PUB - Publikationen an der Universität Bielefeld

The recently introduced multi-layer (ML) multi-configurational time-dependent Hartree (MCTDH) in optimized second quantization representation (oSQR) approach combines the use of an optimized time-dependent orbital basis and the multi-layer MCTDH tensor contraction scheme to efficiently describe the quantum dynamics of system consisting of identical particles. Extending the original work on the subject, which studied propagation in real and imaginary time for Hamiltonians with flexible and fixed particle numbers, here the representation of thermal ensembles and the calculation of thermally averaged observables within the ML-MCTDH-oSQR is investigated. Different statistal sampling schemes for fixed and flexible particle numbers are introduced and analyzed. Numerical calculations studying a Hubbard model are used to illustrate the properties of the different schemes.