magnitude stays in reasonable agreement with experiment, for v > 2. a.u. simulating only low index crystallographic directions is not enough to sample the experimental average values. The ab initio simulations give us access to microscopic quantities, such as non-adiabatic forces, momentum transfer and transient excited state charges of the projectile and host ions, which are not available through other methods. We report these quantities for the first time.

The goal of this work was to develop unique LLNL capabilities for the computational prediction of electrical, optical and thermal transport properties from quantum simulations. Using a recently developed theory of microscopic quantum transport, we were able to model compressed metallic hydrogen and it’s non-linear and out-of-equilibrium contributions in electrical and thermal transport. This theory was implemented in the open-source, real-space time-dependent density functional theory code Octopus. This model is general and widely applicable to high energy density systems that are important to LLNL and NNSA mission areas.

Team is currently working on such specifications and will be publishing them on our website in the near future.

Version 4.0 of the ECP Proxy App Suite is practically unchanged from the previous release. The current set of proxies has proven useful for many aspects of benchmarking and co-design and we see little reason to alter the suite. Although there have been few changes to the ECP suite, the team has been hard at work in other areas. In the area of Machine Learning (ML) we have now created a separate proxy suite dedicated to this scientific applications of ML.

Over the last few years, extraordinary advances in experimental and theoretical tools have allowed us to monitor and control matter at short time and atomic scales with a high degree of precision. An appealing and challenging route toward engineering materials with tailored properties is to find ways to design or selectively manipulate materials, especially at the quantum level. To this end, having a state-of-the-art ab initio computer simulation tool that enables a reliable and accurate simulation of light-induced changes in the physical and chemical properties of complex systems is of utmost importance. The first principles real-space-based Octopus project was born with that idea in mind, i.e., to provide a unique framework that allows us to describe non-equilibrium phenomena in molecular complexes, low dimensional materials, and extended systems by accounting for electronic, ionic, and photon quantum mechanical effects within a generalized time-dependent density functional theory. This article aims to present the new features that have been implemented over the last few years, including technical developments related to performance and massive parallelism. We also describe the major theoretical developments to address ultrafast light-driven processes, such as the new theoretical framework of quantum electrodynamics density-functional formalism for the description of novel light-matter hybrid states. Those advances, and others being released soon as part of the Octopus package, will allow the scientific community to simulate and characterize spatial and time-resolved spectroscopies, ultrafast phenomena in molecules and materials, and new emergent states of matter (quantum electrodynamical-materials).

This chapter provides an overview of selected works of Full Dollar, a phantom entity—"an anthropological enterprise," "a corporation," "an apocryphal society"—initially launched as a mock pop-up gallery in 2004 in Guayaquil, Ecuador. It discusses how locally developed artistic practices with an anthropological background can be transferred to the global art world. The chapter articulates ethnographic findings in collaborative practices, and discusses an expanded notion of fieldwork by reflecting on questions surrounding the production, circulation, and consumption of knowledge so created. Since its opening in 2004, Full Dollar fosters artistic interventions that expand author work as a visual and urban anthropologist. Formerly having a bad reputation due to street violence, administrative chaos, and architectural decay, [Guayaquil] was awarded a UN award as a paradigm for urban development. W. J. T. Mitchell's studies on images and their capability for awakening different sorts of social relations between viewers and objects opened up a series of ethnographic questions.

The electronic stopping power of nickel-based equiatomic solid solutions alloys NiCr, NiFe and NiCo for protons and alpha projectiles is investigated in detail using real-time time-dependent density functional theory over a wide range of velocities. Recently developed numerical electronic structure methods are used to probe fundamental aspects of electron-ion coupling non-perturbatively and in a fully atomistic context, capturing the effect of the atomic scale disorder. The effects of particular electronic band structures and density of states reflect in the low velocity limit behavior.We compare our results for the alloys with those of a pure nickel target to understand how alloying affects the electronic stopping. We discover that NiCo and NiFe have similar stopping behavior as Ni while NiCr has an asymptotic stopping power that is more than a factor of two larger than its counterparts for velocities below \(0.1~\mathrm{a.u.}\). We show that the low-velocity limit of electronic stopping power can be manipulated by controlling the broadening of the \(d\)-band through the chemical disorder. In this regime, the Bragg's additive rule for the stopping of composite materials also fails for NiCr.

Synopsis Using time-dependent density functional theory and Ehrenfest dynamics to study the problem of electronic stopping of molecular hydrogen in aluminum. From this first principles non-linear dynamics approach we explore in details how velocity, orientation and geometry of the molecular hydrogen a↵ects the electronic stopping power and how the dynamics of the interatomic distance a↵ects the dissociation of the molecule.