Sökning: "Path-integral"

Visar resultat 1 - 5 av 15 avhandlingar innehållade ordet Path-integral.

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

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

   Sammanfattning : 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. LÄS MER

3. 2. On path integral localization and the Laplacian

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

   Sammanfattning : 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. LÄS MER

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

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

   Sammanfattning : 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. LÄS MER

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

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

   Sammanfattning : 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. LÄS MER

7. 5. The one-dimensional Kondo Lattice in the Majorana Fermion representation

   Författare :Matteo Bazzanella; Göteborgs universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Majorana fermions; kondo lattice; path integral; spin-selective kondo insulator;

   Sammanfattning : This thesis analyses the possibilities offered by the representation of quantum mechanical operators in terms of Majorana fermions. These objects can be imagined as algebraic constituents of the fermionic degrees of freedom, allowing for a different representation of many Hamiltonians. LÄS MER