Search for dissertations about: "path integral"

Showing result 1 - 5 of 41 swedish dissertations containing the words path integral.

  2. 1. Path Integral studies of quantum systems at finite temperatures

    Author : Sergei Ivanov; Alexander Lyubartsev; Ben Leimkuhler; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; path integral; molecular dynamics; algorithms; quantum simulations; Physical chemistry; Fysikalisk kemi;

    Abstract : This thesis presents and develops the path integral simulation techniques in application to small quantum systems at finite temperatures. The first goal is to obtain exact thermodynamic expressions for systems of noninteractingThe rest and the major part of the thesis is dedicated to the development and testing of Bead-Fourier path integral molecular dynamics. READ MORE

  4. 2. On path integral localization and the Laplacian

    Author : Topi Kärki; Uppsala universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Theoretical physics; Teoretisk fysik; Physics; Fysik; Theoretical Physics; teoretisk fysik;

    Abstract : In this thesis, we develop path integral localization methods that are familiar from topological field theory: the integral over the infinite dimensional integration domain depends only on local data around some finite dimensional subdomain.We introduce a new localization principle that unifies BRST localization, the non-Abelian localization principle and the conformal generalization of the Duistermaat-Heckman integration formula. READ MORE

  5. 3. Modelling of fracture toughness using peridynamics : A Study of J-integral, essential work and homogenisation

    Author : Christer Stenström; Pär Jonsén; Kjell Eriksson; Ugo Galvanetto; Luleå tekniska universitet; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Peridynamics; J-integral; Essential work of fracture; Nonlocal methods; Meshless; Meshfree; Fracture; Crack tip; Exact analytical; Center cracked tension; Double edge notched tensile; fracture toughness; Peridynamik; Brottmekanik; Sprickspets; Brottseghet; Spänningsintensitet; Hållfasthetslära; Solid Mechanics;

    Abstract : Fracture toughness is one of the most important properties of a material. Being able toaccurately estimate the energy that goes into forming new crack surfaces is essential for the development of new materials, quality assurance, structural monitoring and failure analysis. READ MORE

  6. 4. Path integral control endowed robot planning under spatiotemporal logic specifications

    Author : Péter Várnai; Dimos Dimarogonas; Theodorou Evangelos; KTH; []
    Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY;

    Abstract : The increasing level of autonomy and intelligence of robotic systems in carrying out complex tasks can be expected to revolutionize both the industry and our everyday lives. This thesis takes a step towards automation by leveraging the power of path integral control (PIC) methods for solving control problems under such task satisfaction constraints in both a stochastic control and a reinforcement learning setting. READ MORE

  7. 5. Non-Linear Canonical Methods in Strongly Correlated Electron Systems

    Author : Matteo Bazzanella; Göteborgs universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Majorana fermions; Emergent Majorana fermions; Non-linear transformation; canonical transformation; Kondo lattice; Mott insulator; Mean-field; Path-integral;

    Abstract : In this thesis some new ideas to perform the analysis of Strongly Correlated Electronic Systems (SCES) are developed. In particular the use of non-linear canonical transformations is considered thoroughly. READ MORE