The present thesis is devoted to the dynamics in open or closed many-body bosonic systems, with the use of beyond mean-field methods. In the first part, inspired by the state-of-the-art experiments, we study the dynamics of a Bose-Einstein condensation which is loaded in an optical lattice with localized loss channels for the atoms. We prove that the particular form of the dissipation can help us to control the many-body dynamics. The loss allows the local manipulation of the system’s coherence properties and creates attractive fixed points in the classical (mean-field) phase space. We predict the dynamical creation of stable nonlinear structures like discrete bright and dark solitons. Furthermore, for specific initial states, the systems produces highly entangled and long-living states, which are of high relevance for practical applications. The first part of this thesis ends with the study of non-equilibrium bosonic transport across optical one-dimensional lattices. In the second part, we present techniques for bosonic many-body systems which are based on path integrals. We analyze the Bose-Einstein condensation phenomenon by using tools from quantum information theory and field theory. Finally, we introduce a coherent state path integral formalism in the continuum, which allows us the systematic development of approximate methods for the study of bosons in optical lattices.
|Supervisor:||Wimberger, PD Dr. Sandro|
|Date of thesis defense:||6 December 2013|
|Date Deposited:||19 Dec 2013 07:51|
|Faculties / Institutes:||The Faculty of Physics and Astronomy > Institute for Theoretical Physics|
|Controlled Keywords:||Beyond Mean-Field Dynamics, Open Quantum Systems, Bose-Einstein Condensation, Bose-Hubbard Model|
|Uncontrolled Keywords:||Beyond Mean-Field Dynamics, Open Quantum Systems, Optical Lattices, Bose-Einstein Condensation|