Unit:
Τομέας Πυρηνικής Φυσικής και Φυσικής Στοιχειωδών ΣωματιδίωνLibrary of the School of Science
Dissertation committee:
Αλέξανδρος Καρανίκας Αναπλ. Καθηγητής ΕΚΠΑ (επιβλέπων), Dr. Sandro Wimberger PD University of Heidelberg (επιβλέπων), Φώτης Διάκονος Αναπλ. Καθηγητής ΕΚΠΑ
Original Title:
Beyond mean-field dynamics in closed and open bosonic systems
Translated title:
Δυναμική κλειστών και ανοιχτών μποζονικών συστηματων πέραν της θεωρίας μέσου πεδίου
Summary:
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.
Keywords:
Bose-Einstein condensation, Open quantum systems, Optical lattices, Beyond mean-field dynamics, Many-body systems
Number of references:
158
Number of pages:
[6], viii, 157
