Numerical methods for electronic structure calculations

In this thesis, several numerical methods for electronic structure calculations are presented. The first is a quadrature scheme for the accurate and efficient computation of electrostatic potentials. The quadrature is applied to calculations on real-space grids, and to Coulomb integrals over Gaussian-type orbitals. Second, we introduce a real-space representation for three-dimensional scalar functions encountered in electronic structure calculations. In this representation, each function is partitioned into numerical atom-centred parts (the bubbles), and the remainder is represented on a three-dimensional Cartesian grid. The algorithms to carry out the required operations are discussed, along with benchmarks of their computer implementations. The presented methods are all of a divide-and-conquer nature, breaking the problem into simple pieces which are suitable for execution in emerging massively parallel computer architectures, such as general-purpose graphics processing units.Numeriska metoder för beräkning av elektronstrukturen för molekylära system presenteras i denna avhandling. Först diskuteras en kvadratur för noggranna och effektiva beräkningar av elektrostatiska potentialer. Kvadraturen används för numerisk beräkning av Coulomb-integraler över Gaussiska orbitaler. Därefter introduceras en ny numerisk representation av tredimensionella skalära funktioner. Den numeriska representationen används för att beskriva funktioner som förekommer i elektronstrukturberäkningar. Varje funktion uttrycks numeriskt i numeriska atomcentrerade funktioner (bubbles) omkring varje atoms och återstoden representeras numeriskt på ett tredimensionellt punktgitter. Algoritmerna som används för att utföra matematiska operationer och manipuleringar av skalarfunktionerna diskuteras och prestandan för datorimplementeringen av algoritmerna undersöks. Det numeriska tillvägagångsättet hör till kategorin "söndra och härska" dvs. problemet sönderdelas i ett antal enklare problem, som är väl ämnade för moderna massivt parallella datorarkitekturer såsom generella grafikkort (GPGPU), vilka kan användas för mera krävande beräkningsändamål

Understanding Quantum Technologies 2022

Understanding Quantum Technologies 2022 is a creative-commons ebook that provides a unique 360 degrees overview of quantum technologies from science and technology to geopolitical and societal issues. It covers quantum physics history, quantum physics 101, gate-based quantum computing, quantum computing engineering (including quantum error corrections and quantum computing energetics), quantum computing hardware (all qubit types, including quantum annealing and quantum simulation paradigms, history, science, research, implementation and vendors), quantum enabling technologies (cryogenics, control electronics, photonics, components fabs, raw materials), quantum computing algorithms, software development tools and use cases, unconventional computing (potential alternatives to quantum and classical computing), quantum telecommunications and cryptography, quantum sensing, quantum technologies around the world, quantum technologies societal impact and even quantum fake sciences. The main audience are computer science engineers, developers and IT specialists as well as quantum scientists and students who want to acquire a global view of how quantum technologies work, and particularly quantum computing. This version is an extensive update to the 2021 edition published in October 2021.Comment: 1132 pages, 920 figures, Letter forma

Graduate School of Engineering and Management Catalog 2018-2019

The Graduate Catalog represents the offerings, programs, and requirements in effect at the time of publication

GSI Scientific Report 2009 [GSI Report 2010-1]

Displacement design response spectrum is an essential component for the currently-developing displacement-based seismic design and assessment procedures. This paper proposes a new and simple method for constructing displacement design response spectra on soft soil sites. The method takes into account modifications of the seismic waves by the soil layers, giving due considerations to factors such as the level of bedrock shaking, material non-linearity, seismic impedance contrast at the interface between soil and bedrock, and plasticity of the soil layers. The model is particularly suited to applications in regions with a paucity of recorded strong ground motion data, from which empirical models cannot be reliably developed