The multiconfigurational timedependent Hartree approach in optimized second quantization: Imaginary time propagation and particle number conservation
Abstract
The multilayer multiconfigurational timedependent Hartree (MCTDH) in optimized second quantization representation (oSQR) approach combines the tensor contraction scheme of the multilayer MCTDH approach with the use of an optimized timedependent orbital basis. Extending the original work on the subject [U. Manthe and T. Weike, J. Chem. Phys. 146, 064117 (2017)], here MCTDHoSQR propagation in imaginary time and properties related to particle number conservation are studied. Differences between the orbital equation of motion in real and imaginary time are highlighted and a new gauge operator, which facilitates efficient imaginary time propagation, is introduced. Studying BoseHubbard models, particle number conservation in MCTDHoSQR calculations is investigated in detail. Interesting properties of the singleparticle functions used in the multilayer MCTDH representation are identified. Based on these results, a tensor contraction scheme, which explicitly utilizes particle number conservation, is suggested.
 Publication:

Journal of Chemical Physics
 Pub Date:
 January 2020
 DOI:
 10.1063/1.5140984
 arXiv:
 arXiv:1912.00954
 Bibcode:
 2020JChPh.152c4101W
 Keywords:

 Physics  Chemical Physics;
 Physics  Computational Physics
 EPrint:
 18 pages, 12 figures, supported by FCI