Many-Body Schrdinger Dynamics of Bose-Einstein Condensates [Paperback]

At extremely low temperatures, clouds of bosonic atoms form what is known as a Bose-Einstein condensate. Recently, it has become clear that many different types of condensates? -- so called fragmented condensates -- exist. In order to tell whether fragmentation occurs or not, it is necessary to solve the full many-body Schr?dinger equation, a task that remained elusive for experimentally relevant conditions for many years. In this thesis the first numerically exact solutions of the time-dependent many-body Schr?dinger equation for a bosonic Josephson junction are provided and compared to the approximate Gross-Pitaevskii and Bose-Hubbard theories. It is thereby shown that the dynamics of? Bose-Einstein condensates is far more intricate than one would anticipate based on these approximations. A special conceptual innovation in this thesis are optimal lattice models. It is shown how all quantum lattice models of condensed matter physics that are based on Wannier functions, e.g. the? Bose/Fermi Hubbard model, can be optimized variationally. This leads to exciting new physics.

This book offers the first numerically exact solutions of the time-dependent many-body Schr?dinger equation for a bosonic Josephson junction, comparing them to approximate Gross-Pitaevskii and Bose-Hubbard theories. This opens exciting new aspects of physics.General Theory.- General Methods for the Quantum Dynamics of Identical Bosons.- Lattice Models for the Quantum Dynamics of Identical Bosons.-?Reduced Density Matrices and Coherence of Trapped Interacting Bosons.- Exact Quantum Dynamics of a Bosonic? Josephson Junction.- Quantum Dynamics of Attractive vs. Repulsive Bosonic Josephson Junctions: Bose-Hubbard and full-Hamiltonian Results.- Optimal Time-Dependent Lattice Models for Nonequilibrium Dynamics.-Final Remarks and Outlook.-Appendices.

From the reviews:

The work under the present review is a doctoral thesis of the well-known Heidelberg University. The toplÓ