Search for dissertations about: "Bose-Einstein condensation"

Showing result 6 - 10 of 11 swedish dissertations containing the words Bose-Einstein condensation.

  2. 6. Non-Perturbative Quantum Field Theory in Extreme Environments

    Author : Per Liljenberg; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; pair production; Bose-Einstein condensation; functional representation; Schwinger model; external field; boson stars; temperature; magnetisation;

    Abstract : The aim of this thesis is to describe some physical systems which can be treated by non-perturbative methods in quantum field theory. In the thesis we study systems described by quadratic Hamiltonians, possibly extended with an external electromagnetic field and/or with a thermal heat bath. READ MORE

  4. 7. Vortices and Persistent Currents in Rotating Bose Gases - a Diagonalization Approach

    Author : Sara Bargi; Matematisk fysik; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Bose-Einstein condensation; vortices; superfluidity; Fysicumarkivet A:2010:Bargi;

    Abstract : In this thesis, I explore the behavior of rotating ultra-cold Bose gases, by diagonalizing the Hamiltonian. This method has the advantage of being exact in the limit of weak interactions, and thus is a useful complement to the more commonly used Gross-Pitaevskii (GP) equation, which relies on a mean-field approximation. READ MORE

  5. 8. Superfluidity and Supersolidity in Ultracold Atomic Gases Beyond Mean Field

    Author : Mikael Nilsson Tengstrand; NanoLund: Centre for Nanoscience; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Bose-Einstein condensation; superfluidity; supersolidity; ultracold atomic gases; dipolar gases; binary Bose mixtures; quantum droplets; beyond mean field; quantum fluctuations; Fysicumarkivet A:2022:Nilsson;

    Abstract : This thesis investigates ultracold bosonic systems using an extended mean-field formalism with a focus on their superfluid and supersolid properties. The dissertation comprises five chapters and four articles, where the chapters provide some background to the research put forward in articles. READ MORE

  6. 9. Spectral Inequalities and Their Applications in Quantum Mechanics

    Author : Fabian Portmann; Ari Laptev; Robert Seiringer; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Spectral inequalities; quantum mechanics; Hardy inequalities; Sobolev inequalities; Lieb-Thirring inequalities; stability of matter; Bose gases; Bose-Einstein condensation; Mathematics; Matematik; Fysik; Physics;

    Abstract : The work presented in this thesis revolves around spectral inequalities and their applications in quantum mechanics.In Paper A, the ground state energy of an atom confined to two dimensions is analyzed in the limit when the charge of the nucleus Z becomes very large. READ MORE

  7. 10. Comparisons between classical and quantum mechanical nonlinear lattice models

    Author : Peter Jason; Magnus Johansson; Jonas Larson; Linköpings universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Discrete Breathers; Bose-Einstein-Condensation; Instabilities; Oscillatory Instabilities; Classical-Quantum correspondence; Bose-Hubbard model; DNLS; discrete nonlinear Schrödinger equation; nonlinear; nonlinear lattice models; compacton;

    Abstract : In the mid-1920s, the great Albert Einstein proposed that at extremely low temperatures, a gas of bosonic particles will enter a new phase where a large fraction of them occupy the same quantum state. This state would bring many of the peculiar features of quantum mechanics, previously reserved for small samples consisting only of a few atoms or molecules, up to a macroscopic scale. READ MORE