High-order perturbation theory for correlated Boson systems

• Applicant: Professor Dr. Martin Holthaus
• Subject Area: Optics, Quantum Optics and Physics of Atoms, Molecules and Plasmas
• Term: from 2009 to 2013
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 123473015

The last few years have witnessed a far-reaching development involving both quantum optics and condensed-matter physics: Paradigmatically important many-body systems are now being realized by ultracold quantum gases. This might eventually open up the possibility to employ these well-controllable laboratory systems as quantum simulators for still unsolved condensed-matter problems, in the sense originally suggested by Feynman. In order to turn this vision into reality, precise theoretical reference data are needed against which experimental measurements can be gauged. To this end, our group has developed an approach based on numerically executed high-order perturbation theory, which allows one to obtain accurate zero-temperature phase diagrams for ultrald Bosons in optical lattices, and to compute the relevant correlation functions. Within the present project, this approach shall be refined and pushed to the limit of numerical feasibility, and then be applied to various settings of experimental interest.

• DFG Programme: Research Grants