Correlated quantum dynamics of finite ultracold bosonic systems in traps

• Antragsteller: Professor Dr. Peter Schmelcher
• Fachliche Zuordnung: Optik, Quantenoptik und Physik der Atome, Moleküle und Plasmen
• Förderung: Förderung von 2010 bis 2016
• Projektkennung: Deutsche Forschungsgemeinschaft (DFG) - Projektnummer 175351316

• Erstellungsjahr: 2016

Zusammenfassung der Projektergebnisse

The goal of the project was the investigation of the nonequilibrium quantum dynamics of weak to strongly interacting few-body bosonic ensembles with the focus to identify novel fundamental quantum dynamical processes and mechanisms, including the tunneling dynamics and mechanisms in finite optical lattices. The latter constitute an important ingredient for our understanding and design of the transport properties and dynamics of few-body systems and contributions to the field of few-body atomtronics have been envisaged. Since the pathway from weak to strong correlations depends crucially on the dimensionality and the decomposition our aim was to study one- and higher-dimensional bosonic systems. Our computational approach is the Multi-Configuration Time-Dependent Hartree (MCTDH) and their particular bosonic extensions, the MCTDH for bosons and Multi-Layer MCTDH for bosons. They allow to explore stationary properties and, of major importance, the corresponding non-equilibrium dynamics. Overall seven publications and one submitted manuscript (status September 2016) have resulted from this project. Few-boson tunneling in double and triple wells driven by a spatially modulated interaction and by interactions in general were explored in detail. Higher band contributions have been established leading to a variety of different tunneling mechanisms. In the case of binary mixtures strong correlation effects between the species were shown to impact the tunneling severely thereby depending on the initial complete or partial imbalance and on the possible initial phase separation. The inspiration gained by the numerical simulations lead to a deep analytical understanding of the correlated bosons in traps which, as a consequence, allowed us to provide a construction principle for analytical many-body wave functions for correlated bosons in a harmonic trap. Modifying the interaction to a dipolar one intra-well localization effects and general population rearrangement have been observed. For higher spatial dimensions a number of difficulties were faced in order to provide a working methodology for the quantum dynamics out of equilibrium. Most of these problems were associated with the many different length scales participating in the ultra-cold system. A comprehensive set of tools has been developed to finally tackle with the three-dimensional wave packet propagation thereby establishing a unique approach to be used for the future.

Projektbezogene Publikationen (Auswahl)

• Few-boson tunneling in a double well with spatially modulated interaction, Physical Review A 82, 043619 (2010)
  B. Chatterjee, I. Brouzos, S. Zöllner and P. Schmelcher
  
• Interaction driven interbandtunneling of bosons in the triple well, New Journal of Physics 13, 033032 (2011)
  L. Cao, I. Brouzos, S. Zöllner and P. Schmelcher
  
• Construction of Analytical many-body wave functions for correlated bosons in a harmonic trap, Physical Review Letters 108, 045301 (2012)
  I. Brouzos and P. Schmelcher
  
• Few-boson tunneling dynamics of strongly correlated binary mixtures in a double well, Physical Review A 85, 013611 (2012)
  B. Chatterjee, I. Brouzos, L. Cao and P. Schmelcher
  
• The impact of spatial correlations on the tunneling dynamics of bosonic mixtures in a combined triple well and harmonic trap, New Journal of Physics 14, 093011 (2012)
  L. Cao, I. Brouzos, B. Chatterjee and P. Schmelcher
  
• Ultracold bosons in a one-dimensional harmonic and multi-well traps: a quantum Monte-Carlo versus a correlated pair approach, Journal of Physics B 46, 045001 (2013)
  I. Brouzos, F.K. Diakonos and P. Schmelcher
  
• Ultracold dipolar few-boson ensembles in a triple-well trap, Journal of Physics B 46, 085304 (2013)
  B. Chatterjee, I. Brouzos, L. Cao and P. Schmelcher
  
• Beyond mean-field dynamics of ultra-cold bosonic atoms in higher dimensions: facing the challenges with a multi-configurational approach. Journal of Physics B: Atomic, Molecular and Optical Physics, Volume 50, Number 3, 034003, 2017
  V. Bolsinger, S. Krönke and P. Schmelcher